WO2006085615A1 - Self-luminous device and self-luminous panel - Google Patents
Self-luminous device and self-luminous panel Download PDFInfo
- Publication number
- WO2006085615A1 WO2006085615A1 PCT/JP2006/302357 JP2006302357W WO2006085615A1 WO 2006085615 A1 WO2006085615 A1 WO 2006085615A1 JP 2006302357 W JP2006302357 W JP 2006302357W WO 2006085615 A1 WO2006085615 A1 WO 2006085615A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- layer
- organic
- doped
- light emitting
- self
- Prior art date
Links
- 239000000463 material Substances 0.000 claims abstract description 93
- 239000000872 buffer Substances 0.000 claims abstract description 86
- 239000000126 substance Substances 0.000 claims description 66
- 230000000903 blocking effect Effects 0.000 claims description 65
- 239000000758 substrate Substances 0.000 claims description 59
- 230000003287 optical effect Effects 0.000 claims description 14
- 230000007423 decrease Effects 0.000 abstract description 9
- 230000007547 defect Effects 0.000 abstract description 8
- 239000010410 layer Substances 0.000 description 654
- 238000005401 electroluminescence Methods 0.000 description 276
- 238000002347 injection Methods 0.000 description 122
- 239000007924 injection Substances 0.000 description 122
- 230000032258 transport Effects 0.000 description 43
- 239000011347 resin Substances 0.000 description 27
- 229920005989 resin Polymers 0.000 description 27
- 239000000969 carrier Substances 0.000 description 19
- 238000010586 diagram Methods 0.000 description 18
- 230000004888 barrier function Effects 0.000 description 17
- 238000000034 method Methods 0.000 description 16
- -1 Lewis acid compounds Chemical class 0.000 description 15
- 238000007789 sealing Methods 0.000 description 14
- 230000006870 function Effects 0.000 description 13
- 230000005525 hole transport Effects 0.000 description 13
- 239000012044 organic layer Substances 0.000 description 13
- 230000006798 recombination Effects 0.000 description 13
- 238000005215 recombination Methods 0.000 description 13
- 230000015572 biosynthetic process Effects 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 239000011521 glass Substances 0.000 description 10
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 10
- 239000011368 organic material Substances 0.000 description 10
- 229910052782 aluminium Inorganic materials 0.000 description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 9
- 230000008859 change Effects 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 9
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 229910052709 silver Inorganic materials 0.000 description 8
- 239000004332 silver Substances 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 7
- 229910010272 inorganic material Inorganic materials 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- 230000008719 thickening Effects 0.000 description 7
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 6
- 229910052761 rare earth metal Inorganic materials 0.000 description 6
- PCCVSPMFGIFTHU-UHFFFAOYSA-N tetracyanoquinodimethane Chemical compound N#CC(C#N)=C1C=CC(=C(C#N)C#N)C=C1 PCCVSPMFGIFTHU-UHFFFAOYSA-N 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 5
- 230000002950 deficient Effects 0.000 description 5
- 239000011147 inorganic material Substances 0.000 description 5
- 238000009413 insulation Methods 0.000 description 5
- IBHBKWKFFTZAHE-UHFFFAOYSA-N n-[4-[4-(n-naphthalen-1-ylanilino)phenyl]phenyl]-n-phenylnaphthalen-1-amine Chemical compound C1=CC=CC=C1N(C=1C2=CC=CC=C2C=CC=1)C1=CC=C(C=2C=CC(=CC=2)N(C=2C=CC=CC=2)C=2C3=CC=CC=C3C=CC=2)C=C1 IBHBKWKFFTZAHE-UHFFFAOYSA-N 0.000 description 5
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 4
- 239000002841 Lewis acid Substances 0.000 description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 239000003513 alkali Substances 0.000 description 4
- 229910052783 alkali metal Inorganic materials 0.000 description 4
- 150000001340 alkali metals Chemical class 0.000 description 4
- WTEOIRVLGSZEPR-UHFFFAOYSA-N boron trifluoride Chemical compound FB(F)F WTEOIRVLGSZEPR-UHFFFAOYSA-N 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 239000004020 conductor Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 4
- 229910052737 gold Inorganic materials 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 4
- 239000012464 large buffer Substances 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 4
- 239000011777 magnesium Substances 0.000 description 4
- 229910001507 metal halide Inorganic materials 0.000 description 4
- 150000005309 metal halides Chemical class 0.000 description 4
- 229910044991 metal oxide Inorganic materials 0.000 description 4
- 150000004706 metal oxides Chemical class 0.000 description 4
- 150000002910 rare earth metals Chemical class 0.000 description 4
- 230000008439 repair process Effects 0.000 description 4
- 125000001424 substituent group Chemical group 0.000 description 4
- IXHWGNYCZPISET-UHFFFAOYSA-N 2-[4-(dicyanomethylidene)-2,3,5,6-tetrafluorocyclohexa-2,5-dien-1-ylidene]propanedinitrile Chemical compound FC1=C(F)C(=C(C#N)C#N)C(F)=C(F)C1=C(C#N)C#N IXHWGNYCZPISET-UHFFFAOYSA-N 0.000 description 3
- XMWRBQBLMFGWIX-UHFFFAOYSA-N C60 fullerene Chemical class C12=C3C(C4=C56)=C7C8=C5C5=C9C%10=C6C6=C4C1=C1C4=C6C6=C%10C%10=C9C9=C%11C5=C8C5=C8C7=C3C3=C7C2=C1C1=C2C4=C6C4=C%10C6=C9C9=C%11C5=C5C8=C3C3=C7C1=C1C2=C4C6=C2C9=C5C3=C12 XMWRBQBLMFGWIX-UHFFFAOYSA-N 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 3
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- XCJYREBRNVKWGJ-UHFFFAOYSA-N copper(II) phthalocyanine Chemical compound [Cu+2].C12=CC=CC=C2C(N=C2[N-]C(C3=CC=CC=C32)=N2)=NC1=NC([C]1C=CC=CC1=1)=NC=1N=C1[C]3C=CC=CC3=C2[N-]1 XCJYREBRNVKWGJ-UHFFFAOYSA-N 0.000 description 3
- 238000000151 deposition Methods 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 229910003472 fullerene Inorganic materials 0.000 description 3
- 230000005283 ground state Effects 0.000 description 3
- 238000004770 highest occupied molecular orbital Methods 0.000 description 3
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 229910015900 BF3 Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- 229910052693 Europium Inorganic materials 0.000 description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- 150000001339 alkali metal compounds Chemical class 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- 150000001342 alkaline earth metals Chemical class 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- CECABOMBVQNBEC-UHFFFAOYSA-K aluminium iodide Chemical compound I[Al](I)I CECABOMBVQNBEC-UHFFFAOYSA-K 0.000 description 2
- VMPVEPPRYRXYNP-UHFFFAOYSA-I antimony(5+);pentachloride Chemical compound Cl[Sb](Cl)(Cl)(Cl)Cl VMPVEPPRYRXYNP-UHFFFAOYSA-I 0.000 description 2
- YBGKQGSCGDNZIB-UHFFFAOYSA-N arsenic pentafluoride Chemical compound F[As](F)(F)(F)F YBGKQGSCGDNZIB-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000000740 bleeding effect Effects 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000002041 carbon nanotube Substances 0.000 description 2
- 229910021393 carbon nanotube Inorganic materials 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical compound [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 description 2
- GBRBMTNGQBKBQE-UHFFFAOYSA-L copper;diiodide Chemical compound I[Cu]I GBRBMTNGQBKBQE-UHFFFAOYSA-L 0.000 description 2
- 125000004093 cyano group Chemical group *C#N 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 2
- 230000005281 excited state Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- SRVXDMYFQIODQI-UHFFFAOYSA-K gallium(iii) bromide Chemical compound Br[Ga](Br)Br SRVXDMYFQIODQI-UHFFFAOYSA-K 0.000 description 2
- DWRNSCDYNYYYHT-UHFFFAOYSA-K gallium(iii) iodide Chemical compound I[Ga](I)I DWRNSCDYNYYYHT-UHFFFAOYSA-K 0.000 description 2
- 229910003437 indium oxide Inorganic materials 0.000 description 2
- PSCMQHVBLHHWTO-UHFFFAOYSA-K indium(iii) chloride Chemical compound Cl[In](Cl)Cl PSCMQHVBLHHWTO-UHFFFAOYSA-K 0.000 description 2
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 description 2
- 150000002484 inorganic compounds Chemical class 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 238000004020 luminiscence type Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 150000002894 organic compounds Chemical class 0.000 description 2
- DYIZHKNUQPHNJY-UHFFFAOYSA-N oxorhenium Chemical compound [Re]=O DYIZHKNUQPHNJY-UHFFFAOYSA-N 0.000 description 2
- YNPNZTXNASCQKK-UHFFFAOYSA-N phenanthrene Chemical compound C1=CC=C2C3=CC=CC=C3C=CC2=C1 YNPNZTXNASCQKK-UHFFFAOYSA-N 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
- 239000004926 polymethyl methacrylate Substances 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000002310 reflectometry Methods 0.000 description 2
- 229910003449 rhenium oxide Inorganic materials 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- PUGUQINMNYINPK-UHFFFAOYSA-N tert-butyl 4-(2-chloroacetyl)piperazine-1-carboxylate Chemical compound CC(C)(C)OC(=O)N1CCN(C(=O)CCl)CC1 PUGUQINMNYINPK-UHFFFAOYSA-N 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 2
- 229910001887 tin oxide Inorganic materials 0.000 description 2
- 239000012780 transparent material Substances 0.000 description 2
- JKNHZOAONLKYQL-UHFFFAOYSA-K tribromoindigane Chemical compound Br[In](Br)Br JKNHZOAONLKYQL-UHFFFAOYSA-K 0.000 description 2
- FEONEKOZSGPOFN-UHFFFAOYSA-K tribromoiron Chemical compound Br[Fe](Br)Br FEONEKOZSGPOFN-UHFFFAOYSA-K 0.000 description 2
- RMUKCGUDVKEQPL-UHFFFAOYSA-K triiodoindigane Chemical compound I[In](I)I RMUKCGUDVKEQPL-UHFFFAOYSA-K 0.000 description 2
- DURPTKYDGMDSBL-UHFFFAOYSA-N 1-butoxybutane Chemical compound CCCCOCCCC DURPTKYDGMDSBL-UHFFFAOYSA-N 0.000 description 1
- DHDHJYNTEFLIHY-UHFFFAOYSA-N 4,7-diphenyl-1,10-phenanthroline Chemical compound C1=CC=CC=C1C1=CC=NC2=C1C=CC1=C(C=3C=CC=CC=3)C=CN=C21 DHDHJYNTEFLIHY-UHFFFAOYSA-N 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229930185605 Bisphenol Natural products 0.000 description 1
- 108091006149 Electron carriers Proteins 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004695 Polyether sulfone Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000001341 alkaline earth metal compounds Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 235000010290 biphenyl Nutrition 0.000 description 1
- 239000004305 biphenyl Substances 0.000 description 1
- 125000006267 biphenyl group Chemical group 0.000 description 1
- UFVXQDWNSAGPHN-UHFFFAOYSA-K bis[(2-methylquinolin-8-yl)oxy]-(4-phenylphenoxy)alumane Chemical compound [Al+3].C1=CC=C([O-])C2=NC(C)=CC=C21.C1=CC=C([O-])C2=NC(C)=CC=C21.C1=CC([O-])=CC=C1C1=CC=CC=C1 UFVXQDWNSAGPHN-UHFFFAOYSA-K 0.000 description 1
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000002800 charge carrier Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 125000002573 ethenylidene group Chemical group [*]=C=C([H])[H] 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- UPWPDUACHOATKO-UHFFFAOYSA-K gallium trichloride Chemical compound Cl[Ga](Cl)Cl UPWPDUACHOATKO-UHFFFAOYSA-K 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- HEJPGFRXUXOTGM-UHFFFAOYSA-K iron(3+);triiodide Chemical compound [Fe+3].[I-].[I-].[I-] HEJPGFRXUXOTGM-UHFFFAOYSA-K 0.000 description 1
- 239000005355 lead glass Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- YRZZLAGRKZIJJI-UHFFFAOYSA-N oxyvanadium phthalocyanine Chemical compound [V+2]=O.C12=CC=CC=C2C(N=C2[N-]C(C3=CC=CC=C32)=N2)=NC1=NC([C]1C=CC=CC1=1)=NC=1N=C1[C]3C=CC=CC3=C2[N-]1 YRZZLAGRKZIJJI-UHFFFAOYSA-N 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- ZUOUZKKEUPVFJK-UHFFFAOYSA-N phenylbenzene Natural products C1=CC=CC=C1C1=CC=CC=C1 ZUOUZKKEUPVFJK-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000000016 photochemical curing Methods 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- XNGIFLGASWRNHJ-UHFFFAOYSA-L phthalate(2-) Chemical compound [O-]C(=O)C1=CC=CC=C1C([O-])=O XNGIFLGASWRNHJ-UHFFFAOYSA-L 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920001230 polyarylate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920006393 polyether sulfone Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920002689 polyvinyl acetate Polymers 0.000 description 1
- 239000011118 polyvinyl acetate Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- KCTAWXVAICEBSD-UHFFFAOYSA-N prop-2-enoyloxy prop-2-eneperoxoate Chemical compound C=CC(=O)OOOC(=O)C=C KCTAWXVAICEBSD-UHFFFAOYSA-N 0.000 description 1
- 150000003254 radicals Chemical class 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 239000012945 sealing adhesive Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 238000013519 translation Methods 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
- H10K50/17—Carrier injection layers
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K2102/00—Constructional details relating to the organic devices covered by this subclass
- H10K2102/301—Details of OLEDs
- H10K2102/351—Thickness
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
- H10K50/18—Carrier blocking layers
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/30—Devices specially adapted for multicolour light emission
- H10K59/32—Stacked devices having two or more layers, each emitting at different wavelengths
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/80—Constructional details
- H10K59/875—Arrangements for extracting light from the devices
- H10K59/876—Arrangements for extracting light from the devices comprising a resonant cavity structure, e.g. Bragg reflector pair
Definitions
- the present invention relates to a self light emitting element and a self light emitting panel.
- a self-luminous element in which a light emitting layer is provided between a pair of electrodes and light is emitted by recombination of holes and electrons in the light emitting layer when a voltage is applied between the electrodes.
- Such a self-luminous element is used for a self-luminous panel that performs display or illumination and various information displays.
- Examples of such a self-luminous element include an organic EL (Electro Luminescence) element in which a light emitting layer is formed of an organic compound.
- Organic EL elements exhibit diode characteristics when the organic layer is correctly interposed between the electrodes. However, if scratches, protrusions, foreign matters, etc. exist on the support substrate, the film is formed in a state where the electrodes and the organic layer are disturbed. In the organic layer formed in a disordered state, there is a portion where the thickness of the layer is locally thin. Insulation resistance is low in areas where the layer is thin. Similarly, if a conductive foreign substance adheres to the substrate, the film is formed in a state where the electrodes and the organic layer are disturbed, and a part having a low insulation resistance is generated locally.
- the insulation resistance of the organic EL element is low, and the part does not exhibit diode characteristics.
- the insulation resistance in the organic EL element is low, and a short circuit between the electrodes may occur or the so-called leakage current may be generated due to low impedance. The occurrence of leakage current causes element destruction and drive failure.
- the lower electrode is made as smooth as possible, or foreign substances adhering to the substrate are removed.
- Another measure is to prevent short-circuits by covering discontinuous structures on the substrate with an insulating film.
- the substrate is rotated to make it easier to cover the abnormally shaped part, and when the upper electrode is formed, the substrate is kept stationary so that the abnormally shaped part is not covered. Technologies that prevent shorts between electrodes have also been proposed.
- by thickening the organic layer there is a technology that sufficiently covers the leakage current sources such as scratches, protrusions, and foreign objects.
- the organic layer generally has a low carrier density and a resistivity of 1 ⁇ 10 10 ⁇ ′cm or more in general, the thicker film increases the resistance between the electrodes, and the drive voltage There was a problem of increasing the price.
- the self-light emitting element there are various conventional techniques for lowering the driving voltage at the time of light emission.
- a technology that increases the carrier density of an organic layer (hole injection layer, etc.) by doping an electron-accepting substance into an organic layer (hole injection layer, etc.) in contact with the anode, for example.
- Patent Documents 1 and 2 below; For example, see Patent Documents 1 and 2 below;.
- the hole injection barrier from the anode to the organic layer (hole injection layer, etc.) is reduced, or the energy required for hole injection is reduced by using the injection mechanism as tunnel injection, and the driving voltage is reduced. Can be reduced.
- a drive layer is provided by including a doped layer doped with an electron-accepting substance and a buffer layer not containing the electron-accepting substance, and making the thickness of the doped layer larger than the thickness of the buffer layer.
- Patent Document 1 Japanese Patent Application Laid-Open No. 11 251067
- Patent Document 2 Japanese Patent Laid-Open No. 2003-217862
- Patent Document 3 Japanese Translation of Special Publication 2004-537149
- an organic layer doped with an electron-accepting substance uses holes as conductive carriers.
- p-type conductor For this reason, hole injection from the anode to the organic layer (hole injection layer, etc.) can be facilitated, but the electron blocking performance deteriorates due to the increase in conductivity, and electrons injected from the cathode pass through the light emitting layer. Conducted through the doped organic layer (hole injection layer, etc.) and anode.
- the film thickness can be increased without increasing the driving voltage, but because of the doped conductive layer, it is orthogonal to the stacking direction of each layer in the organic EL element. Since conductivity remains in the direction (hereinafter simply referred to as the lateral direction), there is a problem in that a lateral leakage current occurs between the so-called separated electrodes. In the case of a self-light-emitting panel in which a plurality of self-light-emitting elements are arranged on a single substrate, such leakage current causes the periphery of the self-light-emitting element (pixel) to be driven to emit light.
- the self-light-emitting element (pixel) adjacent to the self-light-emitting element to be driven may emit light.
- display defects pixel blurring emission
- the defective light emitting portion By short-circuiting the defective light emitting portion locally and instantaneously, it can be repaired so that the defective portion is physically destroyed by the heat generation or discharge of the minute portion and the local current does not flow between the electrodes.
- the light emitting state of the element can be within a favorable range (repaired).
- This repair can improve the yield in manufacturing the self-luminous panel.
- the above-described leakage current is generated, there is a problem that the current cannot be transferred to the light emitting failure portion in the organic EL element, and the repair cannot be performed.
- An object of the present invention is to deal with such a problem.
- the present invention sufficiently recombines electrons and holes in the light emitting layer to prevent a decrease in brightness of the self light emitting panel, and prevents a lateral leakage current of each layer in the self light emitting element, Suppressing invalid current and bleeding of light emission, preventing display failure due to short-circuit between electrodes of self-luminous panel, improving reverse bias withstand voltage when applying reverse bias of self-luminous element, reverse of self-luminous element
- the purpose is to not use up unnecessary power of the self-luminous panel by improving the bias characteristics, and to improve the manufacturing yield of the self-luminous panel by improving the reverse bias characteristics of the self-luminous elements.
- a self-luminous element according to the invention of claim 1 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, and the light emitting layer.
- a self-luminous element according to the invention of claim 2 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, Provided between the upper electrode and a doped layer doped with an electron-accepting substance; provided between the doped layer and the light-emitting layer; A large buffer layer.
- a self-luminous element according to the invention of claim 7 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, Provided between the lower electrode and a doped layer doped with an electron donating substance; and between the doped layer and the light emitting layer, and the film thickness is greater than the film thickness of the doped layer. Also And a large buffer layer.
- the self-light-emitting element according to the invention of claim 8 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light-emitting layer provided between the electrode pair, the light-emitting layer, Provided between the upper electrode and a doped layer doped with an electron donating substance; and between the doped layer and the light emitting layer, the film thickness is greater than the film thickness of the doped layer.
- a large buffer layer is used to the film thickness of the doped layer.
- a self-luminous panel according to the invention of claim 14 includes an electrode pair comprising a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, Provided between the lower electrode and a doped layer doped with an electron-accepting substance or an electron-donating substance, and provided between the doped layer and the light-emitting layer.
- a plurality of self-luminous elements including a buffer layer larger than the thickness of the doped layer are provided on the substrate.
- the self-luminous panel according to the invention of claim 15 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, Provided between the upper electrode and a doped layer doped with an electron-accepting substance or an electron-donating substance, and provided between the doped layer and the light-emitting layer.
- a plurality of self-luminous elements including a buffer layer larger than the thickness of the doped layer are provided on the substrate.
- the self-light-emitting panel according to the invention of claim 16 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light-emitting layer provided between the electrode pair, the light-emitting layer, and the A doped layer provided between the lower electrode and doped with an electron donating substance; and provided between the doped layer and the light emitting layer, wherein the film thickness is greater than the film thickness of the doped layer.
- a plurality of self-luminous elements each including a large buffer layer are provided on a substrate.
- the self-luminous panel according to the invention of claim 17 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, and the A doped layer provided between the upper electrode and doped with an electron donating substance; and provided between the doped layer and the light emitting layer, wherein the film thickness is equal to the film thickness of the doped layer.
- a plurality of self-luminous elements each having a larger buffer layer are provided on the substrate.
- FIG. 1 is a cross-sectional view showing an example of the structure of an organic EL element in the first embodiment.
- FIG. 2 is a cross-sectional view showing an example of the structure of the organic EL element in the second embodiment.
- FIG. 3 is a cross-sectional view showing an example of the structure of an organic EL element according to a third embodiment.
- FIG. 4 is a cross-sectional view showing an example of the structure of a conventional organic EL element.
- FIG. 5 is an explanatory diagram showing the behavior of a carrier when a reverse bias voltage is applied to a conventional organic EL element.
- FIG. 6 is an explanatory diagram showing the behavior of carriers when a reverse bias is applied to the organic EL element according to the embodiment of the present invention.
- FIG. 7 is an explanatory diagram showing the behavior of carriers when a reverse bias voltage is applied to a conventional organic EL element.
- FIG. 8 is an explanatory diagram showing the behavior of carriers when a reverse bias is applied to the organic EL element according to the embodiment of the present invention.
- FIG. 9 is a cross-sectional view showing an example of a self-luminous panel in the fourth embodiment.
- FIG. 10 is a cross-sectional view showing an example of a self-luminous panel provided with a conventional organic EL element.
- FIG. 11 is a plan view showing the arrangement of organic EL elements in a self-luminous panel.
- FIG. 12 is a graph showing the relationship between the film thickness of the doped layer and the buffer layer and the drive voltage.
- FIG. 13 is an explanatory diagram (part 1) for explaining the effect of thickening the buffer layer.
- FIG. 14 is an explanatory diagram (part 2) for explaining the effect of thickening the buffer layer.
- FIG. 15 is a schematic diagram showing the structures of three types of organic EL elements having different configurations.
- FIG. 16 is a graph showing diode characteristics when a forward bias voltage is applied to an organic EL element and then a reverse bias voltage is applied.
- FIG. 17 is a cross-sectional view illustrating the structure of an organic EL element according to a fifth embodiment.
- FIG. 18 is an explanatory diagram showing an organic EL element according to a sixth embodiment.
- FIG. 19 is a longitudinal side view showing a multi-photon device according to a seventh embodiment.
- FIG. 20 is a schematic diagram showing the operation of a conventional charge generation layer.
- FIG. 21 is a schematic diagram showing the operation of the charge generation layer in the embodiment of the present invention.
- FIG. 22 is a schematic diagram showing a relationship between energy levels of intermediate electrodes in the embodiment of the present invention.
- FIG. 23 is a longitudinal side view showing a multi-photon device according to an embodiment of the present invention.
- FIG. 24 is a longitudinal sectional side view showing a multi-photon device according to another embodiment of the present invention.
- FIG. 1 is a cross-sectional view showing an example of the structure of the organic EL element in the first embodiment.
- an organic EL element 100 in the present embodiment includes an electrode pair 101, a doped layer 102, a buffer layer 103, a light emitting layer 104, and a charge transport layer 105.
- the organic EL element 100 is formed on the substrate 106.
- the substrate 106 is, for example, glass Thus, it is formed of a transparent and insulating material.
- the substrate 106 is not limited to being formed of a transparent material.
- various substrates 106 such as an active drive TFT substrate and a substrate provided with a color filter can be used as appropriate in accordance with the driving method of a self-luminous panel (not shown) using the organic EL element 100. .
- the electrode pair 101 includes an anode 101a and an anode 101b facing the anode 101a.
- the anode 101 a is provided on the substrate 106.
- the lower electrode is realized by the anode 101a
- the upper electrode is realized by the cathode 101b.
- the electrode pair 101 may be provided on the cathode 101b force substrate 106, for example.
- the lower electrode is realized by the cathode 101b and the upper electrode is realized by the anode 101a.
- a layer for the purpose of improving adhesion, preventing alkali elution, or smoothing may be provided between the substrate 106 and the lower electrode.
- the organic EL element 100 has a structure in which the respective components are sequentially laminated in the order of the substrate 106, the anode 101a, the doped layer 102, the buffer layer 103, the light emitting layer 104, the charge transport layer 105, and the cathode 101b. .
- the doped layer 102 is provided between the light emitting layer 104 and the anode 101a.
- the doped layer 102 is a charge transport layer formed mainly of an organic material and having a high charge (electron or hole) density.
- the doped layer 102 is formed by doping a material having a charge transporting property with an electron accepting substance (acceptor).
- the material having a charge transporting property is a hole transporting material having a high hole transporting function.
- the electron-accepting substance doped in the hole transporting material generates electrons in the doped layer 102 by receiving electrons in the doped layer 102.
- the force exemplified for the doped layer 102 including the hole transporting material as the charge transporting material and the electron accepting material is not limited to this.
- the doped layer 102 may be formed by doping an electron-donating substance (donor) with a material having a charge transporting property.
- the material having a charge transporting property is an electron transporting material having a high electron transporting function.
- Electron donation doped in electron transport materials The conductive material generates electrons in the doped layer 102 by donating electrons in the doped layer 102.
- the material having a charge transporting property is, for example, the same material as the material forming the notch layer 103.
- the material having a charge transporting property may be a material different from the material forming the notch layer 103, for example.
- an adhesion layer for improving the adhesion of the dopant layer 102 to the anode 101a or a surface modification layer for improving carrier injection is provided between the anode 101a and the doped layer 102.
- a layer for the purpose of stabilizing the organic EL element 100 may be further provided.
- the buffer layer 103 is provided between the doped layer 102 and the light emitting layer 104.
- the noffer layer 103 blocks charges (electrons or holes), and charges injected from each electrode (anode 101a or cathode 101b) (having opposite characteristics to the blocked charges) as the light emitting layer 104. It has the function of injecting and transporting.
- Buffer layer 103 has a dimension (hereinafter referred to as a film thickness) along the facing direction of electrode pair 101 (the direction of arrow A in FIG. 1) so as to be larger than the film thickness of doped layer 102. Is provided.
- the nother layer 103 may be formed of the same material as that forming the doped layer 102, or may be formed of a material different from the material forming the doped layer 102.
- the buffer layer 103 is formed mainly of an organic material.
- the buffer layer 103 of the first embodiment has a hole transport function of transporting holes conducted from the doped layer 102 to the light emitting layer 104, and electrons that move from the light emitting layer 104 to the doped layer 102.
- Electronic block function to block The details of the electronic block function will be described later.
- the organic EL element 100 all the layers including the buffer layer 103 are the first reflections that reflect the light emitted from the light emitting layer 104 on the surface of the layer on the light emitting layer 104.
- the light is provided in such a film thickness that causes optical interference such that light is emitted from the light emitting layer 104, transmitted through the buffer layer 103, and reflected by the surface on the doped layer 102 side.
- the film thickness is adjusted so that optical interference is generated such that the light emitted in the opposing direction of the electrode pair 101 and multiple-reflected at the interface between the layers is intensified. It doesn't matter.
- the light emitting layer 104 will be described.
- the light emitting layer 104 is provided between the electrode pair 101. More specifically, the light emitting layer 104 of the first embodiment is provided between the notch layer 103 and the charge transport layer 105.
- the light emitting layer 104 of the first embodiment is formed of an organic compound.
- the charge transport layer 105 is provided between the light emitting layer 104 and the cathode 101b.
- the charge transport layer 105 is described as an electron transport layer.
- the charge transport layer 105 is formed mainly of an organic material.
- the charge transport property in the charge transport layer 105 may be manifested by doping this organic material with an electron donating substance (donor).
- a hole blocking layer (not shown) having a low hole transporting property may be inserted between the charge transport layer 105 and the light emitting layer 104. Further, the charge transport layer 105 may be omitted.
- FIG. 2 is a cross-sectional view showing an example of the structure of the organic EL element according to the second embodiment.
- FIG. 2 is a cross-sectional view showing an example of the structure of the organic EL element according to the second embodiment.
- the organic EL element 200 of the second embodiment includes a substrate 106, an electrode pair 201, a hole injection layer,
- Dope layer 202 electron block layer (buffer layer) 203, light emitting layer 204, and electron injecting and transporting layer 205 are provided.
- the thickness of the electron block layer (buffer layer) 203 is larger than that of the hole injection layer (dope layer) 202.
- the electrode pair 201 includes an anode 201a and the anode 2 A cathode 201b facing Ola is provided.
- the anode 201 a is provided on the force substrate 106.
- the anode 201a may be provided directly on the substrate 106, or may be formed after an alkali barrier film, an adhesion improving film, an optical adjustment film, or the like (not shown) is formed on the substrate 106.
- the lower electrode is realized by the anode 201a
- the upper electrode is realized by the cathode 201b.
- the anode 201a will be described as “lower electrode (anode) 201a”
- the cathode 201b will be described as “upper electrode (cathode) 201b”.
- the force for explaining the case where the lower electrode is realized by the anode 201a and the upper electrode is realized by the cathode 201b is not limited to this.
- the upper electrode may be realized by the anode 201a and the lower electrode may be realized by the cathode 201b.
- the organic EL element 200 includes a substrate 106, a lower electrode (anode) 201a, a hole injection layer 202, an electron block layer 203, a light emitting layer 204, an electron injection transport layer 205, and an upper electrode (cathode) 201b in this order. Each structure is sequentially stacked.
- each component included in the organic EL element 200 will be described in detail. Note that the description of the same parts as those described in the first embodiment will be omitted as appropriate.
- the lower electrode (anode) 20 la will be described.
- a material for forming the lower electrode (anode) 20 la for example, a conductive oxide such as tin oxide, indium oxide, and indium tin oxide (ITO), or aluminum, copper, gold, silver, chromium, and the like are used. Metals, inorganic conductive materials such as copper iodide and copper sulfide, and the like can be used.
- the material for forming the lower electrode (anode) 201a is not limited to these materials.
- the upper electrode (cathode) 201b will be described.
- a material for forming the upper electrode (cathode) 201b for example, a simple substance such as aluminum, copper, silver, or gold, an alloy such as magnesium and silver, lithium and silver, or a conductive oxide such as indium tin oxide (ITO) is used. Can be used.
- the hole injection layer 202 and the electron injection / transport layer 205 will be described.
- conventionally used materials regardless of polymer materials, low molecular weight materials, organic materials, and inorganic materials
- the hole injection layer 202 realizes a doped layer provided between the light emitting layer 204 and the lower electrode (anode) 2 Ola and doped with an electron accepting substance.
- the light emitting layer 204 will be described.
- a material for forming the light emitting layer 204 a conventionally used material (regardless of a polymer material, a low molecular material, an organic material, or an inorganic material) can be appropriately selected.
- the luminescent material there are light emission (fluorescence) when returning from the singlet excited state to the ground state and light emission (phosphorescence) when returning from the triplet excited state to the ground state.
- the electron blocking layer 203 is provided between the lower electrode (anode) 201 a and the light emitting layer 204.
- a hole injection layer 202 is provided between the lower electrode (anode) 201a and the electron block layer 203.
- the power explained is not limited to this.
- the electron blocking layer 203 may be in direct contact with the lower electrode (anode) 201a.
- the function of the electronic block layer 203 will be described.
- a voltage is applied in the forward direction with respect to the electrode pair 201, in the organic EL element 200, a force of electrons on the upper electrode (cathode) 201 b side also flows toward the lower electrode (anode) 201 a side.
- the electron blocking layer 203 suppresses the transmission of the electron force reaching the lower electrode (anode) 201a side that has reached the surface on the upper electrode (cathode) 201b side of the two interfaces in the electron blocking layer 203.
- electrons are effectively confined on the lower electrode (anode) 201a side of the light emitting layer 204.
- the electron blocking layer 203 has hole transporting performance, electrons efficiently injected from the lower electrode (anode) 201a are transported to the light emitting layer 204 via the electron blocking layer 203. can do.
- holes efficiently transported to the light-emitting layer 204 through the electron blocking layer 203 and efficiently injected from the upper electrode (cathode) 201b and transported through the electron injecting and transporting layer 205 are then transferred to the electron blocking layer.
- the electrons blocked in 203 can be effectively recombined inside the light emitting layer 204.
- the recombination energy in this recombination Therefore, the light emitting molecules in the light emitting layer 204 are excited and luminescence is obtained. In other words, efficient recombination can be obtained by effective recombination within the light emitting layer 204.
- the organic EL element 200 has a lower electrode (electron force forcibly injected from the lower electrode (anode) 201a ( Anode) Electron flows from the 20 la side to the upper electrode (cathode) 201b side.
- the electron blocking layer 203 suppresses transmission of the electron force reaching the upper electrode (cathode) 201b side, which has reached the surface of the lower electrode (anode) 201a side, out of the two interfaces in the electron blocking layer 203.
- a material having a high electron block performance has a low positive / negative carrier density, but as a material for forming the electron block layer 203, a material having an electron block property and a hole transport performance is preferable. Specifically, for example, it is preferable to use a-NPD (see JP-A-2003-272860).
- the hole injection layer 202 is formed mainly of an organic material.
