JP5617645B2 - ORGANIC ELECTROLUMINESCENT ELEMENT MATERIAL, ORGANIC ELECTROLUMINESCENT ELEMENT, DISPLAY DEVICE AND LIGHTING DEVICE USING THE SAME - Google Patents

Description

  The present invention relates to a novel organic electroluminescent element material, and an organic electroluminescent element, a display element, and a lighting device using the same.

  Conventionally, there is an electroluminescence display (hereinafter referred to as ELD) as a light-emitting electronic display device. As ELD, an inorganic electroluminescence element and an organic electroluminescence element (hereinafter, also referred to as organic EL) can be given. Inorganic electroluminescent elements have been used as planar light sources, but a high voltage is required to drive the light emitting elements. An organic electroluminescence device has a light-emitting layer containing a compound that emits light, and a structure in which a plurality of organic compound layers are sandwiched between a cathode and an anode as necessary. It is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when excitons (excitons) are generated by bonding, and the excitons are deactivated. Since it is capable of emitting light by voltage, and is self-luminous, it has a wide viewing angle, high visibility, and since it is a thin-film complete solid-state device, it has attracted attention from the viewpoint of space saving and portability.

  However, in the organic electroluminescence device for practical use in the future, development of an organic electroluminescence device that emits light with higher efficiency and longer life is desired.

  In addition, it has become clear that not only fluorescent materials but also phosphorescent materials can be used as light-emitting materials for organic electroluminescence elements, and research and development has been conducted earnestly. The generation ratio of singlet excitons and triplet excitons is 1: 3. In the case of fluorescent materials, only excited singlets can be used, whereas in the case of phosphorescent materials, excitation is performed in addition to excited singlets. Since triplet can also be used, the upper limit of internal quantum efficiency can be made 100%. For this reason, when a phosphorescent material is used compared to a fluorescent material, the luminous efficiency is four times in principle, and there is a possibility of obtaining almost the same performance as a cold cathode tube. ing.

  On the other hand, as a means of improving the lifetime of organic electroluminescence devices, research focused on the structure of the compound contained has resulted in the discovery of some materials that could withstand practical use. Yes.

  Regarding materials for organic electroluminescence devices having a cyclic structure, materials having a cyclic structure with an arylene group and a heteroatom or an arylene group and an alkylene group, such as (thia) calixarenes (see, for example, Patent Documents 1 and 2). In addition, a cyclic compound material having an arylene group directly bonded thereto (for example, see Patent Document 3) and a cyclic siloxane structure (for example, see Patent Document 4) have already been disclosed.

  However, these cyclic compounds are superior in stability of the device as compared with chain compounds, but have problems in compatibility with other materials when used as devices, have a long phosphorescence wavelength, and are blue phosphorescent. When using a light-emitting dopant, it became clear that the efficiency was insufficient practically.

JP 2007-335638 A JP 2009-260286 A JP 2007-165377 A International Publication No. 08/053935 Pamphlet

  An object of the present invention is to provide an organic electroluminescence element with high efficiency, long life and few dark spots, and a display device and an illumination device using the organic electroluminescence element.

The above object of the present invention can be achieved by the following configurations 1 to 6 .
Specifically, according to the present invention, in the constitution 1, in the general formula (1), X is SiR ₁ R ₂ , PR ₃ , P (= Y) R ₄ , O, S, SO ₂ , NR ₅ , CR _6. There is provided a material for an organic electroluminescence device which represents R ₇ or C (═O), and at least one X represents SiR ₁ R ₂ , PR ₃ or P (= Y) R ₄ .

  1. An organic electroluminescent element material represented by the following general formula (1).

[In the formula, Ar and X are bonded to each other to form an 8-membered or higher cyclic compound, m and n represent an integer of 1 or more, m Ar may be the same or different, and n m and X may be the same or different. Ar represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring. When all m are 1, at least one X represents SiR ₁ R ₂ , PR ₃ or P (= Y) R _4, and when m is 2 or more, X is SiR ₁ R ₂ , PR ₃ , P (= Y) represents R ₄ , O, S, SO ₂ , NR ₅ , CR ₆ R ₇ or C (═O). Y represents oxygen, sulfur or selenium, and R ₁ to R ₇ each represents a substituent. ]
2. _2. The organic electroluminescent element material according to 1 above, wherein in the general formula (1), X is any _one of SiR ₁ R ₂ , PR ₃ or P (= Y) R ₄ .

  3. 3. An organic electroluminescence device comprising the material for an organic electroluminescence device according to 1 or 2 above.

  4). 3. An organic electroluminescence device, wherein the layer containing the material for an organic electroluminescence device according to the above 1 or 2 is formed by a wet method (wet process).

  5. 5. A display device comprising the organic electroluminescence element as described in 3 or 4 above.

  6). 5. An illuminating device comprising the organic electroluminescence element as described in 3 or 4 above.

