KR20030055140A - Organic electroluminescent device comprising a layer containing a electroconductive polymer - Google Patents

Abstract

The present invention provides a light emitting device capable of emitting light with high luminous efficiency, a light emitting device capable of low voltage driving, and a light emitting device emitting light with high luminous efficiency even in a blue region.

(Solution means) A light emitting device having at least one light emitting layer between a pair of electrodes, wherein the adjacent layer of the light emitting layer contains a conductive polymer, and the light emitting layer is formed by vapor deposition and emits light in a triplet excited state. Light-emitting element containing 1 or more types.

Description

ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING A LAYER CONTAINING A ELECTROCONDUCTIVE POLYMER}

The present invention relates to an organic electroluminescent device usable in the fields of backlight, flat panel display, illumination light source, display device, electrophotographic, organic semiconductor laser, recording light source, exposure light source, read light source, mark, signage, optical communication device, etc. .

Today, research and development of various light emitting devices are being actively conducted. Among them, organic electroluminescent (EL) devices are noted as promising light emitting devices because they are characterized by ultra-thin, lightweight, high-speed response, wide viewing angle, and low voltage driving. It is becoming. In general, an organic EL element is composed of a light emitting layer and a pair of counter electrodes sandwiched between the layers, and utilizes light emission from excitons generated by recombination of electrons injected from the cathode and holes injected from the anode.

At present, it is known that the organic EL device that emits light with high luminance at low voltage has a laminated structure proposed by Tang et al. [Applied Physics Letters, Vol. 51, p. 913, 1987]. The device obtains high luminance green light emission by laminating a material serving as an electron transporting material and a light emitting material with a hole transporting material, and the luminance reaches thousands of cd / m 2 at a DC voltage of 6 to 7V. However, considering practical devices, development of light emitting devices with higher brightness and higher efficiency is required.

Recently, a light emitting device using an ortho-metallized complex of iridium (tris-orthoiridium complex with Ir (ppy) ₃ : 2-phenylpyridine) as a light emitting device as a light emitting material has been reported (Applied Physics Letters). , Vol. 75, p. 4, 1999). This light emitting device uses phosphorescence emission from triplet excitons, and its external quantum efficiency (luminescence efficiency) is 8.3%, which is excellent as it exceeds the external quantum efficiency of 5% known as a conventional limit. In general, the ratio of singlet excitons contributing to fluorescence and triplet excitons contributing to phosphorescence is 1: 3, and luminescence efficiency can be improved by using triplet excitons. However, since the orthometallized complex of iridium is limited to a green light emitting device, when applied to a full color display or a white light emitting device, it is necessary to develop a device that emits light with high efficiency in other colors, especially blue.

In a light emitting device using triplet excitons such as the orthometallated complex of iridium, when the lowest triplet excitation energy level of the host material in the light emitting layer is lower than the light emitting material, the luminous efficiency of the device is lowered. The triplet energy level here must be higher than the lowest triplet energy level of the luminescent material.

In particular, when the light emitting device using triplet excitons emits blue light having excellent color purity, the emission spectrum of the light emitting material becomes shortwave, that is, the lowest triplet excitation energy level of the light emitting material is increased. As the lowest triplet excitation energy level of the luminescent material increases, it is also necessary to increase the lowest triplet excitation energy level of the host material. If the lowest triplet excitation energy level of the host material is high, the charge injection property is lowered. If it is desired to maintain the charge injection property, the driving voltage is increased, which may reduce the durability of the device. Therefore, in order to achieve high efficiency light emission in a light emitting device using triplet excitons, development of a method of efficiently injecting charge into a host material has been required.

In addition, the lowest triplet excitation energy level of the adjacent layer of the light emitting layer is considered important for high-efficiency light emission. When the lowest triplet excitation energy level of the adjacent layer is lower than the lowest triplet energy level of the light emitting material, triplet generated in the host material The excitons do not move energy to the luminescent material but instead move energy to the adjacent layer, whereby the luminous efficiency is lowered. Therefore, development of an adjacent layer that does not prevent energy transfer to the luminescent material has been required. In addition, development of a device having excellent durability in high luminance light emission has been required.

Therefore, as a result of earnestly examining the method of high efficiency light emission of a triplet blue light emitting element, high efficiency blue light emission was achieved by making a conductive polymer adjoin the vapor deposition type light emitting layer.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a light emitting device capable of emitting light with high luminous efficiency, a light emitting device capable of low voltage driving, particularly a light emitting device emitting light with high luminous efficiency even in a blue region.

The said subject was achieved by the following means.

(1) A light emitting layer formed by vapor deposition between an anode and a cathode, the light emitting layer containing at least one light emitting material that emits light in a triplet excited state, and an adjacent layer adjacent to at least one of the anode side and the cathode layer of the light emitting layer. And an adjacent layer contains a conductive polymer.

(2) The organic electroluminescent element according to (1), wherein the lowest triplet excitation energy level of the light emitting material is 63 kW / mol (264 kJ / mol) or more and 81 kW / mol (340 kJ / mol) or less.

(3) The organic electroluminescent element according to (1) or (2), wherein the quantum yield of phosphorescence of the light emitting material is 0.5 or more.

(4) The lowest triplet excitation energy level of the light emitting layer excluding the light emitting material is 64 kW / mol (268 kJ / mol) or more and 82 kW / mol (344 kJ / mol) or less, wherein any one of (1) to (3) The organic electroluminescent element described in.

(5) The organic electroluminescent element according to any one of (1) to (4), wherein the electrical conductivity of the adjacent layer is 10 ^-6 S · cm ⁻¹ or more.

(6) The organic electroluminescent device according to any one of (1) to (5), wherein the conductive polymer is a conjugated polymer doped with a dopant.

(7) The organic electroluminescent device according to any one of (1) to (6), which is a nonconjugated polymer material or a conjugated polymer material in which an aromatic carbocyclic ring or an aromatic heterocycle is linked with a bivalent or higher linking group.

(8) The organic electroluminescent device according to any one of (1) to (6), wherein the conductive polymer has a partial structure represented by the following general formula (1):

(In the meal,

R ¹¹ represents a substituent,

m ¹¹ represents an integer of 0 to 2,

When m ¹¹ represents 2, a plurality of R ¹¹ may be the same or different, and may be connected to each other to form a ring,

n ¹¹ represents an integer of 1 or more).

(9) The organic electroluminescent device according to any one of (1) to (6), wherein the conductive polymer has a partial structure represented by the formula (2):

(In the meal,

L ²¹ and L ²² represent a divalent linking group,

R ²¹ , R ²² , R ²³ represent a substituent,

m ²¹ , m ²² represent an integer of 0 to 4,

m ²³ represents an integer of 0 to 5,

When m ²¹ and m ²² represent an integer of 2 to 4 and m ²³ represents an integer of 2 to 5, a plurality of R ²¹ , R ²² , and R ²³ may be the same or different, and may be connected to each other to form a ring. ,

n ²¹ represents an integer of 1 or more).