- the hole injection layer 202 is preferably made of a material having the highest occupied orbital (HOMO) level close to the work function of the lower electrode (anode) 201a and having hole transport performance.
- HOMO highest occupied orbital
- Electrode (anode) 20 la material is particularly selected.
- Tunnel injection is particularly effective when the hole carrier density of the hole injection layer 202 is high.
- the band at the interface with the lower electrode (anode) 201a is abruptly distorted, and holes are trapped through a distorted thin barrier. Inject the tunnel.
- many materials can be selected as a material for forming the lower electrode (anode) 201a. As a result, the efficiency of hole injection can be increased.
- an electron-accepting substance (acceptor) is doped into a material having hole transport performance. It may be a made material.
- the description will be made on the assumption that the hole carrier density of the hole injection layer 202 is particularly high.
- a material having a hole carrier transporting performance transports holes relatively compared to electron transport. It is a material with high performance. In general, it is said that the hole transport layer has better performance as it is easier to transport holes that are difficult to transport electrons.
- the electron accepting substance (acceptor) generates holes in the hole injection layer 202 by receiving electrons in the hole injection layer 202.
- the hole injection layer 202 includes, for example, the same material as that for forming the electron block layer 203 and an electron accepting material (acceptor).
- the hole injection layer 202 may include a material having hole transport performance different from the material forming the electron blocking layer 203 and an electron accepting material (acceptor).
- Examples of the electron-accepting substance doped in the hole injection layer 202 include Lewis acid compounds, metal oxides, metal halides, fullerenes, and the like. Further, the force described above for the lower electrode (anode) 201a and the hole injection layer 202 is exactly the same for the upper electrode (cathode) 201b and the electron injection / transport layer 205, and can be explained only with different signs. .
- materials for forming the upper electrode (cathode) 201b and the electron injection / transport layer (which may be an electron injection layer or an electron transport layer) 205 will be described.
- the material for forming the upper electrode (cathode) 201b and the electron injecting and transporting layer 205 include a material having an electron transporting property as an electron injecting material, and an electron donating substance (a Examples of the ceptor include alkali metals, alkaline earth metals, rare earth metals, alkali metal compounds, alkaline earth metal compounds, and rare earth compounds.
- Lewis acid compound examples include, for example, ferric chloride, ferric bromide, and Yowi 2nd. Iron, Aluminum chloride, Aluminum bromide, Aluminum iodide, Aluminum chloride, Gallium bromide, Gallium iodide, Indium chloride, Indium bromide, Indium iodide, Antimony pentachloride, Arsenic pentafluoride , Inorganic compounds such as boron trifluoride, DDQ (disananodichloroquinone), TNF (tri-trofluorenone), TCNQ (tetracyanoquinodimethane), F4—TC NQ (tetrafluoroacetate tetracyanoquinodimethane, etc. Is mentioned.
- metal oxides and metal halides include, for example, V 2 O 3
- Potassium earth metals, rare earth metals and their compounds include Li, Cs, Mg, Ca, Eu, LiF, Li 0,
- Examples include CsF, NaCl, KC1, and MgF.
- Examples of the electron-accepting substance (acceptor) include an organic substance having fluorine as a substituent and an organic substance having a cyano group as a substituent.
- the electron accepting substance (acceptor) is not limited to these materials described above.
- an electron transporting material such as tris (8-hydroxyquinolinol) aluminum
- an electron donating property may be obtained by doping with an electron donating substance such as fullerene or carbon nanotube.
- the substance (donor) itself may be used for the electron injecting and transporting layer 205.
- As a material for forming the hole injection layer 202, the electron injection transport layer 205, and the electron block layer 203 various known compounds generally used in the manufacture of the organic EL element 200 are appropriately used. Can be used.
- FIG. 3 is a cross-sectional view showing an example of the structure of the organic EL element according to the third embodiment.
- the organic EL device 300 in the third embodiment includes a substrate 106, an electrode pair 201, a hole injecting and transporting layer 301, a light emitting layer 204, a hole blocking layer (buffer layer) 302, an electron An injection layer (dope layer) 303.
- the hole blocking layer (buffer layer) 302 is thicker than the electron injection layer (dope layer) 303.
- the organic EL element 300 includes a substrate 106, a lower electrode (anode) 201a, a hole injecting and transporting layer 301, The light emitting layer 204, the hole blocking layer 302, the electron injecting layer 303, and the upper electrode (cathode) 201b are sequentially stacked.
- a substrate 106 a lower electrode (anode) 201a
- a hole injecting and transporting layer 301 The light emitting layer 204, the hole blocking layer 302, the electron injecting layer 303, and the upper electrode (cathode) 201b are sequentially stacked.
- the organic EL element 300 of the third embodiment is configured so that the upper electrode (cathode) 201b and the electron injection layer 303 are the lower electrode (anode) 201a in the organic EL element 200 shown in FIG. It has a structure in which the positive and negative signs of the hole injection layer 202 and the carrier are reversed. That is, the thickness of the hole blocking layer (buffer layer) 302 is larger than that of the electron injection layer (dope layer) 303.
- the organic EL device 300 shown in FIG. 3 has exactly the same mechanism as the organic EL device 200 shown in FIG. 2, and carriers are injected and transported by forward and reverse bias voltages.
- the hole blocking layer 302 included in the organic EL element 300 is desirably formed of a material capable of suppressing the passage of holes and efficiently transporting electrons.
- the hole blocking layer 302 efficiently transports electrons injected from the upper electrode (cathode) 201b to the light emitting layer 204, and also lower electrode (anode).
- the holes injected from 201a are blocked on the surface of the hole blocking layer 302 on the light emitting layer 204 side.
- positive and negative carrier recombination can be effectively performed in the light emitting layer 204.
- the hole blocking layer 302 is forcibly injected from the upper electrode (cathode) 201b when a reverse bias voltage (hereinafter referred to as "reverse bias voltage") is applied to the organic EL element 300.
- the formed holes are prevented from transmitting to the lower electrode (anode) 201a side. As a result, the leakage current when a reverse bias voltage is applied can be reduced.
- the electron injection layer 303 of the third embodiment is formed mainly of an organic material or an inorganic material.
- the electron injecting layer 303 may be doped with an electron donating substance (donor) in a material having a charge transporting property.
- the material having a charge transporting property is an electron transporting material having a relatively high performance of transporting electrons compared to the performance of transporting holes, and has an electron transporting performance.
- the electron donating substance generates electrons in the electron injection layer 303 by emitting electrons in the electron injection layer 303. Make it.
- tunnel injection is the same as in the case of hole injection.
- the electron injection layer 303 includes, for example, the same material as that for forming the hole blocking layer 302, and an electron donating substance (donor).
- the electron injection layer 303 may include, for example, a charge transporting material different from the material forming the hole blocking layer 302 and an electron donating substance (donor).
- a material having a hole blocking property is preferable.
- Materials that have hole blocking properties and high electron transport performance include, for example, BCP (2, 9 dimethyl 4, 7 diphenyl 1, 10 phenolic phosphorus), BAlq (l, 1, bisphenol 4-olatobis (2-methyl-8 quinolinolato-Nl, 08)), BPhen (4,7-diphenenole 1, 10 phenanthrene).
- the difference (part 1) between the organic EL element of the embodiment and the conventional organic EL element is described below.
- the structural difference between the organic EL element of the embodiment and the conventional organic EL element will be described.
- the organic EL element of the embodiment of the present invention the organic EL element 100 of the first embodiment shown in FIG. 1 described above (or the organic EL element of the second embodiment shown in FIG. 2). This will be described using the element 200).
- FIG. 4 is a cross-sectional view showing an example of the structure of a conventional organic EL element.
- a conventional organic EL element will be described below with reference to FIG. Note that, in the conventional organic EL element 400 shown in FIG. 4, the same parts as those of the organic EL elements 100, 200, and 300 in the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.
- a conventional organic EL element 400 includes an electrode pair 101, a doped layer 102, a buffer layer 103, a light emitting layer 104, and a charge transport layer 105.
- the electrode pair 101 includes an anode 101a that is a lower electrode and a cathode 101b that is an upper electrode.
- the organic EL element 400 has a structure in which the respective components are sequentially laminated in the order of the substrate 106, the anode 101a, the doped layer 102, the buffer layer 103, the light emitting layer 104, the charge transport layer 105, and the cathode 101b.
- the thickness of the doped layer 102 in the conventional organic EL device 400 is equal to the thickness of the buffer layer 103. It is also big.
- the conductive carrier is a hole, and a hole-derived current is generated regardless of the direction of the bias voltage. That is, the doped layer 102 loses rectification and behaves ohmic.
- FIG. 5 is an explanatory view showing the behavior of carriers when a reverse bias voltage is applied to the organic EL element 400 of the conventional form.
- FIG. 6 is an explanatory diagram showing the behavior of carriers when a reverse bias is applied to the organic EL element 100 according to the embodiment of the present invention.
- the difference in behavior when a reverse bias voltage is applied to the conventional organic EL element 400 and the organic EL element 100 will be described with reference to FIGS. 5 and 6.
- FIG. 5 is an explanatory view showing the behavior of carriers when a reverse bias voltage is applied to the organic EL element 400 of the conventional form.
- FIG. 6 is an explanatory diagram showing the behavior of carriers when a reverse bias is applied to the organic EL element 100 according to the embodiment of the present invention.
- FIG. 5 and FIG. 6 schematically show in which layer many carriers are accumulated when reverse noise voltage is applied to the conventional organic EL element 400 and the organic EL element 100. Yes. Normally, when the organic EL elements 400 and 100 emit light, a positive voltage is applied to the anode 101a side, and a negative voltage is applied to the cathode 101b side (in this embodiment, a noisy voltage applied in such a direction is applied). This will be described as a forward bias voltage.)
- the reverse noise voltage is a voltage in a direction opposite to the direction of the voltage applied when the organic EL elements 400 and 100 emit light.
- the reverse noise may apply a negative voltage to the original anode 101a side and a positive voltage to the original negative electrode 101b side, for example, because of the advantage of improving the performance of the organic EL elements 400 and 100. It is considered that carriers accumulated in the organic EL elements 400 and 100 can be eliminated by applying reverse noise.
- the reverse bias voltage for example, in a self-luminous panel (not shown) in which a plurality of organic EL elements 400, 100 are formed on the substrate 106, the organic EL element 400 , 100 is line-sequentially driven along the scanning line direction.
- the forward noise voltage is applied only to the organic EL elements 400 and 100 existing on the selected scanning line
- the reverse bias voltage is applied to the organic EL elements 400 and 100 existing on the other non-selected scanning lines. Is applied. This enables display without crosstalk.
- the organic EL elements 400 and 100 according to the conventional and the embodiments of the present invention are both “lower electrode Z hole injection layer Z electron blocking layer Z light emission. It has an element structure of “layer Z electron injection transport layer Z upper electrode” (reference numeral omitted).
- the difference in configuration between the organic EL element 400 having the conventional configuration and the organic EL element 100 according to the present embodiment is the thickness of the buffer layer (electronic block layer) 103.
- the doped layer (hole injection layer) 102 is thicker than the buffer layer (electron block layer) 103 having the electron blocking function.
- the buffer layer (electron block layer) 103 is much thicker than the doped layer (hole injection layer) 102.
- the organic EL elements 100, 200, and 300 according to the embodiment of the present invention, recombination of carriers in the light emitting layers 104 and 204 is effectively performed while suppressing an increase in driving voltage. Therefore, the organic EL elements 100, 200, and 300 can emit light efficiently.
- the lower electrode (anode) 101a is formed of ITO, and the doped layer (hole injection layer) 102 is 4F-TC on ⁇ -NPD. It is formed by adding NQ as an electron accepting substance (acceptor), and the buffer layer (electron blocking layer) 103 is formed by ⁇ -NPD so that the film thickness becomes X nm. Further, a buffer layer such as CuPc can be used between ITO and the doped layer (hole injection layer) 102. In this case, it is considered that tunnel injection occurs at the interface between the buffer layer (electron block layer) 103 and the doped layer (hole injection layer) 102. [0096] (Difference in behavior (Part 2))
- the difference (No. 2) between the organic EL element of the embodiment of the present invention and the conventional organic EL element will be described with reference to FIGS.
- the organic EL element according to the third embodiment shown in FIG. 3 will be described as the organic EL element according to the embodiment of the present invention.
- FIG. 7 is an explanatory diagram showing carrier behavior when a reverse bias voltage is applied to a conventional organic EL element.
- a conventional organic EL element will be described with reference to FIG.
- the same parts as those of the organic EL elements 100, 200, and 300 in the above-described embodiments are denoted by the same reference numerals, and the description thereof is omitted.
- a conventional organic EL element 700 includes a substrate 106, electrode pairs 201 a and 201 b, a hole injection / transport layer 301, a light emitting layer 204, a hole blocking layer 302, and an electron injection layer 303.
- a conventional organic EL device 700 includes a substrate 106, a lower electrode (anode) 201a, a hole injection transport layer 301, a light emitting layer 204, a hole blocking layer 302, an electron injection layer 303, and an upper electrode (cathode) 201b. In this order, each structure is sequentially stacked. In the conventional organic EL element 700, the thickness of the electron injection layer (dope layer) 303 is larger than the thickness of the hole blocking layer (buffer layer) 302.
- FIG. 8 is an explanatory view showing the behavior of carriers when a reverse bias is applied to the organic EL element 300 according to the embodiment of the present invention.
- differences in behavior when a reverse bias voltage is applied to the conventional organic EL element 700 and the organic EL element 300 according to the embodiment of the present invention will be described with reference to FIG. 7 and FIG. .
- FIGS. 7 and 8 schematically show in which layer a large amount of carriers are accumulated when a reverse noise voltage is applied to the conventional organic EL element 700 and the organic EL element 300.
- the organic EL elements 700 and 300 of the configuration of the conventional and the present embodiment are both “lower electrode Z hole injection transport layer Z light emitting layer Z hole block layer”. It has an element structure of “Z electron injection layer Z upper electrode” (reference numeral omitted).
- the difference in configuration between the organic EL element 700 having the conventional configuration and the organic EL element 300 according to the present embodiment is the thickness of the hole blocking layer 302.
- the organic EL element 700 having a conventional configuration has a thickness relationship between the doped electron injection layer 303 and the hole blocking layer 302 that are thicker than the doped electron injection layer 303.
- 303 is thicker than the hole blocking layer 302.
- the hole blocking layer 302 is much thicker than the electron injection layer 303.
- the organic EL elements 100, 200, and 300 of the embodiment of the present invention recombination of carriers in the light emitting layers 104 and 204 is effectively performed while suppressing an increase in driving voltage. Therefore, the organic EL elements 100, 200, and 300 can emit light efficiently.
- FIG. 9 is a cross-sectional view showing an example of a self-luminous panel in the fourth embodiment.
- a self-luminous panel according to a fourth embodiment will be described with reference to FIG.
- a self-luminous panel 900 according to the fourth embodiment has a configuration in which a plurality of organic EL elements 100 shown in FIG.
- the self-light-emitting panel 900 may be a passive-drive self-light-emitting panel that displays display data because the data lines formed by the plurality of anodes 101a and the scanning lines formed by the plurality of cathodes 101b are orthogonal to each other.
- An active drive type self-luminous panel having a configuration in which 101a and a drive transistor are connected may be used.
- the voltage applied to the anode 101a of each organic EL element 100 is controlled for each organic EL element 100, thereby controlling the emission Z non-emission in units of 100 of the organic EL elements. Can do. Since the technique for individually controlling the light emission Z non-light emission of each organic EL element 100 arranged in a matrix is a known technique, the description thereof is omitted.
- reference numeral 901 denotes an insulating member that insulates the anodes 101a.
- FIG. 10 is a cross-sectional view showing an example of a self-luminous panel including the conventional organic EL element 400.
- the following is a description of a self-luminous panel 1000 having a conventional organic EL element 400 and a fourth embodiment. Differences from the self-luminous panel 900 in the state will be described.
- the self-luminous panel 1000 having the conventional organic EL element 400 for example, when the organic EL element A emits light and the organic EL element B is extinguished, an anode corresponding to the organic EL element A (hereinafter, positive electrode is used as necessary).
- V ⁇ 0 a reverse bias voltage of V (V ⁇ 0) is applied to the cathode 101b. At this time, the anode
- the potential difference between A and anode B is V -V.
- the light is emitted between the child B and the organic EL element B.
- FIG. 11 is a plan view showing the arrangement of the organic EL elements 100 or 400 in the self-luminous panel 900 or 1000.
- FIG. The leakage current that leaks from the adjacent organic EL element A to the organic EL element B will be described with reference to FIG. 11 and FIG. 10 described above.
- the resistance between the anode A and the anode B is R [ ⁇ ]
- the resistance R is expressed by the following equation (1).
- V AB Potential difference between anodes A and B [V]
- the amount of current leaking from the organic EL element A to the adjacent organic EL element B is proportional to the film thickness t of the doped layer 102 and the conductivity ⁇ of the doped layer 102.
- the conductivity ⁇ is expressed as the reciprocal of the resistivity ⁇ .
- the conductivity in the cadmium doped layer 102 is reduced. It is necessary to take measures to keep the rate ⁇ low.
- the degree L is expressed by the following equation (3).
- 10 4 is the area conversion coefficient of the cm unit system force to the m unit system.
- S is a unit of conductance expressed as the reciprocal of electrical resistance [ ⁇ ].
- the doped layer 102 doped with the electron-accepting substance and the low electron transport property and the hole transport property, but the carrier density is low.
- the organic EL device 100 of the first embodiment can be manufactured using various known techniques.
- the doped layer 102, the nofer layer 103, or the light emitting layer 104 can be formed by using a resistance heating vacuum film forming method. That is, the organic EL element 100 of the present embodiment can be manufactured without any particular change compared to the conventional method for manufacturing an organic EL element. Since a conventional method for manufacturing an organic EL element is a known technique, a description thereof will be omitted.
- FIG. 12 is a graph showing the relationship between the film thickness of the doped layer and the buffer layer and the driving voltage. Next, the relationship between the film thickness of the doped layer and the buffer layer and the drive voltage will be described.
- the organic EL element 100 described in the first embodiment will be described as an example.
- FIG. 13 and FIG. 14 are explanatory views (No. 1) and (No. 2) for explaining the effect of thickening the notfer layer 103.
- FIG. 13 and FIG. 14 are explanatory views (No. 1) and (No. 2) for explaining the effect of thickening the notfer layer 103.
- the foreign matter 1301 exists on the substrate 106 as shown in FIG. 13, or the rate of change is extremely uneven as shown in FIG.
- the portion 1401 is present, a thin portion of the deposited organic layer 103 is generated. In such a thin portion, the thickness resistance of the notfer layer 103 is lowered. In this case, when a voltage is applied between the electrodes (between 101a and 101b), the portion where the breakdown voltage is locally reduced breaks down and a short circuit occurs.
- Table 1 shows driving voltages of the self-luminous panel 900 using the organic EL element 100 when the film thicknesses of the doped layer 102 and the buffer layer 103 are divided into a plurality of stages.
- Table 1 shows driving voltages of the self-luminous panel 900 using the organic EL element 100 when the film thicknesses of the doped layer 102 and the buffer layer 103 are divided into a plurality of stages.
- the thickness of the notched layer 103 is divided into multiple stages.
- the drive voltage is not increased while the conductivity is kept low, and the short circuit between the electrodes is generated.
- the rate can be reduced.
- the second effect of thickening the noffer layer 103 is that optical interference can be used effectively.
- the total thickness of the organic EL element 100 is about a fraction of the wavelength of visible light.
- Light emission from the light emitting layer 104 in the organic EL element 100 is caused by interference between reflected light and radiated light from the interfaces of the anode 101a and the cathode 101b formed of a conductive oxide or metal, the substrate 106, and each of the stacked layers. As a result, the luminous efficiency changes greatly.
- the reflectance of the reflecting surface holding the light emitting layer 104 is unbalanced.
- the reflectance of the reflecting surface holding the light emitting layer 104 is unbalanced.
- the interference analysis of a multilayer stack is carried out when the light source is inherent in the stack, then.
- n Refractive index of the layer through which light passes
- ⁇ Total phase change at the reflecting surface where light is reflected
- the optical interference can be adjusted by adjusting the film thickness of a conductive layer such as a transparent electrode.
- the influence on the driving voltage is small.
- the optical interference can be optimized by the thickness of the transparent electrode.
- the film thickness that optimizes optical interference differs for each emission color. Changing the film thickness of the transparent electrode for each part on the same substrate is not desirable because it increases the number of processes. Therefore, it is necessary to perform optical adjustment with the film thickness of the element portion formed for each emission color.
- FIG. 15 is a schematic diagram showing the structures of three types of organic EL elements having different configurations.
- (a) and (b) exemplify the structure of a conventional organic EL element
- (c) shows the structure of the organic EL element 100 in the first embodiment.
- the organic EL element 1510 shown in (a) is different from the organic EL element 100 in that it does not have the doped layer 102.
- the organic EL element 1520 shown in (b) is different from the organic EL element 100 in that the organic EL element 1520 has a nofer layer 103.
- Table 2 the driving voltage at a current density of each layer of film thickness and a constant of each organic EL element 1510, 1520, 100 shown in FIG. 15 shows a light emission amount .
- the buffer layer 103 has a film thickness in the range of 5 to 100 nm. It can be seen that there is no significant change in the drive voltage even when the change is made. That is, according to the organic EL element 100 of the first embodiment, the drive voltage is not increased even when the thickness of the buffer layer 103 is adjusted in order to improve the light emission efficiency. Furthermore, the emission spectrum can be adjusted by adjusting the interference spectrum.
- the organic EL device 100 includes the doped layer 102 doped with the electron-accepting material and the buffer layer 103 not doped with the electron-accepting material. Therefore, the doped layer 102 is doped with an electron-accepting substance to reduce the driving voltage, and by adjusting the film thickness of the buffer layer 103, the luminous efficiency can be improved. By making the film 103 thick, it is possible to obtain a display with little short-circuit failure between electrodes while maintaining the driving voltage.
- the effects of the first organic EL element 100 have been described by way of example, but the present invention is not limited to this. Even if the electron blocking layer 203 in the organic EL device 200 of the second embodiment or the hole blocking layer 302 in the organic EL device 300 of the third embodiment is thickened, the same effect is obtained. Obtainable.
- FIG. 16 is a graph showing diode characteristics when a forward bias voltage is applied to an organic EL element and then a reverse bias voltage is applied.
- the diode characteristics when a forward bias voltage is applied to the organic EL element and then a reverse bias voltage is applied will be described with reference to FIG.
- the organic EL element 200 of the second embodiment and the conventional organic EL element 700 shown in FIG. 7 will be described as an example.
- the light emitting layer 204 in the organic EL device 200 of the second embodiment and the conventional organic EL device 700 is formed of Alq
- the electron injection transport layer 205 is formed of LiF
- the upper electrode The case where the cathode 201b is formed of A1 will be described.
- a forward bias voltage was applied and then a reverse bias voltage was applied, and the diode characteristics at that time were examined.
- Figure 16 shows that Results are shown.
- the reverse bias withstand voltage is very bad, which is about IV.
- the reverse bias withstand voltage is improved and recovered to about ⁇ 5V.
- an organic EL device having a structure including a doped hole injection layer 202 and an electron blocking layer 203 between a lower electrode (anode) 201a and a light emitting layer 204 Forces shown for leakage current suppression effect for 200
- an organic EL device with a structure including an electron injection layer and a hole blocking layer doped between 20 lb of the upper electrode (cathode) and the light emitting layer 204 see FIG. 18
- the same effect can be expected for the leakage current suppression effect for
- the driving voltage is reduced.
- the electron blocking layer (buffer layer) 203 is provided thickly between the doped hole injection layer 202 and the light emitting layer 204, so that the drive voltage does not increase. A distance between the doped hole injection layer 202 and the light emitting layer 204 can be secured.
- the drive voltage is lowered, and the reverse bias withstand voltage due to the provision of the electron blocking layer 203 thicker than the hole injection layer 202 between the lower electrode (anode) 201a and the light emitting layer 204 is reduced.
- the decrease can be suppressed. That is, since it is possible to prevent the occurrence of a leakage current when a reverse bias voltage is applied, it is possible to reduce the power consumption when driving the organic EL element 200 and the self-luminous panel using the organic EL element 200.
- the organic EL element 200 of the second embodiment has been described as an example, but the same applies to the organic EL element 100 of the first embodiment.
- the drive voltage can be lowered by providing the doped layer 102 between the anode 1 Ola and the light emitting layer 104.
- the buffer layer 103 thick between the doped layer 102 and the light emitting layer 104 by providing the buffer layer 103 thick between the doped layer 102 and the light emitting layer 104, the doped layer 102 and the light emitting layer 104 can be connected without increasing the driving voltage. A distance can be secured.
- the driving voltage is lowered and the drain voltage is reduced.
- the distance between the doped electron injection layer 303 and the light emitting layer 204 is secured by the hole blocking layer 302, so that the doped electron injection layer 303 is formed between the upper electrode (cathode) 201 b and the light emitting layer 204. It is possible to suppress a decrease in the reverse noise breakdown voltage due to the provision.
- the drive voltage can be lowered and the occurrence of leakage current when a reverse bias voltage is applied can be prevented, so that self-light emission using the organic EL element 300 and the organic EL element 300 is possible. It is possible to reduce power consumption when driving the panel.
- the buffer layer 103 has a charge blocking function to block the charge moving from the light emitting layer 104 to the doped layer 102 side, so that the doped layer 102 is provided. It is possible to suppress a decrease in electronic block performance due to an increase in conductivity, and to prevent carriers injected from the cathode 101b or the anode 101a from passing through the light emitting layer 104 and recombining in a region other than the light emitting layer 104. As a result, the generation of leakage current that does not contribute to light emission can be prevented, and current efficiency can be improved.
- the electron blocking layer 203 and the hole blocking layer 302 have a high carrier density layer force and a carrier that blocks the movement of the opposite carrier to the light emitting layer 204.
- the provision of the doped hole injection layer 202 and the doped electron injection layer 303 suppresses the deterioration of the electron blocking performance due to the increase in conductivity, and the upper electrode (cathode) 201b or lower It is possible to prevent the carrier injected from the electrode (anode) 201 a from passing through the light emitting layer 204 and recombining in a region other than the light emitting layer 204. As a result, it is possible to prevent leakage current that does not contribute to light emission and improve current efficiency.
- an electrode is provided between at least one of the light emitting layer 204 and the upper electrode (cathode) 201b and between the light emitting layer 204 and the lower electrode (anode) 201a.
- the charge was injected from the upper electrode (cathode) 201b or the lower electrode (anode) 201a.
- Carriers can be prevented from passing through the light emitting layer 204 and recombining in a region other than the light emitting layer 204. This prevents the occurrence of leakage current that does not contribute to light emission, The current efficiency can be improved.
- the film thicknesses of all the layers are radiated in the opposing direction of the electrode pair 101 out of the light emitted from the light emitting layer 104. Luminous efficiency can be further improved because the optical interference is adjusted so that the light that is multiply reflected at the laminated interface is intensified.
- the organic EL elements 200 and 300 are self-luminous panels (see FIG. 9) in which a plurality of such organic EL elements 200 and 300 are arranged on the substrate 106. A self-luminous panel can be obtained. As for the structure and manufacturing method of the self-luminous panel, conventional techniques can be used except that the organic EL elements 200 and 300 of the second or third embodiment are used. Is omitted.
- FIG. 17 is a cross-sectional view illustrating the structure of an organic EL element according to the fifth embodiment.
- the organic EL element in the fifth embodiment will be described below with reference to FIG.
- An organic EL element 1700 according to the fifth embodiment includes a hole injection layer 1701, a hole transport layer 1702, and a buffer layer 1703 between the anode 101a and the light emitting layer 104 in the organic EL element 100 shown in FIG. It has a 3HTL structure.
- the doped layer 102 in FIG. 1 is realized by the hole injection layer 1701 and the hole transport layer 1702.
- the force is such that the anode 101a is provided on the substrate 106, and the respective layers are sequentially stacked on the anode 101a.
- a cathode may be provided on the substrate 106, and each layer may be sequentially stacked on the cathode.
- the lower electrode is realized by the cathode and the upper electrode is realized by the anode.
- the layers stacked on the cathode are stacked in the order opposite to the stacking order of the layers shown in FIG. Also, the explanation so far is about hole injection from the anode, hole transport from the anode. The same is true for electron injection from the cathode, electron transport, and hole blocking.
- the substrate 106 used in the fifth embodiment may be a substrate in which the anode 101a is preliminarily formed, a substrate on which an anode is formed after an alkali barrier film is formed, an active driving TFT, A substrate and a substrate provided with a color filter can be used as appropriate.
- the substrate 106 need not be transparent.
- the organic EL element 1700 of the fifth embodiment after forming the organic EL element 1700 on the substrate 106, the organic EL element 1700 is sealed to prevent deterioration of the organic EL element 1700.
- the form of sealing there are various forms such as a conventionally known sealing form, solid sealing form, and film sealing form.
- Sealing-type sealing is a sealing method in which the organic EL element 1700 is sealed by bonding the sealing substrate and the substrate 106 using a sealing adhesive.
- glass substrates such as soda glass, lead glass, and hard glass
- plastic substrates such as polyethylene, polypropylene, polyethylene terephthalate, and polymethyl methacrylate
- metal substrates such as aluminum and stainless steel, etc.
- a sealing substrate that has strength such as a material is used.
- Solid sealing refers to "resin layer Z barrier layer”, “resin layer Z barrier layer Z resin layer”, “resin layer Z barrier layer Z resin layer Z barrier layer”
- the organic EL element 1700 is sealed by sequentially laminating a resin layer and a barrier layer.
- the NOR layer is a layer that prevents permeation of moisture and the like.
- the resin layer is formed of a resin material such as a photo-polymerizable resin, a photo-thion polymerizable resin, a photo-curable resin, a thermo-plastic resin, or a thermosetting resin.
- the radical photopolymerizable resin is a resin mainly composed of various acrylates such as polyester acrylate, polyether acrylate, epoxy acrylate, and polyurethane acrylate.
- Light power thione-polymerized resin is a resin mainly composed of resin such as epoxy and butyl ether.
- the photo-curing resin is a resin such as thiol-added resin.
- Thermoplastic resins and thermosetting resins are polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polystyrene, polyethersulfone, polyarylate, polycarbonate, polyurethane, acrylic resin, polyacryl-tolyl.
- Polybulasseta Resins such as rubber, polyamide, polyimide, diacryl phthalate resin, cellulosic plastic, poly (vinyl acetate), polyvinyl chloride, polysalt vinylidene, and two or more of these resins It is a resin such as a copolymer.
- the barrier layer is formed of a ceramic material such as glass or a metal material such as stainless steel or aluminum.
- Film sealing is a sealing method in which the organic EL element 1700 is sealed by sequentially laminating a planarization layer and a barrier layer formed of a filmable material.
- the planarizing layer is composed of an inorganic material such as lithium fluoride, a filmable resin material such as an acrylate-containing monomer or oligomer accompanying a polymerization reaction, or the like.
- the barrier layer is made of a metal such as aluminum or a material such as an inorganic material such as silicon nitride, silicon oxide, or silicon nitride oxide.
- the barrier layer is a layer that prevents penetration of moisture and the like.
- FIG. 18 is an explanatory diagram showing an organic EL element according to the sixth embodiment.
- An organic EL device 1800 shown in FIG. 18 includes an electron block layer (buffer layer) 203 and a hole injection layer 202 on the lower electrode (anode) 201a side of the light emitting layer 204, and is more than the light emitting layer 204.
- a hole blocking layer (buffer layer) 302 and an electron injection layer 303 are provided on the upper electrode (cathode) 201b side.
- FIG. 19 is a longitudinal side view showing the multi-photon device according to the seventh embodiment.
- the seventh embodiment will be described below with reference to FIG. 2, 3, and 18, the organic EL elements 200, 300, and 1800 having a single light emitting layer 204 have been described.
- the present invention is not limited to this, and as shown in FIG. Equipped with an organic EL device (hereinafter referred to as “multiphoton device”) 1900!
- the multiphoton element 1900 is an organic EL element having a structure including a plurality of light-emitting layers 204 in a single element.
- the multiphoton element 1900 is composed of a plurality of organic EL elements 1910 and 1920 having a single light-emitting layer 204, and the organic EL elements 1910 and 1920.
- the layers are stacked along the stacking direction of the layers and connected in series.
- multiphoton element 1900 intermediate electrode 1901 including a charge generation layer (see FIG. 21) is interposed between stacked organic EL elements 1910 and 1920.
- a voltage is applied to the multiphoton element 1900, holes can be injected from the intermediate electrode 1901 to the organic EL element 1910 and electrons can be injected to the organic EL element 1920.
- the multiphoton device 1900 can improve the emission quantum efficiency by the amount of carriers generated inside the device.
- the intermediate electrode 1901 is configured as follows.
- the lower electrode (anode) 201a is the anode.
- the intermediate electrode 1901 is thinly provided with a normal cathode on the organic EL element 1920 side, and charge is generated on the organic EL element 1910 side on this thin cathode.
- Stack layers Furthermore, the hole transport layer (hole injection layer (dope layer) 202 and electron block layer (buffer layer) 203) of the organic EL element 1910 is laminated, and then the light emitting layer 204 and the like are laminated to form a multiphoton element.
- the charge generation layer is usually used as a film made of an electron-accepting material (acceptor) or doped with an electron-accepting material (acceptor) in a hole transporting material.
- FIG. 20 is a schematic diagram showing the operation of a conventional charge generation layer.
- FIG. 21 is a schematic diagram showing the operation of the charge generation layer in the embodiment of the present invention. The operation of the conventional charge generation layer and the charge generation layer according to the embodiment of the present invention will be described below with reference to FIGS. 20 and 21.
- FIG. 20 is a schematic diagram showing the operation of a conventional charge generation layer.