  According to the present invention, it was possible to provide an organic electroluminescence element with high efficiency, long life, and few dark spots, and a display device and an illumination device using the same.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of a display part. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

  In view of the above problems, the present inventors have focused on macrocyclic compounds during intensive studies, and have achieved the present invention by overcoming these problems.

  That is, by using the compound represented by the general formula (1) in which a group represented by X is introduced into a part of the ring structure of the macrocyclic compound, the stability of the device is improved and the combination is used together. The present inventors have found that a stable organic electroluminescence device can be provided that has good compatibility with the organic electroluminescence device material. In addition, it has been found that an organic electroluminescence device exhibiting good device performance can be provided even when a blue light emitting phosphorescent dopant is used, and further, a material capable of being coated and formed can be provided.

  As these factors, by making the structure represented by the general formula (1) in which a group represented by X is introduced into a part of the cyclic compound, the entire ring or the planarity of Ars constituting the ring The torsion can be adjusted to an appropriate level, so the compatibility with other materials is good and the film quality is expected to improve. Furthermore, it is considered that the introduction of a group represented by X has made it possible to suppress the phosphorescence emission wavelength from becoming longer. Due to these factors, when the organic electroluminescent element organic layer is formed using the organic electroluminescent element material of the present invention, the compatibility with other materials is good, and the stability as an element as well as a compound is excellent. In addition, it is presumed that high-efficiency light emission is possible even for blue phosphorescent dopants.

  The material for an organic electroluminescence element of the present invention is represented by the general formula (1).

  In the general formula (1), Ar may be the same or different aromatic hydrocarbon rings (also referred to as aromatic carbocyclic groups, aryl groups, etc., for example, a phenyl group, a p-chlorophenyl group, a mesityl group, Tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrimidyl group, furyl) Group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.)) , Oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothia Ryl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbolyl group (the carbon atom constituting the carboline ring of the carbolinyl group) One of which is replaced by a nitrogen atom), a quinoxalinyl group, a triazinyl group, a quinazolinyl group, a phthalazinyl group, and the like, and more preferable aromatic hydrocarbon rings include a phenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, and a biphenylyl group. Similarly, more preferred aromatic heterocyclic groups include pyridyl group, pyrimidyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, thienyl group, quinolyl group, indolyl group, dibenzofuryl group, A zolyl group, a carbolinyl group, and a diazacarbolinyl group, and more preferably a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, a pyridyl group, a thienyl group, a dibenzofuryl group, a carbazolyl group, a carbolinyl group, a diazacarba A zolyl group may be mentioned. These Ar bonds to other Ar or X at an arbitrary position, and the connecting positions may be the same or different. Ar may further have a substituent. Examples of such a substituent include an alkyl group, a cycloalkyl group, an alkynyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a heterocyclic group (for example, pyrrolidyl Group, imidazolidyl group, morpholinyl group, oxazolidyl group, etc.), alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, acyl group, acyloxy Group, amide group, carbamoyl group, ureido group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group, heteroarylsulfonyl group, amino group, halogen atom, fluorinated hydrocarbon group, cyano group, nitro group, hydroxy group, mercapto group , Silyl group, phosphono group Preferred examples include alkyl groups, aromatic hydrocarbon ring groups, aromatic heterocyclic groups, amino groups, silyl groups, and phosphono groups, and these substituents may be the same or different. It is also possible to form a ring by further substituting and bonding with the above substituents. The carbazolyl group and derivatives thereof can be bonded by a carbon-carbon bond or a nitrogen-carbon bond, but more preferably a substituent bonded by a carbon-carbon bond.

  m represents an integer of 1 or more and 20 or less, preferably an integer of 2 or more and 15 or less, and m Ar may be the same or different from each other.

X represents SiR ₁ R ₂ , PR ₃ , P (= Y) R ₄ , O, S, NR ₅ or CR ₆ R _7, and when all m are 1, at least one X is SiR ₁ R ₂ , PR ₃ , P (= Y) R ₄ , wherein X is preferably SiR ₁ R ₂ , PR ₃ , P (= Y) R ₄ or NR ₅ , more preferably SiR ₁ R ₂ , PR ₃ or P (= Y) R ₄ , more preferably SiR ₁ R ₂ or P (= Y) R ₄ . Y represents oxygen, sulfur or selenium, preferably oxygen or sulfur, more preferably sulfur.

R ₁ to R ₇ each represents a substituent, and examples of the substituent include the above-mentioned substituents, preferably an aromatic hydrocarbon ring group and an aromatic heterocyclic group, more preferably a dibenzofuryl group and a carbazolyl group. A group, a carbolinyl group, a diazacarbazolyl group, and an amino group, which may further have a substituent.

  n represents an integer of 1 or more and 20 or less, and n m and X may be the same or different. The sum of m and n is preferably 2 or more and 40 or less, more preferably 2 or more and 20 or less, still more preferably 3 or more and 10 or less, and any one of 4 to 8 It is more preferable that it is an integer. The magnitude relationship between m and n is not particularly limited, but the difference between m and n is more preferably an integer smaller than 5.

