JP2014086427A - Material for organic electroluminescent element and application thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compound exhibiting a high glass transition temperature, with which a stable thin film can be easily formed since the molecule thereof is hardly crystallized, and which has excellent characteristics such as low voltage drive and long life when used as a blue emitting material for an organic EL element.SOLUTION: In a compound, a carbazole ring bonding at a position 3 to pyrene of the central skeleton is asymmetric, so that amorphous properties are increased, and as a result crystallization is hardly caused. Accordingly, when the compound is used as a material for an organic EL element, the stability of a thin film is improved, dark spots are hardly caused, and the life of an organic EL element is prolonged.

Description

  The present invention relates to a novel material for an organic electroluminescence element (hereinafter abbreviated as an organic EL element) and its use. More specifically, when used in an organic EL device, it can be formed by vapor deposition or spin coating, and has excellent performance (high glass transition temperature, high luminous efficiency, low voltage drive, high color purity, long life). The present invention relates to a material for an organic EL element that exhibits and can be suitably used particularly for a blue light emitting material.

  In recent years, organic EL elements have been required to have a long lifetime. There are various factors that can affect the lifetime of the device. One of the factors is considered to be that the glass transition temperature (Tg) of the material constituting the device has a significant effect on the lifetime of the device. . That is, it is pointed out that when the temperature of the element exceeds the Tg of the constituent material due to the use environment of the element or the heat generated during driving, the constituent material is crystallized and a non-light emitting region called a dark spot is generated. ing. For this reason, materials having higher Tg have been demanded (Non-Patent Documents 1 and 2).

  There are few blue light emitting materials providing blue light emitting elements with excellent durability. As an example, a technique using an anthracene compound for a blue light emitting element is disclosed. Blue light-emitting devices using various anthracene compounds (Patent Documents 1 to 4) have been reported, but all have the disadvantage that the lifetime of the device is short and it is difficult to be a practical material.

  As other blue light emitting materials, organic electroluminescent elements using a pyrene skeleton are disclosed as blue dopant light emitting materials. (Patent Document 5) However, all of these blue light-emitting elements have a low life and lack in practicality.

  Among them, an organic electroluminescent device using a pyrene derivative substituted with a tetraphenylamine unit is disclosed. (Non-patent Document 3) However, the organic electroluminescence device using this pyrene derivative has a low chromaticity of CIE (x, y) = (0.29, 0.34) and a low blue color purity, and a deep blue color. It is difficult to achieve luminescence. Therefore, the device has a problem in manufacturing a full color display.

  In addition, an organic electroluminescent element using a pyrene derivative substituted with a tetraphenylamine unit is disclosed. However, the organic electroluminescent element using this pyrene derivative has low color purity of blue light emission, and it is difficult to achieve deep blue light emission. Therefore, the device has a problem in manufacturing a full color display.

  In addition, an organic electroluminescent element using a pyrene derivative substituted with a carbazolyl unit is disclosed. However, this pyrene derivative has a substitution position different from that of the compound of the present invention, and the organic electroluminescence device has low color purity of blue light emission, and it is difficult to achieve deep blue light emission. Therefore, the device has a problem in manufacturing a full color display.

JP 2003-306454 A Japanese Patent Laid-Open No. 2004-2351 WO2005 / 113531 pamphlet JP 2007-63501 A Japanese Patent Laid-Open No. 04-175395 JP 2007-221113 A JP 2010-195708 A

Toshito Shizushi, Chida Adachi, Hideyuki Murata, Organic EL Display, Ohmsha, 2004, pp. 139-143 Edited by Technical Information Association, the latest collection of latest functional pigments, Technical Information Association, 2007, pages 103-119 Physical Chemical Physics (2011), 13 (39), 17825-17830

  An object of the present invention is to provide a compound having pyrene as a basic skeleton, which is useful for an organic EL device material, can be deposited and formed by coating, and exhibits high Tg, and emits blue light in particular. The object is to provide a compound that can be suitably used as an organic EL device. Furthermore, it is to provide an organic EL element exhibiting excellent characteristics such as high luminous efficiency, low voltage driving, color purity, long life, heat resistance, and the like by using the material for the organic EL element.

  As a result of intensive studies to solve the above problems, the present inventors have arrived at the present invention.

  That is, the present invention relates to a material for an organic electroluminescence element comprising a compound represented by the following general formula [1].

General formula [1]

(Wherein, A ^{1 to} A ⁴ each independently represents a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, or Represents a substituted or unsubstituted aromatic heterocyclic group,
R ^{1 to} R ²⁸ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, Represents a substituted or unsubstituted aromatic heterocyclic group, substituted silyl group, cyano group, alkoxyl group, aryloxy group, or substituted amino group, R ^{1 to} R ⁴ , R ^{11 to} R ¹⁴ , R ^{15 to} R ¹⁸ and R ^{25 to} R ²⁸ may be bonded to each other to form a ring. )

Further, the present invention, A ¹ to A ⁴ are each independently about the organic electroluminescence device material is a group represented by the following general formula [2].

