JP4802645B2 - Materials for organic electroluminescence devices - Google Patents

Description

  The present invention relates to an organic electroluminescence element used for a planar light source and display. More specifically, it has a high glass transition temperature and heat resistance, and can be suitably used as a hole injection layer of an organic electroluminescence element, and can be driven at a low voltage using the material and has excellent heat resistance. The present invention relates to a long-life organic electroluminescence device.

  In recent years, organic electroluminescence devices have been researched and developed mainly for multilayer devices for the purpose of balancing the charge of electrons and holes into the light emitting layer. Here, the layer that transports holes from the anode of the device to the light emitting layer is generally called a hole transport layer or a hole injection transport layer, but these layers are used for the purpose of promoting the transport of holes from the anode. There may be two layers. In that case, the layer that directly contacts the light-emitting layer and transports holes to the light-emitting layer is the hole transport layer, and the layer that directly contacts the anode facilitates the injection of holes from the anode and transports holes to the hole-transporting layer. This layer is called a hole injection layer. The material used for the hole injection layer (hole injection material) preferably has an ionization potential (Ip value, also called work function) in the range of approximately 5.0 to 5.4 eV. Some of these hole-injecting materials are also introduced in Shizutoki Tokito, Chiba Yasada, Hideyuki Murata, Organic EL Display, page 102, Ohmsha (published in 2004). However, it is empirically known that aromatic tetraamine compounds generally exhibit an Ip value of 5.0 to 5.4 eV and exhibit favorable characteristics as a hole injection material.

  On the other hand, in recent years, with the expansion of the application field of organic electroluminescence elements, low voltage driving and heat resistance exceeding 100 ° C. have been required as element performance (remaining important problems of organic LED elements) And Practical Technology, 4 pages, Organic Electronics Materials Study Group, 1999). There are various factors that can affect the heat resistance of the device. One of the factors is that the glass transition temperature (Tg) of the material composing the device has a significant effect on the heat resistance of the device. Yes. That is, a phenomenon has been pointed out that when the temperature of the element exceeds the Tg of the constituent material due to the use environment of the element and the heat generated during driving, the material crystallizes and a non-light emitting region called a dark spot is generated. . In addition, it has been empirically revealed that a device having higher heat resistance generally has a longer lifetime, and therefore, a material exhibiting a higher Tg is being actively developed.

  Incidentally, organic electroluminescence devices using aromatic amine compounds focusing on the phenanthrene structure are disclosed in JP-A-6-346049, JP-A-8-20770, JP-A-8-20771, and the like. ing. However, these publications do not disclose the compound represented by the general formula [1] of the present application and do not disclose the Tg and ionization potential of the aromatic amine compound described.

JP-A-6-346049 JP-A-8-20770 Japanese Patent Laid-Open No. 8-20771

  Although the phenanthrene structure was generally known to have high thermal stability, the materials described in JP-A-6-346049 and JP-A-8-20770 are mainly diamine compounds, so that they are used as a hole injection layer. It is hard to say that it is suitable for use. Further, although the material described in JP-A-8-20771 is a tetraamine compound, it does not satisfy the currently required heat resistance of the device, and therefore, a positive Tg having a higher Tg and an appropriate Ip value. There has been a demand for a hole-injecting material and a long-life organic electroluminescence device excellent in heat resistance.

  As a result of intensive studies to solve the above problems, the present inventors have arrived at the present invention. That is, this invention relates to the material for organic electroluminescent elements containing the compound represented by the following general formula [1].

［式中、Ｒ¹〜Ｒ²⁴は、それぞれ独立に、水素原子、１価の脂肪族炭化水素基、もしくは１価の芳香族炭化水素基を表し、Ａｒ¹〜Ａｒ⁶は、それぞれ独立に、１価の芳香族炭化水素基を表す。］ General formula [1]

[Wherein, R ^{1 to} R ²⁴ each independently represents a hydrogen atom, a monovalent aliphatic hydrocarbon group, or a monovalent aromatic hydrocarbon group, and Ar ^{1 to} Ar ⁶ are each independently, Represents a monovalent aromatic hydrocarbon group. ]

Further, the present invention, R ¹ to R ²⁴ is directed to the organic electroluminescence device material is a hydrogen atom.

In the present invention, the compound represented by the general formula [1] has a molecular weight of 1500 or less, and Ar ^{1 to} Ar ⁶ are each independently a substituted or unsubstituted phenyl group, 1- It is related with the said material for organic electroluminescent elements which is a monovalent | monohydric aromatic hydrocarbon group chosen from a naphthyl group, 2-naphthyl group, o-biphenylyl group, m-biphenylyl group, and p-biphenylyl group.

  Moreover, this invention relates to the said organic electroluminescent element material whose glass transition temperature (Tg) is 130 degreeC or more.

  Moreover, this invention relates to the said organic electroluminescent element material whose value of ionization potential is the range of 5.0-5.4 eV.

  The present invention also provides an organic electroluminescent element having an organic light emitting layer sandwiched between a pair of electrodes or a multilayer organic layer including an organic light emitting layer, wherein at least one of the organic layers is the organic electroluminescent element. The present invention relates to an organic electroluminescence element characterized by containing an element material.

  The present invention further relates to the organic electroluminescence device having a hole injection layer between an anode and a light emitting layer, wherein the hole injection layer contains the material for an organic electroluminescence device.

  Since the material for an organic electroluminescence element of the present invention has a high Tg, the organic electroluminescence element produced using the material exhibits high heat resistance and a long life. Therefore, it can be suitably used as a flat panel display such as a wall-mounted TV or a flat light emitter, and can be applied to light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display boards, marker lamps, and lighting. Is possible.

Hereinafter, the present invention will be described in detail. First, the organic electroluminescent element material represented by the general formula [1] will be described. R ^{1 to} R ²⁴ in the general formula [1] each independently represent a hydrogen atom, a monovalent aliphatic hydrocarbon group, or a monovalent aromatic hydrocarbon group.

  Here, the monovalent aliphatic hydrocarbon group refers to a monovalent aliphatic hydrocarbon group having 1 to 18 carbon atoms, such as an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group. Can be given.

  Therefore, as the alkyl group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, hexyl group, heptyl group, octyl group, C1-C18 alkyl groups, such as a decyl group, a dodecyl group, a pentadecyl group, and an octadecyl group, are mentioned.

  Examples of the alkenyl group include vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-octenyl group, 1-decenyl group, 1 -An alkenyl group having 2 to 18 carbon atoms such as an octadecenyl group.

  Examples of the alkynyl group include ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, 1-octynyl group, 1-decynyl group and 1-octadecynyl group. Examples thereof include alkynyl groups having 2 to 18 carbon atoms.

  In addition, the cycloalkyl group has a carbon number such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclooctadecyl group, 2-bornyl group, 2-isobornyl group, 1-adamantyl group. Examples thereof include 3 to 18 cycloalkyl groups.

  Furthermore, examples of the monovalent aromatic hydrocarbon group include monovalent monocyclic, condensed ring, and ring-aggregated aromatic hydrocarbon groups having 6 to 30 carbon atoms. Here, as a monovalent monocyclic aromatic hydrocarbon group having 6 to 30 carbon atoms, phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2,4-xylyl group, p-cumenyl And monovalent monocyclic aromatic hydrocarbon groups having 6 to 30 carbon atoms such as a group and a mesityl group.

  Examples of the monovalent condensed ring aromatic hydrocarbon group include 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 5-anthryl group, 1-phenanthryl group, 9-phenanthryl group, 1-acenaphthyl group, 2-azurenyl group, 1-pyrenyl group, 2-triphenylyl group, 1-pyrenyl group, 2-pyrenyl group, 1-perylenyl group, 2-perylenyl group, 3-perenylenyl group, 2-trephenylenyl group, Examples thereof include monovalent condensed ring hydrocarbon groups having 10 to 30 carbon atoms such as 2-indenyl group, 1-acenaphthylenyl group, 2-naphthacenyl group, and 2-pentacenyl group.

  The monovalent ring-aggregated aromatic hydrocarbon group has 12 carbon atoms such as o-biphenylyl group, m-biphenylyl group, p-biphenylyl group, terphenylyl group, 7- (2-naphthyl) -2-naphthyl group and the like. To 30 monovalent ring-assembled hydrocarbon groups.