  At this time, the size of the ring formed is not particularly limited as long as it is an 8-membered ring or more, but it is preferably an 8-membered ring or more and a 100-membered ring or less, more preferably a 10-membered ring or more and a 50-membered ring. It is below, More preferably, they are 10-membered ring or more and 30-membered ring or less.

  Hereinafter, although the compound concerning this invention is mentioned, it is not limited to these. The compounds according to the present invention are described in Macromolecules, pages 10413-10420 (2005), Chemistry-A European Journal, pages 1361-1150 (1997), J. Am. Chem. Soc. , Chem. Commun. , 336-339 (1990), Japanese Patent Application Laid-Open No. 2009-260286, and the like.

  Synthesis examples of the compounds of the present invention are shown below.

  << Synthesis of Compound (19) of the Present Invention >>

<Synthesis of Intermediate (C)>
Separately synthesized intermediate (A), 5.0 g and intermediate (B), 2.6 g were placed in a flask, THF (tetrahydrofuran), 200 ml and EtOH, 20 ml were added, and nitrogen was bubbled for 30 minutes. To this solution, 3.0 g of potassium carbonate and 0.3 g of tetrakistriphenylphosphine palladium as a catalyst were added and heated under reflux for 12 hours under a nitrogen stream. After allowing to cool, 100 ml of water was added, the organic layer was extracted, washed with water, dried over sodium sulfate, concentrated, and then subjected to column chromatography to obtain 3.0 g of intermediate (C) (yield 60%).

<Synthesis of Intermediate (E)>
Intermediate (C), 3.0 g, intermediate (D), 3.6 g, and DMAc (dimethylacetamide) 30 ml were placed in a flask and bubbled with nitrogen for 15 minutes. To this solution, 2.1 g of potassium carbonate and 0.8 g of copper as a catalyst were added and reacted at 150 ° C. for 8 hours under a nitrogen stream. After completion of the reaction, water, 200 ml and ethyl acetate, 200 ml were added, the organic layer was extracted, washed with water, dried over sodium sulfate and concentrated, and then 1.9 g of intermediate (E) was obtained by column chromatography (yield). (Rate 39%).

<Synthesis of Compound (19) of the Present Invention>
Intermediate (E) (1.9 g) was placed in a flask, and dehydrated THF (100 ml) was added and dissolved under a nitrogen stream. Under a nitrogen stream, this solution was cooled in a dry ice / acetone bath, and a mixed solution of n-BuLi (1.65 M), 3 ml and THF, 10 ml was added dropwise while maintaining at −70 ° C. or lower. After stirring at low temperature for 30 minutes, dichlorophenylphosphine, 0.4 g and THF, 10 ml were added dropwise. The solution was returned to room temperature and heated to reflux for 3 hours. After completion of the reaction, the organic layer was washed twice with 50 ml of water, 100 ml of a solution obtained by diluting hydrogen peroxide solution (30 to 35.5%) twice was added, and stirred at room temperature for 2 hours. The organic layer was washed with water until neutral, dried over sodium sulfate, and purified by preparative GPC to obtain 0.4 g of the compound (19) of the present invention (yield 22%).

  << Synthesis of Compounds (21) and (32) of the Present Invention >>

<Synthesis of Intermediate (C ')>
Under a nitrogen stream, intermediate (A ') 10.0 g and THF (tetrahydrofuran) separately synthesized in the flask were added and cooled in a dry ice / acetone bath. After cooling to −70 ° C. or lower, 15.8 ml of n-BuLi (1.65 M) was added dropwise, followed by dropwise addition of 3.2 g of dichlorodiphenylsilane (B ′) together with 15 ml of THF. After completion of the dropwise addition, the temperature was gradually returned to room temperature over 3 hours, water and 50 ml were added, liquid separation, washing with water, drying over sodium sulfate, concentration, purification by chromatography, intermediate (C ′) 7.4 g were obtained (72% yield).

<Synthesis of Intermediate (E ')>
Intermediate (C ′), 6.5 g, intermediate (D), 3.7 g and DMSO (dimethyl sulfoxide) 50 ml were placed in a flask and bubbled with nitrogen for 15 minutes. To this solution, 4.9 g of potassium carbonate and 0.9 g of [1,1′-bis (diphenylphosphino) ferrocene] palladium (II) dichloride dichloromethane adduct were added and reacted at 120 ° C. for 8 hours. After allowing to cool, 500 ml of water was gradually added with stirring, and the precipitated solid was collected by filtration and recrystallized from toluene to obtain 5.1 g of intermediate (E ′) (yield 65%).

<Synthesis of Intermediate (F ')>
Intermediate (F ′) (5.0 g) was dissolved in DMF (dimethylformamide) (50 ml), and bromine (0.6 ml) was added while cooling in an ice bath. The solution was further stirred at room temperature for 4 hours, 500 ml of water was added, and the mixture was extracted with toluene. The organic layer was washed with an aqueous sodium thiosulfate solution, further washed with water, dried over magnesium sulfate, and concentrated. As a result, a solid was precipitated, which was collected by filtration and further recrystallized from toluene / THF to give an intermediate (F ′). 4.7 g was obtained (82% yield).