(10) The organic electroluminescent device according to any one of (1) to (6), wherein the conductive polymer has a partial structure represented by the following formula (3):

(In the meal,

L ³¹ represents a trivalent linking group,

L ³² represents a single bond or a divalent linking group,

R ³¹ , R ³² , R ³³ represent a substituent,

m ³¹ represents an integer of 0 to 4,

m ³² and m ³³ represent an integer of 0 to 5,

When m <^31> represents the integer of 2-4 and m <^32> , m <^33> represents the integer of 2-5, some R <^31> , R <^32> , R <^33> may be same or different, and may mutually connect and form a ring. ,

n ³¹ represents an integer of 1 or more).

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The light emitting device of the present invention is a light emitting device having at least one light emitting layer between a pair of electrodes, the adjacent layer of the light emitting layer contains a conductive polymer, and the light emitting layer is formed by vapor deposition and emits light in a triplet excited state. It is characterized by containing at least 1 type of material.

In the light emitting device of the present invention, the light emitting layer is usually sandwiched between a pair of electrodes consisting of an anode and a cathode. In the present invention, a layer containing a conductive polymer is adjacent to the light emitting layer between the pair of electrodes (adjacent layer), but in addition, a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, a protective layer, and the like may be disposed. In addition, each of these layers may have a different function, or the adjacent layer may have the function of each of these layers.

In the light emitting device of the present invention, an adjacent layer may be provided on both the anode side and the cathode side with respect to the light emitting layer. It is preferable to have an adjacent layer on the anode side preferably. In this case, the layer structure which becomes the minimum number of light emitting elements is an anode / adjacent layer / light emitting layer / cathode (/: interface). According to a desired function or property, you may have other layers (the said hole injection layer, a hole transport layer, an electron injection layer, an electron carrying layer, a protective layer, etc.).

In the present invention, the conductive layer contains a conductive polymer, and the electrical conductivity (unit: S · cm ⁻¹ ) of the adjacent layer is preferably set to 10 ⁻⁶ S · cm ⁻¹ or more. More preferably, it is ^10-3 S * cm <^-1> or more, More preferably, it is ^10-1 S * cm <^-1> or more. The higher the electrical conductivity of the adjacent layer, the higher the charge injection transportability to the light emitting layer, thereby increasing the luminous efficiency. It is also effective in suppressing the driving voltage of the device. By forming an adjacent layer, charge injection is easily performed because a level is generated between the electrode and the light emitting layer. The level here means ionization potential or electron affinity.

In the present invention, the conductive material contained in the adjacent layer may be a low molecule or a polymer. Preferably it is a nonconjugated molecular material or conjugated molecular material which connected the aromatic carbocyclic ring or aromatic heterocycle to the bivalent or more coupling group, More preferably, the nonconjugated polymer which connected the aromatic carbocyclic ring or the aromatic heterocycle to the bivalent or more coupling group is carried out. Material or conjugated polymer material.

The polymer material is more preferably a conjugated polymer material from the viewpoint of improving charge injection property to the light emitting layer to increase luminous efficiency. Examples of conjugated polymers include polyacetylene, polydiacetylene, poly (paraphenylene), polyfluorene, polyazene, poly (paraphenylene sulfide), polypyrrole, polythiophene, polyisothianaphthene, polyaniline, poly (Paraphenylenevinylene), poly (2,5-thienylenevinylene), cyclic conjugated polymers (polyperinaphthalene, etc.), metal phthalocyanine polymers, other conjugated polymers (poly (paraxylylene), poly [(alpha)-(5,5'-bithiophendiyl) benzylidene] etc. are mentioned.

As an aromatic carbocyclic ring which forms the said polymeric material, a benzene ring is mentioned, for example, You may form a condensed ring. Moreover, as an aromatic heterocyclic ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an oxazole ring, a thiazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, a triazole ring, tetrazole ring, furan A ring, a thiophene ring, a pyrrole ring, an indole ring, a carbazole ring, a penzoimidazole ring, an imidazopyridine ring, etc. are mentioned, You may form a condensed ring and may have a substituent.

As the conjugated polymer, poly (paraphenylene), polypyrrole, polythiophene, polyaniline, poly (paraphenylenevinylene), and poly (2,5-thienylenevinylene) are preferable. Preferably, poly (paraphenylene), polythiophene, poly (paraphenylene vinylene), etc. are mentioned, Especially preferably, it is a conductive polymer which has the partial structure represented by General formula (1). In formula, R <^11> represents a substituent and the said substituent group is shown below. m ¹¹ represents an integer of 0 to 2; When m <^11> represents 2, some R <^11> may be the same or different, and may mutually connect and form a ring.

(Substituent group)

An alkyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), alkenyl group (preferably C2-C20, more preferably C2-C12, especially preferably C2-C8, Such as vinyl, allyl, 2-butenyl, 3-pentenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 2-octenyl, etc.), alkynyl groups (preferably having from 2 to 3 carbon atoms) 20, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as propargyl, 3-pentynyl, and the like, and an aryl group (preferably 6 to 30 carbon atoms). Preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms. Phenyl, p-methylphenyl, naphthyl and the like), an amino group (preferably 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, Dimethylamino, diethylamino, dibenzylamino, diphenylamino, etc.), an alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms). For example, methoxy, ethoxy, butoxy, hexyloxy, octyloxy, etc.), aryloxy group (preferably C6-C20, More preferably, C6-C16, Especially preferably, C4- 6-12, for example, phenyloxy, 2-naphthyloxy, and the like, an acyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). For example, acetyl, benzoyl, formyl, pivaloyl and the like, alkoxycarbonyl group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, for example) Methoxycarbonyl, ethoxycarbonyl, and the like), aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, for example, phenyloxy). Carbonyl etc.), an acyloxy group (preferably C2-C20, More preferably, it is C2-C16, Especially preferably, it is 2-10, For example, acetoxy, benzoyloxy etc. are mentioned. ), Acylamino group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, for example, acetylamino, benzoylami And an alkoxycarbonylamino group (preferably with 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms), for example, methoxycarbonylamino and the like. Aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, for example, phenyloxycarbonylamino, etc.); Phenylamino group (preferably C1-C20, More preferably, it is C1-C16, Especially preferably, it is C1-C12, For example, methanesulfonylamino, benzenesulfonylamino, etc.), A sulfamoyl group (Preferably 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, for example sulfamoyl, methylsulfamoyl, dimethyl Pamoyl, phenylsulfamoyl and the like), carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, for example carbamoyl, methyl Carbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), an alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). And methylthio, ethylthio, etc.), an arylthio group (preferably 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, for example, phenylthio, etc.). Sulfonyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, mesyl, tosyl, etc.), sulfinyl Groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), and a ureide group (preferably Is 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as ureide, methyl ureide, phenyl ureide, etc.), phosphate amide group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms. Examples include diethyl phosphate amide, phenyl phosphate amide, and the like, hydroxy group, mercapto group and halogen atom (e.g. , Fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably It is a minority 1-20, More preferably, it is C1-C12, As a hetero atom, For example, a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, pyrrolidine, piperidine, piperazine, morpholine, thiophene, furan , Pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazolin, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline Isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, phthalidine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, Benzotriazole, tetrazaindene and the like), silyl group (preferably 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms), such as trimethylsilyl, triphenylsilyl, etc. And the like). These substituents may also be substituted.