The carbon number of the monovalent aliphatic hydrocarbon group or monovalent aromatic hydrocarbon group in R ^{1 to} R ²⁴ described above is preferably 1 to 8, and more preferably 1 to 4. This is because, when the number of carbon atoms of these substituents increases, the molecular weight increases, and thus there is a concern that the vapor deposition property is deteriorated when an element is formed by vapor deposition. The vapor deposition of materials is not necessarily proportional because the structure of the material molecules themselves and the interaction between the molecules influences, but it is generally accepted that the tendency to vapor deposition becomes difficult as the molecular weight increases. .

Therefore, R ^{1 to} R ²⁴ described above are preferably a hydrogen atom or a monovalent aliphatic hydrocarbon group, more preferably a hydrogen atom or an alkyl group, and still more preferably a hydrogen atom or a carbon number of 1 to 4 is an alkyl group, and most preferably a hydrogen atom.

Next, Ar ^{1 to} Ar ⁶ in the general formula [1] will be described. Ar ^{1 to} Ar ⁶ each independently represents a monovalent aromatic hydrocarbon group. The monovalent aromatic hydrocarbon group here is synonymous with the above-described monovalent aromatic hydrocarbon group.

The monovalent aromatic hydrocarbon group of Ar ^{1 to} Ar ⁶ is preferably a substituted or unsubstituted phenyl group, 1-naphthyl group, 2-naphthyl group, o-biphenylyl group, m-biphenylyl group, and p. -A monovalent aromatic hydrocarbon group selected from biphenylyl groups. The reason for this is that, as described above, when the number of carbon atoms increases, the molecular weight increases, and thus there is a concern that the vapor deposition property is deteriorated when an element is formed by vapor deposition.

Furthermore, Ar ¹ and Ar ² are more preferably a monovalent aromatic hydrocarbon group selected from a substituted or unsubstituted phenyl group, o-biphenylyl group, m-biphenylyl group, and p-biphenylyl group. And more preferably a phenyl group. Ar ^{3 to} Ar ⁶ are more preferably a monovalent aromatic hydrocarbon group selected from a phenyl group, a 1-naphthyl group, an m-biphenylyl group, and a p-biphenylyl group. More preferred is a naphthyl group.

  The organic electroluminescent element material of the present invention has a generally high Tg, but Tg is preferably 100 ° C. or higher, more preferably 130 ° C. or higher, further preferably 150 ° C. or higher, and 170 It is particularly preferable that the temperature is at least ° C. The reason why the material of the present invention exhibits a high Tg is not clear, but it is considered that it has a phenanthrene structure. As a result, it can withstand the high temperature during vapor deposition, and the formed film is stable. When used in an element, it exhibits excellent stability in a high temperature environment or a heat generation environment.

  Furthermore, the organic electroluminescent element material of the present invention generally exhibits an Ip value in the range of 5.0 to 5.4 eV, but when used as a hole injection material, the Ip value is 5.1 to 5. Is preferably in the range of .35, and more preferably in the range of 5.2 to 5.35.

The organic electroluminescence element material represented by the general formula [1] used in the present invention has been described above. The molecular weight of these organic electroluminescence element materials is preferably 1500 or less, more preferably 1300 or less, and 1200. More preferred are:
In the substituent such as phenyl group, a methyl group, an ethyl group, a propyl group, a methoxy group, an ethoxy group, an acetyl group and the like may be further substituted with a low molecular weight substituent within the above molecular weight range.

  Hereinafter, although the typical example of the organic electroluminescent element material of this invention is shown in Table 1, this invention is not limited to these at all (however, Ph represents a phenyl group in a table | surface).

  The purification method for obtaining the organic electroluminescent device material of the present invention is not particularly limited, and includes a sublimation purification method, a recrystallization method, a reprecipitation method, a zone melting method, a column purification method, an adsorption method, and the like. A combination of methods can be performed. Of these purification methods, the recrystallization method is preferred for purification of the organic compound. Of the above organic compounds, a compound having sublimation properties is preferably obtained by a sublimation purification method. In the sublimation purification, it is preferable to employ a method in which the sublimation boat is maintained at a temperature lower than the temperature at which the target compound sublimates, and the sublimation impurities are removed in advance. In addition, it is desirable to apply a temperature gradient to the portion where the sublimate is collected so that the sublimate is dispersed in the impurities and the target product. Sublimation purification as described above is purification that separates impurities, and can be applied to the present invention. In addition, sublimation purification is useful for predicting the difficulty of the material vapor deposition.

  By the way, an organic electroluminescence element is composed of an element in which a single layer or a multilayer organic layer is formed between an anode and a cathode. Here, a single layer type organic electroluminescence element is a light emitting layer between an anode and a cathode. The element which consists only of. On the other hand, a multi-layer organic electroluminescent element is one that facilitates the injection of holes and electrons into the light emitting layer in addition to the light emitting layer, and facilitates recombination of holes and electrons in the light emitting layer. For example, a layer in which a hole injection layer, a hole transport layer, a hole blocking layer, an electron injection layer, and the like are stacked is used. Therefore, typical device configurations of the multilayer organic electroluminescence device include (1) anode / hole injection layer / light emitting layer / cathode, and (2) anode / hole injection layer / hole transport layer / light emitting layer / Cathode, (3) anode / hole injection layer / light emitting layer / electron injection layer / cathode, (4) anode / hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode, (5) anode / Hole injection layer / light emitting layer / hole blocking layer / electron injection layer / cathode, (6) anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron injection layer / cathode, (7 An element configuration in which a multilayer structure such as () anode / light emitting layer / hole blocking layer / electron injection layer / cathode, (8) anode / light emitting layer / electron injection layer / cathode is considered.

  The organic electroluminescent element material of the present invention may be used for any of the above-described layers, but can be suitably used particularly for a hole injection layer. The reason is that the work function of the material for an organic electroluminescence device of the present invention is generally 5.0 to 5.4 eV, which is suitable for use as a hole injection material. The organic electroluminescent device material of the present invention can be used not only as a single compound but also as a combination of two or more compounds, that is, mixed, co-evaporated, laminated, etc. It is. Further, in the above-described hole injection layer, hole transport layer, and light emitting layer, they may be used together with other materials.

For the hole injection layer, a hole injection material that exhibits an excellent hole injection effect with respect to the light emitting layer and that can form a hole injection layer excellent in adhesion to the anode interface and thin film formability is used. In addition, when such materials are laminated in multiple layers and a material having a high hole injection effect and a material having a high hole transport effect are laminated, the materials used for each are called a hole injection material and a hole transport material. Sometimes. The organic electroluminescent element material of the present invention can be suitably used for both hole injection materials and hole transport materials. These hole injection materials and hole transport materials need to have a high hole mobility and a small ionization energy of usually 5.5 eV or less. Such a hole injection layer is preferably a material that transports holes to the light emitting layer with a lower electric field strength, and further has a hole mobility of at least when an electric field of 10 ⁴ to 10 ⁶ V / cm is applied. What is 10 ^<-6 > cm ^{< 2} > / V * second is preferable. Other hole injection materials and hole transport materials that can be used by mixing with the organic electroluminescence device material of the present invention are not particularly limited as long as they have the above-mentioned preferable properties. Any one of those commonly used as hole charge transport materials in photoconductive materials and known materials used in hole injection layers of organic electroluminescent elements can be selected and used.