General formula [2]

Wherein R ^{29 to} R ³³ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic Represents a heterocyclic group, a substituted or unsubstituted aromatic heterocyclic group, a substituted silyl group, a cyano group, an alkoxyl group, an aryloxy group, or a substituted amino group, and R ^{29 to} R ³³ represent groups adjacent to each other They may combine to form a ring.)

  Further, the present invention provides an organic electroluminescence device comprising a plurality of organic layers including a light emitting layer between a pair of electrodes, wherein the light emitting layer comprises the material for an organic electroluminescence device. It relates to an element.

  The present invention also relates to the above organic electroluminescent device, wherein the light emitting layer contains an anthracene derivative and a spiro derivative as a host material.

Moreover, this invention relates to the said organic electroluminescent element in which a light emitting layer is formed into a film by application | coating.

  Moreover, this invention relates to the ink composition for organic electroluminescent elements which consists of the said organic electroluminescent element material and an organic solvent.

  Since the organic EL element using the organic EL element material of the present invention is driven at a low voltage and has a long life, it can be suitably used as a flat panel display such as a wall-mounted TV or a flat light emitter, It can be applied to light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display panels, and indicator lights.

  Hereinafter, the present invention will be described in detail.

First, A ^{1 to} A ⁴ in the general formula [1] are each independently a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic ring. A group or a substituted or unsubstituted aromatic heterocyclic group,
R ^{1 to} R ²⁸ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, A substituted or unsubstituted aromatic heterocyclic group, a substituted silyl group, a cyano group, an alkoxyl group, an aryloxy group, or a substituted amino group.

  Here, the aliphatic hydrocarbon group refers to an aliphatic hydrocarbon group having 1 to 18 carbon atoms, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, and a cycloalkyl group.

  Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, heptyl, octyl, 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 -C2-C18 alkenyl groups, such as an octadecenyl group, are mentioned.

  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 include alkynyl groups having 2 to 18 carbon atoms.

  Examples of the cycloalkyl group include cycloalkyl groups having 3 to 18 carbon atoms such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclooctadecyl group.

  Here, examples of the aromatic hydrocarbon group include a single ring, a condensed ring, and a ring assembly hydrocarbon group.

  Moreover, as monocyclic aromatic hydrocarbon group, carbon number 6-6, such as a phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2,4-xylyl group, p-cumenyl group, mesityl group, etc. 18 monocyclic aromatic hydrocarbon groups may be mentioned.

  Examples of the condensed ring 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, Examples thereof include condensed ring hydrocarbon groups having 10 to 18 carbon atoms such as 2-azurenyl group, 1-pyrenyl group and 2-triphenylyl group.

  Examples of the ring assembly hydrocarbon group include ring assembly hydrocarbon groups having 12 to 18 carbon atoms such as an o-biphenylyl group, an m-biphenylyl group, and a p-biphenylyl group.

  Moreover, as an aliphatic heterocyclic group, C3-C18 aliphatic heterocyclic groups, such as 2-pyrazolino group, piperidino group, morpholino group, and 2-morpholinyl group, are mentioned.

  Examples of the aromatic heterocyclic group include triazolyl group, 3-oxadiazolyl group, 2-furanyl group, 3-furanyl group, 2-furyl group, 3-furyl group, 2-thienyl group, 3-thienyl group, 1- Pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazyl group, 2-oxazolyl group, 3-isoxazolyl group, 2 -Thiazolyl group, 3-isothiazolyl group, 2-imidazolyl group, 3-pyrazolyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8 -Quinolyl group, 1-isoquinolyl group, 2-quinoxalinyl group, 2-benzofuryl group, 2-benzothienyl group, N-indolyl group, N-carbazolyl group, N-acridinyl group, 2-thiol Group, 3-thiophenyl group, a bipyridyl group, an aromatic heterocyclic group having 2 to 18 carbon atoms such phenanthrolyl group.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Moreover, as an alkoxyl group, C1-C8 alkoxyl groups, such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a tert-butoxy group, an octyloxy group, a tert-octyloxy group, are mentioned.

  Examples of the aryloxy group include aryloxy groups having 6 to 14 carbon atoms such as phenoxy group, 4-tert-butylphenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, and 9-anthryloxy group. It is done.