The said substituent may be substituted further. In addition, when having two or more substituents, these substituents may mutually be same or different, and when possible, may connect and form a ring. As a ring formed, a benzene ring, a thiophene ring, a dioxane ring, a dithiane ring, etc. are mentioned, for example.

The substituent is preferably an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkylthio group, more preferably an alkyl group, an alkoxy group, an alkylthio group, particularly preferably two R ¹¹ when m ¹¹ is 2 Examples of the alkoxy group and alkylthio group having a silver ring include a dioxane ring and a dithiane ring. When m ¹¹ is 1, R ¹¹ is an alkyl group (preferably an alkyl group having 2 to 8 carbon atoms). In addition, when R ¹¹ is a poly (3-alkylthiophene) which is an alkyl group, the connection form with adjacent thiophene rings includes stereoregular all connected by 2-5 ', and 2-2' and 5-5 '. There are three-dimensional irregular ones, but three-dimensional irregular ones are preferable. n ¹¹ is preferably an integer of 10 to 10000, more preferably 50 to 5000, and particularly preferably 50 to 1000.

Although the specific example of a conjugated polymer is shown below, it is not limited to these. Moreover, the compound etc. which were described in WO98 / 01909 are mentioned.

As a bivalent or more linking group which connects the aromatic carbocyclic ring or aromatic heterocyclic ring which forms the said nonconjugated polymer, Preferably, it is a coupling group formed from a single bond, carbon, silicon, nitrogen, boron, oxygen, sulfur, a metal, metal ion, etc. More preferably, they are a single bond, a carbon atom, a nitrogen atom, a silicon atom, a boron atom, an oxygen atom, a sulfur atom and a combination thereof, and the combination may be a substituted or unsubstituted methylene group, carbonyl group, imino group, sulfonyl group, sulfi And a silyl group, an ester group, an amide group and a silyl group.

As the nonconjugated polymer, particularly preferably, it is a conductive polymer having a partial structure represented by the formula (2) or (3), wherein R ²¹ , R ²² , R ²³ , R ³¹ , R ³² , and R ³³ represent a substituent, The substituent has the same meaning as R ¹¹ in formula (1). m <^21> , m <^22> and m <^31> represent the integer of 0-4, and R <^23> , R <^32> , R <^33> is the integer of 0-5. When m ²¹ , m ²² , m ²³ , m ³¹ , m ³² , and m ³³ represent an integer of 2 or more, a plurality of R ²¹ , R ²² , R ²³ , R ³¹ , R ^32, or R ³³ may be the same or different. May be connected to each other to form a ring. The ring to be formed is preferably an aromatic carbocyclic ring or an aromatic heterocycle. L ²¹ , L ²² , L ³² are divalent linking groups, L ³¹ is a trivalent linking group, and a single bond, aromatic carbocyclic ring, aromatic heterocycle, carbon atom, nitrogen atom, silicon atom, boron atom, oxygen atom and sulfur atom or these And a substituted or unsubstituted methylene group, aromatic carbocyclic group, carbonyl group, imino group, sulfonyl group, sulfinyl group, ester group, amide group and the like.

In the general formula (2), R ²¹ , R ²² and R ²³ are preferably an alkyl group, an alkoxy group or an aryl group, and more preferably an alkyl group or an aryl group. When m ²¹ , m ²² , m ²³ represent an integer of 2 or more, a plurality of R ²¹ , R ²² , R ²³ may be linked to each other to form a ring, and the formed ring is preferably an aromatic carbocyclic ring, an aromatic heterocycle, or the like. Can be mentioned. R ²³ is particularly preferably an aromatic carbocyclic ring having a diarylamino group as a substituent. L ²¹ and L ²² are preferably a group consisting of a substituted or unsubstituted methylene group, carbonyl group, sulfonyl group, sulfinyl group, ester group, aromatic carbocyclic silyl group or a combination thereof.

In the general formula (3), R ³¹ , R ³² and R ³³ are preferably an alkyl group, an alkoxy group or an aryl group, more preferably an alkyl group or an aryl group. When m ³¹ , m ³² , m ³³ represent an integer of 2 or more, a plurality of R ³¹ , R ³² , R ³³ may be linked to each other to form a ring, and the formed ring is preferably an aromatic carbocyclic ring, an aromatic heterocycle, or the like. Can be mentioned. R ³³ is particularly preferably an aromatic carbocyclic ring having a diarylamino group as a substituent. L ²¹ and L ²² are preferably a group consisting of a substituted or unsubstituted methylene group, carbonyl group, sulfonyl group, sulfinyl group, ester group, aromatic carbocyclic silyl group or a combination thereof. n ²¹ and n ³¹ are preferably an integer of 5 to 5000, more preferably 20 to 2000, and particularly preferably 20 to 1000.

Although the specific example of a nonconjugated polymer is shown below, it is not limited to these.

Further, Patent No. 3109895, Japanese Patent Application Laid-Open No. 7-188398, Japanese Patent Application Laid-Open No. 8-188773, Japanese Patent Application Laid-Open No. 8-269446, Japanese Patent Application Laid-Open No. 8-295880, Japanese Patent Application Laid-Open 2000-80167, Japanese Laid-Open Patent Publication No. 2000-150169, Japanese Laid-Open Patent Publication 2001-208087, Japanese Laid-Open Patent Publication 2002-75654, Japanese Laid-Open Patent Publication 2002-117982, Japanese Laid-Open Patent Publication 2002-117983, The compound etc. which were described in Unexamined-Japanese-Patent No. 2002-506481 etc. are mentioned.

As for the weight average molecular weight of the conductive polymer used by this invention, 1000-1 million are preferable, More preferably, it is 10000-500000, More preferably, it is 10000-100000.

From the viewpoint of increasing the electrical conductivity of the adjacent layer and improving the charge injection property to the light emitting layer to increase the luminous efficiency, the conductive polymer material preferably contains at least one dopant, and the dopant is added to the conjugated polymer. It is more preferable to make it contain. Examples of the dopant contained in the conductive polymer material include an electron accepting (acceptor) dopant and an electron donating (donor) dopant.