  Specific examples of such hole injection materials and hole transport materials include triazole derivatives (see US Pat. No. 3,112,197) and oxadiazole derivatives (US Pat. No. 3,189,447). Imidazole derivatives (see Japanese Patent Publication No. 37-16096), polyarylalkane derivatives (US Pat. Nos. 3,615,402, 3,820,989, 3,542,544, JP-B-45-555, JP-A-51-10983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148, JP-A-55- No. 108667, No. 55-156953, No. 56-36656, etc.), pyrazoline derivatives and pyrazolone derivatives (US Pat. No. 3,180, No. 29, No. 4,278,746, JP-A 55-88064, No. 55-88065, No. 49-105537, No. 55-51086, No. 56-80051. No. 56-88141, No. 57-45545, No. 54-112437, No. 55-74546, etc.), phenylenediamine derivatives (US Pat. No. 3,615,404, Japanese Patent Publication Nos. 51-10105, 46-3712, 47-25336, JP 54-53435, 54-110536, 54-1119925, etc.), arylamine Derivatives (US Pat. Nos. 3,567,450, 3,180,703, 3,240,597, 3 No. 658,520, No. 4,232,103, No. 4,175,961, No. 4,012,376, JP-B 49-35702, No. 39 -27577, JP-A-55-144250, JP-A-56-119132, JP-A-56-22437, West German Patent No. 1,110,518, etc.), amino-substituted chalcone derivatives (US patents) No. 3,526,501), oxazole derivatives (disclosed in US Pat. No. 3,257,203, etc.), styryl anthracene derivatives (see JP 56-46234 A, etc.), Fluorenone derivatives (see JP-A-54-110837, etc.), hydrazone derivatives (US Pat. No. 3,717,462, JP-A-54-59143, 55-52063, 55-52064, 55-46760, 55-85495, 57-11350, 57-148749, JP-A-2-311591, etc. Stilbene derivatives (Japanese Patent Laid-Open Nos. 61-210363, 61-228451, 61-14642, 61-72255, 62-47646, 62-36674) 62-10652, 62-30255, 60-93455, 60-94462, 60-174749, 60-175052, etc.), silazane derivatives (US) Patent No. 4,950,950), polysilane (JP-A-2-204996), aniline copolymer (JP-A-2-282263), an electroconductive oligomer (particularly a thiophene oligomer) disclosed in JP-A-1-211399 and the like.

  As the hole injecting material and the hole transporting material, those described above can be used. Porphyrin compounds (Japanese Patent Laid-Open No. 63-295965), aromatic tertiary amine compounds and styrylamine compounds (US Pat. No. 4,127,412, JP-A-53-27033, 54-58445, 54-149634, 54-64299, 55-79450, 55-144250 No. 56-119132, No. 61-295558, No. 61-98353, No. 63-295695, etc.) can also be used. For example, 4,4′-bis (N- (1-naphthyl) -N-phenylamino) biphenyl having two condensed aromatic rings in the molecule described in US Pat. No. 5,061,569, etc. And 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) -N-phenyl, in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type. Amino) triphenylamine, etc. In addition, examples of the hole injection material include phthalocyanine derivatives such as copper phthalocyanine and hydrogen phthalocyanine, and other aromatic dimethylidene compounds, p-type Si, p-type SiC and the like. These inorganic compounds can also be used as materials for hole injection materials and hole transport materials.

  Specific examples of the aromatic tertiary amine derivative include, for example, N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4,4′-diamine, N, N , N ′, N ′-(4-methylphenyl) -1,1′-phenyl-4,4′-diamine, N, N, N ′, N ′-(4-methylphenyl) -1,1′- Biphenyl-4,4′-diamine, N, N′-diphenyl-N, N′-dinaphthyl-1,1′-biphenyl-4,4′-diamine, N, N ′-(methylphenyl) -N, N '-(4-n-Butylphenyl) -phenanthrene-9,10-diamine, N, N-bis (4-di-4-tolylaminophenyl) -4-phenyl-cyclohexane, N, N'-bis (4 '-Diphenylamino-4-biphenylyl) -N, N'-diphenyl Nzine, N, N′-bis (4′-diphenylamino-4-phenyl) -N, N′-diphenylbenzidine, N, N′-bis (4′-diphenylamino-4-phenyl) -N, N ′ -Di (1-naphthyl) benzidine, N, N'-bis (4'-phenyl (1-naphthyl) amino-4-phenyl) -N, N'-diphenylbenzidine, N, N'-bis (4'- Phenyl (1-naphthyl) amino-4-phenyl) -N, N′-di (1-naphthyl) benzidine and the like can be mentioned, and these can be used for both hole injection materials and hole transport materials.

  In order to form this hole injection layer, the above compound is thinned by a known method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. Although there is no restriction | limiting in particular, Usually, they are 5 nm-5 micrometers.

  On the other hand, for the electron injection layer, an electron injection material that exhibits an excellent electron injection effect with respect to the light emitting layer and that can form an electron injection layer excellent in adhesion to the cathode interface and thin film formability is used. Examples of such electron injection materials include metal complex compounds, nitrogen-containing five-membered ring derivatives, fluorenone derivatives, anthraquinodimethane derivatives, diphenoquinone derivatives, thiopyrandioxide derivatives, perylenetetracarboxylic acid derivatives, fluorenylidenemethane. Derivatives, anthrone derivatives, silole derivatives, triarylphosphine oxide derivatives, calcium acetylacetonate, sodium acetate and the like. In addition, inorganic / organic composite materials doped with metal such as cesium in bathophenanthroline (Proceedings of the Society of Polymer Science, Vol. 50, No. 4, 660, published in 2001), and the 50th Applied Physics Related Lecture Lecture Proceedings, No. Examples of electron injection materials include BCP, TPP, T5MPyTZ, etc. published on page 3, 1402, 2003. Electrons can be transported by forming a thin film necessary for device fabrication and injecting electrons from the cathode. If it is material, it will not specifically limit to these.

  Among the electron injection materials, particularly effective electron injection materials include metal complex compounds, nitrogen-containing five-membered ring derivatives, silole derivatives, and triarylphosphine oxide derivatives. As a preferable metal complex compound that can be used in the present invention, a metal complex of 8-hydroxyquinoline or a derivative thereof is suitable. Specific examples of the metal complex of 8-hydroxyquinoline or a derivative thereof include tris (8-hydroxyquinolinate) aluminum, tris (2-methyl-8-hydroxyquinolinato) aluminum, tris (4-methyl-8- Hydroxyquinolinato) aluminum, tris (5-methyl-8-hydroxyquinolinato) aluminum, tris (5-phenyl-8-hydroxyquinolinato) aluminum, bis (8-hydroxyquinolinato) (1-naphtholate) ) Aluminum, bis (8-hydroxyquinolinate) (2-naphtholate) aluminum, bis (8-hydroxyquinolinate) (phenolate) aluminum, bis (8-hydroxyquinolinato) (4-cyano-1-naphtholate) ) Aluminum, bis (4-methyl-8) Hydroxyquinolinato) (1-naphtholato) aluminum, bis (5-methyl-8-hydroxyquinolinato) (2-naphtholato) aluminum, bis (5-phenyl-8-hydroxyquinolinato) (phenolate) aluminum, Bis (5-cyano-8-hydroxyquinolinate) (4-cyano-1-naphtholato) aluminum, bis (8-hydroxyquinolinato) chloroaluminum, bis (8-hydroxyquinolinato) (o-cresolate) Aluminum complex compounds such as aluminum, tris (8-hydroxyquinolinato) gallium, tris (2-methyl-8-hydroxyquinolinato) gallium, tris (4-methyl-8-hydroxyquinolinato) gallium, tris ( 5-Methyl-8-hydroxyquinolinate Gallium, tris (2-methyl-5-phenyl-8-hydroxyquinolinato) gallium, bis (2-methyl-8-hydroxyquinolinato) (1-naphtholato) gallium, bis (2-methyl-8-hydroxy) Quinolinate) (2-naphtholato) gallium, bis (2-methyl-8-hydroxyquinolinato) (phenolate) gallium, bis (2-methyl-8-hydroxyquinolinato) (4-cyano-1-naphtholate) ) Gallium, bis (2,4-dimethyl-8-hydroxyquinolinato) (1-naphtholate) gallium, bis (2,5-dimethyl-8-hydroxyquinolinato) (2-naphtholato) gallium, bis (2 -Methyl-5-phenyl-8-hydroxyquinolinate) (phenolate) gallium, bis (2-methyl-5- Cyano-8-hydroxyquinolinate) (4-cyano-1-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) chlorogallium, bis (2-methyl-8-hydroxyquinolinate) ( In addition to gallium complex compounds such as o-cresolate) gallium, 8-hydroxyquinolinate lithium, bis (8-hydroxyquinolinato) copper, bis (8-hydroxyquinolinato) manganese, bis (10-hydroxybenzo [h And quinolinato) beryllium, bis (8-hydroxyquinolinato) zinc, and bis (10-hydroxybenzo [h] quinolinato) zinc.