- FIG. 21 is a schematic diagram showing the operation of the charge generation layer in the embodiment of the present invention. The operation of the conventional charge generation layer and the charge generation layer according to the embodiment of the present invention will be described below with reference to FIGS. 20 and 21.
- the intermediate electrode 1901 includes a charge generation layer 2001 and a cathode 2002.
- the role of the charge generation layer 2001 is described as generating positive and negative charges in the charge generation layer 2001 and distributing them to the organic EL element 1910 and the organic EL element 1920.
- FIG. 22 is a schematic diagram showing the relationship between the energy levels of intermediate electrode 1901 in the embodiment of the present invention.
- the relationship between the energy levels of the intermediate electrode 1901 in the embodiment of the present invention will be described with reference to FIG.
- a multiphoton intermediate electrode portion will be described as an example of intermediate electrode 1901 in the embodiment of the present invention.
- the energy band at the junction interface between the charge generation layer 2001 having a high hole density and the cathode 2002 is locally distorted, and the holes are not normally injected due to an energy barrier. It is shown that it is effectively injected from the cathode 2002 into the charge generation layer 2001. According to this model, it is the negative electrode 2002 of the organic EL element 1920 that truly generates a charge. For this reason, the charge generation layer 2001 will be hereinafter referred to as a high carrier density layer as appropriate.
- the charge generation layer (high carrier density layer) 2001 for example, ITO which can be generally used as an anode of an organic EL element can be used.
- the cathode 2002 of the organic EL element 1920 and the ITO are in ohmic contact with each other, and two pairs of anode and cathode are connected in series.
- ITO has high conductivity and is defined as a light-emitting area, and the part also emits light, so it cannot be used for a normal light-emitting panel.
- the p-type or n-type charge generation layer (high carrier density layer) 2001 and the charge generation layer (high carrier density layer) are formed on the intermediate electrode 1901 portion of the multiphoton element 1900. An electrode capable of injecting carriers corresponding to 2001 is required.
- Charge generation layer (high carrier density layer) When the conductivity of 2001 is high, the leakage current when the reverse bias voltage is applied as described above, or effective carrier confinement when the forward bias voltage is applied. In order to improve the luminous efficiency due to the above, a carrier block layer is preferably provided as appropriate.
- FIG. 23 is a longitudinal side view showing the multi-photon device according to the embodiment of the present invention.
- a multiphoton element according to an embodiment of the present invention will be described below with reference to FIG. Note that the same components as those described in the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.
- the multiphoton element 2300 includes a lower Between the electrode (anode) 201a and the light emitting layer 204 closest to the lower electrode, a hole injection layer (dope layer) 202 which is a high carrier density layer and an electron block layer (buffer layer) which is a low carrier density layer ) 203.
- a hole injection layer dope layer 202 which is a high carrier density layer
- an electron block layer buffer layer
- the multiphoton element 2300 includes an electron injection layer (dope layer) 303, which is a high carrier density layer, between the upper electrode (cathode) 201b and the light emitting layer 204 closest to the upper electrode (cathode) 20 lb. And a hole blocking layer (buffer layer) 302 which is a low carrier density layer.
- an electron injection layer (dope layer) 303, which is a high carrier density layer, between the upper electrode (cathode) 201b and the light emitting layer 204 closest to the upper electrode (cathode) 20 lb.
- a hole blocking layer (buffer layer) 302 which is a low carrier density layer.
- the accumulated charge distance can be increased by increasing the thickness of the electron blocking layer 203 and the hole blocking layer 302.
- FIG. 24 is a vertical side view showing a multi-photon device according to another embodiment of the present invention.
- a multiphoton element according to another embodiment of the present invention will be described below with reference to FIG.
- a multi-photon device 2400 according to another embodiment of the present invention has a configuration in which three organic EL devices each including a single light emitting layer 204 are stacked along the voltage application direction.
- the multiphoton element 2400 of the present embodiment also has basically the same configuration as the multiphoton element 2300 in which two organic EL elements each having a single light-emitting layer 204 are stacked along the voltage application direction. ing.
- the multiphoton element 2400 of this embodiment includes a hole injection layer (dope layer) 202 that is a high carrier density layer between a lower electrode (anode) 201a and a light emitting layer 204.
- a hole injection layer (dope layer) 202 that is a high carrier density layer between a lower electrode (anode) 201a and a light emitting layer 204.
- an electron injection layer (dope layer) 303 which is a high carrier density layer and a hole blocking layer (buffer) which is a low carrier density layer are provided between the light emitting layer 204 and the light emitting layer 204.
- Layer) 302 a cathode 2002, a charge generation layer (high carrier density layer) 2001, and an electron block layer (buffer layer) 203 are provided.
- this organic EL device has a plurality of light emitting layers 204 along the direction of the electrode pair 201!
- a layer for blocking the corresponding carrier is provided between the lower electrode (anode) 201a and the upper electrode (cathode) 201b and the light emitting layer 204 closest to the electrodes 201a and 201b.
- the organic EL device in the examples will be described.
- the structure of the organic EL element in the example is the same as that of the organic EL element 100 described in the first embodiment.
- the same parts as those of the organic EL element 100 in the first embodiment are denoted by the same reference numerals, and illustration and description thereof are omitted.
- the material for forming each layer will be specifically described.
- the electrode (anode 101a) is provided on a transparent and insulating substrate such as glass.
- the electrode (anode 101a) may be a conductive oxide such as tin oxide, indium oxide, or indium tin oxide (ITO), or a metal such as gold, silver, or chromium, or an inorganic conductive material such as copper iodide or copper sulfide. A sex substance can be used.
- the material for forming the electrode (anode 101a) is not limited to these.
- Lewis acid compound metal oxide, metal halide, alkali metal, alkaline earth metal, rare earth metal, alkali metal compound, alkali Examples include earth metal compounds and rare earth compounds.
- Lewis acid compounds include ferric chloride, ferric bromide, ferric iodide, aluminum chloride, aluminum bromide, aluminum iodide, gallium chloride, gallium bromide, gallium iodide, Inorganic compounds such as indium chloride, indium bromide, indium iodide, antimony pentachloride, arsenic pentafluoride, boron trifluoride, DDQ (disyanodichloroquinone), TNF (tri-trofluorenone), TCNQ ( Tetracyanoquinodimethane), F4—TCNQ (Tetrafluorotetrasia) Nokinodimethane, etc.
- Inorganic compounds such as indium chloride, indium bromide, indium iodide, antimony pentachloride, arsenic pentafluoride, boron trifluoride, DDQ (disyanodichloroquinone), TNF
- metal oxides and metal halides include, for example, V 2 O (vanadium pentoxide
- Potassium earth metals, rare earth metals and their compounds include Li, Cs, Mg, Ca, Eu, LiF, Li 0,
- Examples include CsF, NaCl, KC1, and MgF.
- an electron-accepting substance there are an organic substance having fluorine as a substituent and an organic substance having a cyano group as a substituent, and the material is not limited to these materials. Can also be used.
- an electron transporting material such as tris (8-hydroxyquinolinol) aluminum is used for the doped layer 102
- an electron donating substance such as fullerene or carbon nanotube may be doped.
- the electrode (cathode 101b) may be made of a simple substance such as aluminum, copper, silver, or gold, or an alloy such as magnesium and silver, lithium and silver, or a conductive oxide such as indium tin oxide (ITO). I'll do it.
- a photoresist AZ6112 manufactured by Tokyo Ohka Kogyo Co., Ltd.
- the resist-patterned substrate was immersed in a mixed solution of ferric chloride aqueous solution and hydrochloric acid.
- the portion of the ITO film not covered with the resist was etched.
- the etched glass substrate was immersed in acetone.
- the cash register The stripe was removed and the ITO electrode stripe pattern with a width of 2 mm was formed.
- the glass substrate on which the ITO electrode stripe pattern is formed is washed with a surfactant. Thereafter, UV ozone cleaning was performed for 10 minutes using a UV ozone stripper UV-1 manufactured by Samco International Laboratory. The glass substrate that had been subjected to UV ozone cleaning was put into a vacuum chamber. The degree of vacuum is 1 X 10- 6 ⁇ in vacuum chamber: upon reaching, by the resistance heating evaporation, deposition CuPc the at deposition rate per second 0. 5 nm to a thickness of 25nm as the hole injection layer did.
- ⁇ NPD doped with an electron accepting substance was deposited as a doped layer 102 at a deposition rate of 0.5 nm per second in the same manner as described above.
- acceptor electron accepting substance
- the material used for film formation was heated and evaporated in a vacuum atmosphere (resistance heating vacuum film formation).
- 4F-TCNQ which is a molecule of the electron-accepting substance, was also heated and evaporated at the same time, and a mixed film was formed so that the film formation rate ratio of a-NPD and F4-TCNQ was 10: 1.
- Alq is used as the light emitting layer 104 at 0.5 nm per second.
- resistance heating vacuum film formation was performed until a thickness of 0.5 nm was reached at a film formation rate of 0.0 Olnm per second.
- the thus produced light emitting layer 104 and the charge transport layer 105 is formed so as to cover the stripe ITO film already made form, it was consistently deposited in a high vacuum of 1 X 10- 6 Torr .
- a shadow mask for a cathode was applied in a vacuum, and aluminum was formed into a resistance heating vacuum film to a thickness of lOOnm at a speed of lnm per second. At this time, the aluminum film was formed into a 2 mm wide stripe in a direction perpendicular to the ITO film stripe. .
- the size of the organic EL element 100 determined by the intersection of the anode 101a formed of the ITO film and the cathode 101b formed of aluminum is 2 mm X 2 mm.
- an organic EL device as another comparative example for the above-described specific example will be described.
- an organic EL element exactly the same as the specific example described above was manufactured except that the film thickness of the low carrier density layer was set to 5, 20, and 50 ⁇ m.
- the reverse bias withstand voltage was about IV, which was very low.
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Electroluminescent Light Sources (AREA)
Abstract
Disclosed is a self-luminous device (100) comprising an electrode pair (101) having an anode (101a) and a cathode (101b) arranged opposite to the anode (101a), a light-emitting layer (104) arranged between the electrode pair (101), a doped layer (102) arranged between the light-emitting layer (104) and the anode (101a) and doped with an electron-accepting material, and a buffer layer (103) arranged between the doped layer (102) and the light-emitting layer (104) and having a film thickness larger than that of the doped layer (102). Since the doped layer (102) is doped with an electron-accepting material, a display panel can be improved in luminance decrease and display defect.
Description
明 細 書 Specification
自発光素子および自発光パネル Self-luminous element and self-luminous panel
技術分野 Technical field
[0001] この発明は、自発光素子および自発光パネルに関する。 The present invention relates to a self light emitting element and a self light emitting panel.
背景技術 Background art
[0002] 従来から、電極対の間に発光層が設けられて、当該電極間に電圧が印加されるこ とにより発光層内で正孔と電子との再結合によって発光する自発光素子がある。この ような自発光素子は、ディスプレイあるいは照明や各種情報表示などを行う自発光パ ネルに利用されている。このような自発光素子には、たとえば発光層を有機化合物に よって形成した有機 EL (Electro Luminescence)素子などがある。 [0002] Conventionally, there has been a self-luminous element in which a light emitting layer is provided between a pair of electrodes and light is emitted by recombination of holes and electrons in the light emitting layer when a voltage is applied between the electrodes. . Such a self-luminous element is used for a self-luminous panel that performs display or illumination and various information displays. Examples of such a self-luminous element include an organic EL (Electro Luminescence) element in which a light emitting layer is formed of an organic compound.
[0003] 有機 EL素子は、電極間において有機層が正しく介在している場合にはダイオード 特性を示す。ところが、支持基板上にキズ、突起、異物などが存在すると、電極や有 機層が乱れた状態で成膜されてしまう。乱れた状態で成膜された有機層においては 、局所的に層の厚さが薄い部位が存在する。層の厚さが薄い部位では、絶縁耐性が 低くなる。同様に、導電性の異物が基板上に付着していると、やはり、電極や有機層 が乱れた状態で成膜されてしまい、局所的に絶縁耐性が低い部位が生じてしまう。 [0003] Organic EL elements exhibit diode characteristics when the organic layer is correctly interposed between the electrodes. However, if scratches, protrusions, foreign matters, etc. exist on the support substrate, the film is formed in a state where the electrodes and the organic layer are disturbed. In the organic layer formed in a disordered state, there is a portion where the thickness of the layer is locally thin. Insulation resistance is low in areas where the layer is thin. Similarly, if a conductive foreign substance adheres to the substrate, the film is formed in a state where the electrodes and the organic layer are disturbed, and a part having a low insulation resistance is generated locally.
[0004] 有機 EL素子における絶縁耐性の低 、部位はダイオード特性を示さな 、。また、有 機 EL素子における絶縁耐性の低 、部位は、電極間短絡が発生したり低インピーダ ンスとなっていわゆるリーク電流が発生した状態となったりする。リーク電流の発生は 、素子破壊や駆動不良などの原因となる。 [0004] The insulation resistance of the organic EL element is low, and the part does not exhibit diode characteristics. In addition, the insulation resistance in the organic EL element is low, and a short circuit between the electrodes may occur or the so-called leakage current may be generated due to low impedance. The occurrence of leakage current causes element destruction and drive failure.
[0005] この対策として、従来は、下部電極を極力平滑なものとしたり、基板に付着する異物 を除去したりして対応している。また、基板上に存在する不連続な構造物などを絶縁 膜で覆うことで、ショートを未然に防ぐという対策もある。さらに、有機物を成膜する際 に基板を回転させるなどして、異常形状部を覆いやすくするとともに、上部電極成膜 時には基板を静止させることで、異常形状部を覆わな 、ように成膜して電極間ショー トを防ぐ技術も提案されている。その他、有機層を厚膜化することで、キズ、突起、異 物などのリーク電流の原因部位を十分に覆ってしまう技術もある。
[0006] しかし、有機層は一般的にキャリア密度が低ぐ抵抗率が 1 X 1010 Ω ' cm以上であ ることが多いので、厚膜ィ匕すると電極間の抵抗が増大し、駆動電圧が高くなつてしま うという問題があった。 [0005] Conventionally, as countermeasures, the lower electrode is made as smooth as possible, or foreign substances adhering to the substrate are removed. Another measure is to prevent short-circuits by covering discontinuous structures on the substrate with an insulating film. Furthermore, when forming an organic material, the substrate is rotated to make it easier to cover the abnormally shaped part, and when the upper electrode is formed, the substrate is kept stationary so that the abnormally shaped part is not covered. Technologies that prevent shorts between electrodes have also been proposed. In addition, by thickening the organic layer, there is a technology that sufficiently covers the leakage current sources such as scratches, protrusions, and foreign objects. However, since the organic layer generally has a low carrier density and a resistivity of 1 × 10 10 Ω′cm or more in general, the thicker film increases the resistance between the electrodes, and the drive voltage There was a problem of increasing the price.
[0007] ここで、自発光素子においては、発光に際しての駆動電圧を低くするための各種従 来技術が存在する。その一つとして、たとえば陽極に接する有機層(正孔注入層など )に電子受容性物質をドープすることで、有機層(正孔注入層など)のキャリア密度を 増加させるようにした技術がある(たとえば、下記特許文献 1、 2参照。;)。このような技 術により、陽極から有機層(正孔注入層など)への正孔注入障壁を小さくし、または、 注入機構をトンネル注入として正孔注入に必要なエネルギーを低減して、駆動電圧 を低下させることができる。 [0007] Here, in the self-light emitting element, there are various conventional techniques for lowering the driving voltage at the time of light emission. For example, there is a technology that increases the carrier density of an organic layer (hole injection layer, etc.) by doping an electron-accepting substance into an organic layer (hole injection layer, etc.) in contact with the anode, for example. (For example, see Patent Documents 1 and 2 below;). With this technology, the hole injection barrier from the anode to the organic layer (hole injection layer, etc.) is reduced, or the energy required for hole injection is reduced by using the injection mechanism as tunnel injection, and the driving voltage is reduced. Can be reduced.
[0008] また、電子受容性物質がドープされたドープ層と電子受容性物質を含まないバッフ ァ層とを備え、ドープ層の厚さをバッファ層の厚さよりも厚くすることで、駆動電圧を低 下させるようにした技術がある(たとえば、下記特許文献 3参照。 )0 [0008] In addition, a drive layer is provided by including a doped layer doped with an electron-accepting substance and a buffer layer not containing the electron-accepting substance, and making the thickness of the doped layer larger than the thickness of the buffer layer. there is a technique so as to lower Do (e.g., see below Patent Document 3.) 0
[0009] 特許文献 1 :特開平 11 251067号公報 Patent Document 1: Japanese Patent Application Laid-Open No. 11 251067
特許文献 2:特開 2003— 217862号公報 Patent Document 2: Japanese Patent Laid-Open No. 2003-217862
特許文献 3:特表 2004— 537149号公報 Patent Document 3: Japanese Translation of Special Publication 2004-537149
発明の開示 Disclosure of the invention
発明が解決しょうとする課題 Problems to be solved by the invention
[0010] し力しながら、上述した特許文献 1、 2に記載された従来技術では、電子受容性物 質がドープされた有機層(正孔注入層など)は、正孔を伝導キャリアとする p型導電体 となる。このため、陽極から有機層(正孔注入層など)への正孔注入を容易にすること はできるが、導電性の増加によって電子ブロック性能が低下し、陰極から注入された 電子が発光層を通過してドープされた有機層(正孔注入層など)や陽極に伝導され てしまう。 However, in the conventional techniques described in Patent Documents 1 and 2 described above, an organic layer doped with an electron-accepting substance (such as a hole injection layer) uses holes as conductive carriers. p-type conductor. For this reason, hole injection from the anode to the organic layer (hole injection layer, etc.) can be facilitated, but the electron blocking performance deteriorates due to the increase in conductivity, and electrons injected from the cathode pass through the light emitting layer. Conducted through the doped organic layer (hole injection layer, etc.) and anode.
[0011] その結果、発光層以外の領域でも電子と正孔の再結合が発生し、再結合エネルギ 一が有効に発光エネルギーに変換されなくなったり、電子がそのまま対向電極に達 して再結合に寄与しない電流になり、自発光パネルにおける電流効率が低下したり するという問題点がある。すなわち、無駄な消費電力が力かってしまうという問題があ
つた o As a result, recombination of electrons and holes occurs in a region other than the light emitting layer, and the recombination energy is not effectively converted into light emission energy, or the electrons reach the counter electrode as they are and are recombined. There is a problem that the current does not contribute and the current efficiency of the self-luminous panel is lowered. In other words, there is a problem that wasteful power consumption becomes significant. I
[0012] また、上述した特許文献 3に記載された技術では、駆動電圧を増大させることなく厚 膜ィ匕できるが、ドープされた導電層を挿入することにより、逆ノィァス電圧を印加した ときの漏れ電流 (以下、「膜厚方向の漏れ電流」とする)が増カロしてしまうという問題が あった。特に、駆動に際して発光させない有機 EL素子に対して逆ノ ィァス電圧を印 加する、いわゆるパッシブ駆動型の有機 ELパネルにおいては、逆バイアス電圧の印 加によって発生した漏れ電流はすべて無効電流となってしまい、電力を無駄に消費 してしまうという問題があった。 [0012] Further, in the technique described in Patent Document 3 described above, a thick film can be formed without increasing the driving voltage, but when a reverse noise voltage is applied by inserting a doped conductive layer, There was a problem that the leakage current (hereinafter referred to as “leakage current in the film thickness direction”) increased. In particular, in a so-called passive drive type organic EL panel that applies a reverse noise voltage to an organic EL element that does not emit light during driving, all leakage currents generated by the application of the reverse bias voltage become reactive currents. As a result, there is a problem that power is wasted.
[0013] また、上述した特許文献 3に記載された技術では、駆動電圧を増大させることなく厚 膜化できるが、ドープされた導電層のために、有機 EL素子における各層の積層方向 に直交する方向(以降、単に横方向とする)にも伝導性が残るために、いわゆる分離 された電極間に横方向の漏れ電流が発生してしまうという問題点がある。単一の基板 上に複数の自発光素子が配設された自発光パネルにぉ ヽては、このような漏れ電流 によって、駆動対象である自発光素子 (画素)の周辺がにじんで発光したり、駆動対 象である自発光素子に隣接する自発光素子 (画素)も発光したりすることがある。これ により、たとえば、表示画像のエッジが不鮮明となるなどの表示不良(画素のにじみ発 光)が発生するという問題があった。 [0013] Also, with the technique described in Patent Document 3 described above, the film thickness can be increased without increasing the driving voltage, but because of the doped conductive layer, it is orthogonal to the stacking direction of each layer in the organic EL element. Since conductivity remains in the direction (hereinafter simply referred to as the lateral direction), there is a problem in that a lateral leakage current occurs between the so-called separated electrodes. In the case of a self-light-emitting panel in which a plurality of self-light-emitting elements are arranged on a single substrate, such leakage current causes the periphery of the self-light-emitting element (pixel) to be driven to emit light. In addition, the self-light-emitting element (pixel) adjacent to the self-light-emitting element to be driven may emit light. As a result, there has been a problem that display defects (pixel blurring emission) occur, for example, the edges of the display image become unclear.
[0014] 有機 EL素子の一部に成膜不良などが原因となって発光不良箇所がある場合、発 光不良などの不具合を生じさせる箇所が素子における一部分であれば、この有機 E L素子に適当な大きさの逆バイアス電圧を印加することによって、不良箇所だけに局 所電流が流れ、正常な部位には微小な逆バイアス電流しか流れな 、。 [0014] When a part of the organic EL element has a light emitting defect due to a film formation defect or the like, if the part causing a defect such as a light emitting defect is a part of the element, it is suitable for this organic EL element. By applying a reverse bias voltage of a large magnitude, local current flows only in the defective part and only a small reverse bias current flows in the normal part.
[0015] 発光不良箇所が局所的かつ瞬間的にショートすることで、微小部位の発熱または 放電により、不良箇所が物理的に破壊され、電極間に局所電流が流れなくなるように 補修することができ、当該素子における発光状態を良好な範囲に収める(リペアする )ことが可能である。このリペアによって、自発光パネルの製造に際しての歩留まりの 向上を図ることができる。し力しながら、上述した漏れ電流が発生していると、有機 EL 素子における発光不良箇所に電流^^めることができず、リペアすることができな 、 という問題があった。
[0016] この発明は、このような問題に対処することを課題の一例とするものである。すなわ ち、この発明は、発光層内で電子と正孔の再結合を十分に行い自発光パネルの輝 度の低下を防ぐこと、自発光素子における各層の横方向の漏れ電流を防止し、無効 な電流や発光のにじみを抑止すること、自発光パネルの電極間ショートによる表示不 良を防ぐこと、自発光素子の逆バイアス印加時における逆バイアス耐圧の向上を図る こと、自発光素子の逆バイアス特性向上による自発光パネルの無駄な電力を消費し な!、こと、自発光素子の逆バイアス特性向上による自発光パネルの製造の歩留まり 向上を図ることなどを目的とする。 [0015] By short-circuiting the defective light emitting portion locally and instantaneously, it can be repaired so that the defective portion is physically destroyed by the heat generation or discharge of the minute portion and the local current does not flow between the electrodes. Thus, the light emitting state of the element can be within a favorable range (repaired). This repair can improve the yield in manufacturing the self-luminous panel. However, if the above-described leakage current is generated, there is a problem that the current cannot be transferred to the light emitting failure portion in the organic EL element, and the repair cannot be performed. [0016] An object of the present invention is to deal with such a problem. In other words, the present invention sufficiently recombines electrons and holes in the light emitting layer to prevent a decrease in brightness of the self light emitting panel, and prevents a lateral leakage current of each layer in the self light emitting element, Suppressing invalid current and bleeding of light emission, preventing display failure due to short-circuit between electrodes of self-luminous panel, improving reverse bias withstand voltage when applying reverse bias of self-luminous element, reverse of self-luminous element The purpose is to not use up unnecessary power of the self-luminous panel by improving the bias characteristics, and to improve the manufacturing yield of the self-luminous panel by improving the reverse bias characteristics of the self-luminous elements.
課題を解決するための手段 Means for solving the problem
[0017] 発明者は、実験から、上述した特許文献 3に記載されているように、ドープ層を厚く するとともにバッファ層を薄くするば力りでなぐ lOnm程度のドープ層が存在すること により、有機 EL素子(自発光素子)の駆動電圧力 Sバッファ層の厚さによらず一定にな ることを検証した。 [0017] As described in Patent Document 3 described above, the inventor has found that there is a doped layer of about lOnm that can be made thicker by using a thicker doped layer and a thinner buffer layer. It was verified that the driving voltage force of the organic EL element (self-emitting element) was constant regardless of the thickness of the S buffer layer.
[0018] 請求項 1の発明にかかる自発光素子は、下部電極および当該下部電極に対向す る上部電極を備える電極対と、前記電極対の間に設けられた発光層と、前記発光層 と前記下部電極との間に設けられて、電子受容性物質がドープされたドープ層と、前 記ドープ層と前記発光層との間に設けられて、前記電極対の対向方向に沿った寸法 (以下、膜厚とする)が前記ドープ層の膜厚よりも大きいバッファ層と、を備えることを 特徴とする。 [0018] A self-luminous element according to the invention of claim 1 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, and the light emitting layer. A dimension between the doped layer, which is provided between the lower electrode and doped with an electron-accepting substance, and between the doped layer and the light-emitting layer, along the opposing direction of the electrode pair ( And a buffer layer having a larger thickness than the thickness of the doped layer.
[0019] 請求項 2の発明にかかる自発光素子は、下部電極および当該下部電極に対向す る上部電極を備える電極対と、前記電極対の間に設けられた発光層と、前記発光層 と前記上部電極との間に設けられて、電子受容性物質がドープされたドープ層と、前 記ドープ層と前記発光層との間に設けられて、前記膜厚が前記ドープ層の膜厚よりも 大きいバッファ層と、を備えることを特徴とする。 [0019] A self-luminous element according to the invention of claim 2 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, Provided between the upper electrode and a doped layer doped with an electron-accepting substance; provided between the doped layer and the light-emitting layer; A large buffer layer.
[0020] 請求項 7の発明にかかる自発光素子は、下部電極および当該下部電極に対向す る上部電極を備える電極対と、前記電極対の間に設けられた発光層と、前記発光層 と前記下部電極との間に設けられて、電子供与性物質がドープされたドープ層と、前 記ドープ層と前記発光層との間に設けられて、前記膜厚が前記ドープ層の膜厚よりも
大きいバッファ層と、を備えることを特徴とする。 [0020] A self-luminous element according to the invention of claim 7 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, Provided between the lower electrode and a doped layer doped with an electron donating substance; and between the doped layer and the light emitting layer, and the film thickness is greater than the film thickness of the doped layer. Also And a large buffer layer.
[0021] 請求項 8の発明にかかる自発光素子は、下部電極および当該下部電極に対向す る上部電極を備える電極対と、前記電極対の間に設けられた発光層と、前記発光層 と前記上部電極との間に設けられて、電子供与性物質がドープされたドープ層と、前 記ドープ層と前記発光層との間に設けられて、前記膜厚が前記ドープ層の膜厚よりも 大きいバッファ層と、を備えることを特徴とする。 [0021] The self-light-emitting element according to the invention of claim 8 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light-emitting layer provided between the electrode pair, the light-emitting layer, Provided between the upper electrode and a doped layer doped with an electron donating substance; and between the doped layer and the light emitting layer, the film thickness is greater than the film thickness of the doped layer. A large buffer layer.
[0022] 請求項 14の発明にかかる自発光パネルは、下部電極と当該下部電極に対向する 上部電極とを備える電極対と、前記電極対の間に設けられた発光層と、前記発光層 と前記下部電極との間に設けられて、電子受容性物質または電子供与性物質がドー プされたドープ層と、前記ドープ層と前記発光層との間に設けられて、前記膜厚が前 記ドープ層の膜厚よりも大きいバッファ層と、を備える自発光素子が、基板上に複数 配設されて 、ることを特徴とする。 A self-luminous panel according to the invention of claim 14 includes an electrode pair comprising a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, Provided between the lower electrode and a doped layer doped with an electron-accepting substance or an electron-donating substance, and provided between the doped layer and the light-emitting layer. A plurality of self-luminous elements including a buffer layer larger than the thickness of the doped layer are provided on the substrate.
[0023] 請求項 15の発明にかかる自発光パネルは、下部電極と当該下部電極に対向する 上部電極とを備える電極対と、前記電極対の間に設けられた発光層と、前記発光層 と前記上部電極との間に設けられて、電子受容性物質または電子供与性物質がドー プされたドープ層と、前記ドープ層と前記発光層との間に設けられて、前記膜厚が前 記ドープ層の膜厚よりも大きいバッファ層と、を備える自発光素子が、基板上に複数 配設されて 、ることを特徴とする。 [0023] The self-luminous panel according to the invention of claim 15 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, Provided between the upper electrode and a doped layer doped with an electron-accepting substance or an electron-donating substance, and provided between the doped layer and the light-emitting layer. A plurality of self-luminous elements including a buffer layer larger than the thickness of the doped layer are provided on the substrate.
[0024] 請求項 16の発明にかかる自発光パネルは、下部電極および当該下部電極に対向 する上部電極を備える電極対と、前記電極対の間に設けられた発光層と、前記発光 層と前記下部電極との間に設けられて、電子供与性物質がドープされたドープ層と、 前記ドープ層と前記発光層との間に設けられて、前記膜厚が前記ドープ層の膜厚よ りも大きいバッファ層と、を備える自発光素子が、基板上に複数配設されていることを 特徴とする。 [0024] The self-light-emitting panel according to the invention of claim 16 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light-emitting layer provided between the electrode pair, the light-emitting layer, and the A doped layer provided between the lower electrode and doped with an electron donating substance; and provided between the doped layer and the light emitting layer, wherein the film thickness is greater than the film thickness of the doped layer. A plurality of self-luminous elements each including a large buffer layer are provided on a substrate.
[0025] 請求項 17の発明にかかる自発光パネルは、下部電極および当該下部電極に対向 する上部電極を備える電極対と、前記電極対の間に設けられた発光層と、前記発光 層と前記上部電極との間に設けられて、電子供与性物質がドープされたドープ層と、 前記ドープ層と前記発光層との間に設けられて、前記膜厚が前記ドープ層の膜厚よ
りも大きいバッファ層と、を備える自発光素子が、基板上に複数配設されていることを 特徴とする。 [0025] The self-luminous panel according to the invention of claim 17 includes an electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, the light emitting layer, and the A doped layer provided between the upper electrode and doped with an electron donating substance; and provided between the doped layer and the light emitting layer, wherein the film thickness is equal to the film thickness of the doped layer. A plurality of self-luminous elements each having a larger buffer layer are provided on the substrate.
図面の簡単な説明 Brief Description of Drawings
[図 1]図 1は、第 1の実施の形態における有機 EL素子の構造の一例を示す断面図で ある。 FIG. 1 is a cross-sectional view showing an example of the structure of an organic EL element in the first embodiment.
[図 2]図 2は、第 2の実施の形態における有機 EL素子の構造の一例を示す断面図で ある。 FIG. 2 is a cross-sectional view showing an example of the structure of the organic EL element in the second embodiment.
[図 3]図 3は、第 3の実施の形態における有機 EL素子の構造の一例を示す断面図で ある。 FIG. 3 is a cross-sectional view showing an example of the structure of an organic EL element according to a third embodiment.
[図 4]図 4は、従来の有機 EL素子の構造の一例を示す断面図である。 FIG. 4 is a cross-sectional view showing an example of the structure of a conventional organic EL element.
[図 5]図 5は、従来の形態の有機 EL素子に対して、逆バイアス電圧をかけた場合のキ ャリアの挙動を示す説明図である。 FIG. 5 is an explanatory diagram showing the behavior of a carrier when a reverse bias voltage is applied to a conventional organic EL element.
[図 6]図 6は、この発明の実施の形態の有機 EL素子に対して、逆バイアスをかけた場 合のキャリアの挙動を示す説明図である。 FIG. 6 is an explanatory diagram showing the behavior of carriers when a reverse bias is applied to the organic EL element according to the embodiment of the present invention.
[図 7]図 7は、従来の有機 EL素子に対して、逆バイアス電圧をかけた場合のキャリア の挙動を示す説明図である。 FIG. 7 is an explanatory diagram showing the behavior of carriers when a reverse bias voltage is applied to a conventional organic EL element.
[図 8]図 8は、この発明の実施の形態の有機 EL素子に対して、逆バイアスをかけた場 合のキャリアの挙動を示す説明図である。 FIG. 8 is an explanatory diagram showing the behavior of carriers when a reverse bias is applied to the organic EL element according to the embodiment of the present invention.
[図 9]図 9は、第 4の実施の形態における自発光パネルの一例を示す断面図である。 FIG. 9 is a cross-sectional view showing an example of a self-luminous panel in the fourth embodiment.
[図 10]図 10は、従来の有機 EL素子を備える自発光パネルの一例を示す断面図であ る。 FIG. 10 is a cross-sectional view showing an example of a self-luminous panel provided with a conventional organic EL element.
[図 11]図 11は、自発光パネルにおける有機 EL素子の配列を示す平面図である。 FIG. 11 is a plan view showing the arrangement of organic EL elements in a self-luminous panel.
[図 12]図 12は、ドープ層およびバッファ層の膜厚と駆動電圧との関係を示すグラフで ある。 FIG. 12 is a graph showing the relationship between the film thickness of the doped layer and the buffer layer and the drive voltage.
[図 13]図 13は、バッファ層を厚膜ィ匕することによる効果について説明する説明図 (そ の 1)である。 [FIG. 13] FIG. 13 is an explanatory diagram (part 1) for explaining the effect of thickening the buffer layer.