Examples of electron accepting (acceptor) dopants include halogens (Cl ₂ , Br ₂ , I ₂ , ICl, ICl ₃ , IBr, IF), Lewis acids (PF ₅ , AsF ₅ , SbF ₅ , BF ₃ , BCl ₃ , BBr ₃ , SO ₃ ), protonic acid (HF, HCl, HNO ₃ , H ₂ SO ₄ , HClO ₄ , FSO ₃ H, CISO ₃ H, CF ₃ SO ₃ H, various organic acids, amino acids, etc.), transition metal compounds (FeCl _{3, FeOCl, TiCl 4, ZrCl} 4, HfCl 4, NbF 5, NbCl 5, TaCl 5, MoF 5, MoCl 5, WF 6, WCl 6, UF 6, LnCl 3 (Ln = La, Ce, Pr, Nd, raenta cannabinoids, such as Sm), electrolyte anions ^{(Cl -, Br -, I} -, ClO 4 -, PF 6 -, AsF 6 -, SbF 6 -, BF 4 -, various sulfonic acid anion), or other (O _2, XeOF ^{_{4, (NO 2 +) (}} SbF 6 -), (NO 2 +) (SbCl 6 -), (NO 2 +) (BF 4 -), FSO 2 OOSO 2 F, AgClO 4, H 2 IrCl 6, La (NO ₃ ) ₃ ㆍ 6H ₂ O and the like.

Examples of electron donor (donor) dopants include alkali metals (Li, Na, K, Rb, Cs), alkaline earth metals (Ca, Sr, Ba), lanoids (Eu, etc.), others (R ₄ N ⁺ , R ₄ P ⁺ , R ₄ As ⁺ , R ₃ S ⁺ , and acetylcholine).

In combination with a dopant of the conjugated polymer materials, for example, such as polyacetylene and _{I 2, AsF 5, FeCl 3} , poly (p- phenylene), and AsF _5, K, AsF ₆ ^-, such as, polypyrrole, and ClO ₄ ^-, etc., polythiophene and ClO ₄ ^-, etc., polystyrene sulfonic acid, knitted Raleigh salts, amino salts, quinones, such as polyisobutylene thianaphthene I ₂ and the like, poly (p- phenylene sulfide) and AsF _5, poly (p- phenylene Ethylene oxide), AsF ₅ , poly (p-phenylenevinylene) and H ₂ SO ₄ such as polyaniline and HCl, and polythiophenylenevinylene and I ₂ ; nickel phthalocyanine and I ₂ .

The conductive polymer material may be an ion conductive polymer in which the polymer chain is doped with an electrolyte, and examples of the polymer chain include polyether (polyethylene oxide, polypropylene oxide, etc.), polyester (polyethylene succinate, poly-β- Propiolactone, etc.), polyamine (polyethylene imine, etc.), polysulfide (polyalkylene sulfide, etc.), etc. are mentioned, and various alkali metal salt etc. are mentioned as a doped electrolyte.

Examples of the alkali metal ions constituting the alkali metal salt include Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and the like, and an anion forming a paired salt includes F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , NO _{^{3 -, SCN -, ClO 4}} -, CF 3 SO 3 -, BF 4 -, AsF 6 -, BPh 4 - , and the like.

Examples of the combination of the polymer chain and the alkali metal salt include polyethylene oxide, LiCF ₃ SO ₃ , LiClO ₄ , polyethylene succinate, LiClO ₄ , LiBF ₄ , poly-β-propiolactone and LiClO ₄ , and polyethyleneimine and NaCF. ₃ SO _3, LiBF ₄ or the like, there may be mentioned polyalkyl sulfide with AgNO ₃ or the like.

In the light emitting device of the present invention, it is preferable that the adjacent layer is formed by coating in view of improving durability of the light emitting device. Moreover, the film forming by application | coating is preferable also from the viewpoint of the simplicity of element manufacture which can apply a large area at once. For this reason, it is especially preferable that the conductive polymer contained in the adjacent layer can be coated with an organic solvent.

Next, the material which forms a light emitting layer is demonstrated.

The light emitting material contained in the element of the present invention itself contributes to light emission of the light emitting element, and at least one kind is a triplet light emitting material which emits light in a triplet excited state. As a triplet luminescent material, it is preferable to emit light in a triplet excited state at normal temperature, More preferably, the transition metal complex which has aromatic carbocyclic ring or aromatic heterocycle as a ligand, such as an aromatic carbocyclic ring to an aromatic heterocycle containing a heavy atom, etc. Etc. can be mentioned.

The transition metal atoms constituting the transition metal complex are not particularly limited, but are preferably ruthenium, rhodium, palladium, tungsten, rhenium, iridium and platinum, and more preferably ruthenium, rhenium, iridium and platinum.

Examples of ligands for transition metal complexes include G, Wilkinson et al., [Comprehensive Coordination Chemistry, Pergamon Press, 1987], H. Yersin, Photochemistry and Photophysics of Coordination Compounds, and Springer-Verlag. , Published in 1987], by Akio Yamamoto, [Organic Metal Chemistry-Foundations and Applications-, Shokabosa, 1982], and the like, preferably halogen ligands (preferably chlorine ligands), Nitrogen-containing heterocyclic ligands (eg, phenylpyridine, benzoquinoline, quinolinol, bipyridyl, phenanthroline, etc.), diketone ligands (eg, acetylacetone, etc.), carboxylic acid ligands (eg, acetic acid ligands, etc.) , Carbon monoxide ligand, isonitrile ligand, cyano ligand.

As the transition metal complex, an orthometalated metal complex is preferable. Orthometallic complexes include, for example, "Organic Metal Chemistry-Foundations and Applications-", p150, 232, by Akio Yamamoto, Shokabosa, 1982], "Photochemistry and Photophysics of Coordination Compounds", p71-77, p135 -146, Springer-Verlag, H. Yersin, 1987, et al. Especially preferably, it is a light emitting element material which consists of orthometalated Ir complexes.

Although the valence of the iridium of an ortho metal iridium complex is not specifically limited, Trivalent is preferable. The ligand of the ortho-metalated iridium complex is not particularly limited as long as it can form an ortho-metalated complex, but for example, an aryl group-substituted nitrogen-containing heterocyclic derivative (the substitution position of the aryl group is on the adjacent carbon of the nitrogen-containing heterocyclic nitrogen atom, and aryl Examples of the group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group, and the like, and a carbocyclic ring, a heterocyclic ring and a condensed ring may be formed. Midine, pyrazine, pyridazine, quinoline, isoquinoline, quinoxaline, phthalazine, quinazoline, naphthyridine, cinnoline, perimidine, phenanthroline, pyrrole, imidazole, pyrazole, oxazole, oxadiazole , Triazole, thiadiazole, benzimidazole, benzoxazole, benzthiazole, phenanthridine and the like), heteroaryl group substituted nitrogen-containing heterocyclic derivative (substituted position of heteroaryl group is nitrogen) Heteroaryl groups include, for example, groups containing the nitrogen-containing heterocyclic derivatives, thienyl groups, furyl groups, and the like, 7,8-benzoquinoline, phosphinoaryl, Phosphinoheteroaryl, phosphinoxyaryl, phosphinoxyheteroaryl, aminomethylaryl, aminomethyl heteroaryl, and derivatives thereof.