  Among the electron injection materials that can be used in the present invention, preferable nitrogen-containing five-membered ring derivatives include oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, and triazole derivatives. , 5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1-phenyl) -1, 3,4-oxadiazole, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) 1,3,4-oxadiazole, 2,5-bis (1-naphthyl) -1 , 3,4-oxadiazole, 1,4-bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert-butyl benzene], 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-thiadiazole, 2,5-bis (1-naphthyl) -1,3,4-thiadiazole, 1, 4-bis [2- (5-phenylthiadiazolyl)] benzene, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-triazole, 2,5- Examples thereof include bis (1-naphthyl) -1,3,4-triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like.

In addition, among the electron injection materials that can be used in the present invention, preferred silole derivatives include, for example, the following silole derivatives.

  Of the electron injecting materials that can be used in the present invention, preferred triarylphosphine oxide derivatives include those disclosed in JP-A-2002-63989, JP-A-2004-95221, JP-A-2004-203828, and JP-A-2004. -204140, for example, the following triarylphosphine oxide derivatives are listed.

  Furthermore, a hole blocking material that can prevent holes from passing through the light emitting layer from reaching the electron injection layer and form a layer having excellent thin film formability is used for the hole blocking layer. Examples of such hole blocking materials include aluminum complex compounds such as bis (8-hydroxyquinolinate) (4-phenylphenolate) aluminum, and bis (2-methyl-8-hydroxyquinolinate) ( 4-phenylphenolate) gallium complex compounds such as gallium, and nitrogen-containing condensed aromatic compounds such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

As the light emitting layer of the organic electroluminescence device of the present invention, those having the following functions are suitable.
Injection function; function transport function that can inject holes from the anode or hole injection layer when an electric field is applied, and electrons from the cathode or electron injection layer; electric field of injected charges (electrons and holes) Light emitting function: A function that provides a field for recombination of electrons and holes and connects it to light emission. However, there is a difference between the ease of hole injection and the ease of electron injection. In addition, the transport ability represented by the mobility of holes and electrons may be large or small, but it is preferable to move one of the charges. The light emitting material of the organic electroluminescence element is mainly an organic compound, and specifically, the following compounds are used depending on a desired color tone.

  For example, in the case of obtaining violet emission from the ultraviolet region, a compound represented by the following general formula [2] is preferably used.

General formula [2]

[Wherein, X1 represents a group represented by the following general formula [3], and X2 represents any one of a phenyl group, a 1-naphthyl group, and a 2-naphthyl group. ]

（式中、ｍは２〜５の整数を示す） General formula [3]

(In the formula, m represents an integer of 2 to 5)

  The phenyl group, 1-naphthyl group, 2-naphthyl group, and phenylene group represented by X1 and X2 in the general formula [2] are one or more alkyl groups having 1 to 4 carbon atoms and 1 to 4 carbon atoms. It may be substituted with a substituent such as an alkoxyl group, a hydroxyl group, a sulfonyl group, a carbonyl group, an amino group, a dimethylamino group or a diphenylamino group. Moreover, when there are a plurality of these substituents, they may be bonded to each other to form a ring. Furthermore, the phenylene group represented by X1 is preferably bonded at the para position because it has good bonding properties and can easily form a smooth deposited film. Specific examples of the compound represented by the general formula [2] are as follows (where Ph represents a phenyl group).

Among these compounds, p-quaterphenyl derivatives and p-quinkphenyl derivatives are particularly preferable.
Further, in order to obtain light emission in the visible range, particularly blue to green, for example, a fluorescent brightener such as benzothiazole, benzimidazole, and benzoxazole, a metal chelated oxinoid compound, and a styrylbenzene compound may be used. it can. Specific examples of these compounds include, for example, compounds disclosed in JP-A-59-194393. Still other useful compounds are listed in Chemistry of Synthetic Soybean (1971) pages 628-637 and 640.
As the metal chelated oxinoid compound, for example, compounds disclosed in JP-A-63-295695 can be used. As typical examples, 8-hydroxyquinoline-based metal complexes such as tris (8-quinolinol) aluminum, dilithium epinetridione and the like can be mentioned as suitable compounds.
As the styrylbenzene compound, for example, those disclosed in European Patent No. 0319881 and European Patent No. 0373582 can be used. And the distyrylpyrazine derivative currently disclosed by Unexamined-Japanese-Patent No. 2-252793 can also be used as a material of a light emitting layer. In addition, polyphenyl compounds disclosed in EP 0387715 can also be used as a material for the light emitting layer.

  Further, in addition to the above-described fluorescent brightener, metal chelated oxinoid compound, styrylbenzene compound and the like, for example, 12-phthaloperinone (J. Appl. Phys., Vol. 27, L713 (1988)), 1,4- Diphenyl-1,3-butadiene, 1,1,4,4-tetraphenyl-1,3-butadiene (Appl. Phys. Lett., Vol. 56, L799 (1990)), naphthalimide derivatives No. 2-305886), perylene derivatives (Japanese Patent Laid-Open No. 2-189890), oxadiazole derivatives (Japanese Patent Laid-Open No. Hei 2-216791, or the 38th Applied Physics Related Conference) were disclosed by Hamada et al. Oxadiazole derivatives), aldazine derivatives (JP-A-2-220393), pyrazirine derivatives (JP-A-2-220393) -20394), cyclopentadiene derivatives (JP-A-2-289675), pyrrolopyrrole derivatives (JP-A-2-29691), styrylamine derivatives (Appl. Phys. Lett., Vol. 56, L799 (1990). ), Coumarin compounds (JP-A-2-191694), international patent publications WO90 / 13148 and Appl. Phys. Lett., Vol 58, 18, P1982 (1991), 9 , 9 ′, 10,10′-tetraphenyl-2,2′-bianthracene, PPV (polyparaphenylene vinylene) derivatives, polyfluorene derivatives and copolymers thereof, for example, the following general formula [4] to general formula Having the structure of [6],

［式中、Ｒ^X1およびＲ^X2は、それぞれ独立に、１価の脂肪族炭化水素基を、ｎ１は、３〜１００の整数を表す。］ General formula [4]

[Wherein, R ^X1 and R ^X2 each independently represent a monovalent aliphatic hydrocarbon group, and n1 represents an integer of 3 to 100. ]

［式中、Ｒ^X3およびＲ^X4は、それぞれ独立に、１価の脂肪族炭化水素基を、ｎ２およびｎ３は、それぞれ独立に、３〜１００の整数を表す。］ General formula [5]

[Wherein, R ^X3 and R ^X4 each independently represent a monovalent aliphatic hydrocarbon group, and n2 and n3 each independently represent an integer of 3 to 100. ]

［式中、Ｒ^X5およびＲ^X6は、それぞれ独立に、１価の脂肪族炭化水素基を、ｎ４およびｎ５は、それぞれ独立に、３〜１００の整数を表す。Ｐｈはフェニル基を表す。］ General formula [6]

[Wherein, R ^X5 and R ^X6 each independently represent a monovalent aliphatic hydrocarbon group, and n4 and n5 each independently represent an integer of 3 to 100. Ph represents a phenyl group. ]

9,10-bis (N- (4- (2-phenylvinyl-1-yl) phenyl) -N-phenylamino) anthracene or the like can also be used as a material for the light emitting layer. Furthermore, a phenylanthracene derivative represented by the following general formula [7] as disclosed in JP-A-8-12600 can also be used as a light emitting material.
General formula [7]
A1-L-A2
[Wherein, A1 and A2 each independently represent a monophenylanthryl group or a diphenylanthryl group, which may be the same or different. L represents a single bond or a divalent linking group. ]
Here, the divalent linking group represented by L is preferably a divalent monocyclic or condensed ring aromatic hydrocarbon group which may have a substituent. In particular, phenylanthracene derivatives represented by the following general formulas [8] to [9] are preferable.