  The substituted silyl group is a substituted or unsubstituted alkyl group, or a silyl group substituted by a substituted or unsubstituted aryl group. A monoalkylsilyl group, a monoarylsilyl group, a dialkylsilyl group, a diarylsilyl group And substituted silyl groups such as a group, a trialkylsilyl group, and a triarylsilyl group.

  The monoalkylsilyl group includes monoalkylsilyl groups such as monomethylsilyl group, monoethylsilyl group, monobutylsilyl group, monoisopropylsilyl group, monodecanesilyl, monoicosanesilyl group, and monotriacontanesilyl group. Can be mentioned.

  Examples of the monoarylsilyl group include monoarylsilyl such as monophenylsilyl group, monotolylsilyl group, mononaphthylsilyl group, and monoanthrylsilyl group.

  Examples of the dialkylsilyl group include dialkylsilyl groups such as dimethylsilyl group, diethylsilyl group, dimethylethylsilyl group, diisopropylsilyl group, dibutylsilyl group, dioctylsilyl group, and didecanesilyl group.

  Examples of the diarylsilyl group include diarylsilyl such as diphenylsilyl group and ditolylsilyl group.

  Examples of the trialkylsilyl group include trialkylsilyl groups such as trimethylsilyl group, triethylsilyl group, dimethylethylsilyl group, triisopropylsilyl group, tributylsilyl group, and trioctylsilyl group.

  Examples of the triarylsilyl group include triarylsilyl groups such as a triphenylsilyl group and a tolylsilylsilyl group.

  The substituted amino group includes N-methylamino group, N-ethylamino group, N, N-diethylamino group, N, N-diisopropylamino group, N, N-dibutylamino group, N-benzylamino group, N , N-dibenzylamino group, N-phenylamino group, N-phenyl-N-methylamino group, N, N-diphenylamino group, N, N-bis (m-tolyl) amino group, N, N-bis (P-tolyl) amino group, N, N-bis (p-biphenylyl) amino group, bis [4- (4-methyl) biphenylyl] amino group, N-α-naphthyl-N-phenylamino group, N-β -Substituted amino groups having 2 to 26 carbon atoms such as naphthyl-N-phenylamino group.

These aliphatic hydrocarbon groups, aromatic hydrocarbon groups, aliphatic heterocyclic groups, and aromatic heterocyclic groups in A ^{1 to} A ⁴ and R ^{1 to} R ²⁸ are further substituted by other substituents. May be. Examples of such a substituent include the above-described aliphatic hydrocarbon group, aromatic hydrocarbon group, aliphatic heterocyclic group, and aromatic heterocyclic group.

Furthermore, R ^{29 to} R ³³ in the general formula [2] are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted group. A substituted aliphatic heterocyclic group, a substituted or unsubstituted aromatic heterocyclic group, a substituted silyl group, a cyano group, an alkoxyl group, an aryloxy group, or a substituted amino group.

  Examples of substituted or unsubstituted aliphatic hydrocarbon groups, substituted or unsubstituted aromatic hydrocarbon groups, substituted or unsubstituted aliphatic heterocyclic groups, and substituted or unsubstituted aromatic heterocyclic groups shown here As mentioned above.

Preferred examples of A ^{1 to} A ⁴ in the general formula [1] of the present invention include an unsubstituted monovalent aromatic hydrocarbon group and an unsubstituted monovalent aromatic heterocyclic group, and more preferable. As for the thing, an unsubstituted monovalent | monohydric aromatic hydrocarbon group is mentioned, As a particularly preferable thing, a phenyl group is mentioned.

Further, as the R ¹ to R ²⁸ in the general formula [1], preferred are a hydrogen atom, a monovalent aliphatic hydrocarbon group, or include monovalent aromatic hydrocarbon group, more preferred are , A hydrogen atom, or a monovalent aromatic hydrocarbon group, and particularly preferable examples include a hydrogen atom.

  The superiority of having a 3-carbazolyl group will be described below.

  In general, it is known that an amino group acts as an electron donor, but a nitrogen atom in a carbazole skeleton has little donor property with respect to a substituent bonded on the nitrogen atom. This is thought to be due to the difficulty of taking a planar structure with the substituent on the nitrogen atom bonded to the carbazole ring.

  On the contrary, since the carbazole ring bonded at the 3-position has the planarity of the ring, it can be an electron donor for the benzene ring portion (see Chemical Formula 4). Therefore, as a substitution position with pyrene which is a central skeleton, attention was paid to a carbazolyl group bonded at the 3-position, which can be expected to interact electronically.

In addition, the carbazolyl group substituted at the 3-position is compared with the carbazolyl group substituted at the 9-position,
Since the symmetry of the molecule is low, the crystallinity of the molecule is low and the amorphous property is high. Therefore, it is possible to greatly contribute to the improvement of stability when a thin film is formed.