Preferably, an aryl group-substituted nitrogen-containing aromatic heterocycle, heteroaryl group-substituted nitrogen-containing aromatic heterocycle, 7,8-benzoquinoline and derivatives thereof, phenylpyridine, thienylpyridine, 7,8-benzoquinoline, benzylpyridine , Phenylpyrazole, phenylisoquinoline, phenyl substituents of azoles having two or more nitrogen atoms, and derivatives thereof, more preferably, aryl groups having electron withdrawing groups (e.g., halogen atoms, cyano groups, azole groups) are substituted. Aromatic heterocycles and derivatives thereof are particularly preferred.

As an example of the triplet light-emitting material containing the above, Unexamined-Japanese-Patent No. 2001-181616, Unexamined-Japanese-Patent No. 2001-181617, Unexamined-Japanese-Patent No. 2001-247859, Japan Patent Application 2000-89274, Japanese Patent Application 2000-398908, Japanese Patent Application 2001-45476, Japanese Patent Application 2001-189539, Japanese Patent Application 2001-219909, Japanese Patent Application 2001-239281, Japanese Patent Application 2001-248165, WO00 / 57676 And the compounds described in WO00 / 70655, WO01 / 39234A2, WO01 / 41512A1, US6097147A, and the like.

Preferred light emitting materials of the present invention include the following.

[Specific Examples of Preferred Luminescent Materials]

Although the emission spectrum of the light emitting element of this invention is not specifically limited, When considering application to a full color display etc., it is preferable that the maximum emission wavelength is 500 nm or less (blue light emission). A light-emitting material is a minimum here triplet energy level (T ₁ level) is 45㎉ / ㏖ (188kJ / ㏖) over 90㎉ / ㏖ (378kJ / ㏖) or less is preferred and, 55㎉ / ㏖ (230kJ / ㏖ ) above It is more preferable that it is 85 kPa / mol (356 kJ / mol) or less, and it is especially preferable that it is 63 kPa / mol (264 kJ / mol) or more and 81 kPa / mol (340 kJ / mol) or less for a blue light emitting element. In addition, in order to increase the luminous efficiency of the device, the quantum yield of phosphorescence of the light emitting material is preferably 0.5 or more (more preferably 0.6 or more, particularly preferably 0.7 or more).

Next, the host material will be described.

The host material forms a light emitting layer together with the light emitting material, and when the electric field is applied, holes are injected into the light emitting layer from the anode or the hole injection layer and the hole transport layer, and electrons are injected into the light emitting layer from the cathode or the electron injection layer and the electron transport layer. It also has a function of moving the injected charge in the light emitting layer and sending electrons and hole pair excitons generated by recombining holes and electrons to the light emitting material to emit light of the light emitting material. The host material is not particularly limited as long as it has the above function.

Examples of the compound used as the host material in the light emitting device of the present invention include carbazole, indole, pyrrole, pyrazole, imidazole, benzimidazole, pyrazolopyridine, imidazolopyridine, imidazolopyrazine and benzimidazole. Nitrogen-containing heterocyclic compounds such as benzoxazole, benzoimidazole, benzothiazole, sulfur-containing heterocyclic compounds such as thiophene and benzthiophene, styrylbenzene, polyphenyl, diphenylbutadiene, fluorene, aromatic condensation Carbocyclic compounds (such as naphthalene, anthracene, pyrene), tetraphenylbutadiene, naphthalimide, coumarin, perylene, perinone, oxadiazole, aldazine, pyriridine, cyclopentadiene, bisstyrylanthracene, quina Metal complexes of 8-quinolinol derivatives, such as aniline derivatives such as credon, pyrrolopyridine, thiadiazolopyridine, styrylamine, aromatic dimethylidene compound, triarylamine compound, dialkylaniline compound There may be mentioned various metal complexes, or of the derivative represented by the organometallic complexes or rare earth complexes.

Light may be emitted by excitons generated by the host material itself. In this case, the allowable light emitting area is changed depending on the desired light emitting area in the entire element, but it is usually preferable to have light emission in the green region in the ultraviolet as the host material single film. Such host materials are preferably carbazole, indole, pyrrole, benzimidazole, furyl, benzimidazole, pyrazolopyridine, imidazolopyridine, imidazolopyrazine and the like, nitrogen-containing heterocycles, disubstituted aniline compounds, thi Offenne compounds, polyphenyls and derivatives thereof, or organometallic complexes. More preferably, the material described in Japanese Patent Application No. 2001-197135 is mentioned as a host material. In the present invention, as described above, the light emitting layer made of the host material and the light emitting material is adjacent to the layer containing the conductive polymer.

Of the materials forming the light emitting layer, the excitation triplet energy level (T ₁ level) of the material (host material) other than the light emitting material is required to be larger than the T ₁ level of the light emitting material. By increasing the T ₁ level of the host material than the T ₁ level of the light emitting material, the excitons generated on a host material to move to the light emitting material, the chance of emission is improved higher luminous efficiency. Thus, a light-emitting layer other than the light emitting material T ₁ level 45㎉ / ㏖ (188kJ / ㏖) over 90㎉ / ㏖ (378kJ / ㏖) is preferable and, 55㎉ / ㏖ (230kJ / ㏖ ) over 85㎉ / ㏖ or less It is more preferable that it is (356 kJ / mol) or less. Especially in the case of a blue light emitting element, 64 kPa / mol (268 kJ / mol) or more and 82 kPa / mol (344 kJ / mol) or less (as a lower limit, More preferably, 65 kPa / mol (272 kJ / mol), especially Preferably it is 67 kPa / mol (280 kJ / mol) or more.

Preferred host materials of the present invention include the following.

[Specific Examples of Preferred Host Materials]

The light emitting layer of the light emitting element of this invention is formed into a film by the vapor deposition method. By forming a film by the evaporation method, high efficiency light emission is possible compared with the coating method.

As a vapor deposition method, a resistive heating vapor deposition method etc. are mentioned.

The light emitting layer is made of the above-described light emitting material and host material, but may contain an electron transporting material. Although the film thickness of a light emitting layer is not specifically limited, Usually, it is preferable that it is the range of 1 nm-5 micrometers, More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm.

As an electron carrying material, the example of the electron carrying layer mentioned later is mentioned.