General formula [8]

[Wherein, R ^{Z1 to} R ^Z4 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, a monovalent aromatic hydrocarbon group, an alkoxyl group, an aryloxy group, a diarylamino group, or a monovalent group. Represents an aliphatic heterocyclic group and a monovalent aromatic heterocyclic group, which may be the same or different. r1 to r4 each independently represents 0 or an integer of 1 to 5. When r1 to r4 are each independently an integer of 2 or more, R ^Z1 , R ^Z2 , R ^Z3 , R ^Z4 may be the same or different, and R ^Z1 , R ^Z2 together, R ^Z3 each other, R ^Z4 to each other may form a ring. L1 represents a divalent monocyclic or condensed ring aromatic hydrocarbon group which may have a single bond or a substituent, and a divalent monocyclic or condensed ring aromatic hydrocarbon group which may have a substituent May be an intervening alkylene group, —O—, —S— or —NR— (wherein R represents an alkyl group or an aryl group). ]

General formula [9]

[Wherein, R ^Z5 and R ^Z6 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, a monovalent aromatic hydrocarbon group, an alkoxyl group, an aryloxy group, a diarylamino group, or a monovalent group. Represents an aliphatic heterocyclic group and a monovalent aromatic heterocyclic group, which may be the same or different. r5 and r6 each independently represents 0 or an integer of 1 to 5. When r5 and r6 are each independently an integer of 2 or more, R ^Z5 and R ^Z6 may be the same or different, and R ^Z5 and R ^Z6 are bonded to form a ring. May be. L2 represents a divalent monocyclic or condensed ring aromatic hydrocarbon group which may have a single bond or a substituent, and a divalent monocyclic or condensed ring aromatic hydrocarbon group which may have a substituent May be an intervening alkylene group, —O—, —S— or —NR— (wherein R represents an alkyl group or an aryl group). ]

  Of the general formula [8], phenylanthracene derivatives represented by the following general formula [10] to general formula [11] are more preferable.

Formula [10]

[Wherein, R ^{Z11 to} R ^Z30 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, a monovalent aromatic hydrocarbon group, an alkoxyl group, an aryloxy group, a diarylamino group, a monovalent group. Represents an aliphatic heterocyclic group and a monovalent aromatic heterocyclic group, which may be the same or different. Further, R ^{Z11 to} R ^Z30 may be formed by connecting adjacent groups to form a ring. k1 represents an integer of 0 to 3. ]

General formula [11]

[Wherein, R ^{Z31 to} R ^Z50 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, a monovalent aromatic hydrocarbon group, an alkoxyl group, an aryloxy group, a diarylamino group, or a monovalent group. Represents an aliphatic heterocyclic group and a monovalent aromatic heterocyclic group, which may be the same or different. In addition, R ^{Z31 to} R ^Z50 may be formed by connecting adjacent groups to form a ring. k2 represents an integer of 0 to 3. ]

Of the general formula [9], a phenylanthracene derivative represented by the following general formula [12] is more preferable.

Formula [12]

[Wherein, R ^{Z51 to} R ^Z60 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, a monovalent aromatic hydrocarbon group, an alkoxyl group, an aryloxy group, a diarylamino group, a monovalent group. Represents an aliphatic heterocyclic group and a monovalent aromatic heterocyclic group, which may be the same or different. In addition, R ^{Z51 to} R ^Z60 may be formed by connecting adjacent groups to form a ring. k3 represents an integer of 0 to 3. ]

Specific examples of the general formula [10] to general formula [12] include the following compounds.

Furthermore, the following compounds are also given as specific examples.

An amine compound represented by the following general formula [13] is also useful as a light emitting material.
Formula [13]

[In formula, h is a valence and represents the integer of 1-6. E1 represents an n-valent aromatic hydrocarbon group, and E2 represents an amino group selected from a dialkylamino group, a diarylamino group, and an alkylarylamino group. ]
Here, as a base structure of the n-valent aromatic hydrocarbon group represented by E1, naphthalene, anthracene, 9-phenylanthracene, 9,10-diphenylanthracene, naphthacene, pyrene, perylene, biphenyl, binaphthyl, and bianthryl are preferable. , E1 is preferably a diarylamino group. N is preferably 1 to 4, and most preferably 2. Of the general formula [13], amine compounds represented by the following general formula [14] to general formula [23] are particularly preferable.

General formula [14]

[Wherein, R ^{y1 to} R ^y8 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. Represents a cyclic group or an amino group selected from a dialkylamino group, a diarylamino group, and an alkylarylamino group, and at least one of R ^{y1 to} R ^y8 is a dialkylamino group, a diarylamino group, an alkylarylamino group. Represents an amino group selected from the group; R ^{y1 to} R ^y8 may be the same or different, and adjacent groups may be connected to form a ring. ]

General formula [15]

[ ^Wherein , R ^{y11 to} R ^y20 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. ring group, or a dialkylamino group, a diarylamino group, represents an amino group selected from alkyl aryl amino group, of R ^y11 to R ^y20, at least one, dialkylamino group, diarylamino group, an alkylarylamino Represents an amino group selected from the group; R ^{y11 to} R ^y20 may be the same or different, and adjacent groups may be connected to form a ring. ]

Formula [16]

[ ^Wherein , R ^{y21 to} R ^y34 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. ring group, or a dialkylamino group, a diarylamino group, represents an amino group selected from alkyl aryl amino group, of R ^y21 to R ^Y34, at least one, dialkylamino group, diarylamino group, an alkylarylamino Represents an amino group selected from the group; R ^{y21 to} R ^y34 may be the same or different, and adjacent groups may be connected to form a ring. ]

General formula [17]

[ ^Wherein , R ^{y35 to} R ^y52 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. ring group, or a dialkylamino group, a diarylamino group, represents an amino group selected from alkyl aryl amino group, of R ^y35 to R ^y52, at least one, dialkylamino group, diarylamino group, an alkylarylamino Represents an amino group selected from the group; R ^{y35 to} R ^y52 may be the same or different, and adjacent groups may be connected to form a ring. ]

General formula [18]

[ ^Wherein , R ^{y53 to} R ^y64 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. ring group, or a dialkylamino group, a diarylamino group, represents an amino group selected from alkyl aryl amino group, of R ^y53 to R ^Y64, at least one, dialkylamino group, diarylamino group, an alkylarylamino Represents an amino group selected from the group; R ^{y53 to} R ^y64 may be the same or different, and adjacent groups may be connected to form a ring. ]

General formula [19]

[ ^Wherein R ^{y65 to} R ^y74 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. ring group, or a dialkylamino group, a diarylamino group, represents an amino group selected from alkyl aryl amino group, of R ^Y65 to R ^Y74, at least one, dialkylamino group, diarylamino group, an alkylarylamino Represents an amino group selected from the group; R ^{y65 to} R ^y74 may be the same or different, and adjacent groups may be connected to form a ring. ]

General formula [20]

[ ^Wherein , R ^{y75 to} R ^y86 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. ring group, or a dialkylamino group, a diarylamino group, represents an amino group selected from alkyl aryl amino group, of R ^Y75 to R ^Y86, at least one, dialkylamino group, diarylamino group, an alkylarylamino Represents an amino group selected from the group; R ^{y75 to} R ^y86 may be the same or different, and adjacent groups may be connected to form a ring. ]

Formula [21]

[ ^Wherein R ^{y87 to} R ^y96 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. ring group, or a dialkylamino group, a diarylamino group, represents an amino group selected from alkyl aryl amino group, of ^R y87 ~R y96, at least one, dialkylamino group, diarylamino group, an alkylarylamino Represents an amino group selected from the group; R ^{y87 to} R ^y96 may be the same or different, and adjacent groups may be connected to form a ring. ]

General formula [22]

[ ^Wherein R ^{y97 to} R ^y110 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. ring group, or a dialkylamino group, a diarylamino group, represents an amino group selected from alkyl aryl amino group, of R ^Y97 to R ^y110, at least one, dialkylamino group, diarylamino group, an alkylarylamino Represents an amino group selected from the group; R ^{y97 to} R ^y110 may be the same or different, and adjacent groups may be connected to form a ring. ]

General formula [23]

[ ^Wherein R ^{y111 to} R ^y128 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxyl group, an aryloxy group, a monovalent aliphatic heterocyclic group, or a monovalent aromatic heterocyclic group. ring group, or a dialkylamino group, a diarylamino group, represents an amino group selected from alkyl aryl amino group, of ^R y111 ~R y128, at least one, dialkylamino group, diarylamino group, an alkylarylamino Represents an amino group selected from the group; R ^{y111 to} R ^y128 may be the same or different, and adjacent groups may be connected to form a ring. ]

  The amine compounds of general formula [18] and general formula [20] described above can be suitably used when yellow to red light emission is obtained. Specific examples of the amine compounds represented by the general formulas [13] to [23] described above include compounds having the following structures (where Ph represents a phenyl group).