[図 14]図 14は、バッファ層を厚膜ィ匕することによる効果について説明する説明図 (そ の 2)である。
[図 15]図 15は、それぞれ構成が異なる 3種類の有機 EL素子の構造を示す模式図で ある。 [FIG. 14] FIG. 14 is an explanatory diagram (part 2) for explaining the effect of thickening the buffer layer. FIG. 15 is a schematic diagram showing the structures of three types of organic EL elements having different configurations.
[図 16]図 16は、有機 EL素子に順バイアス電圧をかけた後逆バイアス電圧をかけた 場合のダイオード特性を示すグラフである。 FIG. 16 is a graph showing diode characteristics when a forward bias voltage is applied to an organic EL element and then a reverse bias voltage is applied.
[図 17]図 17は、第 5の実施の形態における有機 EL素子の構造を例示する断面図で ある。 FIG. 17 is a cross-sectional view illustrating the structure of an organic EL element according to a fifth embodiment.
[図 18]図 18は、第 6の実施の形態の有機 EL素子を示す説明図である。 FIG. 18 is an explanatory diagram showing an organic EL element according to a sixth embodiment.
[図 19]図 19は、第 7の実施の形態のマルチフオトン素子を示す縦断側面図である。 FIG. 19 is a longitudinal side view showing a multi-photon device according to a seventh embodiment.
[図 20]図 20は、従来の電荷発生層の動作を示す模式図である。 FIG. 20 is a schematic diagram showing the operation of a conventional charge generation layer.
[図 21]図 21は、この発明の実施の形態における電荷発生層の動作を示す模式図で ある。 FIG. 21 is a schematic diagram showing the operation of the charge generation layer in the embodiment of the present invention.
[図 22]図 22は、この発明の実施の形態における中間電極のエネルギーレベルの関 係を示す模式図である。 FIG. 22 is a schematic diagram showing a relationship between energy levels of intermediate electrodes in the embodiment of the present invention.
[図 23]図 23は、この発明の実施の形態のマルチフオトン素子を示す縦断側面図であ る。 FIG. 23 is a longitudinal side view showing a multi-photon device according to an embodiment of the present invention.
[図 24]図 24は、この発明の別の実施の形態のマルチフオトン素子を示す縦断側面図 である。 FIG. 24 is a longitudinal sectional side view showing a multi-photon device according to another embodiment of the present invention.
符号の説明 Explanation of symbols
100 有機 EL素子 100 organic EL elements
101 電極対 101 electrode pair
102 ドープ層 102 doped layer
103 ノ ッファ層 103 Noffer layer
104 発光層 104 Light-emitting layer
105 電荷輸送層 105 Charge transport layer
200 有機 EL素子 200 organic EL elements
201 電極対 201 electrode pair
202 正孔注入層(ドープ層) 202 Hole injection layer (dope layer)
203 電子ブロック層(バッファ層)
204 発光層 203 Electronic block layer (buffer layer) 204 Light-emitting layer
205 電子注入輸送層 205 Electron injection transport layer
300 有機 EL素子 300 OLED device
301 正孔注入輸送層 301 Hole injection transport layer
302 正孔ブロック層(バッファ層) 302 Hole blocking layer (buffer layer)
303 電子注入層(ドープ層) 303 Electron injection layer (dope layer)
900 自発光パネル 900 Self-luminous panel
1700 有機 EL素子 1700 OLED device
1701 正孔注入層 1701 Hole injection layer
1702 正孔輸送層 1702 Hole transport layer
1703 ノ ッファ層 1703 Noffer layer
1900 マノレチフオトン素子 1900 Manolet ophton element
1910 有機 EL素子 1910 Organic EL device
1920 有機 EL素子 1920 Organic EL device
2300 マノレチフォ卜ン素子 2300 Mano rephon phone element
2400 マルチフオトン素子 2400 Multi photon element
発明を実施するための最良の形態 BEST MODE FOR CARRYING OUT THE INVENTION
[0028] 以下に添付図面を参照して、この発明にかかる自発光素子および自発光パネルの 好適な実施の形態を詳細に説明する。以下に説明する各実施の形態では、自発光 素子として有機 EL素子を用いた一例について説明する。すなわち、本実施の形態 では、有機 EL素子によって自発光素子が実現されて!、る。 [0028] Preferred embodiments of a self-light-emitting element and a self-light-emitting panel according to the present invention will be described below in detail with reference to the accompanying drawings. In each embodiment described below, an example in which an organic EL element is used as a self-luminous element will be described. That is, in this embodiment, a self-luminous element is realized by an organic EL element!
[0029] (第 1の実施の形態) [0029] (First embodiment)
図 1は、第 1の実施の形態における有機 EL素子の構造の一例を示す断面図である 。はじめに、第 1の実施の形態における有機 EL素子の構造の一例について、図 1を 参照して説明する。図 1に示すように、本実施の形態における有機 EL素子 100は、 電極対 101と、ドープ層 102と、バッファ層 103と、発光層 104と、電荷輸送層 105と 、を備える。 FIG. 1 is a cross-sectional view showing an example of the structure of the organic EL element in the first embodiment. First, an example of the structure of the organic EL element in the first embodiment will be described with reference to FIG. As shown in FIG. 1, an organic EL element 100 in the present embodiment includes an electrode pair 101, a doped layer 102, a buffer layer 103, a light emitting layer 104, and a charge transport layer 105.
[0030] 有機 EL素子 100は、基板 106上に形成されている。基板 106は、たとえば、ガラス
のように、透明かつ絶縁性を有する材料によって形成される。基板 106は、透明な材 料によって形成されるものに限らない。たとえば、有機 EL素子 100を用いた自発光 パネル(図示省略)における駆動方式に応じて、アクティブ駆動用 TFT基板、カラー フィルタを設けた基板など、各種の基板 106を適宜使用することが可能である。 The organic EL element 100 is formed on the substrate 106. The substrate 106 is, for example, glass Thus, it is formed of a transparent and insulating material. The substrate 106 is not limited to being formed of a transparent material. For example, various substrates 106 such as an active drive TFT substrate and a substrate provided with a color filter can be used as appropriate in accordance with the driving method of a self-luminous panel (not shown) using the organic EL element 100. .
[0031] つづいて、有機 EL素子 100が備える各構成について説明する。まず、電極対 101 について説明する。電極対 101は、陽極 101aおよび当該陽極 101aに対向する陰 極 101bを備える。図 1に示す電極対 101においては、陽極 101aが、基板 106上に 設けられている。この場合、陽極 101aによって下部電極が実現され、陰極 101bによ つて上部電極が実現される。 Next, each configuration provided in the organic EL element 100 will be described. First, the electrode pair 101 will be described. The electrode pair 101 includes an anode 101a and an anode 101b facing the anode 101a. In the electrode pair 101 shown in FIG. 1, the anode 101 a is provided on the substrate 106. In this case, the lower electrode is realized by the anode 101a, and the upper electrode is realized by the cathode 101b.
[0032] なお、電極対 101においては、たとえば、陰極 101b力 基板 106上に設けられて いてもよい。この場合、陰極 101bによって下部電極が実現され、陽極 101aによって 上部電極が実現される。いずれの場合にも、基板 106と下部電極との間に、密着性 改善、アルカリ溶出防止、平滑ィ匕などを目的とする層を設けてもよい。 Note that the electrode pair 101 may be provided on the cathode 101b force substrate 106, for example. In this case, the lower electrode is realized by the cathode 101b and the upper electrode is realized by the anode 101a. In any case, a layer for the purpose of improving adhesion, preventing alkali elution, or smoothing may be provided between the substrate 106 and the lower electrode.
[0033] 有機 EL素子 100は、基板 106、陽極 101a、ドープ層 102、バッファ層 103、発光 層 104、電荷輸送層 105、陰極 101b、の順に、各構成を順次積層した構造を有して いる。 [0033] The organic EL element 100 has a structure in which the respective components are sequentially laminated in the order of the substrate 106, the anode 101a, the doped layer 102, the buffer layer 103, the light emitting layer 104, the charge transport layer 105, and the cathode 101b. .
[0034] つぎに、ドープ層 102について説明する。ドープ層 102は、発光層 104と陽極 101 aとの間に設けられている。ドープ層 102は、有機材料を主体として形成されて、高い 電荷 (電子または正孔)密度を有する電荷輸送層である。ドープ層 102は、電荷輸送 性を有する材料に電子受容性物質 (ァクセプタ)がドープされて形成されている。ここ で、電荷輸送性を有する材料は、高い正孔輸送機能を有する正孔輸送性材料であ る。正孔輸送性材料にドープされた電子受容性物質は、ドープ層 102において電子 を受け取ることにより、ドープ層 102に正孔を生じさせる。 Next, the doped layer 102 will be described. The doped layer 102 is provided between the light emitting layer 104 and the anode 101a. The doped layer 102 is a charge transport layer formed mainly of an organic material and having a high charge (electron or hole) density. The doped layer 102 is formed by doping a material having a charge transporting property with an electron accepting substance (acceptor). Here, the material having a charge transporting property is a hole transporting material having a high hole transporting function. The electron-accepting substance doped in the hole transporting material generates electrons in the doped layer 102 by receiving electrons in the doped layer 102.
[0035] なお、第 1の実施の形態では、電荷輸送性材料としての正孔輸送性材料と電子受 容性物質とを含むドープ層 102について例示している力 これに限定されるものでは ない。ドープ層 102は、電荷輸送性を有する材料に電子供与性物質 (ドナー)がドー プされて形成されていてもよい。この場合、電荷輸送性を有する材料は、高い電子輸 送機能を有する電子輸送性材料である。電子輸送性材料にドープされた電子供与
性物質は、ドープ層 102において電子を供与することにより、ドープ層 102に電子を 生じさせる。 In the first embodiment, the force exemplified for the doped layer 102 including the hole transporting material as the charge transporting material and the electron accepting material is not limited to this. . The doped layer 102 may be formed by doping an electron-donating substance (donor) with a material having a charge transporting property. In this case, the material having a charge transporting property is an electron transporting material having a high electron transporting function. Electron donation doped in electron transport materials The conductive material generates electrons in the doped layer 102 by donating electrons in the doped layer 102.
[0036] ドープ層 102において、電荷輸送性を有する材料は、たとえば、ノ ッファ層 103を 形成する材料と同じ材料である。なお、ドープ層 102において、電荷輸送性を有する 材料は、たとえば、ノ ッファ層 103を形成する材料とは異なる材料であってもよい。 [0036] In the doped layer 102, the material having a charge transporting property is, for example, the same material as the material forming the notch layer 103. In the doped layer 102, the material having a charge transporting property may be a material different from the material forming the notch layer 103, for example.
[0037] 図示を省略するが、陽極 101aとドープ層 102との間には、陽極 101aに対するドー プ層 102の密着性を向上させるための密着層、または、キャリア注入を改善する表面 改質層、または、有機 EL素子 100の安定ィ匕を目的とする層をさらに設けてもよい。 [0037] Although not shown, an adhesion layer for improving the adhesion of the dopant layer 102 to the anode 101a or a surface modification layer for improving carrier injection is provided between the anode 101a and the doped layer 102. Alternatively, a layer for the purpose of stabilizing the organic EL element 100 may be further provided.
[0038] つぎに、バッファ層 103について説明する。バッファ層 103は、ドープ層 102と発光 層 104との間に設けられている。ノ ッファ層 103は、電荷(電子または正孔)をブロッ クし、各電極(陽極 101aまたは陰極 101b)から注入された電荷 (ブロックされる電荷 とは逆の特性を有するもの)を発光層 104に注入 ·輸送する機能を有して 、る。 Next, the buffer layer 103 will be described. The buffer layer 103 is provided between the doped layer 102 and the light emitting layer 104. The noffer layer 103 blocks charges (electrons or holes), and charges injected from each electrode (anode 101a or cathode 101b) (having opposite characteristics to the blocked charges) as the light emitting layer 104. It has the function of injecting and transporting.
[0039] バッファ層 103は、電極対 101の対向方向(図 1中、矢印 Aの方向)に沿った寸法( 以下、膜厚とする)が、ドープ層 102の膜厚よりも大きくなるように設けられている。ノ ッファ層 103は、ドープ層 102を形成する材料と同じ材料によって形成されてもよいし 、ドープ層 102を形成する材料とは異なる材料によって形成されてもよい。バッファ層 103は、有機材料を主体として形成される。 Buffer layer 103 has a dimension (hereinafter referred to as a film thickness) along the facing direction of electrode pair 101 (the direction of arrow A in FIG. 1) so as to be larger than the film thickness of doped layer 102. Is provided. The nother layer 103 may be formed of the same material as that forming the doped layer 102, or may be formed of a material different from the material forming the doped layer 102. The buffer layer 103 is formed mainly of an organic material.
[0040] 第 1の実施の形態のバッファ層 103は、ドープ層 102から電導する正孔を発光層 1 04へ輸送するホール輸送機能を有するとともに、発光層 104からドープ層 102へ移 動する電子をブロックする電子ブロック機能を備えている。なお、電子ブロック機能に ついては、詳細を後述する。 [0040] The buffer layer 103 of the first embodiment has a hole transport function of transporting holes conducted from the doped layer 102 to the light emitting layer 104, and electrons that move from the light emitting layer 104 to the doped layer 102. Electronic block function to block. The details of the electronic block function will be described later.
[0041] 有機 EL素子 100において、バッファ層 103をはじめとする全ての層は、発光層 104 で発光される光が発光層 104上に積まれる層の面にぉ 、て反射する第 1の反射光と 、発光層 104で発光されバッファ層 103を透過してドープ層 102側の面で反射する 第 2の反射光と、が強め合うような光干渉を生じさせる膜厚に設けられている。また、 発光層 104で発光された光のうち、電極対 101の対向方向に放射され、積層界面で 多重反射される光が強め合うような光学干渉を生じさせるように膜厚を調整して設け ても構わない。
[0042] つぎに、発光層 104について説明する。発光層 104は、電極対 101の間に設けら れている。より詳細に、第 1の実施の形態の発光層 104は、ノ ッファ層 103と電荷輸 送層 105との間に設けられている。第 1の実施の形態の発光層 104は、有機化合物 によって形成されている。 [0041] In the organic EL element 100, all the layers including the buffer layer 103 are the first reflections that reflect the light emitted from the light emitting layer 104 on the surface of the layer on the light emitting layer 104. The light is provided in such a film thickness that causes optical interference such that light is emitted from the light emitting layer 104, transmitted through the buffer layer 103, and reflected by the surface on the doped layer 102 side. In addition, of the light emitted from the light-emitting layer 104, the film thickness is adjusted so that optical interference is generated such that the light emitted in the opposing direction of the electrode pair 101 and multiple-reflected at the interface between the layers is intensified. It doesn't matter. Next, the light emitting layer 104 will be described. The light emitting layer 104 is provided between the electrode pair 101. More specifically, the light emitting layer 104 of the first embodiment is provided between the notch layer 103 and the charge transport layer 105. The light emitting layer 104 of the first embodiment is formed of an organic compound.
[0043] つぎに、電荷輸送層 105について説明する。電荷輸送層 105は、発光層 104と陰 極 101bとの間に設けられている。なお、第 1の実施の形態では、電荷輸送層 105を 電子輸送層として説明する。電荷輸送層 105は、有機材料を主体として形成されて いる。電荷輸送層 105における電荷輸送性は、この有機材料に電子供与性物質 (ド ナー)をドープすることで発現してもよ 、。電荷輸送層 105と発光層 104との間には、 正孔輸送性の低い正孔ブロック層(図示省略)を挿入してもよい。また、電荷輸送層 1 05を省略しても構わない。 [0043] Next, the charge transport layer 105 will be described. The charge transport layer 105 is provided between the light emitting layer 104 and the cathode 101b. In the first embodiment, the charge transport layer 105 is described as an electron transport layer. The charge transport layer 105 is formed mainly of an organic material. The charge transport property in the charge transport layer 105 may be manifested by doping this organic material with an electron donating substance (donor). A hole blocking layer (not shown) having a low hole transporting property may be inserted between the charge transport layer 105 and the light emitting layer 104. Further, the charge transport layer 105 may be omitted.
[0044] 図 1に示す有機 EL素子 100における電極対 101に順方向バイアス電圧を印加す ると、陰極 101bから電荷輸送層 105に注入された電子が発光層 104へ移動し、陽 極 101aからドープ層 102に注入された正孔が発光層 104へ移動する。発光層 104 に移動した電子および正孔は、発光層 104内部において再結合する。この再結合ェ ネルギ一が発光層 104中の発光分子を励起させる。有機 EL素子 100においては、 励起された発光分子が基底状態に戻る際に光を放射することで、エレクト口ルミネッ センスが発生する。 When a forward bias voltage is applied to the electrode pair 101 in the organic EL element 100 shown in FIG. 1, electrons injected into the charge transport layer 105 from the cathode 101b move to the light emitting layer 104, and from the cathode 101a. The holes injected into the doped layer 102 move to the light emitting layer 104. The electrons and holes that have moved to the light emitting layer 104 are recombined inside the light emitting layer 104. This recombination energy excites the light emitting molecules in the light emitting layer 104. In the organic EL element 100, electoric luminescence is generated by emitting light when the excited luminescent molecule returns to the ground state.
[0045] (第 2の実施の形態) [0045] (Second embodiment)
図 2は、第 2の実施の形態における有機 EL素子の構造の一例を示す断面図である 。つぎに、第 2の実施の形態における有機 EL素子の構造の一例について、図 2を参 照して説明する。なお、上述した第 1の実施の形態と同一の構成については同一符 号を用いて示し、説明も省略する。 FIG. 2 is a cross-sectional view showing an example of the structure of the organic EL element according to the second embodiment. Next, an example of the structure of the organic EL element in the second embodiment will be described with reference to FIG. Note that the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.
[0046] 第 2の実施の形態の有機 EL素子 200は、基板 106と、電極対 201と、正孔注入層 [0046] The organic EL element 200 of the second embodiment includes a substrate 106, an electrode pair 201, a hole injection layer,
(ドープ層) 202と、電子ブロック層(バッファ層) 203と、発光層 204と、電子注入輸送 層 205と、を備える。電子ブロック層(バッファ層) 203の膜厚は、正孔注入層(ドープ 層) 202の膜厚よりも厚い。 (Dope layer) 202, electron block layer (buffer layer) 203, light emitting layer 204, and electron injecting and transporting layer 205 are provided. The thickness of the electron block layer (buffer layer) 203 is larger than that of the hole injection layer (dope layer) 202.
[0047] まず、電極対 201について説明する。電極対 201は、陽極 201aおよび当該陽極 2
Olaに対向する陰極 201bを備える。図 2に示す電極対 201においては、陽極 201a 力 基板 106上に設けられている。陽極 201aは、基板 106上に直接設けられていて もよいし、基板 106上にアルカリバリア膜や密着性改善膜、光学調整膜など(図示省 略)を形成した後に形成されたものであってもょ 、。 [0047] First, the electrode pair 201 will be described. The electrode pair 201 includes an anode 201a and the anode 2 A cathode 201b facing Ola is provided. In the electrode pair 201 shown in FIG. 2, the anode 201 a is provided on the force substrate 106. The anode 201a may be provided directly on the substrate 106, or may be formed after an alkali barrier film, an adhesion improving film, an optical adjustment film, or the like (not shown) is formed on the substrate 106. Well ...
[0048] 第 2の実施の形態においては、陽極 201aによって下部電極が実現され、陰極 201 bによって上部電極が実現される。以下、陽極 201aを「下部電極(陽極) 201a」として 説明し、陰極 201bを「上部電極(陰極) 201b」として説明する。 [0048] In the second embodiment, the lower electrode is realized by the anode 201a, and the upper electrode is realized by the cathode 201b. Hereinafter, the anode 201a will be described as “lower electrode (anode) 201a” and the cathode 201b will be described as “upper electrode (cathode) 201b”.
[0049] なお、第 2の実施の形態では、陽極 201aによって下部電極が実現され、陰極 201 bによって上部電極が実現される場合について説明する力 これに限るものではない 。陽極 201aによって上部電極が実現され、陰極 201bによって下部電極が実現され ていてもよい。 [0049] In the second embodiment, the force for explaining the case where the lower electrode is realized by the anode 201a and the upper electrode is realized by the cathode 201b is not limited to this. The upper electrode may be realized by the anode 201a and the lower electrode may be realized by the cathode 201b.
[0050] 有機 EL素子 200は、基板 106、下部電極(陽極) 201a、正孔注入層 202、電子ブ ロック層 203、発光層 204、電子注入輸送層 205、上部電極(陰極) 201b、の順に、 各構成を順次積層した構造を有している。以下に、有機 EL素子 200が備える各構 成について詳細に説明する。なお、上述した第 1の実施の形態で説明した構成と同 一部分については、適宜説明を省略する。 [0050] The organic EL element 200 includes a substrate 106, a lower electrode (anode) 201a, a hole injection layer 202, an electron block layer 203, a light emitting layer 204, an electron injection transport layer 205, and an upper electrode (cathode) 201b in this order. Each structure is sequentially stacked. Hereinafter, each component included in the organic EL element 200 will be described in detail. Note that the description of the same parts as those described in the first embodiment will be omitted as appropriate.
[0051] つぎに、下部電極(陽極) 20 laについて説明する。下部電極(陽極) 20 laを形成 する材料としては、たとえば、酸化錫、酸化インジウム、酸ィ匕錫インジウム (ITO)など の導電性酸化物、あるいは、アルミニウム、銅、金、銀、クロムなどの金属や、ヨウ化銅 、硫化銅などの無機導電性物質、などを用いることができる。下部電極 (陽極) 201a を形成する材料としては、これらに限るものではな 、。 [0051] Next, the lower electrode (anode) 20 la will be described. As a material for forming the lower electrode (anode) 20 la, for example, a conductive oxide such as tin oxide, indium oxide, and indium tin oxide (ITO), or aluminum, copper, gold, silver, chromium, and the like are used. Metals, inorganic conductive materials such as copper iodide and copper sulfide, and the like can be used. The material for forming the lower electrode (anode) 201a is not limited to these materials.
[0052] つぎに、上部電極(陰極) 201bについて説明する。上部電極(陰極) 201bを形成 する材料としては、たとえば、アルミニウム、銅、銀、金などの単体またはマグネシウム と銀、リチウムと銀などの合金、酸化錫インジウム (ITO)などの導電性酸化物を使用 することができる。 Next, the upper electrode (cathode) 201b will be described. As a material for forming the upper electrode (cathode) 201b, for example, a simple substance such as aluminum, copper, silver, or gold, an alloy such as magnesium and silver, lithium and silver, or a conductive oxide such as indium tin oxide (ITO) is used. Can be used.
[0053] つぎに、正孔注入層 202および電子注入輸送層 205について説明する。正孔注入 層 202および電子注入輸送層 205は、従来使用されている材料 (高分子材料、低分 子材料や有機材料、無機材料を問わない)を適宜選択することが可能である。第 2の
実施の形態においては、正孔注入層 202によって、発光層 204と下部電極(陽極) 2 Olaとの間に設けられて、電子受容性物質がドープされたドープ層が実現されている Next, the hole injection layer 202 and the electron injection / transport layer 205 will be described. For the hole injecting layer 202 and the electron injecting and transporting layer 205, conventionally used materials (regardless of polymer materials, low molecular weight materials, organic materials, and inorganic materials) can be appropriately selected. Second In the embodiment, the hole injection layer 202 realizes a doped layer provided between the light emitting layer 204 and the lower electrode (anode) 2 Ola and doped with an electron accepting substance.
[0054] つぎに、発光層 204について説明する。発光層 204を形成する材料としては、従来 使用されている材料 (高分子材料、低分子材料や有機材料、無機材料を問わない) を適宜選択することが可能である。発光材料においては、一重項励起状態から基底 状態に戻る際の発光 (蛍光)と三重項励起状態から基底状態に戻る際の発光(りん光 )とがあるが、第 2の実施の形態では、どちらの発光を用いた有機 EL素子 200におい ても利用可能である。 Next, the light emitting layer 204 will be described. As a material for forming the light emitting layer 204, a conventionally used material (regardless of a polymer material, a low molecular material, an organic material, or an inorganic material) can be appropriately selected. In the luminescent material, there are light emission (fluorescence) when returning from the singlet excited state to the ground state and light emission (phosphorescence) when returning from the triplet excited state to the ground state. In the second embodiment, It can be used in the organic EL element 200 using either light emission.
[0055] つぎに、電子ブロック層 203について説明する。電子ブロック層 203は、下部電極( 陽極) 201aと発光層 204との間に設けられている。第 2の実施の形態においては、た とえば、正孔注入効率の改善を目的として、下部電極(陽極) 201aと電子ブロック層 203との間に正孔注入層 202が設けられている例について説明した力 これに限るも のではない。電子ブロック層 203は、下部電極(陽極) 201aに直接密着していてもよ い。 Next, the electronic block layer 203 will be described. The electron blocking layer 203 is provided between the lower electrode (anode) 201 a and the light emitting layer 204. In the second embodiment, for example, for the purpose of improving the hole injection efficiency, an example in which a hole injection layer 202 is provided between the lower electrode (anode) 201a and the electron block layer 203 will be described. The power explained is not limited to this. The electron blocking layer 203 may be in direct contact with the lower electrode (anode) 201a.
[0056] ここで、電子ブロック層 203の機能について説明する。電極対 201に対して順方向 に電圧が印加された場合、有機 EL素子 200においては、上部電極(陰極) 201b側 力も下部電極(陽極) 201a側へ向力 電子の流れが発生する。電子ブロック層 203 は、電子ブロック層 203における 2つの界面のうち、上部電極(陰極) 201b側の面に 到達した電子力 下部電極(陽極) 201a側に透過することを抑制する。これにより、 発光層 204における下部電極(陽極) 201a側において、電子を有効に閉じ込めるこ とがでさる。 Here, the function of the electronic block layer 203 will be described. When a voltage is applied in the forward direction with respect to the electrode pair 201, in the organic EL element 200, a force of electrons on the upper electrode (cathode) 201 b side also flows toward the lower electrode (anode) 201 a side. The electron blocking layer 203 suppresses the transmission of the electron force reaching the lower electrode (anode) 201a side that has reached the surface on the upper electrode (cathode) 201b side of the two interfaces in the electron blocking layer 203. As a result, electrons are effectively confined on the lower electrode (anode) 201a side of the light emitting layer 204.
[0057] さらに、電子ブロック層 203が正孔輸送性能を有している場合、下部電極(陽極) 2 01 aから効率よく注入された電子を、電子ブロック層 203を介して発光層 204に輸送 することができる。この場合、電子ブロック層 203を介して発光層 204に効率よく輸送 された正孔と、上部電極(陰極) 201bから効率よく注入され、電子注入輸送層 205を 介して輸送されてから電子ブロック層 203にお ヽてブロックされた電子とが、発光層 2 04内部で有効に再結合することができる。この再結合における再結合エネルギーに
よって、発光層 204における発光分子が励起されて、ルミネッセンスが得られる。すな わち、発光層 204内部で再結合が有効におこなわれることにより、効率のよいルミネ ッセンスが得られる。 [0057] Further, when the electron blocking layer 203 has hole transporting performance, electrons efficiently injected from the lower electrode (anode) 201a are transported to the light emitting layer 204 via the electron blocking layer 203. can do. In this case, holes efficiently transported to the light-emitting layer 204 through the electron blocking layer 203 and efficiently injected from the upper electrode (cathode) 201b and transported through the electron injecting and transporting layer 205 are then transferred to the electron blocking layer. The electrons blocked in 203 can be effectively recombined inside the light emitting layer 204. The recombination energy in this recombination Therefore, the light emitting molecules in the light emitting layer 204 are excited and luminescence is obtained. In other words, efficient recombination can be obtained by effective recombination within the light emitting layer 204.
[0058] これに対し、電子ブロック層 203に対して逆方向に電圧が印加された場合、有機 E L素子 200においては、下部電極(陽極) 201aから強制的に注入された電子力 下 部電極(陽極) 20 la側から上部電極(陰極) 201b側へ向かう電子の流れが発生する 。電子ブロック層 203は、電子ブロック層 203における 2つの界面のうち、下部電極( 陽極) 201a側の面に到達した電子力 上部電極(陰極) 201b側に透過することを抑 制する。 On the other hand, when a voltage is applied to the electron blocking layer 203 in the reverse direction, the organic EL element 200 has a lower electrode (electron force forcibly injected from the lower electrode (anode) 201a ( Anode) Electron flows from the 20 la side to the upper electrode (cathode) 201b side. The electron blocking layer 203 suppresses transmission of the electron force reaching the upper electrode (cathode) 201b side, which has reached the surface of the lower electrode (anode) 201a side, out of the two interfaces in the electron blocking layer 203.
[0059] つぎに、電子ブロック層 203を形成する材料について説明する。一般的に、電子ブ ロック性能の高い材料は、正負のキャリア密度が低いが、電子ブロック層 203を形成 する材料としては、電子ブロック性と正孔輸送性能とを有する材料が好ましい。具体 的には、たとえば、 a—NPDを用いることが好ましい(特開 2003— 272860号公報 参照)。 Next, materials for forming the electron block layer 203 will be described. In general, a material having a high electron block performance has a low positive / negative carrier density, but as a material for forming the electron block layer 203, a material having an electron block property and a hole transport performance is preferable. Specifically, for example, it is preferable to use a-NPD (see JP-A-2003-272860).
[0060] つぎに、正孔注入層 202を形成する材料について説明する。正孔注入層 202は、 有機材料を主体として形成されている。正孔注入層 202は、下部電極(陽極) 201a の仕事関数と近 、最高被占軌道 (HOMO)準位を持ち、正孔輸送性能を有する材 料が好ましい。下部電極(陽極) 201aの仕事関数より HOMO準位が大きい場合、下 部電極(陽極) 201aからの正孔注入はオーム性となり、整流性のないスムーズなキヤ リア注入が可能になる。 Next, materials for forming the hole injection layer 202 will be described. The hole injection layer 202 is formed mainly of an organic material. The hole injection layer 202 is preferably made of a material having the highest occupied orbital (HOMO) level close to the work function of the lower electrode (anode) 201a and having hole transport performance. When the HOMO level is larger than the work function of the lower electrode (anode) 201a, hole injection from the lower electrode (anode) 201a becomes ohmic, and smooth carrier injection without rectification becomes possible.
[0061] 下部電極(陽極) 201aの仕事関数より HOMO準位が小さ 、場合、注入界面のェ ネルギー障壁を超えて注入される熱拡散正孔注入となる。この場合、正孔がェネル ギー障壁を超えるのに必要な電圧を要するとともに、注入界面の正孔注入層 202側 に発生した空乏層のためにスムーズな正孔注入が得に《なるため、下部電極(陽極 ) 20 laの材料を特に選ぶ。 [0061] When the HOMO level is smaller than the work function of the lower electrode (anode) 201a, thermal diffusion hole injection is performed that exceeds the energy barrier at the injection interface. In this case, the voltage required for the holes to exceed the energy barrier is required, and smooth hole injection is obtained because of the depletion layer generated on the hole injection layer 202 side of the injection interface. Electrode (anode) 20 la material is particularly selected.
[0062] また、別の注入形態として、トンネル注入がある。トンネル注入は、特に、正孔注入 層 202の正孔キャリア密度が高い場合に有効である。トンネル注入に際しては、下部 電極(陽極) 201aとの界面のバンドが急激に歪み、歪んだ薄い障壁を通して正孔をト
ンネル注入させる。トンネル注入では、下部電極(陽極) 201aと正孔注入層 202との エネルギー障壁を考える必要がないため、下部電極(陽極) 201aを形成する材料と して多くの材料を選択することができ、これにより正孔注入の効率も高くすることがで きる。 [0062] Another injection form is tunnel injection. Tunnel injection is particularly effective when the hole carrier density of the hole injection layer 202 is high. During tunnel injection, the band at the interface with the lower electrode (anode) 201a is abruptly distorted, and holes are trapped through a distorted thin barrier. Inject the tunnel. In tunnel injection, since it is not necessary to consider the energy barrier between the lower electrode (anode) 201a and the hole injection layer 202, many materials can be selected as a material for forming the lower electrode (anode) 201a. As a result, the efficiency of hole injection can be increased.
[0063] 正孔注入層 202を形成する材料としては、正孔注入層 202の正孔キャリア密度を 高くするために、正孔輸送性能を有する材料に電子受容性物質 (ァクセプター)がド ープされた材料であってもよい。これより以降では、特に、正孔注入層 202の正孔キ ャリア密度が高 、ことを前提に説明する。 [0063] As a material for forming the hole injection layer 202, in order to increase the hole carrier density of the hole injection layer 202, an electron-accepting substance (acceptor) is doped into a material having hole transport performance. It may be a made material. Hereinafter, the description will be made on the assumption that the hole carrier density of the hole injection layer 202 is particularly high.
[0064] 電子受容性物質 (ァクセプター)がドープされた正孔注入層 202にお 、て、正孔キ ャリア輸送性能を有する材料とは、電子の輸送に比べて、比較的正孔を輸送する性 能が高い材料である。一般的に、電子を輸送しにくぐ正孔を輸送しやすいほど性能 の良い正孔輸送層であるとされる。 [0064] In the hole injection layer 202 doped with an electron-accepting substance (acceptor), a material having a hole carrier transporting performance transports holes relatively compared to electron transport. It is a material with high performance. In general, it is said that the hole transport layer has better performance as it is easier to transport holes that are difficult to transport electrons.
[0065] 電子受容性物質 (ァクセプター)は、正孔注入層 202において電子を受け取ること により正孔注入層 202に正孔を生じさせる。正孔注入層 202は、たとえば、電子ブロ ック層 203を形成する材料と同じ材料と、電子受容性材料 (ァクセプター)と、を含む 。正孔注入層 202は、電子ブロック層 203を形成する材料とは異なる正孔輸送性能 を有する材料と、電子受容性材料 (ァクセプター)と、を含んでいてもよい。 The electron accepting substance (acceptor) generates holes in the hole injection layer 202 by receiving electrons in the hole injection layer 202. The hole injection layer 202 includes, for example, the same material as that for forming the electron block layer 203 and an electron accepting material (acceptor). The hole injection layer 202 may include a material having hole transport performance different from the material forming the electron blocking layer 203 and an electron accepting material (acceptor).