Next, layers other than the adjacent layer and the light emitting layer containing the conductive material of the present invention will be described.

An anode supplies holes to a hole injection layer, a hole transport layer, a light emitting layer, etc., and a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used, and preferably a material having a work function of 4 eV or more. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, and indium tin oxide (ITO) or metals such as gold, silver, chromium and nickel, and mixtures or laminates of these metals with conductive metal oxides. And inorganic conductive materials such as copper iodide and copper sulfide, organic conductive polymers such as polyaniline, polythiophene and polypyrrole, and laminates of these and ITO, and are preferably conductive metal oxides. , ITO is preferable from the viewpoint of transparency. Although the film thickness of an anode can be suitably selected according to a material, it is preferable that it is the range of 10 nm-5 micrometers normally, More preferably, it is 50 nm-1 micrometer, More preferably, it is 100 nm-500 nm.

As the anode, a layer formed on a soda lime glass, an alkali free glass, a transparent resin substrate, or the like is usually used. When using glass, it is preferable to use alkali-free glass in order to reduce the elution ion from glass about the material. Moreover, when using soda-lime glass, it is preferable to use what gave barrier coating, such as a silica. Although the thickness of a board | substrate will not be restrict | limited especially if it is thickness enough to maintain mechanical strength, When using glass, the thing of 0.2 mm or more normally, Preferably it is 0.7 mm or more is used.

Various methods are used to fabricate the anode, depending on the material. For example, in the case of ITO, a film is formed by an electron beam method, a sputtering method, a resistive heating deposition method, a chemical reaction method (sol-gel method, etc.), or a dispersion of ITO. .

It is also possible to lower the drive voltage of the device or to increase the luminous efficiency by cleaning and other processes of the anode. For example, in the case of ITO, UV-ozone treatment, plasma treatment and the like are effective.

A cathode supplies electrons to an electron injection layer, an electron carrying layer, a light emitting layer, etc., and it selects in consideration of adhesiveness, ionization potential, stability, etc. with layers adjacent to a cathode, such as an electron injection layer, an electron carrying layer, and a light emitting layer. As the material of the negative electrode, a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. Specific examples thereof include an alkali metal (for example, Li, Na, K, Cs, etc.) or a fluoride thereof, an oxide thereof, an alkali Earth metals (such as Mg, Ca, etc.) or fluorides thereof, oxides thereof, gold, silver, lead, aluminum, sodium-potassium alloys or mixed metals thereof, lithium-aluminum alloys or mixed metals thereof, magnesium-silver alloys or mixtures thereof Rare earth metals, such as a metal, indium, and ytterbium, are mentioned, Preferably it is a material which has a work function of 4 eV or less, More preferably, they are aluminum, a lithium-aluminum alloy, their mixed metal, magnesium-silver alloy, their mixed metal, etc. Although the film thickness of a cathode can be suitably selected according to a material, it is preferable that it is the range of 10 nm-5 micrometers normally, More preferably, it is 50 nm-1 micrometer, More preferably, it is 100 nm-1 micrometer.

In the preparation of the cathode, a method such as an electron beam method, a sputtering method, a resistive heating vapor deposition method, or a coating method is used. The metal may be deposited in a single body or two or more components may be deposited simultaneously. It is also possible to form an alloy electrode by depositing a plurality of metals at the same time, or may deposit a previously adjusted alloy.

It is preferable that the sheet resistance of an anode and a cathode is low, and several hundred ohm / square or less is preferable.

The material of the hole injection layer and the hole transport layer may be any one of a function of injecting holes from the anode, a function of transporting holes, and a function of barriering electrons injected from the cathode. Specific examples thereof include carbazole, imidazole, triazole, oxazole, oxadiazole, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino substituted chalcone, styrylanthracene, fluorenone, hydra Zone, stilbene, silazane, aromatic tertiary amine compound, styrylamine, aromatic dimethylidene compound, porphyrin compound, polysilane compound, poly (N-vinylcarbazole), aniline copolymer, thiophene oligomer And conductive polymer oligomers such as polymers and polythiophenes, polymers, carbon films and the derivatives thereof. The film thickness of the hole injection layer and the hole transport layer is not particularly limited depending on the material, but is usually in the range of 1 nm to 5 μm, more preferably 5 nm to 1 μm, still more preferably 10 nm to 500 nm. The hole injection layer and the hole transport layer may be a single layer structure composed of one or two or more kinds of the above-described materials, or may be a multilayer structure composed of a plurality of layers of the same composition or different species composition.

As a method of forming the hole injection layer and the hole transport layer, a method of coating by dissolving or dispersing the hole injection material and the hole transport material in a solvent by vacuum deposition, LB method, ink jet method, printing method, transfer method, electrophotographic method ( Spin coating, casting, dip coating, etc.) are used. In the case of the coating method, it can be dissolved or dispersed together with the resin component, and the resin component is, for example, polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene , Poly (N-vinylcarbazole), hydrocarbon resin, ketone resin, phenoxy resin, polyamide, ethylcellulose, vinyl acetate, ABS resin, polyurethane, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, silicone Resin and the like.

The material of the electron injection layer and the electron transport layer may be any one of a function of injecting electrons from the cathode, a function of transporting electrons, and a function of barriering holes that can be injected from the anode. Specific examples thereof include a heterocyclic skeleton containing two or more heteroatoms, oxadiazole, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyrandioxide, carbodiimide, and fluorenylidene Represented by metal complexes of aromatic ring tetracarboxylic anhydrides such as methane, distyrylpyrazine, naphthalene perylene, phthalocyanine and 8-quinolinol derivatives, and metal complexes having metal phthalocyanine, benzoxazole or benzothiazole as ligands Various metal complexes, the said derivatives, etc. are mentioned.

As a heterocyclic skeleton containing two or more heteroatoms, a heterocyclic compound containing at least two heteroatoms is a compound having two or more atoms in the basic skeleton having atoms other than carbon atoms and hydrogen atoms, and monocyclic or condensed. It may be. The heterocyclic skeleton is preferably one having two or more atoms selected from N, O, and S atoms, more preferably an aromatic heterocycle having at least one N atom in the skeleton, particularly preferably an N atom Is an aromatic heterocycle having two or more in the skeleton. The heteroatoms may be in the condensation position or in the non-condensation position. For example, pyrazole, imidazole, oxazole, thiazole, triazole, oxadiazole, thiadiazole, pyrazine, pyrimidine, imidazole, purine, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline , Pteridine, perimidine, phenanthroline, pyrrolimidazole, pyrrolotriazole, pyrazoloimidazole, pyrazolotriazole, pyrazolopyrimidine, pyrazolotriazine, imidazoimidazole, imidazo Pyridazine, imidazopyridine, imidazopyrazine, triazolopyridine, benzoimidazole, naphthoimidazole, benzoxazole, naphthooxazole, benzothiazole, naphthothiazole, benzotriazole, tetrazadene, triazine Etc. can be mentioned. Among these, Preferably triazole, oxadiazole, thiadiazole, imidazopyridazine, imidazopyridine, imidazopyrazine, benzoimidazole, naphthoimidazole, benzoxazole, naphthooxazole, benzothiazole , Naphthothiazole, triazine, more preferably imidazopyridine, imidazopyrazine, benzoimidazole, naphthoimidazole, still more preferably imidazopyridine, benzoimidazole, naphthoimidazole, triazine. .