  In addition, in the above general formula [13] to general formula [23], a compound containing at least one styryl group represented by the following general formula [24] to general formula [25] instead of an amino group (for example, EP 0388768, JP-A-3-231970, etc.) can also be suitably used as the light emitting material.

General formula [24]

[ ^Wherein , R ^{y129 to} R ^y131 each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, or a monovalent aromatic hydrocarbon group. In R ^{y129 to} R ^y131 , adjacent groups may be connected to form a ring. ]

General formula [25]

[ ^Wherein , R ^{y132 to} R ^y138 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, or a monovalent aromatic hydrocarbon group. R ^{y134 to} R ^y138 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a monovalent aromatic hydrocarbon group, or an amino group selected from a dialkylamino group, a diarylamino group, and an alkylarylamino group. As shown, at least one of R ^{y134 to} R ^y138 is an amino group selected from a dialkylamino group, a diarylamino group, and an alkylarylamino group. In R ^{y132 to} R ^y138 , adjacent groups may be connected to form a ring. ]

  Specific examples of the compound containing at least one styryl group represented by the general formulas [24] to [25] described above can include compounds having the following structure (where Ph represents a phenyl group): .

Further, the general formula (Rs-Q) _2- Al-O-L3 [wherein L3 is a hydrocarbon having 6 to 24 carbon atoms containing a phenyl moiety, as described in JP-A-5-258862, etc. O-L3 is a phenolate ligand, Q represents a substituted 8-quinolinolato ligand, Rs sterically represents that two or more substituted 8-quinolinolato ligands are bonded to an aluminum atom. And an 8-quinolinolate ring substituent selected so as to interfere.]. Specific examples include bis (2-methyl-8-quinolinolato) (para-phenylphenolate) aluminum (III), bis (2-methyl-8-quinolinolato) (1-naphtholato) aluminum (III), and the like. .

  In addition, there is a method for obtaining a high-efficiency blue and green mixed light emission using doping described in JP-A-6-9953. In this case, examples of the host include the above-described light-emitting materials, and examples of the dopant include strong fluorescent dyes from blue to green, for example, coumarin-based or similar fluorescent dyes used as the above-described host. Specifically, a light-emitting material having a distyrylarylene skeleton as a host, particularly preferably 4,4′-bis (2,2-diphenylvinyl) biphenyl, and diphenylaminovinylarylene as a dopant, particularly preferably, for example, N, N-diphenyl Mention may be made of aminovinylbenzene.

Although there is no restriction | limiting in particular as a light emitting layer which obtains white light emission, The following can be used.
The energy level of each layer of the organic electroluminescence laminated structure is defined and light is emitted using tunnel injection (European Patent No. 0390551).
Similarly, a white light emitting element is described as an example of an element using tunnel injection (Japanese Patent Laid-Open No. 3-230584).
A light-emitting layer having a two-layer structure is described (JP-A-2-220390 and JP-A-2-216790).
A structure in which a light emitting layer is divided into a plurality of materials each having a different emission wavelength (Japanese Patent Laid-Open No. 4-51491).
A structure in which a blue phosphor (fluorescence peak 380 to 480 nm) and a green phosphor (480 to 580 nm) are stacked and a red phosphor is further contained (Japanese Patent Laid-Open No. 6-207170).
The blue light emitting layer contains a blue fluorescent dye, the green light emitting layer has a region containing a red fluorescent dye, and further contains a green phosphor (Japanese Patent Laid-Open No. 7-142169).
Among these, those having the above-described configuration are particularly preferable.

Furthermore, for example, the following known compounds are preferably used as the light emitting material (where Ph represents a phenyl group).

  In the organic electroluminescence device of the present invention, a phosphorescent material can be used. Examples of phosphorescent materials or doping materials that can be used in the organic electroluminescence device of the present invention include, for example, organometallic complexes, where the metal atom is usually a transition metal, and preferably has a fifth period or a sixth period. In terms of the period and group, elements from Group 6 to Group 11 and more preferably Group 8 to Group 10 are targeted. Specific examples include iridium and platinum. Examples of the ligand include 2-phenylpyridine and 2- (2′-benzothienyl) pyridine, and the carbon atom on these ligands is directly bonded to the metal. Another example is a porphyrin or tetraazaporphyrin ring complex, and the central metal is platinum. For example, the following known compounds are suitably used as the phosphorescent material (where Ph represents a phenyl group).

  Next, as a method for forming a light emitting layer using the above materials, for example, a known method such as a vapor deposition method, a spin coating method, or an LB method can be applied. The light emitting layer is particularly preferably a molecular deposited film. Here, the molecular deposited film is a thin film formed by deposition from a material compound in a gas phase state or a film formed by solidifying from a material compound in a solution state or a liquid phase state. Can be classified from a thin film (accumulated film) formed by the LB method according to a difference in an agglomerated structure and a higher-order structure and a functional difference resulting therefrom. Further, as disclosed in JP-A-57-51781, a binder such as a resin and a material compound are dissolved in a solvent to form a solution, which is then thinned by a spin coat method or the like. A light emitting layer can be formed.

There is no restriction | limiting in particular about the film thickness of the light emitting layer formed in this way, Although it can select suitably according to a condition, Usually, the range of 5 nm-5 micrometers is preferable. This light emitting layer may be composed of a single layer made of one or more of the materials described above, or may be a laminate of a light emitting layer made of a compound different from the above light emitting layer.

  The organic electroluminescent element material of the present invention can be used in the light emitting layer of the organic electroluminescent element. That is, two or more kinds of other light emitting materials, host materials, doping materials, and hole transport materials can be used in combination as necessary. Further, the hole injection layer, the light emitting layer, and the electron injection layer may each be formed with a layer configuration of two or more layers.

Furthermore, the material used for the anode of the organic electroluminescence device of the present invention is preferably a material having a work function (4 eV or more) metal, alloy, electrically conductive compound or a mixture thereof as an electrode material. Specific examples of such an electrode substance include metals such as Au, Ag, Al, and Cr, and conductive materials such as CuI, ITO (Indium tin oxide), SnO ₂ , and ZnO. In order to form this anode, a thin film can be formed from these electrode materials by a method such as vapor deposition or sputtering. The anode desirably has such a characteristic that when light emitted from the light emitting layer is extracted from the anode, the transmittance of the anode for light emission is greater than 10%. The sheet resistance of the anode is preferably several hundred Ω / □ or less. Further, although the film thickness of the anode depends on the material, it is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.

  The material used for the cathode of the organic electroluminescence device of the present invention is a material having a work function (4 eV or less) metal, alloy, electrically conductive compound and a mixture thereof as an electrode material. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / silver alloy, aluminum / aluminum oxide, aluminum / lithium alloy, indium, and rare earth metals. The cathode can be formed by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Here, when light emitted from the light-emitting layer is extracted from the cathode, the transmittance of the cathode for light emission is preferably greater than 10%. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually 10 nm to 1 μm, preferably 50 to 200 nm.

  Regarding the method for producing the organic electroluminescence device of the present invention, an anode, a light emitting layer, a hole injection layer as necessary, and an electron injection layer as necessary are formed by the above materials and methods, and finally a cathode is formed. What is necessary is just to form. Moreover, an organic electroluminescent element can also be produced from the cathode to the anode in the reverse order.

  This organic electroluminescence element is manufactured on a translucent substrate. This light-transmitting substrate is a substrate that supports the organic electroluminescence element. Regarding the light-transmitting property, it is desirable that the light transmittance in the visible region of 400 to 700 nm is 50% or more, preferably 90% or more. Further, it is preferable to use a smoother substrate.

  These substrates have mechanical and thermal strengths and are not particularly limited as long as they are transparent. For example, glass plates, synthetic resin plates and the like are preferably used. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the synthetic resin plate include plates such as polycarbonate resin, acrylic resin, polyethylene terephthalate resin, polyether sulfide resin, and polysulfone resin.

  In addition, as a method for forming each layer of the organic electroluminescence device of the present invention, a dry film forming method such as vacuum deposition, electron beam irradiation, sputtering, plasma, ion plating, or a wet method such as spin coating, dipping, flow coating, etc. Any method of film formation can be applied. The film thickness of each layer is not particularly limited, but if the film thickness is too thick, a large applied voltage is required to obtain a constant light output, resulting in poor efficiency. Conversely, if the film thickness is too thin, pinholes, etc. And it becomes difficult to obtain sufficient light emission luminance even when an electric field is applied. Accordingly, the thickness of each layer is suitably in the range of 1 nm to 1 μm, but more preferably in the range of 10 nm to 0.2 μm.