[0066] 正孔注入層 202においてドープされる電子受容性物質としては、ルイス酸ィ匕合物、 金属酸化物、金属ハロゲン化物、フラーレンなどがあげられる。また、これまで下部電 極(陽極) 201aと正孔注入層 202とについて説明した力 上部電極(陰極) 201bと電 子注入輸送層 205に関しても全く同様であり、符号の正負のみ異なる説明ができる。 [0066] Examples of the electron-accepting substance doped in the hole injection layer 202 include Lewis acid compounds, metal oxides, metal halides, fullerenes, and the like. Further, the force described above for the lower electrode (anode) 201a and the hole injection layer 202 is exactly the same for the upper electrode (cathode) 201b and the electron injection / transport layer 205, and can be explained only with different signs. .
[0067] つぎに、上部電極(陰極) 201b,電子注入輸送層(電子注入層あるいは電子輸送 層でも可) 205を形成する材料について説明する。上部電極(陰極) 201b、電子注 入輸送層 205を形成する材料としては、たとえば、電子注入材料として電子輸送性 能を有する材料が挙げられ、この電子注入材料にドープする電子供与性物質 (ァク セプター)としてアルカリ金属、アルカリ土類金属、希土類金属、アルカリ金属化合物 、アルカリ土類金属化合物、希土類ィ匕合物などが挙げられる。 Next, materials for forming the upper electrode (cathode) 201b and the electron injection / transport layer (which may be an electron injection layer or an electron transport layer) 205 will be described. Examples of the material for forming the upper electrode (cathode) 201b and the electron injecting and transporting layer 205 include a material having an electron transporting property as an electron injecting material, and an electron donating substance (a Examples of the ceptor include alkali metals, alkaline earth metals, rare earth metals, alkali metal compounds, alkaline earth metal compounds, and rare earth compounds.
[0068] ルイス酸ィ匕合物として、具体的には、たとえば、塩化第 2鉄、臭化第 2鉄、ヨウィ匕第 2
鉄、塩ィ匕アルミニウム、臭化アルミニウム、ヨウ化アルミニウム、塩ィ匕ガリウム、臭化ガリ ゥム、ヨウ化ガリウム、塩化インジウム、臭化インジウム、ヨウ化インジウム、 5塩化アン チモン、 5フッ化砒素、 3フッ化硼素などの無機化合物や、 DDQ (ジシァノージクロロ キノン)、 TNF (トリ-トロフルォレノン)、 TCNQ (テトラシァノキノジメタン)、 F4— TC NQ (テトラフルォ口一テトラシァノキノジメタンなどが挙げられる。 [0068] Specific examples of the Lewis acid compound include, for example, ferric chloride, ferric bromide, and Yowi 2nd. Iron, Aluminum chloride, Aluminum bromide, Aluminum iodide, Aluminum chloride, Gallium bromide, Gallium iodide, Indium chloride, Indium bromide, Indium iodide, Antimony pentachloride, Arsenic pentafluoride , Inorganic compounds such as boron trifluoride, DDQ (disananodichloroquinone), TNF (tri-trofluorenone), TCNQ (tetracyanoquinodimethane), F4—TC NQ (tetrafluoroacetate tetracyanoquinodimethane, etc. Is mentioned.
[0069] 金属酸化物、金属ハロゲン化物としては、具体的には、たとえば、 V O (5酸化バナ [0069] Specific examples of metal oxides and metal halides include, for example, V 2 O 3
2 5 twenty five
ジゥム)または Re O (7酸化レニウム)、 MoO 、 WOなどがある。アルカリ金属、アル Dium) or Re 2 O (rhenium oxide), MoO, WO, etc. Alkali metal, Al
2 7 3 3 2 7 3 3
カリ土類金属、希土類金属とその化合物として、 Li、 Cs、 Mg、 Ca、 Eu、 LiF、 Li 0、 Potassium earth metals, rare earth metals and their compounds include Li, Cs, Mg, Ca, Eu, LiF, Li 0,
2 2
CsF、 NaCl、 KC1、 MgFなどが挙げられる。 Examples include CsF, NaCl, KC1, and MgF.
2 2
[0070] また、電子受容性物質 (ァクセプター)としては、たとえば、フッ素を置換基として有 する有機物質やシァノ基を置換基として有する有機物もある。なお、電子受容性物 質 (ァクセプター)は、上述したこれらの材料に限定されるものではない。 [0070] Examples of the electron-accepting substance (acceptor) include an organic substance having fluorine as a substituent and an organic substance having a cyano group as a substituent. The electron accepting substance (acceptor) is not limited to these materials described above.
[0071] 電子注入輸送層 205に、トリス(8—ヒドロキシキノリノール)アルミニウムなどの電子 輸送性材料を用いた場合は、フラーレン、カーボンナノチューブなどの電子供与性 物質をドープしてもよぐ電子供与性物質 (ドナー)そのものを電子注入輸送層 205に 用いても良い。ほ力に、正孔注入層 202、電子注入輸送層 205、電子ブロック層 203 を形成する材料としては、有機 EL素子 200の製造に際して一般的に使用されている 公知の各種ィ匕合物を適宜用いることができる。 [0071] When an electron transporting material such as tris (8-hydroxyquinolinol) aluminum is used for the electron injecting and transporting layer 205, an electron donating property may be obtained by doping with an electron donating substance such as fullerene or carbon nanotube. The substance (donor) itself may be used for the electron injecting and transporting layer 205. As a material for forming the hole injection layer 202, the electron injection transport layer 205, and the electron block layer 203, various known compounds generally used in the manufacture of the organic EL element 200 are appropriately used. Can be used.
[0072] (第 3の実施の形態) [Third Embodiment]
図 3は、第 3の実施の形態における有機 EL素子の構造の一例を示す断面図である 。つぎに、第 3の実施の形態における有機 EL素子の構造の一例について、図 3を参 照して説明する。なお、上述した第 1、第 2の実施の形態と同一の構成については同 一符号を用いて示し、説明も省略する。 FIG. 3 is a cross-sectional view showing an example of the structure of the organic EL element according to the third embodiment. Next, an example of the structure of the organic EL element in the third embodiment will be described with reference to FIG. Note that the same components as those in the first and second embodiments described above are denoted by the same reference numerals, and description thereof is omitted.
[0073] 第 3の実施の形態における有機 EL素子 300は、基板 106と、電極対 201と、正孔 注入輸送層 301と、発光層 204と、正孔ブロック層(バッファ層) 302と、電子注入層 ( ドープ層) 303と、を備える。正孔ブロック層(バッファ層) 302の膜厚は、電子注入層 (ドープ層) 303の膜厚よりも厚!ヽ。 [0073] The organic EL device 300 in the third embodiment includes a substrate 106, an electrode pair 201, a hole injecting and transporting layer 301, a light emitting layer 204, a hole blocking layer (buffer layer) 302, an electron An injection layer (dope layer) 303. The hole blocking layer (buffer layer) 302 is thicker than the electron injection layer (dope layer) 303.
[0074] 有機 EL素子 300は、基板 106、下部電極(陽極) 201a,正孔注入輸送層 301と、
発光層 204、正孔ブロック層 302、電子注入層 303、上部電極(陰極) 201b、の順に 、各構成を順次積層した構造を有している。以下に、有機 EL素子 300が備える各構 成について詳細に説明する。なお、上述した第 1、第 2の実施の形態で説明した構成 と同一部分については、適宜説明を省略する。 [0074] The organic EL element 300 includes a substrate 106, a lower electrode (anode) 201a, a hole injecting and transporting layer 301, The light emitting layer 204, the hole blocking layer 302, the electron injecting layer 303, and the upper electrode (cathode) 201b are sequentially stacked. Below, each structure with which the organic EL element 300 is provided is demonstrated in detail. Note that the description of the same parts as those described in the first and second embodiments is omitted as appropriate.
[0075] 第 3の実施の形態の有機 EL素子 300は、上部電極(陰極) 201bと電子注入層 30 3について、上述した図 2に示した有機 EL素子 200における下部電極(陽極) 201a 、正孔注入層 202およびキャリアの正負の符号を逆にしただけの構造を備える。すな わち、正孔ブロック層(バッファ層) 302の膜厚は、電子注入層(ドープ層) 303の膜厚 よりも厚い。図 3に示す有機 EL素子 300は、図 2に示す有機 EL素子 200と全く類似 のメカニズムで、順方向および逆方向バイアス電圧によってキャリアが注入 '輸送され る。 [0075] The organic EL element 300 of the third embodiment is configured so that the upper electrode (cathode) 201b and the electron injection layer 303 are the lower electrode (anode) 201a in the organic EL element 200 shown in FIG. It has a structure in which the positive and negative signs of the hole injection layer 202 and the carrier are reversed. That is, the thickness of the hole blocking layer (buffer layer) 302 is larger than that of the electron injection layer (dope layer) 303. The organic EL device 300 shown in FIG. 3 has exactly the same mechanism as the organic EL device 200 shown in FIG. 2, and carriers are injected and transported by forward and reverse bias voltages.
[0076] 有機 EL素子 300が備える正孔ブロック層 302は、正孔の通過を抑制するとともに、 電子の輸送を効率よく行うことができる材料によって形成されて 、ることが望ま 、。 正孔ブロック層 302は、有機 EL素子 300に順方向バイアス電圧が印可された場合に 、上部電極 (陰極) 201bから注入された電子を効率よく発光層 204に輸送するととも に、下部電極(陽極) 201aから注入された正孔を正孔ブロック層 302における発光層 204側の面でブロックする。これにより、正負のキャリア再結合を、発光層 204内で有 効におこなわせることができる。 [0076] The hole blocking layer 302 included in the organic EL element 300 is desirably formed of a material capable of suppressing the passage of holes and efficiently transporting electrons. When a forward bias voltage is applied to the organic EL element 300, the hole blocking layer 302 efficiently transports electrons injected from the upper electrode (cathode) 201b to the light emitting layer 204, and also lower electrode (anode). ) The holes injected from 201a are blocked on the surface of the hole blocking layer 302 on the light emitting layer 204 side. Thus, positive and negative carrier recombination can be effectively performed in the light emitting layer 204.
[0077] また、正孔ブロック層 302は、有機 EL素子 300に逆方向バイアス電圧(以下、「逆 バイアス電圧」という)が印可された場合に、上部電極(陰極) 201bから強制的に注 入された正孔が、下部電極(陽極) 201a側に透過することを防ぐ。これにより、逆バイ ァス電圧を印加した場合における漏れ電流を小さくすることができる。 [0077] The hole blocking layer 302 is forcibly injected from the upper electrode (cathode) 201b when a reverse bias voltage (hereinafter referred to as "reverse bias voltage") is applied to the organic EL element 300. The formed holes are prevented from transmitting to the lower electrode (anode) 201a side. As a result, the leakage current when a reverse bias voltage is applied can be reduced.
[0078] 第 3の実施の形態の電子注入層 303は、有機材料または無機材料を主体として形 成されている。より高い電子キャリア密度を有するために、電子注入層 303に、電荷 輸送性を有する材料に電子供与性物質 (ドナー)がドープされていてもよい。このとき 電荷輸送性を有する材料は、正孔を輸送する性能に比べて、電子を輸送する性能 が比較的高!、電子輸送性能を有する電子輸送性材料である。電子供与性物質は、 電子注入層 303において電子を放出することにより電子注入層 303に電子を生じさ
せる。キャリア密度が高くなると、トンネル注入となるのは正孔注入の場合と同様であ る。 [0078] The electron injection layer 303 of the third embodiment is formed mainly of an organic material or an inorganic material. In order to have a higher electron carrier density, the electron injecting layer 303 may be doped with an electron donating substance (donor) in a material having a charge transporting property. At this time, the material having a charge transporting property is an electron transporting material having a relatively high performance of transporting electrons compared to the performance of transporting holes, and has an electron transporting performance. The electron donating substance generates electrons in the electron injection layer 303 by emitting electrons in the electron injection layer 303. Make it. When the carrier density is high, tunnel injection is the same as in the case of hole injection.
[0079] 電子注入層 303は、たとえば、正孔ブロック層 302を形成する材料と同じ材料と、電 子供与性物質 (ドナー)と、を含む。また、電子注入層 303は、たとえば、正孔ブロック 層 302を形成する材料とは異なる電荷輸送性材料と、電子供与性物質 (ドナー)と、を 含んでいてもよい。 [0079] The electron injection layer 303 includes, for example, the same material as that for forming the hole blocking layer 302, and an electron donating substance (donor). The electron injection layer 303 may include, for example, a charge transporting material different from the material forming the hole blocking layer 302 and an electron donating substance (donor).
[0080] 正孔ブロック層 302を形成する材料としては、正孔ブロック性を有する材料が好まし い。正孔ブロック性を有するとともに、電子輸送性能が高い材料として、たとえば、 BC P (2, 9 ジメチル 4、 7 ジフエ-ル一 1、 10フエナント口リン)、 BAlq (l、 1,ビスフエ -ル一 4—ォラートビス(2—メチル 8 キノリノラート一 Nl、 08) )、 BPhen (4、 7— ジフエニノレー 1、 10フエナント口リン)などがある。 [0080] As a material for forming the hole blocking layer 302, a material having a hole blocking property is preferable. Materials that have hole blocking properties and high electron transport performance include, for example, BCP (2, 9 dimethyl 4, 7 diphenyl 1, 10 phenolic phosphorus), BAlq (l, 1, bisphenol 4-olatobis (2-methyl-8 quinolinolato-Nl, 08)), BPhen (4,7-diphenenole 1, 10 phenanthrene).
[0081] (実施の形態の有機 EL素子と従来の有機 EL素子との差異 (その 1) ) [0081] (Difference between the organic EL device of the embodiment and the conventional organic EL device (Part 1))
以下に、実施の形態の有機 EL素子と従来の有機 EL素子との差異 (その 1)につい て説明する。はじめに、実施の形態の有機 EL素子と従来の有機 EL素子との構造上 の差異について説明する。ここでは、この発明の実施の形態の有機 EL素子として、 上述した図 1に示した第 1の実施の形態の有機 EL素子 100 (あるいは、図 2に示した 第 2の実施の形態の有機 EL素子 200でも可)を用いて説明する。 The difference (part 1) between the organic EL element of the embodiment and the conventional organic EL element is described below. First, the structural difference between the organic EL element of the embodiment and the conventional organic EL element will be described. Here, as the organic EL element of the embodiment of the present invention, the organic EL element 100 of the first embodiment shown in FIG. 1 described above (or the organic EL element of the second embodiment shown in FIG. 2). This will be described using the element 200).
[0082] (従来の有機 EL素子の構造) [0082] (Conventional organic EL device structure)
図 4は、従来の有機 EL素子の構造の一例を示す断面図である。以下に、従来の有 機 EL素子について図 4を参照して説明する。なお、図 4に示す従来の有機 EL素子 4 00〖こおいて、上述した各実施の形態における有機 EL素子 100、 200、 300と同一 部分は同一符号で示し、説明も省略する。 FIG. 4 is a cross-sectional view showing an example of the structure of a conventional organic EL element. A conventional organic EL element will be described below with reference to FIG. Note that, in the conventional organic EL element 400 shown in FIG. 4, the same parts as those of the organic EL elements 100, 200, and 300 in the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.
[0083] 図 4に示すように、従来の有機 EL素子 400は、電極対 101と、ドープ層 102と、バッ ファ層 103と、発光層 104と、電荷輸送層 105と、を備える。電極対 101は、下部電 極である陽極 101aと上部電極である陰極 101bと、を備える。有機 EL素子 400は、 基板 106、陽極 101a、ドープ層 102、バッファ層 103、発光層 104、電荷輸送層 10 5、陰極 101b、の順に、各構成を順次積層した構造を有している。 As shown in FIG. 4, a conventional organic EL element 400 includes an electrode pair 101, a doped layer 102, a buffer layer 103, a light emitting layer 104, and a charge transport layer 105. The electrode pair 101 includes an anode 101a that is a lower electrode and a cathode 101b that is an upper electrode. The organic EL element 400 has a structure in which the respective components are sequentially laminated in the order of the substrate 106, the anode 101a, the doped layer 102, the buffer layer 103, the light emitting layer 104, the charge transport layer 105, and the cathode 101b.
[0084] 従来の有機 EL素子 400におけるドープ層 102の膜厚は、バッファ層 103の膜厚よ
りも大きい。従来の有機 EL素子 400では、ドープ層 102における電気伝導に際して は、電導キャリアが正孔であり、バイアス電圧の向きによらない正孔由来の電流が発 生する。すなわち、ドープ層 102においては、整流性が失われ、ォーミックに振る舞う [0084] The thickness of the doped layer 102 in the conventional organic EL device 400 is equal to the thickness of the buffer layer 103. It is also big. In the conventional organic EL element 400, when conducting in the doped layer 102, the conductive carrier is a hole, and a hole-derived current is generated regardless of the direction of the bias voltage. That is, the doped layer 102 loses rectification and behaves ohmic.
[0085] (挙動の差異 (その 1) ) [0085] (Difference in behavior (part 1))
図 5は、従来の形態の有機 EL素子 400に対して、逆バイアス電圧をかけた場合の キャリアの挙動を示す説明図である。図 6は、この発明の実施の形態の有機 EL素子 100に対して、逆バイアスをかけた場合のキャリアの挙動を示す説明図である。以下 に、従来の有機 EL素子 400および有機 EL素子 100に対して、それぞれ逆バイアス 電圧をかけた場合の挙動の差異について、図 5および図 6を参照して説明する。 FIG. 5 is an explanatory view showing the behavior of carriers when a reverse bias voltage is applied to the organic EL element 400 of the conventional form. FIG. 6 is an explanatory diagram showing the behavior of carriers when a reverse bias is applied to the organic EL element 100 according to the embodiment of the present invention. Hereinafter, the difference in behavior when a reverse bias voltage is applied to the conventional organic EL element 400 and the organic EL element 100 will be described with reference to FIGS. 5 and 6. FIG.
[0086] 図 5および図 6には、従来の有機 EL素子 400および有機 EL素子 100に対して逆 ノィァス電圧をかけた場合、どの層にキャリアが多く蓄積しているか力 模式的に示さ れている。通常、有機 EL素子 400、 100を発光させる場合、陽極 101a側に +電圧 を印加し、陰極 101b側に—電圧を印加する(この実施の形態では、このような方向 に印加するノ ィァス電圧を、順方向バイアス電圧として説明する。)。 FIG. 5 and FIG. 6 schematically show in which layer many carriers are accumulated when reverse noise voltage is applied to the conventional organic EL element 400 and the organic EL element 100. Yes. Normally, when the organic EL elements 400 and 100 emit light, a positive voltage is applied to the anode 101a side, and a negative voltage is applied to the cathode 101b side (in this embodiment, a noisy voltage applied in such a direction is applied). This will be described as a forward bias voltage.)
[0087] 逆ノ ィァス電圧とは、これとは別に、有機 EL素子 400、 100を発光させる際に印加 する電圧の方向とは逆方向の電圧である。逆ノィァスは、たとえば、有機 EL素子 40 0、 100の性能が向上するなどの利点から、本来の陽極 101a側に—電圧、本来の陰 極 101b側に +電圧を印加することがある。逆ノィァスを印加することにより、有機 EL 素子 400、 100内に蓄積したキャリアを無くすことができると考えられる。 Apart from this, the reverse noise voltage is a voltage in a direction opposite to the direction of the voltage applied when the organic EL elements 400 and 100 emit light. The reverse noise may apply a negative voltage to the original anode 101a side and a positive voltage to the original negative electrode 101b side, for example, because of the advantage of improving the performance of the organic EL elements 400 and 100. It is considered that carriers accumulated in the organic EL elements 400 and 100 can be eliminated by applying reverse noise.
[0088] 逆バイアス電圧を印加する具体的な利用例としては、たとえば、有機 EL素子 400、 100が、基板 106上に複数形成されている自発光パネル(図示省略)において、有 機 EL素子 400、 100を走査線方向に沿って線順次駆動する場合が挙げられる。こ の場合、選択された走査線上に存在する有機 EL素子 400、 100のみに順方向ノィ ァス電圧を印加し、その他の非選択走査線上に存在する有機 EL素子 400、 100に は逆バイアス電圧を印加することを行う。これにより、クロストークのない表示が可能と なる。 [0088] As a specific application example of applying the reverse bias voltage, for example, in a self-luminous panel (not shown) in which a plurality of organic EL elements 400, 100 are formed on the substrate 106, the organic EL element 400 , 100 is line-sequentially driven along the scanning line direction. In this case, the forward noise voltage is applied only to the organic EL elements 400 and 100 existing on the selected scanning line, and the reverse bias voltage is applied to the organic EL elements 400 and 100 existing on the other non-selected scanning lines. Is applied. This enables display without crosstalk.
[0089] また、逆バイアス電圧を印加することにより、発光不良箇所を修復する、いわゆる自
己リペアが可能になる。なお、自己リペアについては公知の技術であるため、説明を 省略する。 [0089] Further, by applying a reverse bias voltage, a defective light emitting portion is repaired, so-called auto You can repair yourself. Since self-repair is a known technique, the description thereof is omitted.
[0090] 図 5および図 6から分力るように、従来およびこの発明の実施の形態の構成の有機 EL素子 400、 100は、いずれも「下部電極 Z正孔注入層 Z電子ブロック層 Z発光層 Z電子注入輸送層 Z上部電極」(符号省略)という素子構造を有している。従来の構 成の有機 EL素子 400と、本実施の形態の有機 EL素子 100との構成の違いは、バッ ファ層(電子ブロック層) 103の厚さである。 As shown in FIG. 5 and FIG. 6, the organic EL elements 400 and 100 according to the conventional and the embodiments of the present invention are both “lower electrode Z hole injection layer Z electron blocking layer Z light emission. It has an element structure of “layer Z electron injection transport layer Z upper electrode” (reference numeral omitted). The difference in configuration between the organic EL element 400 having the conventional configuration and the organic EL element 100 according to the present embodiment is the thickness of the buffer layer (electronic block layer) 103.
[0091] 上述したように、従来の有機 EL素子 400は、ドープ層(正孔注入層) 102の方が、 電子ブロック機能を有するバッファ層(電子ブロック層) 103よりも厚い。これに対し、こ の発明の実施の形態の有機 EL素子 100は、バッファ層(電子ブロック層) 103の方が 、ドープ層(正孔注入層) 102よりもはるかに厚い。 [0091] As described above, in the conventional organic EL element 400, the doped layer (hole injection layer) 102 is thicker than the buffer layer (electron block layer) 103 having the electron blocking function. On the other hand, in the organic EL device 100 according to the embodiment of the present invention, the buffer layer (electron block layer) 103 is much thicker than the doped layer (hole injection layer) 102.
[0092] これにより、陰極 101b側から発光層 104内へ注入された電子力 発光層 104を透 過してバッファ層 103側へ移動することを防止することができるので、上述したように、 発光層 104内でのキャリアの再結合を有効におこなわせることができる。 [0092] This prevents the electron force light-emitting layer 104 injected from the cathode 101b side into the light-emitting layer 104 from moving to the buffer layer 103 side. Carrier recombination within layer 104 can be effectively performed.
[0093] ここで、通常は、高抵抗率のバッファ層(電子ブロック層) 103を膜厚化すると、抵抗 増加にともなう駆動電圧上昇が懸念されるが、発明者らはキャリアの注入がオーム性 であれば注入界面のキャリア蓄積が消失し、バッファ層(電子ブロック層) 103を膜厚 化しても電圧の上昇が小さ 、ことを見出して 、る。 [0093] Here, normally, when the thickness of the high-resistivity buffer layer (electronic block layer) 103 is increased, there is a concern that the drive voltage increases as the resistance increases. Then, it is found that the carrier accumulation at the injection interface disappears, and the increase in voltage is small even when the buffer layer (electron block layer) 103 is made thicker.
[0094] すなわち、この発明の実施の形態の有機 EL素子 100、 200、 300によれば、駆動 電圧の増加を抑制しながら、発光層 104、 204内でのキャリアの再結合を有効におこ なわせ、有機 EL素子 100、 200、 300を効率よく発光させることができる。 That is, according to the organic EL elements 100, 200, and 300 according to the embodiment of the present invention, recombination of carriers in the light emitting layers 104 and 204 is effectively performed while suppressing an increase in driving voltage. Therefore, the organic EL elements 100, 200, and 300 can emit light efficiently.
[0095] なお、図 5および図 6に示す有機 EL素子 100、 400においては、下部電極(陽極) 101aは ITOによって形成され、ドープ層(正孔注入層) 102は α— NPDに 4F— TC NQを電子受容性物質 (ァクセプター)として添加することによって形成され、バッファ 層(電子ブロック層) 103は α— NPDによって膜厚が Xnmとなるように形成されてい る。また、 ITOとドープ層(正孔注入層) 102との間には、 CuPcなどのバッファ層を用 いることができる。この場合、バッファ層(電子ブロック層) 103とドープ層(正孔注入層 ) 102の界面でトンネル注入が起こると考えられる。
[0096] (挙動の差異 (その 2) ) [0095] In the organic EL devices 100 and 400 shown in Figs. 5 and 6, the lower electrode (anode) 101a is formed of ITO, and the doped layer (hole injection layer) 102 is 4F-TC on α-NPD. It is formed by adding NQ as an electron accepting substance (acceptor), and the buffer layer (electron blocking layer) 103 is formed by α-NPD so that the film thickness becomes X nm. Further, a buffer layer such as CuPc can be used between ITO and the doped layer (hole injection layer) 102. In this case, it is considered that tunnel injection occurs at the interface between the buffer layer (electron block layer) 103 and the doped layer (hole injection layer) 102. [0096] (Difference in behavior (Part 2))
つぎに、この発明の実施の形態の有機 EL素子と従来の有機 EL素子との差異 (そ の 2)について、図 7および図 8を参照して説明する。ここでは、この発明の実施の形 態の有機 EL素子として、上述した図 3に示した第 3の実施の形態の有機 EL素子 30 0を用いて説明する。 Next, the difference (No. 2) between the organic EL element of the embodiment of the present invention and the conventional organic EL element will be described with reference to FIGS. Here, the organic EL element according to the third embodiment shown in FIG. 3 will be described as the organic EL element according to the embodiment of the present invention.
[0097] (従来の有機 EL素子の構造) [0097] (Conventional organic EL device structure)
図 7は、従来の有機 EL素子に対して、逆バイアス電圧をかけた場合のキャリアの挙 動を示す説明図である。以下に、従来の有機 EL素子について図 7を参照して説明 する。なお、図 7に示す従来の有機 EL素子 700において、上述した各実施の形態に おける有機 EL素子 100、 200、 300と同一部分は同一符号で示し、説明も省略する FIG. 7 is an explanatory diagram showing carrier behavior when a reverse bias voltage is applied to a conventional organic EL element. Hereinafter, a conventional organic EL element will be described with reference to FIG. In the conventional organic EL element 700 shown in FIG. 7, the same parts as those of the organic EL elements 100, 200, and 300 in the above-described embodiments are denoted by the same reference numerals, and the description thereof is omitted.
[0098] 従来の有機 EL素子 700は、基板 106と、電極対 201aおよび 201bと、正孔注入輸 送層 301、発光層 204、正孔ブロック層 302、電子注入層 303と、を備える。従来の 有機 EL素子 700は、基板 106、下部電極(陽極) 201a、正孔注入輸送層 301と、発 光層 204と、正孔ブロック層 302と、電子注入層 303、上部電極(陰極) 201b、の順 に、各構成を順次積層した構造を有している。従来の有機 EL素子 700では、電子注 入層(ドープ層) 303の膜厚が、正孔ブロック層(バッファ層) 302の膜厚よりも厚い。 A conventional organic EL element 700 includes a substrate 106, electrode pairs 201 a and 201 b, a hole injection / transport layer 301, a light emitting layer 204, a hole blocking layer 302, and an electron injection layer 303. A conventional organic EL device 700 includes a substrate 106, a lower electrode (anode) 201a, a hole injection transport layer 301, a light emitting layer 204, a hole blocking layer 302, an electron injection layer 303, and an upper electrode (cathode) 201b. In this order, each structure is sequentially stacked. In the conventional organic EL element 700, the thickness of the electron injection layer (dope layer) 303 is larger than the thickness of the hole blocking layer (buffer layer) 302.
[0099] 図 8は、この発明の実施の形態の有機 EL素子 300に対して、逆バイアスをかけた 場合のキャリアの挙動を示す説明図である。以下に、従来の有機 EL素子 700および この発明の実施の形態の有機 EL素子 300に対して、それぞれ逆バイアス電圧をか けた場合の挙動の差異について、図 7および図 8を参照して説明する。 FIG. 8 is an explanatory view showing the behavior of carriers when a reverse bias is applied to the organic EL element 300 according to the embodiment of the present invention. Hereinafter, differences in behavior when a reverse bias voltage is applied to the conventional organic EL element 700 and the organic EL element 300 according to the embodiment of the present invention will be described with reference to FIG. 7 and FIG. .
[0100] 図 7および図 8には、従来の有機 EL素子 700および有機 EL素子 300に対して逆 ノィァス電圧をかけた場合、どの層にキャリアが多く蓄積しているか力 模式的に示さ れている。図 7および図 8から分力るように、従来および本実施の形態の構成の有機 EL素子 700、 300は、いずれも「下部電極 Z正孔注入輸送層 Z発光層 Z正孔ブロ ック層 Z電子注入層 Z上部電極」(符号省略)という素子構造を有している。従来の 構成の有機 EL素子 700と、本実施の形態の有機 EL素子 300との構成の違いは、正 孔ブロック層 302の厚さである。
[0101] 従来の構成の有機 EL素子 700は、ドープされた電子注入層 303が厚ぐドープさ れた電子注入層 303と正孔ブロック層 302との厚さの関係はドープされた電子注入 層 303の方が正孔ブロック層 302よりも厚い。これに対し、本実施の形態の有機 EL 素子 300は、正孔ブロック層 302の方が電子注入層 303よりもはるかに厚い。 [0100] FIGS. 7 and 8 schematically show in which layer a large amount of carriers are accumulated when a reverse noise voltage is applied to the conventional organic EL element 700 and the organic EL element 300. Yes. As can be seen from FIG. 7 and FIG. 8, the organic EL elements 700 and 300 of the configuration of the conventional and the present embodiment are both “lower electrode Z hole injection transport layer Z light emitting layer Z hole block layer”. It has an element structure of “Z electron injection layer Z upper electrode” (reference numeral omitted). The difference in configuration between the organic EL element 700 having the conventional configuration and the organic EL element 300 according to the present embodiment is the thickness of the hole blocking layer 302. [0101] The organic EL element 700 having a conventional configuration has a thickness relationship between the doped electron injection layer 303 and the hole blocking layer 302 that are thicker than the doped electron injection layer 303. 303 is thicker than the hole blocking layer 302. In contrast, in the organic EL element 300 of the present embodiment, the hole blocking layer 302 is much thicker than the electron injection layer 303.
[0102] これにより、上部電極 201bから注入された電子を電子注入層 303によって効率よく 発光層 204側へ注入するとともに、下部電極(陽極) 201aから注入された正孔が発 光層 204を透過してバッファ層 302側へ移動することを防止することができるので、上 述したように、発光層 204内でのキャリアの再結合を有効におこなわせることができる [0102] Thereby, electrons injected from the upper electrode 201b are efficiently injected into the light emitting layer 204 side by the electron injection layer 303, and holes injected from the lower electrode (anode) 201a are transmitted through the light emitting layer 204. As a result, it is possible to effectively recombine carriers in the light emitting layer 204 as described above.
[0103] すなわち、この発明の実施の形態の有機 EL素子 100、 200、 300によれば、駆動 電圧の増加を抑制しながら、発光層 104、 204内でのキャリアの再結合を有効におこ なわせ、有機 EL素子 100、 200、 300を効率よく発光させることができる。 That is, according to the organic EL elements 100, 200, and 300 of the embodiment of the present invention, recombination of carriers in the light emitting layers 104 and 204 is effectively performed while suppressing an increase in driving voltage. Therefore, the organic EL elements 100, 200, and 300 can emit light efficiently.
[0104] (第 4の実施の形態) [Fourth embodiment]
図 9は、第 4の実施の形態における自発光パネルの一例を示す断面図である。つぎ に、第 4の実施の形態の自発光パネルについて図 9を参照して説明する。第 4の実施 の形態における自発光パネル 900は、図 1に示した有機 EL素子 100が、基板 106 上で複数マトリクス状に配列された構成を有している。 FIG. 9 is a cross-sectional view showing an example of a self-luminous panel in the fourth embodiment. Next, a self-luminous panel according to a fourth embodiment will be described with reference to FIG. A self-luminous panel 900 according to the fourth embodiment has a configuration in which a plurality of organic EL elements 100 shown in FIG.
[0105] 自発光パネル 900は、複数の陽極 101aで形成するデータラインと複数の陰極 101 bで形成する走査ラインが互いに直交し、表示データを表示するパッシブ駆動型の自 発光パネルでも良ぐ陽極 101aと駆動トランジスタを接続した構成を有するァクティ ブ駆動型の自発光パネルでも構わな 、。 [0105] The self-light-emitting panel 900 may be a passive-drive self-light-emitting panel that displays display data because the data lines formed by the plurality of anodes 101a and the scanning lines formed by the plurality of cathodes 101b are orthogonal to each other. An active drive type self-luminous panel having a configuration in which 101a and a drive transistor are connected may be used.