<Synthesis of Compound (32) of the Present Invention>
Under a nitrogen stream, intermediate (F ′), 4.5 g, THF, 450 ml were placed in a flask, cooled in a dry ice / acetone bath, and maintained at −70 ° C. or lower while maintaining n-BuLi (1.65 M), 4 7 ml was added dropwise. After stirring at low temperature for 30 minutes, dichlorophenylphosphine (G ′), 0.7 g and THF, 50 ml were added dropwise. The solution was gradually returned to room temperature and then heated to reflux for 8 hours. After completion of the reaction, the organic layer was washed twice with water, and then the insoluble matter in the organic layer was filtered off. This solution was further washed with water, dehydrated with magnesium sulfate, and purified by preparative GPC to obtain 0.38 g of the compound (32) of the present invention (yield 9%).

<Synthesis of Compound (21) of the Present Invention>
50 ml of a solution obtained by dissolving 0.35 g of the compound (32) of the present invention in 100 ml of EtOH and diluting a hydrogen peroxide solution (30 to 35.5%) three times was added and stirred for 2 hours. After completion of the reaction, the solution was neutralized with an aqueous sodium hydroxide solution, and the solution was concentrated under reduced pressure. To the concentrated reaction solution, 50 ml of THF was added, washed with water, dried over magnesium sulfate, and purified by preparative GPC to obtain 0.27 g of the compound (21) of the present invention (yield 76%).

  << Synthesis of Compound (25) of the Present Invention >>

<Synthesis of Intermediate (C ")>
Under a nitrogen stream, 2,2′-dibromobiphenyl (A ″), 12.0 g and dehydrated Et 2 O (diethyl ether), 200 ml were added to the flask, and the solution was cooled to −70 ° C. or lower in a dry ice / acetone bath. Then, a mixed solution of tetrachlorosilane (B ″), 26.0 g, Et 2 O and 150 ml was dropped. The mixture was stirred for 6 hours while maintaining at -70 ° C or lower, and returned to room temperature. The precipitated solid was filtered off, and the filtrate was concentrated under reduced pressure to obtain 5.0 g of intermediate (C ″) (yield 52%).

<Synthesis of Intermediate (E ")>
Under a nitrogen stream, 1,4-dibromobenzene (D ″), 4.7 g and THF, 50 ml were added and cooled in a dry ice / acetone bath. N-BuLi (1.65 M) was maintained at −70 ° C. or lower. 12.6 ml), and after stirring at low temperature for 1 hour, a mixed solution of Intermediate (C ″), 2.5 g and THF, 50 ml was gradually added to this solution. After completion of the dropwise addition, the mixture was further stirred for 2 hours at a low temperature, and then the temperature was raised. Water and 100 ml were added at -10 ° C. The reaction mixture was separated, washed with water, dehydrated with sodium sulfate, and purified by column chromatography to obtain 2.1 g of intermediate (E ″) (43% yield).

<Synthesis of Compound (25) of the Present Invention>
Under a nitrogen stream, intermediate (E ″), 2.0 g and THF, 200 ml were added and cooled in a dry ice / acetone bath. N-BuLi (1.65 M), 5.2 ml while maintaining at −70 ° C. or lower. Then, a mixed solution of 10 ml of THF and 10 ml of THF was dropped, and the mixture was stirred as it was at low temperature for 30 minutes, and then 1.1 g of intermediate (C ″) and THF, 30 ml were dropped. After further stirring at low temperature for 1 hour, the solution was returned to room temperature and heated to reflux for 4 hours. After completion of the reaction, water was added, followed by liquid separation, washing with water, drying over sodium sulfate, and purification by preparative GPC to obtain 0.3 g of the compound (25) of the present invention (yield 14%).

  In the preparation of the organic EL device of the present invention, which will be described later, a sample that was further subjected to sublimation purification twice was used.

  The compound according to the present invention may be contained in any organic layer in the organic electroluminescence device, but is preferably used as a host compound, a hole transport material, or an electron transport material, more preferably a host. It is used as a material and a hole transport material. At this time, each organic layer may be composed of the compound according to the present invention alone, or may be used by mixing with other materials.

≪Component layer of organic EL element≫
The constituent layers of the organic EL element of the present invention will be described. In the present invention, preferred specific examples of the layer structure of the organic EL element are shown below, but the present invention is not limited thereto.
(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode In the organic EL device of the present invention, the blue light emitting layer preferably has a light emission maximum wavelength of 430 to 480 nm, and the green light emitting layer has a light emission maximum wavelength of 510 to 550 nm, The red light emitting layer is preferably a monochromatic light emitting layer having a light emission maximum wavelength in the range of 600 to 640 nm, and is preferably a display element using these. Alternatively, a white light emitting layer may be formed by laminating at least three light emitting layers. Further, a non-light emitting intermediate layer may be provided between the light emitting layers. The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

  Each layer which comprises the organic EL element of this invention is demonstrated.