  Further, in order to improve the stability of the organic electroluminescence element against temperature, humidity, atmosphere, etc., a protective layer may be provided on the surface of the element, or the entire element may be covered or sealed with a resin or the like. In particular, when the entire element is covered or sealed, a photocurable resin that is cured by light is preferably used.

  The organic electroluminescence device material of the present invention is an environment of 50 ° C. or less (more preferably 30 ° C. or less) and humidity of 80% or less (more preferably 60% or less) in a sealed container that is shielded from the outside air under light shielding. Preferably stored below.

  The current applied to the organic electroluminescence element of the present invention is usually a direct current, but a pulse current or an alternating current may be used. The current value and the voltage value are not particularly limited as long as the element is within a range not destroying the element. However, considering the power consumption and life of the element, it is desirable to efficiently emit light with as little electrical energy as possible.

  The organic electroluminescence device of the present invention can be driven not only by the passive matrix method but also by the active matrix method. The organic electroluminescence device of the present invention can be applied not only to a method called bottom emission in which light is extracted from the anode side but also to a method called top emission to extract light from the cathode side. These methods and techniques are described in Shinji Kido, “All about organic EL”, published by Nihon Jitsugyo Shuppansha (published in 2003).

  The organic electroluminescence element of the present invention may adopt a microcavity structure. This is an organic electroluminescence element having a structure in which a light emitting layer is sandwiched between an anode and a cathode, and the emitted light causes multiple interference between the anode and the cathode, but the reflectance of the anode and the cathode, A technology that actively utilizes the multiple interference effect and controls the emission wavelength extracted from the device by appropriately selecting the optical characteristics such as transmittance and the film thickness of the organic layer sandwiched between them. is there. Thereby, it is also possible to improve the emission chromaticity. For the mechanism of this multiple interference effect, see J.A. Yamada et al., AM-LCD Digest of Technical Papers, OD-2, p. 77-80 (2002).

  As described above, since the organic electroluminescence element material of the present invention has a high glass transition temperature and good heat resistance, the organic electroluminescence element prepared using the organic electroluminescence element material of the present invention is high. It shows heat resistance and has a long life. Therefore, it can be suitably used as a flat panel display such as a wall-mounted TV or a flat light emitter, and can be applied to light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display boards, marker lamps, and lighting. Is possible.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example at all. First, prior to examples, a synthesis example of the material for an organic electroluminescence element of the present invention will be described.

Synthesis example 1
Synthesis method and purification method of Compound 1 9,10-di (N-phenylamino) phenanthrene 3.6 g, 4-diphenylamino-4′-chlorobiphenyl 7.8 g, palladium acetate, 0.074 g, tri-t-butyl 0.22 g of phosphine and 100 ml of xylene were mixed and heated to reflux for 2 hours under a nitrogen atmosphere. The reaction was filtered at 80 ° C. and 800 mL of methanol was added to the filtrate. The precipitated solid was purified by column chromatography (silica gel, using a mixed solvent of cyclohexane and toluene) to obtain 7.2 g of a pale yellow powder. Next, 1.0 g of this pale yellow powder was sublimated at a temperature of 330 to 350 ° C. and a pressure of 2 to 4 × 10 ⁻³ Pa to obtain 0.84 g of Compound 1. Compound 1 had a glass transition temperature of 162 ° C. (according to DSC measurement) and an Ip value of 5.27 eV (according to measurement using AC-1 manufactured by Riken Keiki Co., Ltd.).

Examples of the present invention are shown below. In Examples, in addition to the materials listed in Table 1 above, known compounds shown in Table 2 and Table 3 below were used. Unless otherwise noted, all mixing ratios are weight ratios. In the production of the organic electroluminescence element, the vapor deposition was performed in a vacuum of 10 ⁻⁶ Torr without controlling the substrate temperature. In addition, the characteristics of the element are measured with an electrode area of 2 mm × 2 mm, and the half life is 5000 hours at 25 ° C. using an element sealed in a nitrogen atmosphere having an oxygen concentration and a water concentration of 1 ppm or less. Measurements were made to the limit.

Example 1
On a glass plate with an ITO electrode, the compound 5 shown in Table 1 was dissolved in 1,1,2-trichloroethane, and a hole injection layer having a thickness of 50 nm was formed by a spin coating method. Next, a tris (8-hydroxyquinolinate) aluminum complex (Alq3) is deposited to form an electron injecting light emitting layer having a thickness of 30 nm, and an alloy in which magnesium and silver are mixed at a ratio of 10: 1. An electrode having a thickness of 100 nm was formed to obtain an organic electroluminescence element. The light emission efficiency of this device at a DC voltage of 8.4 V was 2.2 (lm / W). In addition, the half-life when driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 2
On the glass plate with an ITO electrode, the compound 1 of Table 1 was vapor-deposited to form a hole injection layer having a thickness of 80 nm. Next, Alq3 was vapor-deposited to form an electron-injecting light-emitting layer having a thickness of 40 nm, and an electrode was formed thereon by vacuum vapor deposition of 1 nm of lithium fluoride and 200 nm of aluminum to obtain an organic electroluminescence device. . When this element was driven at a current density of 10 (mA / cm ² ), the voltage was 4.7 (V), the luminance was 290 (cd / m ² ), and the light emission efficiency was 1.7 (lm / W). . In addition, when this device was driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ), the half life was 5000 hours or more. Next, the same element was prepared, stored in an oven at 130 ° C. for 1 hour, and similarly measured for element characteristics when driven at a current density of 10 (mA / cm ² ). The luminance was 7 (V), the luminance was 285 (cd / m ² ), and the luminous efficiency was 1.7 (lm / W). Furthermore, when this device was driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ), the half-life was 5000 hours or more.

Comparative Examples 1-3
Experiments were performed on the known compounds A1 to A6 listed in Table 2 under the same conditions as in Example 2. The results are shown in Table 4 together with Example 2.

  From the results shown in Table 4, the device produced using Compound 1 of the present invention was driven at the same current density as the device produced using the known compounds A1 to A6. It is clear that the lifetime is excellent.

Example 3
On the glass plate with an ITO electrode, the compound 2 of Table 1 was vapor-deposited to form a hole injection layer having a film thickness of 60 nm, and then the compound A1 of Table 2 was vapor-deposited to form a hole transport layer having a film thickness of 20 nm. . Next, Alq3 was vapor-deposited to form an electron-injecting light-emitting layer having a thickness of 60 nm, and an electrode was formed thereon by vacuum vapor deposition of 1 nm of lithium fluoride and 200 nm of aluminum to obtain an organic electroluminescence device. . The light emission efficiency of this device at a DC voltage of 5.0 V was 1.9 (lm / W). In addition, the half-life when driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 4
On the glass plate with an ITO electrode, the compound 6 of Table 1 was vapor-deposited to form a 60 nm-thick hole injection layer, and then the compound 4 of Table 1 was vapor-deposited to form a 20-nm-thick hole transport layer. . Next, Alq3 was vapor-deposited to form an electron-injecting light-emitting layer having a thickness of 60 nm, and an electrode was formed thereon by vacuum vapor deposition of 1 nm of lithium fluoride and 200 nm of aluminum to obtain an organic electroluminescence device. . The light emission efficiency of this device at a DC voltage of 5.7 V was 2.0 (lm / W). In addition, the half-life when driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 5
On the glass plate with an ITO electrode, the compound 7 and the compound 8 in Table 1 were co-evaporated at a composition ratio of 1: 1 to form a hole injection layer having a thickness of 70 nm. Next, the light emitting layer with a film thickness of 20 nm was formed by vapor-depositing the compound B of Table 3. Further, Alq3 was deposited to form an electron injection layer having a thickness of 20 nm. An electrode was formed thereon by vacuum deposition of 1 nm of lithium fluoride and 150 nm of aluminum, to obtain an organic electroluminescence device. This device showed a luminous efficiency of 2.4 (lm / W) at a DC voltage of 5.2V. In addition, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 6
On the glass plate with an ITO electrode, the compound 10 of Table 1 was vapor-deposited to form a hole injection layer having a thickness of 55 nm. Next, Compound C and Compound D in Table 3 were co-evaporated at a composition ratio of 20: 1 to form a light emitting layer having a thickness of 30 nm. Further, Alq3 was deposited to form an electron injection layer having a thickness of 20 nm. On top of that, an electrode was formed by vacuum vapor deposition of 1 nm of lithium fluoride and 200 nm of aluminum to obtain an organic electroluminescence element. This device had a luminous efficiency of 5.4 (lm / W) at a DC voltage of 6.6 V. In addition, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 7
On the glass plate with an ITO electrode, the compound 12 of Table 1 was vapor-deposited to form a hole injection layer having a thickness of 35 nm. Next, Compound E and Compound F in Table 3 were co-evaporated at a composition ratio of 20: 1 to form a light emitting layer having a thickness of 40 nm. Further, Alq3 was deposited to form an electron injection layer with a thickness of 30 nm. An electrode was formed thereon by vacuum deposition of 1 nm of lithium fluoride and 180 nm of aluminum, to obtain an organic electroluminescence element. This device had a luminous efficiency of 3.5 (lm / W) at a DC voltage of 3.4 V. In addition, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 8
On the glass plate with an ITO electrode, the compound 13 of Table 1 was vapor-deposited to form a hole injection layer having a thickness of 60 nm. Next, compound G of Table 3 and Alq3 were co-evaporated at a composition ratio of 1: 1 to form an electron transporting light emitting layer having a thickness of 50 nm. Furthermore, an electrode having a thickness of 200 nm was formed from an alloy in which magnesium and silver were mixed at a ratio of 1: 3 to obtain an organic electroluminescence device. The light emission efficiency of this device at a DC voltage of 7.5 V was 1.8 (lm / W). Further, the half-life when driven at a constant current at room temperature with an emission luminance of 400 (cd / m ² ) was 5000 hours or more.