[0106] 自発光パネル 900では、各有機 EL素子 100が備える陽極 101aに印加する電圧を 、有機 EL素子 100毎に制御することによって、有機 EL素子 100単位で発光 Z非発 光を制御することができる。マトリクス状に配置された各有機 EL素子 100の発光 Z非 発光を個々に制御する技術については、公知の技術であるため、その説明は省略す る。図 9中、符号 901は、陽極 101a間を絶縁する絶縁部材である。 [0106] In the self-luminous panel 900, the voltage applied to the anode 101a of each organic EL element 100 is controlled for each organic EL element 100, thereby controlling the emission Z non-emission in units of 100 of the organic EL elements. Can do. Since the technique for individually controlling the light emission Z non-light emission of each organic EL element 100 arranged in a matrix is a known technique, the description thereof is omitted. In FIG. 9, reference numeral 901 denotes an insulating member that insulates the anodes 101a.
[0107] 図 10は、従来の有機 EL素子 400を備える自発光パネルの一例を示す断面図であ る。以下に、従来の有機 EL素子 400を備える自発光パネル 1000と第 4の実施の形
態における自発光パネル 900との差異について説明する。従来の有機 EL素子 400 を備える自発光パネル 1000において、たとえば、有機 EL素子 Aを発光させ、有機 E L素子 Bを消灯させる場合、有機 EL素子 Aに相当する陽極 (以降、必要に応じて陽 極 Aとする) 101aに、陽極 101aと陰極 101bとの間に V (V >0、かつ、 Vは閾電圧 FIG. 10 is a cross-sectional view showing an example of a self-luminous panel including the conventional organic EL element 400. The following is a description of a self-luminous panel 1000 having a conventional organic EL element 400 and a fourth embodiment. Differences from the self-luminous panel 900 in the state will be described. In the self-luminous panel 1000 having the conventional organic EL element 400, for example, when the organic EL element A emits light and the organic EL element B is extinguished, an anode corresponding to the organic EL element A (hereinafter, positive electrode is used as necessary). A) 101a and V between anode 101a and cathode 101b (V> 0, where V is the threshold voltage)
A A A A A A
より大き ヽ)の電位差を発生させる電圧を印加する。 Apply a voltage that generates a larger potential difference ヽ).
[0108] 有機 EL素子 Bに相当する陽極 (以降、必要に応じて陽極 Bとする) 101aには、陰 極 101bと等電位 (すなわち、 V =0)、または、閾電圧以下の順バイアス電圧、ある [0108] The anode corresponding to the organic EL element B (hereinafter referred to as anode B if necessary) 101a has the same potential as the negative electrode 101b (ie, V = 0) or a forward bias voltage equal to or lower than the threshold voltage. ,is there
B B
いは陰極 101bに対して V (Vく 0)となる逆バイアス電圧を印加する。このとき、陽極 Alternatively, a reverse bias voltage of V (V <0) is applied to the cathode 101b. At this time, the anode
B B B B
Aと陽極 Bの間の電位差は V -Vである。 The potential difference between A and anode B is V -V.
A B A B
[0109] 本来、陽極 Aおよび陽極 Bに印加する電圧をこのように制御することにより、有機 EL 素子 Aのみが発光する。しかしながら、ドープ層 102が導電性を有する場合、陽極 A と陽極 Bはドープ層 102を介して電気的に接続されてしまい、陽極 Aと陽極 B間の抵 抗および V -Vに応じた横方向の漏れ電流が発生し、有機 EL素子 Aと有機 EL素 [0109] Originally, only the organic EL element A emits light by controlling the voltage applied to the anode A and the anode B in this way. However, when doped layer 102 is conductive, anode A and anode B are electrically connected through doped layer 102, and the resistance between anode A and anode B and the lateral direction according to V-V Leakage current occurs, and organic EL element A and organic EL element
A B A B
子 Bの間や有機 EL素子 Bが発光してしまう。 The light is emitted between the child B and the organic EL element B.
[0110] 図 11は、自発光パネル 900または 1000における有機 EL素子 100または 400の配 列を示す平面図である。図 11と上述した図 10とを参照して、隣り合う有機 EL素子 A から有機 EL素子 Bへ漏れる漏れ電流について説明する。まず、陽極 Aと陽極 Bとの 間の抵抗を R [ Ω ]とした場合、抵抗 R は、下記の(1)式によって表される。 FIG. 11 is a plan view showing the arrangement of the organic EL elements 100 or 400 in the self-luminous panel 900 or 1000. FIG. The leakage current that leaks from the adjacent organic EL element A to the organic EL element B will be described with reference to FIG. 11 and FIG. 10 described above. First, when the resistance between the anode A and the anode B is R [Ω], the resistance R is expressed by the following equation (1).
AB AB AB AB
[0111] [数 1] [0111] [Equation 1]
RAB ? [Ω] …( R AB? [Ω]… (
t x l t x l
ただし However,
P:ドープ層の抵抗率 [ Q . cm] P: Resistivity of doped layer [Q.cm]
d :隣接する有機 EL素子間の距離 [ cm ] t :ドープ層の膜厚 [ cm ] d: Distance between adjacent organic EL elements [cm] t: Thickness of doped layer [cm]
I:有機 EL素子の長さ寸法 [ cm ]
[0112] 陽極 Aから陽極 Bへ流れ込む電流 (漏れ電流) I [A]は、(1)式を用いて、下記の( I: Length of organic EL element [cm] [0112] The current flowing from anode A to anode B (leakage current) I [A] is calculated using the following equation (1):
AB AB
2)式によって表される。 It is expressed by equation (2).
[0113] [数 2] [0113] [Equation 2]
X _ ABX_AB
ΑΒ ΑΒ
P d P d
: VAB ' 1 : VAB '1
d P d P
= ^ ( σ) [A] 〜(2) = ^ (σ) [A] ~ (2)
a a
ただし However,
VAB :陽極 A- Bの電位差 [V] V AB: Potential difference between anodes A and B [V]
び:ドーブ層の導電率 [Sん m] B: Dove layer conductivity [Sm]
[0114] (2)式より、有機 EL素子 Aから隣接する有機 EL素子 Bへ漏れる電流の量は、ドー プ層 102の膜厚 tと、ドープ層 102における導電率 σと、に比例することが分かる。導 電率 σは、抵抗率 ρの逆数で表される。すなわち、(2)式より、隣接する有機 EL素 子 Α力 有機 EL素子 Βへの漏れ電流の発生を抑制するためには、ドープ層 102の 膜厚 tを薄くするカゝドープ層 102における導電率 σを低く抑えるカゝ、という対応を取る 必要がある。 [0114] From equation (2), the amount of current leaking from the organic EL element A to the adjacent organic EL element B is proportional to the film thickness t of the doped layer 102 and the conductivity σ of the doped layer 102. I understand. The conductivity σ is expressed as the reciprocal of the resistivity ρ. In other words, from equation (2), in order to suppress the occurrence of leakage current to the adjacent organic EL element Α, the conductivity in the cadmium doped layer 102 is reduced. It is necessary to take measures to keep the rate σ low.
[0115] 漏れ電流 I [Α]が上記の(2)式によって表される場合、有機 EL素子 Βにおける輝 [0115] When the leakage current I [Α] is expressed by the above equation (2), the brightness in the organic EL device Β
ΑΒ ΑΒ
度 Lは、下記(3)式によって表される。 The degree L is expressed by the following equation (3).
Β Β
4 VAB t 4 VAB t
= 10" x a = 10 "x a
P d - w P d-w
ただし However,
a:有機 EL素子の電流輝度効率 [Gd/A] a: Current luminance efficiency of organic EL elements [ G d / A]
SB :有機 EL素子 Bの面積 [cm2] S B: Area of organic EL element B [cm 2 ]
w :有機 EL素子の幅寸法 [cm] w: Width of organic EL element [cm]
A=104 x (定数) A = 10 4 x (constant)
[0117] (3)式中、 104は、 cm単位系力も m単位系への面積変換係数である。(3)式におい て、ドープ層 102における導電率 σと抵抗率 pとの関係は、 lZ /o [ Ω ' cm] = σ [S Zcm]である。なお、 Sは、電気抵抗 [ Ω ]の逆数で表されるコンダクタンスの単位 (ジ 一メンス)である。 [0117] In the equation (3), 10 4 is the area conversion coefficient of the cm unit system force to the m unit system. In the equation (3), the relationship between the conductivity σ and the resistivity p in the doped layer 102 is lZ / o [Ω ′ cm] = σ [S Zcm]. S is a unit of conductance expressed as the reciprocal of electrical resistance [Ω].
[0118] (3)式からも、有機 EL素子 Βにおける輝度 Lを低く抑えるには、ドープ層 102の膜 [0118] Also from equation (3), in order to keep the luminance L in the organic EL element Β low, the film of the doped layer 102
Β Β
厚 tを薄くする力ドープ層 102における導電率 σを低く抑える力、という対応を取る必 要があることが分かる。 F4— TCNQを VOPcにドープした場合の導電率 σの変化は 、たとえば、 Applied Physics Letters, Volume73, No. 22, 3202 (1998) , M . Pfeifferらにおける FIG. 1 (a)に記載されている。 It can be seen that it is necessary to take measures to reduce the electrical conductivity σ in the force-doped layer 102 that reduces the thickness t. F4—Changes in conductivity σ when TCNQ is doped into VOPc are described, for example, in FIG. 1 (a) in Applied Physics Letters, Volume 73, No. 22, 3202 (1998), M. Pfeiffer et al. .
[0119] ところで、たとえば、 p型有機半導体の層を得るために、有機 EL素子 100において 電子受容性物質をドープしたドープ層 102を設けることは、(3)式における σを大きく することと同意である。すなわち、ノ ッファ層 103よりもドープ層 102の膜厚の方が大 きく形成されている従来の有機 EL素子 400を備える自発光パネル 1000では、有機
EL素子 Bにおける輝度が高くなる傾向にあると言える。 [0119] By the way, for example, to obtain a p-type organic semiconductor layer, providing the doped layer 102 doped with an electron-accepting substance in the organic EL element 100 agrees with increasing σ in the equation (3). It is. In other words, in the self-luminous panel 1000 including the conventional organic EL element 400 in which the thickness of the doped layer 102 is larger than that of the nofer layer 103, It can be said that the luminance of EL element B tends to increase.
[0120] また、陽極 101aからの正孔注入率を向上させるために電子受容性物質をドープす ることにより、ドープ層 102における電子ブロック性能が低下し、有機 EL素子 Aにお ける輝度が低下してしまう。 [0120] Also, by doping the electron-accepting substance to improve the hole injection rate from the anode 101a, the electron blocking performance in the doped layer 102 is lowered, and the luminance in the organic EL element A is lowered. Resulting in.
[0121] これに対し、第 1の実施の形態の有機 EL素子 100では、電子受容性物質がドープ されたドープ層 102と、電子輸送性が低ぐかつホール輸送性を有するがキャリア密 度の低いバッファ層 103と、を備え、かつ、抵抗率が低い(たとえば I X 105 Ω 'cm程 度)ドープ層 102の膜厚よりも抵抗率が高 ^ (1 Χ 1Ο10Ω · cm以上)バッファ層 103の 膜厚の方が大き 、ため、発光層 104からのドープ層 102への電子の流入を防止して 発光層 104に対する正孔注入効率の向上を図るとともに、隣接する画素への横方向 の漏れ電流の発生を防止することができる。 [0121] In contrast, in the organic EL device 100 of the first embodiment, the doped layer 102 doped with the electron-accepting substance and the low electron transport property and the hole transport property, but the carrier density is low. A low buffer layer 103 and a low resistivity (for example, about IX 10 5 Ω 'cm) and a higher resistivity than the thickness of the doped layer 102 ^ (1 Χ 1Ο 10 Ω · cm or more) Since the film thickness of the layer 103 is larger, the inflow of electrons from the light emitting layer 104 to the doped layer 102 is prevented to improve the hole injection efficiency to the light emitting layer 104, and the lateral direction to the adjacent pixels The generation of leakage current can be prevented.
[0122] これによつて、駆動電圧の低下、および、有機 EL素子 Aにおける輝度低下の防止 の両立を図ることができる。また、有機 EL素子 Aからの漏れ電流の発生を防止し、有 機 EL素子 Aにおける画素のにじみ発光を防止することによって、自発光パネル 100 0における表示不良を回避し、鮮明な表示を行うことができる。 [0122] This makes it possible to achieve both reduction in drive voltage and prevention of reduction in luminance in the organic EL element A. In addition, by preventing the occurrence of leakage current from the organic EL element A and preventing pixel bleeding in the organic EL element A, it is possible to avoid display defects in the self-luminous panel 1000 and perform a clear display. Can do.
[0123] 第 1の実施の形態の有機 EL素子 100は、公知の各種技術を用いて製造することが できる。たとえば、ドープ層 102, ノ ッファ層 103あるいは発光層 104は、抵抗加熱真 空成膜法を用いることによって成膜することができる。すなわち、本実施の形態の有 機 EL素子 100は、従来の有機 EL素子の製造方法と比較して格別な変更を行うこと なく製造することができる。従来の有機 EL素子の製造方法については、公知の技術 であるため、説明を省略する。 [0123] The organic EL device 100 of the first embodiment can be manufactured using various known techniques. For example, the doped layer 102, the nofer layer 103, or the light emitting layer 104 can be formed by using a resistance heating vacuum film forming method. That is, the organic EL element 100 of the present embodiment can be manufactured without any particular change compared to the conventional method for manufacturing an organic EL element. Since a conventional method for manufacturing an organic EL element is a known technique, a description thereof will be omitted.
[0124] (ドープ層およびバッファ層の膜厚と駆動電圧との関係) [0124] (Relationship between film thickness of doped layer and buffer layer and driving voltage)
図 12は、ドープ層およびバッファ層の膜厚と駆動電圧との関係を示すグラフである 。つぎに、ドープ層およびバッファ層の膜厚と駆動電圧との関係について説明する。 なお、ここでは、上述した第 1の実施の形態で説明した有機 EL素子 100を例にして 説明する。 FIG. 12 is a graph showing the relationship between the film thickness of the doped layer and the buffer layer and the driving voltage. Next, the relationship between the film thickness of the doped layer and the buffer layer and the drive voltage will be described. Here, the organic EL element 100 described in the first embodiment will be described as an example.
[0125] 上述した第 1の実施の形態における有機 EL素子 100のように、ノ ッファ層 103を厚 膜ィ匕することによる第 1の効果は、電極間(陽極 101aと陰極 101bとの間)のショート
を防止することである。ここで、図 13および図 14は、ノ ッファ層 103を厚膜ィ匕すること による効果について説明する説明図(その 1)、(その 2)である。 [0125] Like the organic EL element 100 according to the first embodiment described above, the first effect obtained by thickening the nofer layer 103 is between the electrodes (between the anode 101a and the cathode 101b). Short Is to prevent. Here, FIG. 13 and FIG. 14 are explanatory views (No. 1) and (No. 2) for explaining the effect of thickening the notfer layer 103. FIG.
[0126] 真空蒸着を用いてバッファ層 103を成膜する有機 EL素子 100において、図 13に 示すように基板 106上に異物 1301が存在したり、図 14に示すように変化率の激 ヽ 凹凸部 1401が存在したりする場合、蒸着された有機層 103の膜厚が薄い部分が発 生する。このような膜厚が薄い部分では、ノ ッファ層 103の耐厚が低下する。この場 合、電極間(101aと 101bとの間)に電圧を印加すると、局所的に耐圧が低下した部 分が絶縁破壊し、ショート不良が発生する。 [0126] In the organic EL device 100 in which the buffer layer 103 is formed by vacuum evaporation, the foreign matter 1301 exists on the substrate 106 as shown in FIG. 13, or the rate of change is extremely uneven as shown in FIG. When the portion 1401 is present, a thin portion of the deposited organic layer 103 is generated. In such a thin portion, the thickness resistance of the notfer layer 103 is lowered. In this case, when a voltage is applied between the electrodes (between 101a and 101b), the portion where the breakdown voltage is locally reduced breaks down and a short circuit occurs.
[0127] ノ ッファ層 103を十分に厚い膜厚にした場合、最も弱い部分の耐圧性も向上し、シ ョート不良発生率を低減できることがわ力 ている。一般的な有機材料は高抵抗率で あるため、そのまま厚膜ィ匕した場合、駆動電圧が上昇してしまう。上述した特許文献 3 では、導電性を有するドープ層を厚膜化しており、ドープ層の厚膜化に伴う電圧上昇 を防ぐことが記載されて 、る。 [0127] When the noffer layer 103 is made sufficiently thick, the pressure resistance of the weakest part is improved, and the short-circuit failure rate can be reduced. Since a general organic material has a high resistivity, when a thick film is formed as it is, a driving voltage increases. Patent Document 3 described above describes that the conductive doped layer is thickened to prevent voltage increase due to thickening of the doped layer.
[0128] しかしながら、導電性の膜を厚膜ィ匕することは、上述したように、横方向の絶縁性を 低下させることにつながる。発明者は、実験の結果、導電性の高いドープ層を 10nm 程度挿入することで、導電性の低!ヽ正孔輸送層を厚膜化しても駆動電圧に変化がな いことを発見した。 [0128] However, increasing the thickness of the conductive film leads to a decrease in lateral insulation as described above. As a result of the experiment, the inventor has found that the drive voltage does not change even when the thickness of the low-conductivity hole transport layer is increased by inserting a highly conductive doped layer of about 10 nm.
[0129] [表 1] [0129] [Table 1]
表 1 table 1
表 1は、ドープ層 102およびバッファ層 103の膜厚を、それぞれ複数段階に振り分 けた場合における、有機 EL素子 100を用いた自発光パネル 900の駆動電圧を示し ている。表 1から分力るように、ドープ層 102がない場合 (X=Onm)を除き、ドープ層 102の厚さが一定であれば、ノ ッファ層 103の膜厚を複数段階に振り分けた場合に
も、駆動電圧に大きな変化は見られない。表 1からは、ドープ層 102がない場合 (X= Onm)、バッファ層 103の膜厚の変化は、駆動電圧の変動をもたらすことも分かる。 Table 1 shows driving voltages of the self-luminous panel 900 using the organic EL element 100 when the film thicknesses of the doped layer 102 and the buffer layer 103 are divided into a plurality of stages. As shown in Table 1, unless the doped layer 102 is present (X = Onm), if the doped layer 102 has a constant thickness, the thickness of the notched layer 103 is divided into multiple stages. However, there is no significant change in the driving voltage. From Table 1, it can also be seen that in the absence of the doped layer 102 (X = Onm), a change in the thickness of the buffer layer 103 causes a change in drive voltage.
[0131] これにより第 1の実施の形態の有機 EL素子 100を用いた自発光パネル 900によれ ば、導電性を低く抑えながら、駆動電圧の上昇を招くことなぐかつ、電極間ショート 不良の発生率を低減することができる。 [0131] Thus, according to the self-luminous panel 900 using the organic EL element 100 of the first embodiment, the drive voltage is not increased while the conductivity is kept low, and the short circuit between the electrodes is generated. The rate can be reduced.
[0132] ノ ッファ層 103を厚膜ィ匕することによる第 2の効果は、光学的干渉を有効に利用で きることである。一般的に、有機 EL素子 100の全体での厚さは、可視光線の波長の 数分の 1程度である。有機 EL素子 100における発光層 104からの発光は、導電性酸 化物や金属によって形成された陽極 101aや陰極 101b、基板 106、積層された各層 の各々の界面からの反射光と放射光との干渉などによって、発光効率が大きく変化 する。 [0132] The second effect of thickening the noffer layer 103 is that optical interference can be used effectively. In general, the total thickness of the organic EL element 100 is about a fraction of the wavelength of visible light. Light emission from the light emitting layer 104 in the organic EL element 100 is caused by interference between reflected light and radiated light from the interfaces of the anode 101a and the cathode 101b formed of a conductive oxide or metal, the substrate 106, and each of the stacked layers. As a result, the luminous efficiency changes greatly.
[0133] 電極対 101を構成する一方の電極が透明または半透明で、もう一方の電極が高反 射性を有する素子構造では、発光層 104を狭持する反射面の反射率がアンバランス な弱い微小光学共振器として働く。厳密には、多層積層体の干渉解析を、光源が積 層体中に内在する場合にっ 、ておこなえばょ 、。 [0133] In an element structure in which one electrode constituting the electrode pair 101 is transparent or translucent and the other electrode has high reflectivity, the reflectance of the reflecting surface holding the light emitting layer 104 is unbalanced. Works as a weak micro-optical resonator. Strictly speaking, if the interference analysis of a multilayer stack is carried out when the light source is inherent in the stack, then.
[0134] 双方の電極の反射率が高かったり、明示的に素子中に高反射となったりする部位 を設けた場合は強い (Q値の高い)光学共振器となり、共振器中の発光点の位置によ らず、特定の波長を増強することができる。この場合の共振条件は、おおまかに下記 (4)式によって表される。 [0134] When a portion where both electrodes have a high reflectivity or a high reflection factor is explicitly provided in the element, a strong (high Q) optical resonator is formed, and the light emitting point in the resonator is reduced. Regardless of the position, a specific wavelength can be enhanced. The resonance condition in this case is roughly expressed by the following equation (4).
[0135] [数 4] [0135] [Equation 4]
2ηά = λ(νη - Φ / 2π) ,mは正の整数 ■■■ (4) 2ηά = λ (νη-Φ / 2π), m is a positive integer ■■■ (4)
ただし However,
n :光が透過する層の屈折率 n: Refractive index of the layer through which light passes
d:光が透過する層の合計の厚さ d: Total thickness of the layer through which light passes
Φ:光が反射される反射面での位相変化の合計 Φ: Total phase change at the reflecting surface where light is reflected
[0136] 光学的干渉の調整は、透明電極などの導電性の層の膜厚で行えば、表示素子の
駆動電圧への影響は少ない。表示パネルの全面が同一色で発光する場合などは透 明電極の膜厚で光学的干渉を最適化することが出来る。一方、同一表示パネル上に 多色が存在する場合、発光色毎に光学的干渉を最適とする膜厚が異なる。同一基 板上で透明電極の膜厚を部位ごとに変えるのは、工程が増えるために望ましくはな い。そこで発光色ごとに成膜される素子部の膜厚で光学調整を行う必要がある。 [0136] The optical interference can be adjusted by adjusting the film thickness of a conductive layer such as a transparent electrode. The influence on the driving voltage is small. When the entire surface of the display panel emits light with the same color, the optical interference can be optimized by the thickness of the transparent electrode. On the other hand, when multiple colors exist on the same display panel, the film thickness that optimizes optical interference differs for each emission color. Changing the film thickness of the transparent electrode for each part on the same substrate is not desirable because it increases the number of processes. Therefore, it is necessary to perform optical adjustment with the film thickness of the element portion formed for each emission color.
[0137] (4)式より、光学的な最適化を図るために、一般的な有機 EL素子におけるいずれ 力ゝの膜厚を増加させた場合、膜厚増加に伴って当該有機 EL素子における抵抗が増 加することが分かる。抵抗が増加することにより、駆動電圧が上昇し、有機 EL素子に おける電力発光効率が低下してしまう。このように、従来の有機 EL素子では、光学的 な最適化を図るための膜厚の増加と、駆動電圧の低下と、を両立させることが困難で ある。 [0137] From equation (4), in order to achieve optical optimization, when increasing the film thickness of a general organic EL element, the resistance in the organic EL element increases as the film thickness increases. It can be seen that increases. As the resistance increases, the drive voltage increases and the power emission efficiency of the organic EL element decreases. Thus, it is difficult for conventional organic EL devices to achieve both an increase in film thickness for optical optimization and a decrease in drive voltage.
[0138] ここで、図 15は、それぞれ構成が異なる 3種類の有機 EL素子の構造を示す模式図 である。図 15中、(a)および (b)は従来の有機 EL素子の構造を例示しており、(c)は 第 1の実施の形態における有機 EL素子 100の構造をそれぞれ示している。 (a)に示 す有機 EL素子 1510は、有機 EL素子 100と比較して、ドープ層 102を有していない 点が異なる。(b)に示す有機 EL素子 1520は、有機 EL素子 100と比較して、ノ ッファ 層 103を有して 、な 、点が異なる。 Here, FIG. 15 is a schematic diagram showing the structures of three types of organic EL elements having different configurations. In FIG. 15, (a) and (b) exemplify the structure of a conventional organic EL element, and (c) shows the structure of the organic EL element 100 in the first embodiment. The organic EL element 1510 shown in (a) is different from the organic EL element 100 in that it does not have the doped layer 102. The organic EL element 1520 shown in (b) is different from the organic EL element 100 in that the organic EL element 1520 has a nofer layer 103.
[0139] [表 2] [0139] [Table 2]
表 2 Table 2
(馬区動電流フ .SmA/cm2) 表 2は、図 15に示す各有機 EL素子 1510, 1520, 100における各層の膜厚や一 定の電流密度における駆動電圧、発光量を示している。表 2から分力るように、第 1の 実施の形態の有機 EL素子 100では、バッファ層 103の膜厚を 5〜100nmの範囲で
変更した場合にも、駆動電圧に大きな変化が見られないことが分かる。すなわち、第 1の実施の形態の有機 EL素子 100によれば、発光効率の向上を図るためにバッファ 層 103の膜厚を調整した場合にも、駆動電圧を増加させることがない。さらに、干渉 スペクトルを調整することで、発光スペクトルを調整することもできる。 (Horse-ku dynamic current off .sma / cm 2) Table 2, the driving voltage at a current density of each layer of film thickness and a constant of each organic EL element 1510, 1520, 100 shown in FIG. 15 shows a light emission amount . As shown in Table 2, in the organic EL element 100 according to the first embodiment, the buffer layer 103 has a film thickness in the range of 5 to 100 nm. It can be seen that there is no significant change in the drive voltage even when the change is made. That is, according to the organic EL element 100 of the first embodiment, the drive voltage is not increased even when the thickness of the buffer layer 103 is adjusted in order to improve the light emission efficiency. Furthermore, the emission spectrum can be adjusted by adjusting the interference spectrum.
[0141] このように、第 1の実施の形態の有機 EL素子 100は、電子受容性物質がドープさ れたドープ層 102と、電子受容性物質がドープされていないバッファ層 103と、を備 えるため、ドープ層 102に電子受容性物質をドープすることで駆動電圧の低下を実 現するとともに、バッファ層 103の膜厚を調整することで発光効率の向上を図ることが でき、さらにバッファ層 103を厚膜にすることで、駆動電圧を維持しながら電極間ショ ート不良の少ないディスプレイを得ることができる。 As described above, the organic EL device 100 according to the first embodiment includes the doped layer 102 doped with the electron-accepting material and the buffer layer 103 not doped with the electron-accepting material. Therefore, the doped layer 102 is doped with an electron-accepting substance to reduce the driving voltage, and by adjusting the film thickness of the buffer layer 103, the luminous efficiency can be improved. By making the film 103 thick, it is possible to obtain a display with little short-circuit failure between electrodes while maintaining the driving voltage.
[0142] これにより、従来の有機 EL素子 400を備える自発光パネル 1000のように、漏れ電 流が発生することによって表示画像のエッジが不鮮明となるなどの表示不良を発生さ せることがない。 [0142] Thus, unlike the self-luminous panel 1000 including the conventional organic EL element 400, a display defect such as an edge of a display image becoming unclear due to the occurrence of a leakage current does not occur.
[0143] なお、ここでは、第 1の有機 EL素子 100を例にして、その効果について説明したが 、これに限るものではない。第 2の実施の形態の有機 EL素子 200における電子プロ ック層 203、あるいは、第 3の実施の形態の有機 EL素子 300における正孔ブロック層 302を厚膜ィ匕しても同様の効果を得ることができる。 [0143] Here, the effects of the first organic EL element 100 have been described by way of example, but the present invention is not limited to this. Even if the electron blocking layer 203 in the organic EL device 200 of the second embodiment or the hole blocking layer 302 in the organic EL device 300 of the third embodiment is thickened, the same effect is obtained. Obtainable.
[0144] (有機 EL素子のダイオード特性) [0144] (Diode characteristics of organic EL elements)
図 16は、有機 EL素子に順バイアス電圧をかけた後逆バイアス電圧をかけた場合 のダイオード特性を示すグラフである。つぎに、有機 EL素子に順バイアス電圧をかけ た後逆バイアス電圧をかけた場合のダイオード特性について図 16を参照して説明す る。ここでは、第 2の実施の形態の有機 EL素子 200と、図 7に示した従来の有機 EL 素子 700を例にして説明する。 FIG. 16 is a graph showing diode characteristics when a forward bias voltage is applied to an organic EL element and then a reverse bias voltage is applied. Next, the diode characteristics when a forward bias voltage is applied to the organic EL element and then a reverse bias voltage is applied will be described with reference to FIG. Here, the organic EL element 200 of the second embodiment and the conventional organic EL element 700 shown in FIG. 7 will be described as an example.
[0145] ここでは、第 2の実施の形態の有機 EL素子 200および従来の有機 EL素子 700に おける発光層 204が Alqによって形成され、電子注入輸送層 205が LiFによって形 成され、上部電極(陰極) 201bが A1によって形成されて 、る場合にっ 、て説明する 。このような有機 EL素子 200、 700に対して、それぞれ、順バイアス電圧を印加した 後に、逆バイアス電圧を印加し、そのときのダイオード特性を調べた。図 16は、その
結果を示している。 Here, the light emitting layer 204 in the organic EL device 200 of the second embodiment and the conventional organic EL device 700 is formed of Alq, the electron injection transport layer 205 is formed of LiF, and the upper electrode ( The case where the cathode 201b is formed of A1 will be described. For each of these organic EL devices 200 and 700, a forward bias voltage was applied and then a reverse bias voltage was applied, and the diode characteristics at that time were examined. Figure 16 shows that Results are shown.
[0146] 図 16から分かるように、電子ブロック層 203の膜厚 Xが X= 5〜50nmの範囲にお いては、逆バイアス耐圧が非常に悪ぐ—IV程度であることが分かる。これに対し、 第 2の実施の形態の有機 EL素子 200のように、膜厚を lOOnmまで大きくした場合、 逆バイアス耐圧が改善し、 - 5V程度まで回復して 、ることが分かる。 As can be seen from FIG. 16, in the range where the film thickness X of the electron block layer 203 is X = 5 to 50 nm, the reverse bias withstand voltage is very bad, which is about IV. In contrast, when the film thickness is increased to lOOnm as in the case of the organic EL element 200 of the second embodiment, the reverse bias withstand voltage is improved and recovered to about −5V.
[0147] なお、第 2の実施の形態においては、下部電極(陽極) 201aと発光層 204との間に ドープされた正孔注入層 202、および、電子ブロック層 203を備える構成の有機 EL 素子 200に関しての漏れ電流抑制効果について示した力 さらに、上部電極(陰極) 20 lbと発光層 204との間にドープされた電子注入層および正孔ブロック層を備える 構成の有機 EL素子(図 18参照)に関しての漏れ電流抑制効果についても同様の効 果が期待できる。 In the second embodiment, an organic EL device having a structure including a doped hole injection layer 202 and an electron blocking layer 203 between a lower electrode (anode) 201a and a light emitting layer 204 Forces shown for leakage current suppression effect for 200 In addition, an organic EL device with a structure including an electron injection layer and a hole blocking layer doped between 20 lb of the upper electrode (cathode) and the light emitting layer 204 (see FIG. 18) The same effect can be expected for the leakage current suppression effect for
[0148] 以上説明したように、第 2の実施の形態によれば、下部電極(陽極) 201aと発光層 204との間にドープされた正孔注入層 202を設けることによって、駆動電圧の低下を 図ることができる。また、第 2の実施の形態によれば、ドープされた正孔注入層 202と 発光層 204との間に電子ブロック層(バッファ層) 203を厚く設けることによって、駆動 電圧の上昇を伴うことなくドープされた正孔注入層 202と発光層 204との距離を確保 することができる。 As described above, according to the second embodiment, by providing the doped hole injection layer 202 between the lower electrode (anode) 201a and the light emitting layer 204, the driving voltage is reduced. Can be achieved. Further, according to the second embodiment, the electron blocking layer (buffer layer) 203 is provided thickly between the doped hole injection layer 202 and the light emitting layer 204, so that the drive voltage does not increase. A distance between the doped hole injection layer 202 and the light emitting layer 204 can be secured.
[0149] これによつて、駆動電圧の低下を図るとともに、下部電極(陽極) 201aと発光層 204 との間に正孔注入層 202より厚い電子ブロック層 203を設けたことによる逆バイアス 耐圧の低下を抑制することができる。すなわち、逆バイアス電圧印加時における漏れ 電流の発生を防止することができるので、有機 EL素子 200および有機 EL素子 200 を用いた自発光パネルの駆動に際しての消費電力の低減を図ることができる。 As a result, the drive voltage is lowered, and the reverse bias withstand voltage due to the provision of the electron blocking layer 203 thicker than the hole injection layer 202 between the lower electrode (anode) 201a and the light emitting layer 204 is reduced. The decrease can be suppressed. That is, since it is possible to prevent the occurrence of a leakage current when a reverse bias voltage is applied, it is possible to reduce the power consumption when driving the organic EL element 200 and the self-luminous panel using the organic EL element 200.