≪Luminescent layer≫
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May also be the interface between the light emitting layer and the adjacent layer.

  There is no particular limitation on the total thickness of the light emitting layer, but from the viewpoint of preventing the application of unnecessary high voltage during film homogeneity and light emission, and improving the stability of the light emission color with respect to the drive current It is preferable to adjust to the range of 5 micrometers, More preferably, it adjusts to the range of 2-200 nm, Especially preferably, it is the range of 10-40 nm.

  The light emitting layer of the organic EL device of the present invention contains a light emitting dopant (phosphorescent dopant (also referred to as phosphorescent dopant group) or fluorescent dopant) compound and a host compound.

(Luminescent dopant compound)
The luminescent dopant compound will be described.

  As the luminescent dopant compound, a fluorescent dopant compound or a phosphorescent dopant compound can be used.

(Phosphorescent dopant compound)
The phosphorescent dopant compound according to the present invention will be described.

  The phosphorescent dopant compound according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.), and a phosphorescence quantum yield of 25 ° C. The phosphorescence quantum yield is preferably 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectra II, page 398 (1992 version, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant compound according to the present invention can be measured in any solvent if the phosphorescence yield of 0.01 or more is achieved. good.

  There are two types of emission principles of the phosphorescent dopant compound. One is the recombination of carriers on the host compound to which carriers are transported, and the excited state of the luminescent host compound is generated. Energy transfer type that obtains light emission from phosphorescent dopant by moving to optical dopant. The other is a carrier trap type in which the phosphorescent dopant compound itself becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant compound is obtained. It is a condition for obtaining good light emission that the excited state energy of the phosphorescent dopant compound is lower than the excited state energy of the host compound.

  Although the specific example of the well-known compound used as a phosphorescence dopant below is shown, this invention is not limited to these. These compounds are described in, for example, Inorg. Chem. 40, pages 1704 to 1711, and the like.

  Although the example of a light emission dopant is given to the following, it is not limited to these.

(Fluorescent dopant compound)
As fluorescent dopant compounds, coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squarylium dyes, oxobenzoanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, Examples include stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

(Luminescent host compound (also referred to as luminescent host))
As the light-emitting host compound used in the light-emitting layer and the light-emitting unit of the organic EL device of the present invention, among the compounds contained in the light-emitting layer, the mass ratio in the layer is 20% or more and room temperature (25 ° C) is defined as a compound having a phosphorescence quantum yield of less than 0.1, preferably a phosphorescence quantum yield of less than 0.01. Moreover, it is preferable that the mass ratio in a layer is 20% or more among the compounds contained in a light emitting layer.

  As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of carriers, and the performance of the organic EL element can be further increased. Moreover, it becomes possible to mix different light emission by using multiple types of well-known compounds used as the said phosphorescence dopant, and, thereby, arbitrary luminescent colors can be obtained.

  The light emitting host used in the present invention may be a low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). Alternatively, one or a plurality of such compounds may be used.

  Known light-emitting host compounds typically include those having a basic skeleton such as carbazole derivatives, triarylamine derivatives, aromatic derivatives, nitrogen-containing heterocyclic compounds, thiophene derivatives, furan derivatives, oligoarylene compounds, carboline derivatives, And diazacarbazole derivatives.

  A known host compound that may be used in combination is preferably a compound that has a hole transporting ability and an electron transporting ability, prevents a long wavelength of light emission, and has a high Tg (glass transition temperature).

  Specific examples of known host compounds include, but are not limited to, compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  Next, an injection layer, a blocking layer, a transport layer, and the like used as a constituent layer of the organic EL element of the present invention will be described.

≪Injection layer: electron injection layer, hole transport layer≫
The injection layer is provided as necessary, and has an electron injection layer and a hole injection layer, and is present between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer as described above. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to lower drive voltage and improve light emission luminance. “Organic EL element and its industrialization front line (November 30, 1998, issued by NTT) 2 of Chapter 2 “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45579, JP-A-9-260062, JP-A-8-288069, and the like, and representative examples thereof include copper phthalocyanine. Phthalocyanine buffer layers, oxide buffer layers typified by vanadium oxide, amorphous carbon buffer layers, polymer buffer layers using conductive polymers such as polyaniline (emeraldine) and polythiophene, and the like.

  Details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium or aluminum Metal buffer layer represented by lithium fluoride, alkali metal compound buffer layer represented by lithium fluoride, alkaline earth metal compound buffer layer represented by magnesium fluoride, oxide buffer layer represented by aluminum oxide, etc. It is done.

  The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

≪Blocking layer: hole blocking layer, electron blocking layer≫
As described above, the blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film. For example, described in JP-A Nos. 11-204158 and 11-204359, and “Organic EL devices and the forefront of industrialization (November 30, 1998, issued by NTS Corporation)” on page 237, etc. There is a hole blocking layer (hole blocking layer).