An electron injection layer, an electron transport layer is in the preferred in that light-emitting efficiency comprising a, particularly preferably a compound having a high T ₁ level higher than the material forming the light emitting layer. Therefore, T ₁ level of the electron transporting material is a single film, 45㎉ / ㏖ (188kJ / ㏖ ) over 90㎉ / ㏖ (378kJ / ㏖) is preferable and, 58㎉ / ㏖ (243kJ / ㏖ ) over 85㎉ / ㏖ or less It is more preferable that it is (356 kJ / mol) or less. In particular, in the case of a blue light emitting element, it is preferable that they are 64 kPa / mol (268kJ / mol) or more and 82 kPa / mol (344kJ / mol) or less.

The following are mentioned as a preferable electron transport material of this invention.

[Specific Examples of Preferred Electron Transport Materials]

Although the film thickness of an electron injection layer and an electron carrying layer is not specifically limited, Usually, it is preferable that it is the range of 1 nm-5 micrometers, More preferably, it is 5 nm-1 micrometer, More preferably, it is 10 nm-500 nm. . The electron injection layer and the electron transport layer may have a single layer structure composed of one or two or more kinds of the above materials, or may have a multilayer structure composed of a plurality of layers of the same composition or different compositions.

As a method for forming an electron injection layer and an electron transporting layer, a method of coating by dissolving or dispersing a vacuum deposition method, an LB method, an inkjet method, a printing method, a transfer method, an electrophotographic method, the electron injection material, or an electron transporting material in a solvent (spinning Coating method, cast method, dip coating method, etc.) are used. In the case of a coating method, it can melt | dissolve or disperse | distribute with a resin component, and what was illustrated in the case of a hole injection / transport layer as a resin component is applicable, for example.

In the light emitting device of the present invention, a protective layer may be formed on the outermost surface.

The material of the protective layer may be one having a function of suppressing entry into the device by promoting device degradation such as moisture and oxygen. Specific examples thereof include metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, Ni, MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, Fe ₂ O ₃ , metal oxides such as Y ₂ O ₃ , TiO ₂ , nitrides such as SiNx, SiNxOy, metal fluorides such as MgF ₂ , LiF, AlF ₃ , CaF ₂ , polyethylene, polypropylene, polymethylmethacrylate, poly Mead, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymers of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene and at least one nose The copolymer obtained by copolymerizing the monomer mixture containing a monomer, the fluorine-containing copolymer which has a cyclic structure in a copolymer main chain, the water absorptivity of 1% or more of water absorption, and the moisture proof material of 0.1% or less of water absorption, etc. are mentioned.

The method for forming the protective layer is not particularly limited, and for example, the vacuum deposition method, the sputtering method, the reactive sputtering method, the MBE (molecular beam epitaxy) method, the citter ion beam method, the ion plating method, the plasma polymerization method (high frequency excitation ion) Plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, inkjet method, printing method, transfer method, and electrophotographic method.

EXAMPLE

Although an Example is given to the following and this invention is concretely demonstrated to it, this invention is not limited by this.

Example 1

A film having a thickness of 150 nm formed on a glass substrate of 25 mm x 25 mm x 0.7 mm (manufactured by Tokyo Sanyo Shinku Co., Ltd.) was used as a transparent support substrate. After etching and cleaning the transparent support substrate, spin coating is performed on the substrate on which Baytron P (PEDOT-PSS aqueous product (polyethylenedioxythiophene-polystyrenesulfonic acid dopant) / Bayer Corporation) was washed as a conductive polymer to form an adjacent layer. (1000 rpm, 30 seconds) and vacuum dried at 150 캜 for 1.5 hours. The film thickness of the adjacent layer was 50 nm. The substrate was placed in a vapor deposition apparatus under a vacuum of 10 ^-3 to 10 ^-4 Pa, and the light emitting material (D-1) and the host material (H-1) were respectively deposited at a deposition rate of 0.04 nm / under conditions of a substrate temperature of room temperature. The light emitting layer was formed by evaporating at a thickness of 36 nm at 0.4 nm / second. Again, electron transport material (E-1) was deposited at 36 nm, a mask (pattern having a light emission area of 4 mm x 5 mm) was deposited on the organic thin film to deposit 5 nm of lithium fluoride, and then aluminum 50 nm was deposited. Then, the element was sealed and the EL element was produced (element No. 101).

Example 2

Instead of Baytron P of Example 1, a substrate spin-coated with the same conductive polymer TPDPES-TBPA was placed in a vapor deposition apparatus, and the same device as in Example 1 was fabricated (Device No. 102).

Example 3

Instead of the electron transporting material (E-1) of Example 2, 10 nm of BCP and 30 nm of Alq ₃ were deposited thereon, and lithium fluoride and aluminum were deposited in the same manner as in Example 1, and then the element was sealed to seal the EL element. Was prepared (device No. 103).

Example 4

An element using CBP as a host material was manufactured using Ir (ppy) ₃ instead of the light emitting material (D-1) of Example 3 (device No. 104).

Comparative Example 1

In the same manner as in Example 2, a substrate spin-coated with TPDPES-TBPA was placed in a vapor deposition apparatus, and NPD was deposited by 50 nm under conditions of a substrate temperature of room temperature in a vacuum of 10 ^-3 to 10 ^-4 Pa. Next, the light emitting material Ir (ppy) ₃ and the host material (CBP) were co-deposited at a deposition rate of 0.04 nm / second and 0.4 nm / second so as to have a thickness of 36 nm, thereby forming a light emitting layer. Further, 10 nm of BCP and 30 nm of Alq ₃ were deposited thereon, and lithium fluoride and aluminum were deposited in the same manner as in Example 1, and then the device was sealed to prepare an EL device (Device No. 105).

Comparative Example 2

The same device was produced by changing the light emitting material of Comparative Example 1 to (D-1) (device No. 106).

Comparative Example 3

The same device was produced by changing the host material of Comparative Example 2 to (H-1) (device No. 107).