Example 9
On the glass plate with an ITO electrode, the compound 15 of Table 1 was vapor-deposited to form a 65-nm-thick hole injection layer. Next, Compound H and Compound J in Table 3 were co-evaporated at a composition ratio of 200: 1 to form a light emitting layer having a thickness of 25 nm. Further, BCP was deposited to form an electron injection layer having a thickness of 25 nm. On top of this, 0.5 nm of lithium and 150 nm of silver were vapor-deposited to obtain an organic electroluminescence element. This device showed a luminous efficiency of 0.88 (lm / W) at a DC voltage of 11V. In addition, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 10
On the glass plate with an ITO electrode, the compound 1 of Table 1 was vapor-deposited to form a hole injection layer having a thickness of 35 nm. Next, Compound E and Compound F in Table 3 were co-evaporated at a composition ratio of 20: 1 to form a light emitting layer having a thickness of 35 nm. Further, Alq3 was deposited to form an electron injection layer with a thickness of 30 nm. On top of that, an electrode was formed by vacuum vapor deposition of 1 nm of lithium fluoride and 200 nm of aluminum to obtain an organic electroluminescence element. This device showed a luminous efficiency of 3.6 (lm / W) at a DC voltage of 3.2 V. In addition, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 11
On the glass plate with an ITO electrode, the compound 18 of Table 1 was vapor-deposited to form a hole injection layer having a thickness of 40 nm. Next, Compound K in Table 3 was deposited to a thickness of 10 nm to form a hole transport layer. Further, Compound L and Compound M were co-evaporated at a composition ratio of 1: 9 to form a light emitting layer having a thickness of 23 nm. Further, BCP was deposited to form a 15 nm hole blocking layer. Further, Alq3 was deposited to form an electron injection layer having a thickness of 25 nm. On top of this, a cathode was formed by vapor deposition of 1 nm of lithium fluoride and 100 nm of aluminum to obtain an organic electroluminescence element. This device showed an external quantum efficiency of 7.4% at a DC voltage of 10V. Further, the half-life when driven at a constant current at an emission luminance of 100 (cd / m ² ) was 5000 hours or more.

Example 12
Copper phthalocyanine was deposited on a glass plate with an ITO electrode to form a hole injection layer having a thickness of 25 nm. Next, Compound 19 in Table 1 was deposited by 50 nm to form a hole transport layer. Further, Compound N and Compound P in Table 3 were co-evaporated at a composition ratio of 8: 100 to form a light emitting layer having a thickness of 40 nm. Further, Compound Q shown in Table 3 was deposited to form an electron injection layer having a thickness of 20 nm. On top of that, a cathode was formed by vapor deposition of 1 nm of lithium oxide and 100 nm of aluminum to obtain an organic electroluminescence element. This device showed an external quantum efficiency of 6.6% at a DC voltage of 10V. Further, the half-life when driven at a constant current at an emission luminance of 200 (cd / m ² ) was 5000 hours or more.

Example 13
On a glass plate with an ITO electrode, 70 nm of the compound 21 shown in Table 1 was deposited to form a hole injection layer. Further, Alq3 was deposited to form a light emitting layer with a thickness of 20 nm. Further, Compound R shown in Table 3 was deposited to form an electron injection layer having a thickness of 30 nm. On top of that, a cathode was formed by vapor deposition of 1 nm of lithium oxide and 100 nm of aluminum to obtain an organic electroluminescence element. This device showed a light emission efficiency of 2.0 (lm / W) at a DC voltage of 5V. In addition, the half-life when driven at a constant current at an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 14
On the glass plate with an ITO electrode, the compound S of Table 3 was vapor-deposited to form a hole injection layer having a thickness of 60 nm, and then the compound 24 of Table 1 was vapor-deposited to form a hole transport layer having a thickness of 20 nm. . Next, Alq3 was vapor-deposited to form an electron-injecting light-emitting layer having a thickness of 60 nm, and an electrode was formed thereon by vacuum vapor deposition of 1 nm of lithium fluoride and 200 nm of aluminum to obtain an organic electroluminescence device. . The light emission efficiency of this device at a DC voltage of 5 V was 1.8 (lm / W). In addition, the half-life when driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ) was 5000 hours or more.

Example 15
In order to evaluate the heat resistance of the element, the same element as that prepared in Example 1 and Examples 3 to 14 was prepared, and the current before and after storage in an oven at 130 ° C. for 1 hour. The luminance at a density of 10 (mA / cm ² ) was compared. As a result, the decrease in brightness due to oven storage was less than 5% before storage in the oven. Furthermore, when these devices were driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ), the half-life was 5000 hours or more.

  As described above, as described in the Examples, it has been clarified that all the organic electroluminescence elements prepared using the organic electroluminescence element material of the present invention have an excellent half life.

Claims (7)

An organic electroluminescent element material comprising a compound represented by the following general formula [1].
General formula [1]

[Wherein, R ^{1 to} R ²⁴ each independently represents a hydrogen atom, a monovalent aliphatic hydrocarbon group, or a monovalent aromatic hydrocarbon group, and Ar ^{1 to} Ar ⁶ are each independently, Represents a monovalent aromatic hydrocarbon group. ] The organic electroluminescent element material according to claim 1, wherein R ^{1 to} R ²⁴ are hydrogen atoms. The compound represented by the general formula [1] has a molecular weight of 1500 or less, and Ar ^{1 to} Ar ⁶ are each independently a substituted or unsubstituted phenyl group, 1-naphthyl group, 2-naphthyl. The organic electroluminescent element material according to claim 1 or 2, which is a monovalent aromatic hydrocarbon group selected from a group, an o-biphenylyl group, an m-biphenylyl group, and a p-biphenylyl group. The organic electroluminescent element material according to any one of claims 1 to 3, wherein the glass transition temperature (Tg) is 130 ° C or higher. The material for an organic electroluminescence element according to any one of claims 1 to 4, wherein an ionization potential value is in a range of 5.0 to 5.4 eV. 6. An organic electroluminescent device having an organic light emitting layer or a multilayer organic layer including an organic light emitting layer sandwiched between a pair of electrodes, wherein at least one of the organic layers is according to any one of claims 1 to 5. An organic electroluminescence device comprising a material for an organic electroluminescence device. Furthermore, it has a positive hole injection layer between an anode and a light emitting layer, The said positive hole injection layer contains the organic electroluminescent element material in any one of Claims 1 thru | or 5. Luminescence element.