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material having a function of transporting electrons and having a remarkably small ability to transport holes. By blocking hole transport, the recombination probability of electrons and holes can be improved. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

  The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

  The hole blocking layer preferably contains the carbazole derivative, carboline derivative, diazacarbazole derivative, or the like mentioned as the host compound.

  Moreover, when it has several light emitting layers from which luminescent color differs, it is preferable that the light emitting layer with the shortest light emission maximum wavelength is the closest to an anode among all the light emitting layers. In such a case, it is preferable to additionally provide a hole blocking layer between the shortest wave light emitting layer and the light emitting layer next to the anode next to the light emitting layer. Further, it is preferable that 50% by mass or more of the compound of the hole blocking layer provided at the position is 0.3 eV or more larger than the ionization potential of the host compound of the shortest wave emitting layer.

  The ionization potential is defined as the energy required to emit electrons at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained by, for example, the following method.

  (1) Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), a molecular orbital calculation software manufactured by Gaussian, USA The ionization potential can be obtained as a value obtained by rounding off the second decimal place of the value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  (2) It can also be determined by a method of direct measurement by photoelectron spectroscopy. Yes. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material having a function of transporting holes and a very small ability to transport electrons, and transporting electrons while transporting holes. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed.

  The film thickness of the hole blocking layer and the electron blocking layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

≪Hole transport layer≫
The hole transport layer is made of a hole transport material having a function of transporting holes. In a broad sense, the hole transport layer and the electron blocking layer can be regarded as being included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers and conductive polymers (polymers and oligomers), particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound. In addition, the organic EL device material of the present invention can be preferably used in the same manner.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4 '. -Diamine (TPD), 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), 4,4 ', 4 "-tris [N- (3-methylphenyl) ) -N-phenylamino] triphenylamine (MTDATA).

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or a polymer main chain can also be used. Inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole transport material. JP-A-11-251067, J. Org. Huang et al. A p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used.

  The hole transport layer is formed by thinning the hole transport material as described above by, for example, a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. be able to. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-5 micrometers, Preferably it is 5-200 nm. Further, the hole transport material may have a single layer structure composed of a plurality of types of materials.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used.

≪Electron transport layer≫
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  An electron transport material (also serving as a hole blocking material) used for the electron transport layer adjacent to the cathode side with respect to the light emitting layer may have a function of transmitting electrons injected from the cathode to the light emitting layer. As the material, any one of conventionally known compounds can be selected and used. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthra Examples include quinodimethane and anthrone derivatives, oxadiazole derivatives, and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material. In addition, phthalocyanine materials and derivatives thereof can also be preferably used as the electron transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials. Further, an electron transport layer having a high n property doped with impurities can also be used.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used.

  For the anode, a thin film may be formed by vapor deposition or sputtering of these electrode materials, and a pattern may be formed through a photolithography method or a mask. Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually in the range of 10 to 1000 nm, preferably in the range of 10 to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

  Moreover, after producing the said metal with a film thickness of 1-20 nm on a cathode, a transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
The support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc., and is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellulose esters (cellulose acetate propionate (CAP), cellulose acetate phthalate (TAC), and cellulose nitrate. Etc.) or derivatives thereof, polyvinylidene chloride, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, polyethersulfone (PES), polyphenylene sulfide, polysulfones, polyether Imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic Alternatively polyarylates, and cycloolefin resins such as ARTON (manufactured by JSR) or APEL (manufactured by Mitsui Chemicals).

On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. Water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24 h) or less, and further, oxygen measured by a method according to JIS K 7126-1987. Preferably, the film is a high barrier film having a permeability of 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻³ g / (m ² · 24 h) or less, and moreover, a water vapor transmission rate. The degree is more preferably 10 ⁻⁵ g / (m ² · 24 h) or less.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing intrusion of moisture or oxygen that causes deterioration of the element. For example, silicon oxide, silicon dioxide, silicon nitride, or the like is preferably used. it can. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, and an atmospheric pressure plasma polymerization method is particularly preferable.

  Examples of the opaque support substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, and ceramic substrates.

  The external extraction quantum efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors with a phosphor may be used in combination. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, transparency and electrical insulation are not particularly limited.

  Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned. Further, the polymer film has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less, and conforms to JIS K 7129-1992. The water permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by the method is preferably 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

  In addition, when using a thermosetting adhesive, since an organic EL element may deteriorate with heat processing, what can be adhesively cured from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum is also possible. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, etc.), metal halides. Perchloric acids and the like, and anhydrous salts are preferably used.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when sealing is performed by the sealing film, it is preferable to provide a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, etc. used for the sealing can be used. It is preferable to use a film.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1) and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (US Pat. No. 4,774,435), A method of improving efficiency by providing a light collecting property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (Japanese Patent Laid-Open No. 1-220394), and light emission from a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the bodies (Japanese Patent Laid-Open No. 62-172691), a flat having a lower refractive index between the substrate and the light emitter than the substrate A method of introducing a layer (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer and a light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951) Gazette).