[0150] なお、第 2の実施の形態の有機 EL素子 200を例にして説明したが、第 1の実施の 形態の有機 EL素子 100においても同様である。第 1の実施の形態によれば、陽極 1 Olaと発光層 104との間にドープ層 102を設けることによって、駆動電圧の低下を図 ることができる。また、第 1の実施の形態によれば、ドープ層 102と発光層 104との間 にバッファ層 103を厚く設けることによって、駆動電圧の上昇を伴うことなくドープ層 1 02と発光層 104との距離を確保することができる。
[0151] 同様に、第 3の実施の形態によれば、上部電極(陰極) 201bと発光層 204との間に ドープされた電子注入層 303を設けることによって駆動電圧の低下を図るとともに、ド ープされた電子注入層 303と発光層 204との距離を正孔ブロック層 302によって確 保することによって、上部電極(陰極) 201bと発光層 204との間にドープされた電子 注入層 303を設けたことによる逆ノィァス耐圧の低下を抑制することができる。 [0150] The organic EL element 200 of the second embodiment has been described as an example, but the same applies to the organic EL element 100 of the first embodiment. According to the first embodiment, the drive voltage can be lowered by providing the doped layer 102 between the anode 1 Ola and the light emitting layer 104. Further, according to the first embodiment, by providing the buffer layer 103 thick between the doped layer 102 and the light emitting layer 104, the doped layer 102 and the light emitting layer 104 can be connected without increasing the driving voltage. A distance can be secured. [0151] Similarly, according to the third embodiment, by providing the doped electron injection layer 303 between the upper electrode (cathode) 201b and the light emitting layer 204, the driving voltage is lowered and the drain voltage is reduced. The distance between the doped electron injection layer 303 and the light emitting layer 204 is secured by the hole blocking layer 302, so that the doped electron injection layer 303 is formed between the upper electrode (cathode) 201 b and the light emitting layer 204. It is possible to suppress a decrease in the reverse noise breakdown voltage due to the provision.
[0152] これによつて、駆動電圧の低下を図るとともに、逆バイアス電圧印加時における漏 れ電流の発生を防止することができるので、有機 EL素子 300および有機 EL素子 30 0を用いた自発光パネルの駆動に際しての消費電力の低減を図ることができる。 [0152] As a result, the drive voltage can be lowered and the occurrence of leakage current when a reverse bias voltage is applied can be prevented, so that self-light emission using the organic EL element 300 and the organic EL element 300 is possible. It is possible to reduce power consumption when driving the panel.
[0153] また、第 1の実施の形態によれば、バッファ層 103が、発光層 104からドープ層 102 側へ移動する電荷をブロックする電荷ブロック機能を備えるため、ドープ層 102を設 けることによる導電性の増加に伴う電子ブロック性能の低下を抑制し、陰極 101bまた は陽極 101aから注入されたキャリアが発光層 104を通過して発光層 104以外の領 域で再結合することを防止できる。これによつて、発光に寄与しない漏れ電流の発生 を防止し、電流効率の向上を図ることができる。 [0153] Also, according to the first embodiment, the buffer layer 103 has a charge blocking function to block the charge moving from the light emitting layer 104 to the doped layer 102 side, so that the doped layer 102 is provided. It is possible to suppress a decrease in electronic block performance due to an increase in conductivity, and to prevent carriers injected from the cathode 101b or the anode 101a from passing through the light emitting layer 104 and recombining in a region other than the light emitting layer 104. As a result, the generation of leakage current that does not contribute to light emission can be prevented, and current efficiency can be improved.
[0154] 同様に、第 2あるいは第 3の実施の形態によれば、電子ブロック層 203および正孔 ブロック層 302が、高キャリア密度層力も発光層 204への対向キャリアの移動をブロッ クするキャリアブロッキング性能を備えるため、ドープされた正孔注入層 202、ドープ された電子注入層 303を設けることによる導電性の増加に伴う電子ブロック性能の低 下を抑制し、上部電極(陰極) 201bまたは下部電極(陽極) 201aから注入されたキヤ リアが発光層 204を通過して発光層 204以外の領域で再結合することを防止できる。 これによつて、発光に寄与しない漏れ電流の発生を防止し、電流効率の向上を図る ことができる。 Similarly, according to the second or third embodiment, the electron blocking layer 203 and the hole blocking layer 302 have a high carrier density layer force and a carrier that blocks the movement of the opposite carrier to the light emitting layer 204. In order to provide blocking performance, the provision of the doped hole injection layer 202 and the doped electron injection layer 303 suppresses the deterioration of the electron blocking performance due to the increase in conductivity, and the upper electrode (cathode) 201b or lower It is possible to prevent the carrier injected from the electrode (anode) 201 a from passing through the light emitting layer 204 and recombining in a region other than the light emitting layer 204. As a result, it is possible to prevent leakage current that does not contribute to light emission and improve current efficiency.
[0155] 第 2あるいは第 3の実施の形態によれば、発光層 204と上部電極(陰極) 201bとの 間および発光層 204と下部電極(陽極) 201aとの間の少なくともいずれかに、電極対 201に印加された電圧に応じて移動する電荷キャリアの発光層 204への移動をプロ ックするブロック層を備えるため、上部電極(陰極) 201bまたは下部電極(陽極) 201 aから注入されたキャリアが発光層 204を通過して発光層 204以外の領域で再結合 することを防止できる。これによつて、発光に寄与しない漏れ電流の発生を防止し、
電流効率の向上を図ることができる。 [0155] According to the second or third embodiment, an electrode is provided between at least one of the light emitting layer 204 and the upper electrode (cathode) 201b and between the light emitting layer 204 and the lower electrode (anode) 201a. In order to provide a blocking layer that blocks the movement of charge carriers that move according to the voltage applied to the pair 201 to the light-emitting layer 204, the charge was injected from the upper electrode (cathode) 201b or the lower electrode (anode) 201a. Carriers can be prevented from passing through the light emitting layer 204 and recombining in a region other than the light emitting layer 204. This prevents the occurrence of leakage current that does not contribute to light emission, The current efficiency can be improved.
[0156] また、第 1の実施の形態によれば、有機 EL素子 100において、全ての層の膜厚が 、発光層 104で発光された光のうち、電極対 101の対向方向に放射され、積層界面 で多重反射される光が強め合うような光学的干渉を生じさせるように調整されている ため、発光効率を一層高めることができる。 [0156] Also, according to the first embodiment, in the organic EL element 100, the film thicknesses of all the layers are radiated in the opposing direction of the electrode pair 101 out of the light emitted from the light emitting layer 104. Luminous efficiency can be further improved because the optical interference is adjusted so that the light that is multiply reflected at the laminated interface is intensified.
[0157] 上述したように、発光に寄与しな 、漏れ電流の発生を防止することで、有機 EL素 子に強い電圧を印加することによる発光不良箇所のリペアを確実に行うことができる 。これによつて、自発光パネルの製造に際しての歩留まりの向上を図ることができる。 [0157] As described above, by preventing the occurrence of leakage current without contributing to light emission, it is possible to reliably repair a defective light emission location by applying a strong voltage to the organic EL element. Thereby, it is possible to improve the yield when manufacturing the self-luminous panel.
[0158] また、図示を省略する力 このような有機 EL素子 200、 300が、基板 106上に複数 配設された自発光パネル (図 9参照)とすることにより、上述したような作用効果を奏 する自発光パネルを得ることができる。なお、自発光パネルの構成および製造方法 については、第 2あるいは第 3の実施の形態の有機 EL素子 200、 300を用いる以外 は従来の技術を用いることが可能であるため、ここでは図示および説明を省略する。 [0158] Further, the power to be omitted from the illustration. The organic EL elements 200 and 300 are self-luminous panels (see FIG. 9) in which a plurality of such organic EL elements 200 and 300 are arranged on the substrate 106. A self-luminous panel can be obtained. As for the structure and manufacturing method of the self-luminous panel, conventional techniques can be used except that the organic EL elements 200 and 300 of the second or third embodiment are used. Is omitted.
[0159] (第 5の実施の形態) [0159] (Fifth embodiment)
図 17は、第 5の実施の形態における有機 EL素子の構造を例示する断面図である 。以下に、第 5の実施の形態における有機 EL素子について図 17を参照して説明す る。第 5の実施の形態における有機 EL素子 1700は、図 1に示した有機 EL素子 100 における陽極 101aと発光層 104との間に、正孔注入層 1701、正孔輸送層 1702お よびバッファ層 1703を備える 3HTL構造を有して 、る。 FIG. 17 is a cross-sectional view illustrating the structure of an organic EL element according to the fifth embodiment. The organic EL element in the fifth embodiment will be described below with reference to FIG. An organic EL element 1700 according to the fifth embodiment includes a hole injection layer 1701, a hole transport layer 1702, and a buffer layer 1703 between the anode 101a and the light emitting layer 104 in the organic EL element 100 shown in FIG. It has a 3HTL structure.
[0160] 有機 EL素子 1700によれば、正孔注入層 1701および正孔輸送層 1702によって 図 1におけるドープ層 102が実現される。有機 EL素子 1700によれば、ノ ッファ層 17 03によって図 1におけるバッファ層 103が実現される。 According to the organic EL element 1700, the doped layer 102 in FIG. 1 is realized by the hole injection layer 1701 and the hole transport layer 1702. According to the organic EL element 1700, the buffer layer 103 in FIG.
[0161] なお、第 5の実施の形態では、基板 106上に陽極 101aを設け、この陽極 101a上 に各層を順次積層するようにした力 これに限るものではない。たとえば、基板 106上 に陰極を設け、この陰極上に各層を順次積層するようにしてもよい。この場合、陰極 によって下部電極が実現され、陽極によって上部電極が実現される。 [0161] In the fifth embodiment, the force is such that the anode 101a is provided on the substrate 106, and the respective layers are sequentially stacked on the anode 101a. For example, a cathode may be provided on the substrate 106, and each layer may be sequentially stacked on the cathode. In this case, the lower electrode is realized by the cathode and the upper electrode is realized by the anode.
[0162] なお、この場合には、陰極上に積層される各層は、図 17に示す各層の積層順序と は反対の順序で積層される。また、これまでの説明は陽極からの正孔注入、正孔輸
送、電子ブロックについて行った力 陰極からの電子注入、電子輸送、正孔ブロック についても同様である。 In this case, the layers stacked on the cathode are stacked in the order opposite to the stacking order of the layers shown in FIG. Also, the explanation so far is about hole injection from the anode, hole transport from the anode. The same is true for electron injection from the cathode, electron transport, and hole blocking.
[0163] 第 5の実施の形態で使用する基板 106は、陽極 101aをあらカゝじめ形成したもので も良いし、アルカリバリア膜を形成した後に陽極を形成した基板、アクティブ駆動用 T FT基板、カラーフィルタを設けた基板を適宜使用することが可能である。基板 106は 透明でなくとも良い。 [0163] The substrate 106 used in the fifth embodiment may be a substrate in which the anode 101a is preliminarily formed, a substrate on which an anode is formed after an alkali barrier film is formed, an active driving TFT, A substrate and a substrate provided with a color filter can be used as appropriate. The substrate 106 need not be transparent.
[0164] 第 5の実施の形態の有機 EL素子 1700に関して、基板 106上に有機 EL素子 170 0を形成した後、この有機 EL素子 1700を封止することにより、有機 EL素子 1700の 劣化を防止する。封止の形態としては、従来より知られているような、密封型の封止 形態、固体封止の形態、膜封止の形態など、各種の形態がある。 [0164] Regarding the organic EL element 1700 of the fifth embodiment, after forming the organic EL element 1700 on the substrate 106, the organic EL element 1700 is sealed to prevent deterioration of the organic EL element 1700. To do. As the form of sealing, there are various forms such as a conventionally known sealing form, solid sealing form, and film sealing form.
[0165] 密封型の封止とは、封止用基板と基板 106とを、封止用接着剤を用いて貼り合わ せることによって有機 EL素子 1700を封止する封止方法である。密封型の封止にお いては、ソーダガラス、鉛ガラス、硬質ガラスなどのガラス基材、ポリエチレン、ポリプロ ピレン、ポリエチレンテレフタレート、ポリメチルメタタリレートなどのプラスチック基材、 アルミニウム、ステンレスなどの金属基材など力もなる封止用基板を用いる。 [0165] Sealing-type sealing is a sealing method in which the organic EL element 1700 is sealed by bonding the sealing substrate and the substrate 106 using a sealing adhesive. For hermetic sealing, glass substrates such as soda glass, lead glass, and hard glass, plastic substrates such as polyethylene, polypropylene, polyethylene terephthalate, and polymethyl methacrylate, metal substrates such as aluminum and stainless steel, etc. A sealing substrate that has strength such as a material is used.
[0166] 固体封止とは、「榭脂層 Zバリア層」、「榭脂層 Zバリア層 Z榭脂層」、「榭脂層 Zバ リア層 Z榭脂層 Zバリア層」のように、榭脂層やバリア層を順次積層することによって 有機 EL素子 1700を封止する封止方法である。ここで、ノ リア層とは、水分などの浸 透を防止する層である。 [0166] Solid sealing refers to "resin layer Z barrier layer", "resin layer Z barrier layer Z resin layer", "resin layer Z barrier layer Z resin layer Z barrier layer" In this sealing method, the organic EL element 1700 is sealed by sequentially laminating a resin layer and a barrier layer. Here, the NOR layer is a layer that prevents permeation of moisture and the like.
[0167] 榭脂層は、光ラジカル重合性榭脂、光力チオン重合性榭脂、光硬化性榭脂、熱可 塑性榭脂、熱硬化型榭脂などの榭脂材料によって形成される。光ラジカル重合性榭 脂は、ポリエステルアタリレート、ポリエーテルアタリレート、エポキシアタリレート、ポリ ウレタンアタリレートなどの各種アタリレートを主成分とする榭脂である。光力チオン重 合性榭脂は、エポキシ、ビュルエーテルなどの榭脂を主成分とする榭脂である。光硬 化性榭脂は、チオール'ェン付加型榭脂などの榭脂である。 [0167] The resin layer is formed of a resin material such as a photo-polymerizable resin, a photo-thion polymerizable resin, a photo-curable resin, a thermo-plastic resin, or a thermosetting resin. The radical photopolymerizable resin is a resin mainly composed of various acrylates such as polyester acrylate, polyether acrylate, epoxy acrylate, and polyurethane acrylate. Light power thione-polymerized resin is a resin mainly composed of resin such as epoxy and butyl ether. The photo-curing resin is a resin such as thiol-added resin.
[0168] 熱可塑性榭脂、熱硬化型榭脂は、ポリエチレン、ポリプロピレン、ポリエチレンテレフ タレート、ポリメチルメタタリレート、ポリスチレン、ポリエーテルスルホン、ポリアリレート 、ポリカーボネート、ポリウレタン、アクリル榭脂、ポリアクリル-トリル、ポリビュルァセタ
ール、ポリアミド、ポリイミド、ジアクリルフタレート榭脂、セルロース系プラスチック、ポリ 酢酸ビュル、ポリ塩化ビニル、ポリ塩ィ匕ビユリデンなどの榭脂や、これらの榭脂が 2種 類または 3種類以上含まれる共重合体などの榭脂である。バリア層は、ガラスなどの セラミック材料、ステンレスやアルミニウムなどの金属材料によって形成される。 [0168] Thermoplastic resins and thermosetting resins are polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polystyrene, polyethersulfone, polyarylate, polycarbonate, polyurethane, acrylic resin, polyacryl-tolyl. , Polybulasseta Resins such as rubber, polyamide, polyimide, diacryl phthalate resin, cellulosic plastic, poly (vinyl acetate), polyvinyl chloride, polysalt vinylidene, and two or more of these resins It is a resin such as a copolymer. The barrier layer is formed of a ceramic material such as glass or a metal material such as stainless steel or aluminum.
[0169] 膜封止とは、成膜可能な材料によって形成された平坦化層やバリア層を順次積層 することによって有機 EL素子 1700を封止する封止方法である。膜封止では、平坦 化層は、フッ化リチウムなどの無機材料、重合反応を伴うアタリレート含有のモノマー やオリゴマーなどの成膜可能な榭脂材料などによって構成される。バリア層は、アルミ ニゥムなどの金属や、窒化珪素、酸化珪素、窒化酸ィ匕珪素などの無機材料のような 材料などによって構成される。バリア層は、水分などの浸透を防止する層である。 [0169] Film sealing is a sealing method in which the organic EL element 1700 is sealed by sequentially laminating a planarization layer and a barrier layer formed of a filmable material. In film sealing, the planarizing layer is composed of an inorganic material such as lithium fluoride, a filmable resin material such as an acrylate-containing monomer or oligomer accompanying a polymerization reaction, or the like. The barrier layer is made of a metal such as aluminum or a material such as an inorganic material such as silicon nitride, silicon oxide, or silicon nitride oxide. The barrier layer is a layer that prevents penetration of moisture and the like.
[0170] (第 6の実施の形態) [0170] (Sixth embodiment)
図 18は、第 6の実施の形態の有機 EL素子を示す説明図である。つぎに、第 6の実 施の形態の有機 EL素子について図 18を参照して説明する。図 18に示す有機 EL素 子 1800は、発光層 204よりも下部電極(陽極) 201a側に、電子ブロック層(バッファ 層) 203と正孔注入層 202とを備えており、発光層 204よりも上部電極(陰極) 201b 側に正孔ブロック層(バッファ層) 302と電子注入層 303とを備えている。 FIG. 18 is an explanatory diagram showing an organic EL element according to the sixth embodiment. Next, an organic EL element according to a sixth embodiment will be described with reference to FIG. An organic EL device 1800 shown in FIG. 18 includes an electron block layer (buffer layer) 203 and a hole injection layer 202 on the lower electrode (anode) 201a side of the light emitting layer 204, and is more than the light emitting layer 204. A hole blocking layer (buffer layer) 302 and an electron injection layer 303 are provided on the upper electrode (cathode) 201b side.
[0171] このような有機 EL素子 1800とすることにより、上述した図 2および図 3に示した有機 EL素子 200、 300がそれぞれ奏する効果を、単一の有機 EL素子 1800によって実 現することができる。 [0171] By adopting such an organic EL element 1800, the effects exhibited by the organic EL elements 200 and 300 shown in FIGS. 2 and 3 described above can be realized by a single organic EL element 1800. it can.
[0172] (第 7の実施の形態) [0172] (Seventh embodiment)
図 19は、第 7の実施の形態のマルチフオトン素子を示す縦断側面図である。以下 に、第 7の実施の形態について図 19を参照して説明する。図 2、図 3および図 18で は、単一の発光層 204を備える有機 EL素子 200、 300、 1800について説明したが 、これに限るものではなぐ図 19に示すように複数の発光層 204を備える有機 EL素 子(以下、「マルチフオトン素子」と 、う) 1900であってもよ!/、。 FIG. 19 is a longitudinal side view showing the multi-photon device according to the seventh embodiment. The seventh embodiment will be described below with reference to FIG. 2, 3, and 18, the organic EL elements 200, 300, and 1800 having a single light emitting layer 204 have been described. However, the present invention is not limited to this, and as shown in FIG. Equipped with an organic EL device (hereinafter referred to as “multiphoton device”) 1900!
[0173] マルチフオトン素子 1900は、単一の素子において複数の発光層 204を備える構成 を有する有機 EL素子である。マルチフオトン素子 1900は、原理的には、単一の発光 層 204を備える複数の有機 EL素子 1910、 1920を、有機 EL素子 1910、 1920にお
ける各層の積層方向に沿って積層し、直列に接続した構成を有している。 [0173] The multiphoton element 1900 is an organic EL element having a structure including a plurality of light-emitting layers 204 in a single element. In principle, the multiphoton element 1900 is composed of a plurality of organic EL elements 1910 and 1920 having a single light-emitting layer 204, and the organic EL elements 1910 and 1920. The layers are stacked along the stacking direction of the layers and connected in series.
[0174] マルチフオトン素子 1900では、重ね合わされた有機 EL素子 1910と 1920との間に 、電荷発生層(図 21参照)を含む中間電極 1901を介在させる。これにより、マルチフ オトン素子 1900に電圧を印加した場合に、中間電極 1901から有機 EL素子 1910に は正孔を注入し、有機 EL素子 1920には電子を注入することができる。すなわち、マ ルチフオトン素子 1900では、素子内部で発生したキャリアの分だけ発光量子効率を 向上させることができる。 In multiphoton element 1900, intermediate electrode 1901 including a charge generation layer (see FIG. 21) is interposed between stacked organic EL elements 1910 and 1920. Thus, when a voltage is applied to the multiphoton element 1900, holes can be injected from the intermediate electrode 1901 to the organic EL element 1910 and electrons can be injected to the organic EL element 1920. In other words, the multiphoton device 1900 can improve the emission quantum efficiency by the amount of carriers generated inside the device.
[0175] 中間電極 1901は、つぎのように構成される。下部電極(陽極) 201aが陽極である 一般的な有機 EL素子の場合、中間電極 1901の有機 EL素子 1920側には通常の 陰極を薄く設け、この薄い陰極上に有機 EL素子 1910側における電荷発生層を積 層する。さらに、有機 EL素子 1910の正孔輸送層(正孔注入層(ドープ層) 202およ び電子ブロック層(バッファ層) 203)を積層し以後発光層 204などを積層してマルチ フオトン素子とする。電荷発生層は、通常電子受容性材料 (ァクセプター)からなる膜 を用い、または正孔輸送性材料に電子受容性材料 (ァクセプター)をドープしても用 いられる。 [0175] The intermediate electrode 1901 is configured as follows. The lower electrode (anode) 201a is the anode. In the case of a general organic EL element, the intermediate electrode 1901 is thinly provided with a normal cathode on the organic EL element 1920 side, and charge is generated on the organic EL element 1910 side on this thin cathode. Stack layers. Furthermore, the hole transport layer (hole injection layer (dope layer) 202 and electron block layer (buffer layer) 203) of the organic EL element 1910 is laminated, and then the light emitting layer 204 and the like are laminated to form a multiphoton element. . The charge generation layer is usually used as a film made of an electron-accepting material (acceptor) or doped with an electron-accepting material (acceptor) in a hole transporting material.
[0176] (電荷発生層の動作) [0176] (Operation of charge generation layer)
図 20は、従来の電荷発生層の動作を示す模式図である。図 21は、この発明の実 施の形態における電荷発生層の動作を示す模式図である。以下に、従来の電荷発 生層およびこの発明の実施の形態の電荷発生層の動作について図 20および図 21 を参照して説明する。 FIG. 20 is a schematic diagram showing the operation of a conventional charge generation layer. FIG. 21 is a schematic diagram showing the operation of the charge generation layer in the embodiment of the present invention. The operation of the conventional charge generation layer and the charge generation layer according to the embodiment of the present invention will be described below with reference to FIGS. 20 and 21. FIG.
[0177] 図 20および図 21に示すように、中間電極 1901は、電荷発生層 2001と陰極 2002 とを備えている。電荷発生層 2001の役割は、図 20に示すように、電荷発生層 2001 内で正負の電荷を発生させ、これを有機 EL素子 1910と有機 EL素子 1920とに振り 分けると説明されている。 As shown in FIGS. 20 and 21, the intermediate electrode 1901 includes a charge generation layer 2001 and a cathode 2002. As shown in FIG. 20, the role of the charge generation layer 2001 is described as generating positive and negative charges in the charge generation layer 2001 and distributing them to the organic EL element 1910 and the organic EL element 1920.
[0178] しかし、実験および考察の結果によれば、電荷発生層 2001の役割は電荷の発生 ではなぐ高キャリア密度によるエネルギーバンドの歪みによって、有機 EL素子 192 0に配された陰極 2002の上面からトンネル注入による正孔注入を有効に生じせしめ ることにあるといえる。
[0179] 図 22は、この発明の実施の形態における中間電極 1901のエネルギーレベルの関 係を示す模式図である。以下に、この発明の実施の形態における中間電極 1901の エネルギーレベルの関係について図 22を参照して説明する。図 22においては、この 発明の実施の形態における中間電極 1901として、マルチフオトン中間電極部を例に して説明する。 However, according to the results of experiments and discussions, the role of the charge generation layer 2001 is from the upper surface of the cathode 2002 disposed in the organic EL element 1920 due to the distortion of the energy band due to the high carrier density that is not the generation of charges. It can be said that the hole injection by tunnel injection is effectively generated. FIG. 22 is a schematic diagram showing the relationship between the energy levels of intermediate electrode 1901 in the embodiment of the present invention. Hereinafter, the relationship between the energy levels of the intermediate electrode 1901 in the embodiment of the present invention will be described with reference to FIG. In FIG. 22, a multiphoton intermediate electrode portion will be described as an example of intermediate electrode 1901 in the embodiment of the present invention.
[0180] 図 22においては、正孔密度が高い電荷発生層 2001と陰極 2002との接合界面の エネルギーバンドが局所的に歪み、通常はエネルギー障壁のために注入されること のな 、正孔が陰極 2002から電荷発生層 2001に有効に注入されて 、ることを示して いる。このモデルによれば、真に電荷を発生させているのは有機 EL素子 1920の陰 極 2002である。この理由により、以下、電荷発生層 2001を適宜高キャリア密度層と 称して説明する。 [0180] In FIG. 22, the energy band at the junction interface between the charge generation layer 2001 having a high hole density and the cathode 2002 is locally distorted, and the holes are not normally injected due to an energy barrier. It is shown that it is effectively injected from the cathode 2002 into the charge generation layer 2001. According to this model, it is the negative electrode 2002 of the organic EL element 1920 that truly generates a charge. For this reason, the charge generation layer 2001 will be hereinafter referred to as a high carrier density layer as appropriate.
[0181] 電荷発生層(高キャリア密度層) 2001としては、たとえば、有機 EL素子の陽極とし て一般的に用いることのできる ITOなどを用いることができる。この場合は、有機 EL 素子 1920の陰極 2002と ITOとはオーム性接触をしており、 2組の陽極と陰極のペア を直列に接続して 、るに過ぎな、、。 [0181] As the charge generation layer (high carrier density layer) 2001, for example, ITO which can be generally used as an anode of an organic EL element can be used. In this case, the cathode 2002 of the organic EL element 1920 and the ITO are in ohmic contact with each other, and two pairs of anode and cathode are connected in series.
[0182] ところで、 ITOは導電性が高く、発光エリアとして規定して 、な 、部位も発光してし まうため、通常の発光パネルには使用できない。し力しながら、上述したように、マル チフオトン素子 1900の中間電極 1901部分には、 p型または n型の電荷発生層(高キ ャリア密度層) 2001と、電荷発生層(高キャリア密度層) 2001に対応するキャリアを 注入できる電極とが必要である。 [0182] By the way, ITO has high conductivity and is defined as a light-emitting area, and the part also emits light, so it cannot be used for a normal light-emitting panel. However, as described above, the p-type or n-type charge generation layer (high carrier density layer) 2001 and the charge generation layer (high carrier density layer) are formed on the intermediate electrode 1901 portion of the multiphoton element 1900. An electrode capable of injecting carriers corresponding to 2001 is required.
[0183] 電荷発生層(高キャリア密度層) 2001の導電性が高 、場合には、上述した逆バイ ァス電圧印加時の漏れ電流や、順方向バイアス電圧印加時の有効なキャリア閉じこ めによる発光効率を改善するために、適宜好ま 、キャリアブロック層を設ける。 [0183] Charge generation layer (high carrier density layer) When the conductivity of 2001 is high, the leakage current when the reverse bias voltage is applied as described above, or effective carrier confinement when the forward bias voltage is applied. In order to improve the luminous efficiency due to the above, a carrier block layer is preferably provided as appropriate.
[0184] 図 23は、この発明の実施の形態のマルチフオトン素子を示す縦断側面図である。 FIG. 23 is a longitudinal side view showing the multi-photon device according to the embodiment of the present invention.
以下に、この発明の実施の形態のマルチフオトン素子について図 23を参照して説明 する。なお、上述した各実施の形態において説明した構成と同一の構成については 同一の符号で示し、説明も省略する。 A multiphoton element according to an embodiment of the present invention will be described below with reference to FIG. Note that the same components as those described in the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.
[0185] 図 23に示すように、この発明の実施の形態のマルチフオトン素子 2300は、下部電
極(陽極) 201aと,下部電極に最も近い発光層 204との間に、高キャリア密度層であ る正孔注入層(ドープ層) 202と、低キャリア密度層である電子ブロック層(バッファ層 ) 203とを備えている。 As shown in FIG. 23, the multiphoton element 2300 according to the embodiment of the present invention includes a lower Between the electrode (anode) 201a and the light emitting layer 204 closest to the lower electrode, a hole injection layer (dope layer) 202 which is a high carrier density layer and an electron block layer (buffer layer) which is a low carrier density layer ) 203.
[0186] 同様に、マルチフオトン素子 2300は、上部電極(陰極) 201bと上部電極(陰極) 20 lbに最も近い発光層 204との間に、高キャリア密度層である電子注入層(ドープ層) 303と、低キャリア密度層である正孔ブロック層(バッファ層) 302と、を備えている。 [0186] Similarly, the multiphoton element 2300 includes an electron injection layer (dope layer) 303, which is a high carrier density layer, between the upper electrode (cathode) 201b and the light emitting layer 204 closest to the upper electrode (cathode) 20 lb. And a hole blocking layer (buffer layer) 302 which is a low carrier density layer.
[0187] このように、複数の発光層を電子ブロック層 203と正孔ブロック層 302とによって挟 むことで、順方向電圧を印力 Πした場合に、キャリアが対向電極まで突き抜けたり、発 光層 204以外の層で再結合したりすることを防ぐことができる。また、逆バイアス電圧 を印加した場合に、ブロックされて界面に蓄積された電荷どうしの間隔を広く取ること ができる。 [0187] As described above, when a plurality of light-emitting layers are sandwiched between the electron block layer 203 and the hole block layer 302, when a forward voltage is applied, carriers penetrate to the counter electrode or light emission occurs. Recombination in layers other than layer 204 can be prevented. In addition, when a reverse bias voltage is applied, the interval between the charges that are blocked and accumulated at the interface can be widened.
[0188] これによつて、耐久性の高いマルチフオトン素子 2300を得ることができる。特に、マ ルチフオトン素子 2300においては、電子ブロック層 203と正孔ブロック層 302とを厚 くすることで、蓄積電荷の距離をより広くとることができる。 Thus, a highly durable multiphoton element 2300 can be obtained. In particular, in the multiphoton element 2300, the accumulated charge distance can be increased by increasing the thickness of the electron blocking layer 203 and the hole blocking layer 302.
[0189] さらに、 2つの発光層 204の内側に、電子ブロック層 203と正孔ブロック層 302とを 設けることで、発光層 204内のキャリア閉じ込めが有効に機能し、発光量子効率を改 善することができる。 [0189] Furthermore, by providing the electron blocking layer 203 and the hole blocking layer 302 inside the two light emitting layers 204, carrier confinement in the light emitting layer 204 functions effectively, and the light emission quantum efficiency is improved. be able to.
[0190] 図 24は、この発明の別の実施の形態のマルチフオトン素子を示す縦断側面図であ る。以下に、この発明の別の実施の形態のマルチフオトン素子について図 24を参照 して説明する。この発明の別の実施の形態のマルチフオトン素子 2400は、単一の発 光層 204を備える有機 EL素子を、電圧の印加方向に沿って 3つ積層した構成を有し ている。本実施の形態のマルチフオトン素子 2400においても、単一の発光層 204を 備える有機 EL素子を電圧の印加方向に沿って 2つ積層したマルチフオトン素子 230 0と、基本的には同様の構成を有している。 FIG. 24 is a vertical side view showing a multi-photon device according to another embodiment of the present invention. A multiphoton element according to another embodiment of the present invention will be described below with reference to FIG. A multi-photon device 2400 according to another embodiment of the present invention has a configuration in which three organic EL devices each including a single light emitting layer 204 are stacked along the voltage application direction. The multiphoton element 2400 of the present embodiment also has basically the same configuration as the multiphoton element 2300 in which two organic EL elements each having a single light-emitting layer 204 are stacked along the voltage application direction. ing.
[0191] この実施の形態のマルチフオトン素子 2400は、下部電極(陽極) 201aと発光層 20 4との間に高キャリア密度層である正孔注入層(ドープ層) 202を備えている。マルチ フオトン素子 2400において発光層 204と発光層 204との間には、高キャリア密度層 である電子注入層(ドープ層) 303、低キャリア密度層である正孔ブロック層(バッファ
層) 302、および陰極 2002、電荷発生層(高キャリア密度層) 2001、電子ブロック層 (バッファ層) 203が設けられて!/、る。 The multiphoton element 2400 of this embodiment includes a hole injection layer (dope layer) 202 that is a high carrier density layer between a lower electrode (anode) 201a and a light emitting layer 204. In the multiphoton element 2400, an electron injection layer (dope layer) 303 which is a high carrier density layer and a hole blocking layer (buffer) which is a low carrier density layer are provided between the light emitting layer 204 and the light emitting layer 204. Layer) 302, a cathode 2002, a charge generation layer (high carrier density layer) 2001, and an electron block layer (buffer layer) 203 are provided.
[0192] 上述したよう【こマノレチフ才トン素子 1900、 2300、 2400【こよれ ίま、、電極対 201の対 向方向に沿って複数の発光層 204を有して!/、る有機 EL素子 2300、 2400にお!/、て 、下部電極(陽極) 201aと上部電極(陰極) 201bと、これら電極 201a、 201bに最も 近い発光層 204との間に、対応するキャリアをブロックする層を設けることで、高キヤリ ァ密度層 2001や電子注入層(ドープ層) 303、正孔注入層(ドープ層) 202を設ける ことによって懸念されるキャリアブロック性能の低下を抑制し、電流効率の向上と逆バ ィァス電圧印加時の漏れ電流特性の改善を図ることができる。 [0192] As described above, this organic EL device has a plurality of light emitting layers 204 along the direction of the electrode pair 201! In 2300 and 2400, a layer for blocking the corresponding carrier is provided between the lower electrode (anode) 201a and the upper electrode (cathode) 201b and the light emitting layer 204 closest to the electrodes 201a and 201b. By providing the high carrier density layer 2001, the electron injection layer (dope layer) 303, and the hole injection layer (dope layer) 202, the decrease in carrier block performance, which is a concern, is suppressed. It is possible to improve the leakage current characteristics when the bias voltage is applied.