Comparative Example 4

As in Example 1, 40 mg of poly (N-vinylcarbazole) and 4 mg of Ir (ppy) ₃ were dissolved in 2.5 ml of dichloroethane on a substrate coated with PEDOT-PSS. The total film thickness of the organic layer was 80 nm. The substrate was placed in a vapor deposition apparatus, and then, in a vacuum of 10 ^-3 to 10 ^-4 Pa, the following TAZ was deposited at 30 nm and Alq at 20 nm under the conditions of a substrate temperature of room temperature, and lithium fluoride and aluminum in the same manner as in Example 1. Was deposited, and the device was then sealed to prepare an EL device (device No. 108).

The structure of the compound used by this invention below is shown.

Next, each element produced by the following method was evaluated. The evaluation results are shown in Table 1.

Using a Toyo Technica source measure unit 2400, ITO is used as an anode and aluminum as a cathode, a direct current constant current is applied to the organic thin film, and the comparative example and the device of the present invention are made to emit light, and the luminance thereof is measured by the luminance meter BM of Dofcon Corporation. -8 and emission wavelength were measured using the spectrum analyzer PMA-11 by Hamamatsu Photonics, and the luminous efficiency was calculated | required. In addition, the device was driven with a constant current at an initial luminance of 100 cd / m 2, and the luminance half life time was measured. Moreover, as a result of measuring the lowest triplet excitation energy level of the light emitting layer film | membrane except a light emitting material from the light emitting layer, CBP was 62 kV / mol (260kJ / mol), and H-1 was 65 kV / mol (272kJ / mol).

Element No. ELmax Chromaticity (x, y) External quantum efficiency Driving voltage (5000cd / ㎡) Remarks 101 488 nm (0.15,0.52) 22% 10.0 V The present invention 102 486 nm (0.17,0.49) 20% 10.2V The present invention 103 484 nm (0.16,0.52) 15% 10.5V The present invention 104 517 nm (0.31,0.61) 17% 10.4V The present invention 105 516 nm (0.31,0.61) 16% 12.0V Comparative example 106 485 nm (0.17,0.49) 4% 15.0 V Comparative example 107 485 nm (0.17,0.49) 5% 14.1V Comparative example 108 514 nm (0.31,0.60) 2% 12.3V Comparative example

Here, chromaticity represents the value of chromaticity coordinates (x, y) defined by the CIE colorimetric system.

As can be seen from the results in Table 1, the device produced by evaporation of the light emitting layer is excellent in luminous efficiency as compared with the device (device No. 108) produced by application of the light emitting layer. When the light emitting material of the high-efficiency green light emitting device (element No. 105) was changed to the short-wave light emitting material (D-1) of blue light emission, the light emission efficiency was greatly reduced (device No. 106, 107), but the conductive polymer layer was formed on the light emitting layer. It can be seen that high-efficiency light emission can be achieved by using a host material having a high lowest triplet excitation energy level in the vicinity of each other (elements No. 101 to 103). In addition, when the driving voltage when the light emission luminance of the device is 5000 cd / m 2 is compared, the device of the present invention is about 10V, and it is possible to drive a lower voltage as compared with the comparison device. The high-efficiency light emitting device of the present invention is excellent in durability, and the device 101 / element 107 = 11 times and element 104 / element 105 = 2 times compared with the luminance maintenance ratio after constant voltage driving for 30 minutes at an initial luminance of 5000 cd / m 2. The device of the invention is excellent in durability at the time of high luminance light emission. In addition, the device of the present invention does not cause destruction of the device under a high voltage and a high current as compared with the device of the comparative example, it is possible to emit high luminance.

According to the present invention, since the light emitting layer is formed by a vapor deposition method and has an adjacent layer of a specific conductivity (material or physical property), a light emitting device capable of low voltage driving and emitting high efficiency can be obtained. In particular, the triplet blue light emitting device can emit high efficiency.

Claims (10)

A light emitting layer formed by vapor deposition between the anode and the cathode, the light emitting layer containing at least one light emitting material that emits light in a triplet excited state, and having an adjacent layer adjacent to at least one of the anode side and the cathode layer of the light emitting layer, The layer contains an organic electroluminescent device, characterized in that it contains a conductive polymer. The organic electroluminescent device according to claim 1, wherein the lowest triplet excitation energy level of the light emitting material is 63 kW / mol (264 kJ / mol) or more and 81 kW / mol (340 kJ / mol) or less. The organic electroluminescent device according to claim 1 or 2, wherein the quantum yield of phosphorescence of the light emitting material is 0.5 or more. The lowest excitation triplet energy level of the light emitting layer excluding the light emitting material is 64 kV / mol (268 kJ / mol) or more and 82 kV / mol (344 kJ / mol) or less, characterized in that An organic electroluminescent device. The organic electroluminescent device, characterized in that at least 6S and ㎝ ^{-1 -} any one of claims 1 to A method according to any one of claim 4, wherein the electric conductivity of the adjacent layer 10. The organic electroluminescent device according to any one of claims 1 to 5, wherein the conductive polymer is a conjugated polymer doped with a dopant. The organic electroluminescent device according to any one of claims 1 to 6, wherein the organic electroluminescent device is a nonconjugated polymer material or a conjugated polymer material obtained by connecting an aromatic carbocyclic ring or an aromatic heterocycle with a bivalent or more linking group. The organic electroluminescent device according to any one of claims 1 to 6, wherein the conductive polymer has a partial structure represented by the following Chemical Formula 1. [Formula 1] (In the meal, R ¹¹ represents a substituent, m ¹¹ represents an integer of 0 to 2, When m ¹¹ represents 2, a plurality of R ¹¹ may be the same or different, and may be connected to each other to form a ring, n ¹¹ represents an integer of 1 or more). The organic electroluminescent device according to any one of claims 1 to 6, wherein the conductive polymer has a partial structure represented by the following general formula (2): [Formula 2] (In the meal, L ²¹ and L ²² represent a divalent linking group, R ²¹ , R ²² , R ²³ represent a substituent, m ²¹ , m ²² represent an integer of 0 to 4, m ²³ represents an integer of 0 to 5, When m ²¹ and m ²² represent an integer of 2 to 4 and m ²³ represents an integer of 2 to 5, a plurality of R ²¹ , R ²² , and R ²³ may be the same or different, and may be connected to each other to form a ring. , n ²¹ represents an integer of 1 or more). The organic electroluminescent device according to any one of claims 1 to 6, wherein the conductive polymer has a partial structure represented by the following general formula (3): [Formula 3] (In the meal, L ³¹ represents a trivalent linking group, L ³² represents a single bond or a divalent linking group, R ³¹ , R ³² , R ³³ represent a substituent, m ³¹ represents an integer of 0 to 4, m ³² and m ³³ represent an integer of 0 to 5, When m <^31> represents the integer of 2-4 and m <^32> , m <^33> represents the integer of 2-5, some R <^31> , R <^32> , R <^33> may be same or different, and may mutually connect and form a ring. , n ³¹ represents an integer of 1 or more).