  In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used. In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction, such as first-order diffraction or second-order diffraction, and light generated from the light-emitting layer. The light that cannot go out due to total reflection between layers, etc. is diffracted by introducing a diffraction grating in any layer or medium (in the transparent substrate or transparent electrode). It is intended to be taken out.

  The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much. However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or in the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium.

  The arrangement of the diffraction grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condenser sheet>
The organic EL device of the present invention can be processed to provide, for example, a microlens array-like structure on the light extraction side of the substrate, or combined with a so-called condensing sheet, for example, in a specific direction, for example, the device light emitting surface. On the other hand, the brightness | luminance in a specific direction can be raised by condensing in a front direction.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode will be described.

  First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm, thereby producing an anode.

  Next, an organic compound thin film of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a hole blocking layer, which are organic EL element materials, is formed thereon.

  As a method for forming each of these layers, there are a vapor deposition method, a wet process (spin coating method, casting method, ink jet method, printing method) and the like as described above. In view of the above, in the present invention, a wet process is preferable, and film formation by a coating method such as a spin coating method, an ink jet method, or a printing method is particularly preferable.

  Examples of the liquid medium for dissolving or dispersing the organic EL device material of the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as DMF and DMSO can be used. Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

  After these layers are formed, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 50 to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.

  In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do.

  The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with the total CS-1000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates.

Further, when the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is X when the 2 ° viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

  Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing an example of a display device composed of organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

  The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of a plurality of pixels based on image information from the outside. The image information is sequentially emitted to scan the image and display the image information on the display unit A.

  FIG. 2 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.

  In the figure, the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

  The scanning line 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at the orthogonal positions (details are illustrated). Not)

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data.

  Full-color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region on the same substrate.

  FIG. 3 is a schematic diagram of the lighting device, and the organic EL element 101 is covered with a glass cover 102 (in addition, the sealing operation with the glass cover is performed in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. (In a high purity nitrogen gas atmosphere with a purity of 99.999% or more). FIG. 4 is a cross-sectional view of the lighting device. In FIG. 4, a cathode 105, an organic EL layer 106, and a glass substrate 107 with a transparent electrode are shown. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

  In addition, although the display of "%" is used in an Example, unless otherwise indicated, "mass%" is represented. In addition, standard compounds and comparative compounds used in Examples are shown below.

Example 1
<< Production of organic EL element >>
[Production of Organic EL Element 1-1]
Using a substrate in which ITO (indium tin oxide) is formed to a thickness of 200 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm, the ITO film is patterned to obtain a light emitting area of 50 mm × 50 mm, and an anode electrode (ITO) A transparent electrode) was prepared, ultrasonically cleaned with isopropyl alcohol, dried with nitrogen gas, and further subjected to UV ozone cleaning to prepare a transparent support substrate.

This transparent support substrate was put into a commercially available vacuum deposition apparatus, and after reducing the pressure to 4 × 10 ⁻⁴ Pa or less, CuPc (copper phthalocyanine) was deposited as a hole injection layer to provide a 20 nm hole injection layer.

The HT-1 and 20nm deposited a hole transport layer continues further, a light emitting layer of D-36 was as dopant concentration of 6% and to reduction compound host material thereon and (15) as a dopant material 30 nm was deposited. Further, 30 nm of ET-1 is evaporated to form an electron transport layer, 0.5 nm of lithium fluoride is subsequently evaporated to form an electron injection layer, 120 nm of aluminum is evaporated to form a cathode, and the organic EL device 1-1 is formed. did. Each element after fabrication was evaluated by covering the non-light emitting surface with a glass case and sealing the peripheral edge with an epoxy adhesive.

<< Production of Organic EL Elements 1-2 to 1-15 >>
In the production of the organic EL element 1-1, the organic EL elements 1-2 to 1-15 were produced in the same manner except that the electron transport material, the host material, and the hole transport material were changed as shown in Table 1. did.

<< Evaluation of Organic EL Elements 1-1 to 1-15 >>
The efficiency and stability of the organic EL elements 1-1 to 1-15 were evaluated by the following methods. The results are shown in Table 1.

(efficiency)
About the produced organic EL elements 1-1 to 1-15, the external extraction quantum efficiency when a constant current of ^2.5 mA / cm ² was applied was measured. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used. The values of efficiency in Table 1 are 100 for the organic EL elements 1-1 to 1-6, and 100 for the organic EL elements 1-7 to 1-11. The measured value of the EL element 1-7 was set to 100, and relative to the organic EL elements 1-12 to 1-15, the measured value of the organic EL element 1-12 was set to 100.

(Stability)
About the produced organic EL elements 1-1 to 1-15, a constant current drive is performed with a current that gives an initial luminance of 1000 cd / m ² , and a time that is ½ (500 cd / m ² ) of the initial luminance is measured. A measure of stability. Similar to the evaluation of efficiency, the stability value is 100 for the organic EL elements 1-1 to 1-6, and the measured value of the organic EL element 1-1 is 100. 11 is a relative value when the measured value of the organic EL element 1-7 is 100, and the measured value of the organic EL element 1-12 is 100 for the organic EL elements 1-12 to 1-15. expressed. An element whose initial luminance did not reach 1000 cd / m ² is indicated by a cross.