実施例 Example
[0193] つぎに、実施例における有機 EL素子について説明する。実施例における有機 EL 素子の構造は、上述した第 1の実施の形態で説明した有機 EL素子 100と同様であ る。このため、上述した第 1の実施の形態における有機 EL素子 100と同一部分は同 一符号で示し、図示および説明を省略する。ここでは、各層を形成する材料などにつ いて具体的に説明する。 [0193] Next, the organic EL device in the examples will be described. The structure of the organic EL element in the example is the same as that of the organic EL element 100 described in the first embodiment. For this reason, the same parts as those of the organic EL element 100 in the first embodiment are denoted by the same reference numerals, and illustration and description thereof are omitted. Here, the material for forming each layer will be specifically described.
[0194] 電極(陽極 101a)は、たとえば、ガラスのような、透明かつ絶縁性の基板に設けられ ている。電極(陽極 101a)としては、酸化錫,酸化インジウム,酸ィ匕錫インジウム (ITO )などの導電性酸化物、あるいは、金,銀,クロムなどの金属やヨウ化銅,硫化銅など の無機導電性物質、などを用いることができる。電極 (陽極 101a)を形成する材料と しては、これらに限るものではない。 [0194] The electrode (anode 101a) is provided on a transparent and insulating substrate such as glass. The electrode (anode 101a) may be a conductive oxide such as tin oxide, indium oxide, or indium tin oxide (ITO), or a metal such as gold, silver, or chromium, or an inorganic conductive material such as copper iodide or copper sulfide. A sex substance can be used. The material for forming the electrode (anode 101a) is not limited to these.
[0195] ドープ層 102においてドープされる電子受容性物質としては、ルイス酸ィ匕合物、金 属酸化物、金属ハロゲン化物、アルカリ金属、アルカリ土類金属、希土類金属、アル カリ金属化合物、アルカリ土類金属化合物、希土類ィ匕合物などが挙げられる。ルイス 酸化合物として、塩化第 2鉄、臭化第 2鉄、ヨウ化第 2鉄、塩化アルミニウム、臭化ァ ルミ-ゥム、ヨウ化アルミニウム、塩ィ匕ガリウム、臭化ガリウム、ヨウ化ガリウム、塩化イン ジゥム、臭化インジウム、ヨウ化インジウム、 5塩化アンチモン、 5フッ化砒素、 3フツイ匕 硼素などの無機化合物や、 DDQ (ジシァノージクロロキノン)、 TNF (トリ-トロフルォ レノン)、 TCNQ (テトラシァノキノジメタン)、 F4— TCNQ (テトラフルォローテトラシァ
ノキノジメタン、などがある。 [0195] As the electron-accepting substance doped in the doped layer 102, Lewis acid compound, metal oxide, metal halide, alkali metal, alkaline earth metal, rare earth metal, alkali metal compound, alkali Examples include earth metal compounds and rare earth compounds. Lewis acid compounds include ferric chloride, ferric bromide, ferric iodide, aluminum chloride, aluminum bromide, aluminum iodide, gallium chloride, gallium bromide, gallium iodide, Inorganic compounds such as indium chloride, indium bromide, indium iodide, antimony pentachloride, arsenic pentafluoride, boron trifluoride, DDQ (disyanodichloroquinone), TNF (tri-trofluorenone), TCNQ ( Tetracyanoquinodimethane), F4—TCNQ (Tetrafluorotetrasia) Nokinodimethane, etc.
[0196] 金属酸化物、金属ハロゲン化物としては、具体的には、たとえば、 V O (5酸化バナ [0196] Specific examples of metal oxides and metal halides include, for example, V 2 O (vanadium pentoxide
2 5 ジゥム)または Re O (7酸化レニウム)、 MoO、 WOなどがある。アルカリ金属、アル 2 5 Dimu) or Re 2 O (Rhenium oxide), MoO, WO, etc. Alkali metal, Al
2 7 3 3 2 7 3 3
カリ土類金属、希土類金属とその化合物として、 Li、 Cs、 Mg、 Ca、 Eu、 LiF、 Li 0、 Potassium earth metals, rare earth metals and their compounds include Li, Cs, Mg, Ca, Eu, LiF, Li 0,
2 2
CsF、 NaCl、 KC1、 MgFなどが挙げられる。 Examples include CsF, NaCl, KC1, and MgF.
2 2
[0197] また、電子受容性物質として、フッ素を置換基として有する有機物質やシァノ基を 置換基として有する有機物もあり、これらの材料に限定されるものではないし、バッフ ァ層 103を構成する材料にも使用することができる。一方、ドープ層 102にトリス(8— ヒドロキシキノリノール)アルミニウムなどの電子輸送性材料を用いた場合は、フラーレ ン、カーボンナノチューブなどの電子供与性物質をドープしてもよ 、。 [0197] Further, as an electron-accepting substance, there are an organic substance having fluorine as a substituent and an organic substance having a cyano group as a substituent, and the material is not limited to these materials. Can also be used. On the other hand, when an electron transporting material such as tris (8-hydroxyquinolinol) aluminum is used for the doped layer 102, an electron donating substance such as fullerene or carbon nanotube may be doped.
[0198] 他に、ドープ層 102およびバッファ層 103を形成する材料としては、一般的に有機 EL素子の製造に使用されている公知の各種ィ匕合物を適宜用いることができる。発光 層 104および電荷輸送層 105については、ここでは説明を省略する力 発光層 104 および電荷輸送層 105を形成する公知の各種材料を用いることが可能である。 [0198] In addition, as materials for forming the doped layer 102 and the buffer layer 103, various known compounds generally used in the manufacture of organic EL elements can be used as appropriate. For the light-emitting layer 104 and the charge transport layer 105, various known materials for forming the light-emitting layer 104 and the charge transport layer 105 can be used.
[0199] 電極(陰極 101b)は、アルミニウム、銅、銀、金などの単体またはマグネシウムと銀、 リチウムと銀などの合金、酸化錫インジウム (ITO)などの導電性酸化物を使用するこ とがでさる。 [0199] The electrode (cathode 101b) may be made of a simple substance such as aluminum, copper, silver, or gold, or an alloy such as magnesium and silver, lithium and silver, or a conductive oxide such as indium tin oxide (ITO). I'll do it.
[0200] (具体例) [0200] (Specific example)
つぎに、有機 EL素子 100および有機 EL素子 100を用いた自発光パネル 900の具 体例について説明する。この具体例では、以下のような手順に基づき作成した有機 E L素子 100および有機 EL素子 100を用いた自発光パネル 900について説明する。 図示を省略するが、本具体例の有機 EL素子 100および有機 EL素子 100を用 ヽた 自発光パネル 900の製造に際しては、まず、ガラス基板上に l lOnmの ITOをスパッ タ法により成膜した。 Next, specific examples of the organic EL element 100 and the self-luminous panel 900 using the organic EL element 100 will be described. In this specific example, a self-luminous panel 900 using the organic EL element 100 and the organic EL element 100 created based on the following procedure will be described. Although illustration is omitted, when manufacturing the organic EL element 100 of this specific example and the self-luminous panel 900 using the organic EL element 100, first, lOnm ITO was formed on a glass substrate by a sputtering method. .
[0201] つぎに、フォトレジスト AZ6112 (東京応化工業製)を、 ITO膜上に 2mmの幅でパタ ーン形成した。レジストをパターン形成した基板を、塩化第 2鉄水溶液と塩酸の混合 液中に浸漬させた。これにより、レジストに覆われていない部分の ITO膜がエツチン グされた。エッチングされたガラス基板を、アセトン中に浸漬させた。これにより、レジ
ストが除去され、 2mmの幅に設けられた ITO電極のストライプパターンが形成された [0201] Next, a photoresist AZ6112 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was patterned on the ITO film with a width of 2 mm. The resist-patterned substrate was immersed in a mixed solution of ferric chloride aqueous solution and hydrochloric acid. As a result, the portion of the ITO film not covered with the resist was etched. The etched glass substrate was immersed in acetone. As a result, the cash register The stripe was removed and the ITO electrode stripe pattern with a width of 2 mm was formed.
[0202] ITO電極のストライプパターンが形成されたガラス基板を、界面活性剤にて洗浄す る。その後、サムコインターナショナル研究所製 UVオゾンストリッパー UV—1を用い て、 UVオゾン洗浄を 10分間行った。 UVオゾン洗浄を行ったガラス基板を、真空槽 に投入した。真空槽における真空度が 1 X 10— 6Τοπ:に達してから、抵抗加熱蒸着を 用いて、正孔注入層としての CuPcを毎秒 0. 5nmの成膜速度にて 25nmの厚さに成 膜した。 [0202] The glass substrate on which the ITO electrode stripe pattern is formed is washed with a surfactant. Thereafter, UV ozone cleaning was performed for 10 minutes using a UV ozone stripper UV-1 manufactured by Samco International Laboratory. The glass substrate that had been subjected to UV ozone cleaning was put into a vacuum chamber. The degree of vacuum is 1 X 10- 6 Τοπ in vacuum chamber: upon reaching, by the resistance heating evaporation, deposition CuPc the at deposition rate per second 0. 5 nm to a thickness of 25nm as the hole injection layer did.
[0203] つづ!/、て、電子受容性物質(ァクセプター)をドープした α NPDを、ドープ層 10 2として、上述と同様に毎秒 0. 5nmの成膜速度にて成膜した。成膜に際しては、真 空とした雰囲気中で、成膜に用いる材料を抵抗体を用いて加熱させて蒸発させた( 抵抗加熱真空成膜)。このとき、電子受容性物質の分子である 4F— TCNQも同時に 加熱蒸発させ、 a—NPDと F4— TCNQの成膜速度比が 10 : 1となるようにして混合 膜を成膜した。同様に、膜の厚さを xnmとし, x= 10, 50, lOOnmの 3種類の異なる 膜厚のサンプルを作製した。 [0203] Next, αNPD doped with an electron accepting substance (acceptor) was deposited as a doped layer 102 at a deposition rate of 0.5 nm per second in the same manner as described above. During film formation, the material used for film formation was heated and evaporated in a vacuum atmosphere (resistance heating vacuum film formation). At this time, 4F-TCNQ, which is a molecule of the electron-accepting substance, was also heated and evaporated at the same time, and a mixed film was formed so that the film formation rate ratio of a-NPD and F4-TCNQ was 10: 1. Similarly, samples with different film thicknesses of x = 10, 50, lOOnm were prepared, where the film thickness was xnm.
[0204] つづいて、 a NPDのみを用いて、上述と同様に、毎秒 0. 5nmの成膜速度で抵 抗加熱真空成膜した。このときの膜の厚さを ynmとすると、 y= 10, 50, lOOnmの 3 種類の異なる膜厚のサンプルを製造した。上述のように有機 EL素子を形成すること により、膜厚 Xと膜厚 yの組合せで複数種類のサンプルとした。 [0204] Subsequently, a resistance heating vacuum film formation was performed at a film formation rate of 0.5 nm per second in the same manner as described above, using only NPD. If the film thickness at this time is ynm, samples with three different film thicknesses of y = 10, 50, lOOnm were manufactured. By forming the organic EL element as described above, a plurality of types of samples were obtained by combining the film thickness X and the film thickness y.
[0205] つづいて、上記の複数種類の各サンプルに、発光層 104として Alqを毎秒 0. 5nm [0205] Next, in each of the above-mentioned plural types of samples, Alq is used as the light emitting layer 104 at 0.5 nm per second.
3 Three
の成膜速度で、 60nmの厚さになるまで抵抗加熱真空成膜した。 Alq上に、 LiFを、 Resistance heating vacuum film formation was performed until the film thickness reached 60 nm at a film formation speed of. LiF on Alq
3 Three
電子注入添加剤として、毎秒 0. Olnmの成膜速度で 0. 5nmの厚さになるまで抵抗 加熱真空成膜した。このように製造された発光層 104と電荷輸送層 105は、既に形 成されている ITO膜のストライプを覆うように形成され、一貫して 1 X 10— 6Torr以下の 高真空で成膜した。 As an electron injection additive, resistance heating vacuum film formation was performed until a thickness of 0.5 nm was reached at a film formation rate of 0.0 Olnm per second. The thus produced light emitting layer 104 and the charge transport layer 105 is formed so as to cover the stripe ITO film already made form, it was consistently deposited in a high vacuum of 1 X 10- 6 Torr .
[0206] 電荷輸送層 105上に、真空中にて陰極用のシャドウマスクを施し、アルミニウムを毎 秒 lnmの速度で lOOnmの厚さに抵抗加熱真空成膜した。このとき、アルミニウムの 膜は、 ITO膜のストライプと直交するような方向で、 2mm幅のストライプ状に成膜した
。このようにして作成した自発光パネル 900においては、 ITO膜によって形成された 陽極 101aとアルミニウムによって形成された陰極 101bとが交差する部分によって確 定される、有機 EL素子 100の大きさが 2mm X 2mmであった。 [0206] On the charge transport layer 105, a shadow mask for a cathode was applied in a vacuum, and aluminum was formed into a resistance heating vacuum film to a thickness of lOOnm at a speed of lnm per second. At this time, the aluminum film was formed into a 2 mm wide stripe in a direction perpendicular to the ITO film stripe. . In the self-luminous panel 900 thus produced, the size of the organic EL element 100 determined by the intersection of the anode 101a formed of the ITO film and the cathode 101b formed of aluminum is 2 mm X 2 mm.
[0207] (比較例) [0207] (Comparative example)
つぎに、上述した具体例に対する比較例としての有機 EL素子について説明する。 図示を省略するが、比較例としての有機 EL素子は、上述した具体例として説明した 有機 EL素子における電子受容性物質がドープされたドープ層 102の成膜工程以外 は、具体例と全て同様にして製造した。ドープ層 102の成膜工程においては、 x=0n m、 y= 10、 50、 lOOnmとした。 Next, an organic EL element as a comparative example for the above-described specific example will be described. Although illustration is omitted, the organic EL element as a comparative example is the same as the specific example except for the step of forming the doped layer 102 doped with the electron-accepting substance in the organic EL element described as the specific example. Manufactured. In the process of forming the doped layer 102, x = 0 nm, y = 10, 50, and lOOnm.
[0208] このようにして作製した具体例および比較例の各サンプルに対して、 7. 5mA/cm 2の電流を流すために必要な印加電圧とバッファ層 103の厚さ yとの関係を調べた。こ の結果、比較例では、バッファ層 103の厚さによって駆動電圧が所定の割合で増加 した。これに対し、電子受容性物質をドープしたドープ層 102を設けた具体例では、 ノ ッファ層 103の厚さによる駆動電圧の上昇が見られな力つた (上記実施の形態に おける図 12および表 1参照)。 [0208] For each sample of the specific example and the comparative example manufactured in this way, the relationship between the applied voltage necessary to pass a current of 7.5 mA / cm 2 and the thickness y of the buffer layer 103 was examined. It was. As a result, in the comparative example, the drive voltage increased at a predetermined rate depending on the thickness of the buffer layer 103. In contrast, in the specific example in which the doped layer 102 doped with the electron-accepting substance was provided, the driving voltage did not increase due to the thickness of the notch layer 103 (see FIG. 12 and the table in the above embodiment). 1).
[0209] なお、バッファ層 103の厚さに応じた駆動電圧の増加に関しては、 α NPDと F4 — TCNQの混合層を、陽極 101aの上に直接成膜した場合にも、 CuPcを介して成 膜した場合にも、同様の効果が現れるのを確認した。すなわち、電子受容性物質をド ープしたドープ層 102を設けた具体例では、バッファ層 103の厚さの違いによる駆動 電圧の上昇は確認されなかった。なお、 α— NPDと F4— TCNQとの混合比を、 10 0: 5〜: L00: 50の範囲で割り振った限りにお!/、ては、バッファ層 103の厚さの違いに よる駆動電圧の上昇は生じな 、ことを確認した。 [0209] Note that regarding the increase in drive voltage according to the thickness of the buffer layer 103, even when a mixed layer of αNPD and F4 — TCNQ is formed directly on the anode 101a, it is formed via CuPc. It was confirmed that the same effect appeared when the film was formed. That is, in the specific example in which the doped layer 102 doped with the electron accepting substance was provided, an increase in driving voltage due to the difference in the thickness of the buffer layer 103 was not confirmed. As long as the mixing ratio of α-NPD and F4-TCNQ is allocated in the range of 100: 5 to L00: 50! /, The drive voltage due to the difference in the thickness of the buffer layer 103 It was confirmed that there was no increase.
[0210] (比較例) [0210] (Comparative example)
つぎに、上述した具体例に対する別の比較例としての有機 EL素子にっ 、て説明 する。上述した具体例に対する比較例として、低キャリア密度層の膜厚を 5、 20、 50η mとした以外は、上述した具体例と全く同様な有機 EL素子を製造した。その結果、こ れら素子のダイオード特性を測定したところ、逆バイアス耐圧は約 IVであり非常に 低かった。
Next, an organic EL device as another comparative example for the above-described specific example will be described. As a comparative example to the specific example described above, an organic EL element exactly the same as the specific example described above was manufactured except that the film thickness of the low carrier density layer was set to 5, 20, and 50 ηm. As a result, when the diode characteristics of these elements were measured, the reverse bias withstand voltage was about IV, which was very low.
Claims
[1] 下部電極および当該下部電極に対向する上部電極を備える電極対と、 [1] an electrode pair comprising a lower electrode and an upper electrode facing the lower electrode;
前記電極対の間に設けられた発光層と、 A light emitting layer provided between the electrode pair;
前記発光層と前記下部電極との間に設けられて、電子受容性物質がドープされた ドープ層と、 A doped layer provided between the light emitting layer and the lower electrode and doped with an electron accepting substance;
前記ドープ層と前記発光層との間に設けられて、前記電極対の対向方向に沿った 寸法 (以下、膜厚とする)が前記ドープ層の膜厚よりも大きいバッファ層と、 A buffer layer provided between the doped layer and the light emitting layer and having a dimension along the opposing direction of the electrode pair (hereinafter referred to as a film thickness) greater than the film thickness of the doped layer;
を備えることを特徴とする自発光素子。 A self-luminous element comprising:
[2] 下部電極および当該下部電極に対向する上部電極を備える電極対と、 [2] an electrode pair comprising a lower electrode and an upper electrode facing the lower electrode;
前記電極対の間に設けられた発光層と、 A light emitting layer provided between the electrode pair;
前記発光層と前記上部電極との間に設けられて、電子受容性物質がドープされた ドープ層と、 A doped layer provided between the light emitting layer and the upper electrode and doped with an electron accepting substance;
前記ドープ層と前記発光層との間に設けられて、前記膜厚が前記ドープ層の膜厚 よりも大きいバッファ層と、 A buffer layer provided between the doped layer and the light emitting layer, the film thickness being larger than the film thickness of the doped layer;
を備えることを特徴とする自発光素子。 A self-luminous element comprising:
[3] 前記バッファ層は、前記発光層から前記ドープ層側へ移動する電荷をブロックする 電荷ブロック機能を備えることを特徴とする請求項 1または 2に記載の自発光素子。 [3] The self-luminous element according to [1] or [2], wherein the buffer layer has a charge blocking function for blocking charges moving from the light emitting layer to the doped layer side.
[4] 前記バッファ層は、前記発光層で発光される光が前記発光層上に積まれる層の面 において反射する第 1の反射光と、前記発光層で発光され前記バッファ層を透過し て前記ドープ層側の面で反射する第 2の反射光と、が強め合うような光干渉を生じさ せる膜厚に設けられていることを特徴とする請求項 3に記載の自発光素子。 [4] The buffer layer includes first reflected light that is reflected on a surface of a layer on which the light emitted from the light emitting layer is stacked, and light that is emitted from the light emitting layer and passes through the buffer layer. 4. The self-luminous element according to claim 3, wherein the self-luminous element is provided with a film thickness that causes optical interference that strengthens the second reflected light reflected by the surface on the doped layer side.
[5] 前記ドープ層は、前記バッファ層を形成する材料と同じ材料と、前記電子受容性物 質と、を含むことを特徴とする請求項 1または 2に記載の自発光素子。 [5] The self-luminous element according to [1] or [2], wherein the doped layer includes the same material as that for forming the buffer layer and the electron accepting substance.
[6] 前記ドープ層は、前記バッファ層を形成する材料とは異なる材料と、前記電子受容 性物質と、を含むことを特徴とする請求項 1または 2に記載の自発光素子。 6. The self-luminous element according to claim 1, wherein the doped layer includes a material different from a material forming the buffer layer and the electron-accepting substance.
[7] 下部電極および当該下部電極に対向する上部電極を備える電極対と、 [7] an electrode pair comprising a lower electrode and an upper electrode facing the lower electrode;
前記電極対の間に設けられた発光層と、 A light emitting layer provided between the electrode pair;
前記発光層と前記下部電極との間に設けられて、電子供与性物質がドープされた
ドープ層と、 Provided between the light emitting layer and the lower electrode and doped with an electron donating substance A doped layer;
前記ドープ層と前記発光層との間に設けられて、前記膜厚が前記ドープ層の膜厚 よりも大きいバッファ層と、 A buffer layer provided between the doped layer and the light emitting layer, the film thickness being larger than the film thickness of the doped layer;
を備えることを特徴とする自発光素子。 A self-luminous element comprising:
[8] 下部電極および当該下部電極に対向する上部電極を備える電極対と、 [8] an electrode pair comprising a lower electrode and an upper electrode facing the lower electrode;
前記電極対の間に設けられた発光層と、 A light emitting layer provided between the electrode pair;
前記発光層と前記上部電極との間に設けられて、電子供与性物質がドープされた ドープ層と、 A doped layer provided between the light emitting layer and the upper electrode and doped with an electron donating substance;
前記ドープ層と前記発光層との間に設けられて、前記膜厚が前記ドープ層の膜厚 よりも大きいバッファ層と、 A buffer layer provided between the doped layer and the light emitting layer, the film thickness being larger than the film thickness of the doped layer;
を備えることを特徴とする自発光素子。 A self-luminous element comprising:
[9] 前記バッファ層は、前記発光層から前記ドープ層側へ移動する電荷をブロックする 電荷ブロック機能を備えることを特徴とする請求項 7または 8に記載の自発光素子。 [9] The self-luminous element according to [7] or [8], wherein the buffer layer has a charge blocking function for blocking charges moving from the light emitting layer to the doped layer side.
[10] 前記バッファ層は、前記発光層で発光される光が前記発光層上に積まれる層の面 において反射する第 1の反射光と、前記発光層で発光され前記バッファ層を透過し て前記ドープ層側の面で反射する第 2の反射光と、が強め合うような光干渉を生じさ せる膜厚に設けられていることを特徴とする請求項 9に記載の自発光素子。 [10] The buffer layer includes first reflected light that is reflected on a surface of the layer on which the light emitted from the light emitting layer is stacked, and light that is emitted from the light emitting layer and passes through the buffer layer. 10. The self-luminous element according to claim 9, wherein the self-luminous element is provided with a film thickness that causes optical interference that strengthens the second reflected light reflected by the surface on the doped layer side.
[11] 前記ドープ層は、前記バッファ層を形成する材料と同じ材料と、前記電子供与性物 質と、を含むことを特徴とする請求項 7または 8に記載の自発光素子。 [11] The self-luminous element according to [7] or [8], wherein the doped layer includes the same material as the material forming the buffer layer and the electron donating substance.
[12] 前記ドープ層は、前記バッファ層を形成する材料とは異なる材料と、前記電子供与 性物質と、を含むことを特徴とする請求項 7または 8に記載の自発光素子。 [12] The self-luminous element according to [7] or [8], wherein the doped layer includes a material different from a material forming the buffer layer and the electron donating substance.
[13] 前記自発光素子は、有機 EL素子であることを特徴とする請求項 1、 2、 7または 8の V、ずれか一つに記載の自発光素子。 13. The self-luminous element according to claim 1, 2, 7 or 8, wherein the self-luminous element is an organic EL element.
[14] 下部電極と当該下部電極に対向する上部電極とを備える電極対と、前記電極対の 間に設けられた発光層と、前記発光層と前記下部電極との間に設けられて、電子受 容性物質または電子供与性物質がドープされたドープ層と、前記ドープ層と前記発 光層との間に設けられて、前記膜厚が前記ドープ層の膜厚よりも大きいバッファ層と 、を備える自発光素子が、基板上に複数配設されていることを特徴とする自発光パネ
ル。 [14] An electrode pair including a lower electrode and an upper electrode facing the lower electrode, a light emitting layer provided between the electrode pair, and an electron pair provided between the light emitting layer and the lower electrode, A doped layer doped with an acceptor substance or an electron-donating substance, a buffer layer provided between the doped layer and the light emitting layer, wherein the film thickness is larger than the film thickness of the doped layer; A self-light-emitting panel comprising a plurality of self-light-emitting elements provided on a substrate Le.
下部電極と当該下部電極に対向する上部電極とを備える電極対と、前記電極対の 間に設けられた発光層と、前記発光層と前記上部電極との間に設けられて、電子受 容性物質または電子供与性物質がドープされたドープ層と、前記ドープ層と前記発 光層との間に設けられて、前記膜厚が前記ドープ層の膜厚よりも大きいバッファ層と 、を備える自発光素子が、基板上に複数配設されていることを特徴とする自発光パネ ノレ
An electrode pair including a lower electrode and an upper electrode facing the lower electrode; a light emitting layer provided between the electrode pair; and an electron accepting property provided between the light emitting layer and the upper electrode. A doped layer doped with a substance or an electron-donating substance, and a buffer layer provided between the doped layer and the light emitting layer, wherein the film thickness is larger than the film thickness of the doped layer. A self-luminous panel comprising a plurality of light-emitting elements disposed on a substrate.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2005035314 | 2005-02-10 | ||
JP2005-035314 | 2005-02-10 | ||
JP2005-061684 | 2005-03-04 | ||
JP2005061684 | 2005-03-04 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2006085615A1 true WO2006085615A1 (en) | 2006-08-17 |
Family
ID=36793184
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2006/302357 WO2006085615A1 (en) | 2005-02-10 | 2006-02-10 | Self-luminous device and self-luminous panel |
Country Status (1)
Country | Link |
---|---|
WO (1) | WO2006085615A1 (en) |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009069434A1 (en) * | 2007-11-28 | 2009-06-04 | Fuji Electric Holdings Co., Ltd. | Organic electroluminescent device |
JP2009252458A (en) * | 2008-04-03 | 2009-10-29 | Rohm Co Ltd | Organic electroluminescent element |
JP2011009639A (en) * | 2009-06-29 | 2011-01-13 | Toshiba Mobile Display Co Ltd | Organic el device and method of manufacturing the same |
WO2011105330A1 (en) * | 2010-02-25 | 2011-09-01 | 住友化学株式会社 | Light emitting device and a method for producing same |
WO2012008281A1 (en) * | 2010-07-13 | 2012-01-19 | 東レ株式会社 | Light emitting element |
CN103579522A (en) * | 2012-07-24 | 2014-02-12 | 三星显示有限公司 | Organic light-emitting device and organic light-emitting display apparatus including the same |
EP2833407A3 (en) * | 2013-07-31 | 2015-02-18 | LG Display Co., Ltd. | White organic light emitting diode device |
WO2017038381A1 (en) * | 2015-09-03 | 2017-03-09 | 株式会社カネカ | Organic el emission device |
CN113471372A (en) * | 2020-03-31 | 2021-10-01 | 双叶电子工业株式会社 | Organic EL device |
US20220102663A1 (en) * | 2020-09-28 | 2022-03-31 | Boe Technology Group Co., Ltd. | Organic light-emitting diode, method for manufacturing same, and display panel |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000243573A (en) * | 1999-02-18 | 2000-09-08 | Pioneer Electronic Corp | Organic electroluminescent element and manufacture thereof |
JP2000252077A (en) * | 1999-02-26 | 2000-09-14 | Matsushita Electric Ind Co Ltd | Organic electroluminescence element |
JP2002289351A (en) * | 2001-03-28 | 2002-10-04 | Toray Ind Inc | Light emitting element |
JP2003229278A (en) * | 2001-11-30 | 2003-08-15 | Semiconductor Energy Lab Co Ltd | Light emitting device |
JP2004307380A (en) * | 2003-04-04 | 2004-11-04 | Mitsubishi Chemicals Corp | New compound, charge transport material, organic electroluminescent element material and organic electroluminescent element |
-
2006
- 2006-02-10 WO PCT/JP2006/302357 patent/WO2006085615A1/en not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000243573A (en) * | 1999-02-18 | 2000-09-08 | Pioneer Electronic Corp | Organic electroluminescent element and manufacture thereof |
JP2000252077A (en) * | 1999-02-26 | 2000-09-14 | Matsushita Electric Ind Co Ltd | Organic electroluminescence element |
JP2002289351A (en) * | 2001-03-28 | 2002-10-04 | Toray Ind Inc | Light emitting element |
JP2003229278A (en) * | 2001-11-30 | 2003-08-15 | Semiconductor Energy Lab Co Ltd | Light emitting device |
JP2004307380A (en) * | 2003-04-04 | 2004-11-04 | Mitsubishi Chemicals Corp | New compound, charge transport material, organic electroluminescent element material and organic electroluminescent element |
Cited By (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8299458B2 (en) | 2007-11-28 | 2012-10-30 | Sharp Kabushiki Kaisha | Organic electroluminescent device |
WO2009069434A1 (en) * | 2007-11-28 | 2009-06-04 | Fuji Electric Holdings Co., Ltd. | Organic electroluminescent device |
JP2009252458A (en) * | 2008-04-03 | 2009-10-29 | Rohm Co Ltd | Organic electroluminescent element |
JP2011009639A (en) * | 2009-06-29 | 2011-01-13 | Toshiba Mobile Display Co Ltd | Organic el device and method of manufacturing the same |
US8357997B2 (en) | 2009-06-29 | 2013-01-22 | Japan Display Central Inc. | Organic EL device and manufacturing method thereof |
US9356251B2 (en) | 2010-02-25 | 2016-05-31 | Sumitomo Chemical Company, Limited | Light-emitting device including a first resistance layer with a creeping-up portion |
WO2011105330A1 (en) * | 2010-02-25 | 2011-09-01 | 住友化学株式会社 | Light emitting device and a method for producing same |
JP2011176190A (en) * | 2010-02-25 | 2011-09-08 | Sumitomo Chemical Co Ltd | Light emitting device and method of manufacturing the same |
WO2012008281A1 (en) * | 2010-07-13 | 2012-01-19 | 東レ株式会社 | Light emitting element |
CN102918677A (en) * | 2010-07-13 | 2013-02-06 | 东丽株式会社 | Light emitting element |
JPWO2012008281A1 (en) * | 2010-07-13 | 2013-09-09 | 東レ株式会社 | Light emitting element |
CN103579522A (en) * | 2012-07-24 | 2014-02-12 | 三星显示有限公司 | Organic light-emitting device and organic light-emitting display apparatus including the same |
TWI627774B (en) * | 2012-07-24 | 2018-06-21 | 三星顯示器有限公司 | Organic light-emitting device and organic light-emitting display apparatus including the same |
US9281487B2 (en) | 2013-07-31 | 2016-03-08 | Lg Display Co., Ltd. | White organic light emitting diode device |
EP2833407A3 (en) * | 2013-07-31 | 2015-02-18 | LG Display Co., Ltd. | White organic light emitting diode device |
WO2017038381A1 (en) * | 2015-09-03 | 2017-03-09 | 株式会社カネカ | Organic el emission device |
CN113471372A (en) * | 2020-03-31 | 2021-10-01 | 双叶电子工业株式会社 | Organic EL device |
JP2021163829A (en) * | 2020-03-31 | 2021-10-11 | 双葉電子工業株式会社 | Organic EL device |
JP7295824B2 (en) | 2020-03-31 | 2023-06-21 | 双葉電子工業株式会社 | Organic EL device |
US20220102663A1 (en) * | 2020-09-28 | 2022-03-31 | Boe Technology Group Co., Ltd. | Organic light-emitting diode, method for manufacturing same, and display panel |
US11882713B2 (en) * | 2020-09-28 | 2024-01-23 | Boe Technology Group Co., Ltd. | Organic light-emitting diode, method for manufacturing same, and display panel |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2006085615A1 (en) | Self-luminous device and self-luminous panel | |
US6469437B1 (en) | Highly transparent organic light emitting device employing a non-metallic cathode | |
TWI300314B (en) | Electroluminescence device | |
KR101234469B1 (en) | Intermediate electrodes for stacked OLEDs | |
US8445895B2 (en) | Organic electroluminescence element | |
KR20010102087A (en) | Opto-electrical devices | |
US9620568B2 (en) | Display substrate, fabricating method thereof and display apparatus | |
KR20060095985A (en) | Compound electrodes for electronic devices | |
US7960723B2 (en) | Stacked electro-optically active organic diode with inorganic semiconductor connection layer | |
JP2009530804A (en) | Electroluminescence device | |
JP4131924B2 (en) | Organic EL display device | |
US7233105B2 (en) | Organic electroluminescent display device having plural carrier transportation layers | |
JP2011258373A (en) | Organic el element and organic el display | |
JP2004171957A (en) | Organic el device, and organic el display | |
KR100888148B1 (en) | Organic Electro luminescence Device and fabrication method of thereof | |
JP2006114844A (en) | Selecting method of organic el device material, organic el device and manufacturing method thereof | |
KR102009804B1 (en) | Organic light emitting diode display device and method for manufacturing the same | |
JP2003297575A (en) | Organic electroluminescent element | |
US7071614B2 (en) | Electron and hole modulating electrodes in organic light emitting diodes | |
US8895964B2 (en) | Organic EL element and production method thereof | |
KR100699966B1 (en) | Organic electroluminescence device and organic electroluminescence display | |
KR20180047546A (en) | Organic Light Emitting Device and Organic Light Emitting Display Device | |
US7812517B2 (en) | Organic electroluminescent device and method of manufacturing the same | |
JP2004152595A (en) | Display apparatus | |
KR102477831B1 (en) | Organic light emitting device including nano-island structures and manufacturing method thereof |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 06713500 Country of ref document: EP Kind code of ref document: A1 |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 6713500 Country of ref document: EP |
|
NENP | Non-entry into the national phase |
Ref country code: JP |