(Dark spot)
About the organic EL element 1-1 to 1-15 after stability evaluation, the presence or absence of a dark spot was confirmed visually, and evaluation was performed according to the following evaluation criteria. Practically, it is preferable that it is (double-circle)-(circle). In addition, what was x mark by stability evaluation is not evaluated.

◎: No dark spot is confirmed. ○: 1 to 5 dark spots are confirmed. △: 6 or more dark spots are confirmed, but the emission area is more than half of the device. Is non-luminous

  From the above, it has been clarified that by using the organic EL element material of the present invention, an organic EL element having excellent efficiency and stability and having few dark spots can be provided.

Example 2
<< Production of White Light Emitting Element and White Lighting Device-1 >>
On the glass substrate with ITO patterned to 20 mm × 20 mm as the anode, HT-1 as a hole injecting / transporting layer was formed to a thickness of 25 nm in the same manner as in Example 1, and the compound (24) and D-34 and D-39 were adjusted such that the deposition rate was 100: 0.5: 8, and a light-emitting layer having a thickness of 40 nm was provided. Next, 10 nm of BAlq was formed as a hole blocking layer, and then 40 nm of Alq ₃ was formed to provide an electron transport layer. Subsequently, lithium fluoride was formed to a thickness of 0.5 nm as an electron injection layer, and then 150 nm of aluminum was formed as a cathode. The non-light emitting surface was covered with a glass case and sealed with an epoxy adhesive.

  The flat lamp shown in FIGS. 3 and 4 was produced using this element. When this flat lamp was energized, it was found that almost white light was obtained and it could be used as a lighting device.

Example 3
<< Production of White Light Emitting Element and White Lighting Device-2 >>
Poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) is 70% pure water on the same substrate as that for preparation of the white light emitting element and the white lighting device. The solution diluted in (1) was spin-coated at 3000 rpm for 30 seconds and then dried to provide a hole transport layer having a thickness of 30 nm.

Furthermore, this board | substrate with a positive hole transport layer was moved under nitrogen atmosphere, and the solution which melt | dissolved the compound 13 (120 mg), D-34 (3.5 mg), and D-7 (3.0 mg) in 8 ml of toluene was 1000 rpm and 30 seconds. After spin coating, it was dried under vacuum at 100 ° C. to obtain a light emitting layer. Subsequently, this substrate was transferred to a vacuum deposition apparatus, and Alq ₃ was formed to a thickness of 40 nm as an electron transport layer at a degree of vacuum of 4.0 × 10 ⁻⁴ Pa, and subsequently, lithium fluoride was set to a thickness of 0.04 as an electron injection layer. After forming to a thickness of 5 nm, aluminum 150 nm was formed as a cathode, the non-light emitting surface was covered with a glass case, and sealed with an epoxy adhesive. When this element was energized, it was found that substantially white light was obtained and it could be used as a lighting device.

<Production of comparative light-emitting element>
White Light Emitting Element In the same manner as in Preparation of White Light Emitting Element and White Lighting Device-2, except that Compound 13 was changed to Comparative Compound 1 (120 mg), Comparative Compound 2 (120 mg), and Comparative Compound 3 (120 mg), respectively. Was made. However, when Comparative Compound 1 was used, the film could not be formed due to insufficient solubility in toluene. Further, when Comparative Compounds 2 and 3 were used, although the film was formed, the film was cracked during drying at 100 ° C. under vacuum under reduced pressure, and therefore the subsequent operations could not be performed. For this reason, with regard to the comparative compounds 2 and 3, the drying condition was changed to 23 ° C. under reduced pressure to obtain a light emitting layer.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line A Display part B Control part 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with a transparent electrode 108 Nitrogen gas 109 Water trapping agent

Claims (6)

An organic electroluminescent element material represented by the following general formula (1).

[In the formula, Ar and X are bonded to each other to form an 8-membered or higher cyclic compound, m and n represent an integer of 1 or more, m Ar may be the same or different, and n m and X may be the same or different. Ar represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring . X is _{SiR 1 R 2, PR 3,} P (= Y) R 4, O, S, SO 2, NR 5, CR 6 R 7 or C (= O) was Table, at least one X is _SiR 1 R ₂ , PR ₃ or P (= Y) R ₄ is represented. Y represents oxygen, sulfur or selenium, and R ₁ to R ₇ each represents a substituent. ] In Formula (1), X is _SiR 1 _R 2, PR ₃ or P (= Y) The material for an organic electroluminescence device according to claim 1, characterized in that any one of _{R 4.}   An organic electroluminescent device comprising the organic electroluminescent device material according to claim 1.   An organic electroluminescence device, wherein the layer containing the material for an organic electroluminescence device according to claim 1 or 2 is formed by a wet method (wet process).   A display device comprising the organic electroluminescence element according to claim 3.   An illuminating device comprising the organic electroluminescence element according to claim 3.

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