Therefore, since the carbazole compound of the present invention is asymmetric, it has high amorphousness.
As a result, crystallization hardly occurs. When used as a material for an organic EL device, this property improves the stability of the thin film, makes it difficult for dark spots to occur, and increases the lifetime of the organic EL device.

Furthermore, in order to improve the solubility, it is preferable to introduce a substituent into any of R ^{29 to} R ³³ , and the type is most preferably an aliphatic hydrocarbon group having a large steric hindrance.

  As mentioned above, although the organic EL element material represented by the general formula [1] of the present invention has been described, when an organic EL element is formed by vapor deposition using these organic EL element materials, The molecular weight is preferably 1500 or less, more preferably 1200 or less, still more preferably 1000 or less, and particularly preferably 800 or less. This is because, when the molecular weight is large, there is a concern that it is difficult to produce an element by vapor deposition.

  Although the typical example of the organic EL element material of this invention is shown in the following Table 1, this invention is not limited to this representative example.

  Next, representative examples of compounds used as host materials in the present invention are shown in Tables 2 and 3 below, but the present invention is not limited to these representative examples.

  In the present invention, the wet film forming method is a coating method, an inkjet method, a dip coating method, a die coating method, a spray coating method, a spin coating method, a roll coater method, a dipping coating method, a screen printing method, flexographic printing, The composition is applied to form a film by a screen printing method, an LB method, or the like.

  High-purity materials are required for materials for organic EL devices, but the compounds of the present invention can be obtained by sublimation purification method, recrystallization method, reprecipitation method, zone melting method, column purification method, adsorption method, etc. A combination of methods can be performed. Of these purification methods, the recrystallization method is preferred. For compounds having sublimation properties, it is preferable to employ 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.

  Next, the ink composition for organic EL elements will be described.

  The ink composition for organic EL elements in the present invention contains at least the material for organic EL elements of the present invention and a solvent.

  Various solvents are applicable as the solvent contained in the above-mentioned ink composition for organic EL elements, and are not particularly limited. For example, aromatic hydrocarbons such as toluene, xylene, methicylene, cyclohexylbenzene and tetralin; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene and trichlorobenzene; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene and anisole , Phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole and other aromatic ethers; phenyl acetate, phenyl propionate, methyl benzoate, benzoic acid Aromatic esters such as ethyl, propyl benzoate and n-butyl benzoate; ketones having an alicyclic ring such as cyclohexanone and cyclooctanone; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; methyl ethyl ketone and cyclohexano Alcohol having an alicyclic ring such as ruthenium or cyclooctanol; Aliphatic alcohol such as butanol or hexanol; Aliphatic ether such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether or propylene glycol-1-monomethyl ether acetate (PGMEA); Ethyl acetate And aliphatic esters such as n-butyl acetate, ethyl lactate and n-butyl lactate.

  Of these, aromatic hydrocarbons such as toluene, xylene, methicylene, cyclohexylbenzene, tetralin and the like are preferable in that they have low water solubility and are not easily altered.

  These solvents may be used alone or in combination. In addition, the solvent which can be used is not limited to these.

  Since organic electroluminescent devices use many materials such as cathodes that deteriorate significantly due to moisture, the presence of moisture in the composition causes moisture to remain in the dried film, degrading the device characteristics. The possibility is considered and it is not preferable.

  Further, in order to reduce a decrease in film formation stability due to solvent evaporation from the composition during wet film formation, the boiling point is 100 ° C. or higher, preferably 150 ° C. as the solvent of the composition for organic EL elements. As described above, it is more effective to use a solvent having a boiling point of 200 ° C. or higher.

  The ink composition for an organic EL element of the present invention is preferably used for an organic EL light emitting element in which a light emitting material is a low molecular material and a layer containing the light emitting material is formed by a wet film forming method.

  The ink composition for organic EL elements of the present invention is mainly used for containing a light emitting material and forming a light emitting layer, but may be used for other layers such as a hole transport layer.

  In the present invention, as long as the object of the present invention is not impaired, the ink composition of the present invention may optionally contain other known light-emitting materials in the light emitting layer. A light-emitting layer containing another known light-emitting material may be stacked on the light-emitting layer formed by a wet film formation method. In this case, the light emitting layer containing another known light emitting material may be formed by a dry method such as a vacuum evaporation method.

  In general, the organic EL element is manufactured on a light-transmitting substrate. The translucent substrate referred to here is a substrate that supports the organic EL element, and is preferably a smooth substrate having a light transmittance in the visible region of 400 to 700 nm of 50% or more.

  Specifically, a glass plate, a polymer plate, etc. are mentioned. 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 polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone.

  In the organic EL element ink composition of the present invention, the content of the organic EL element material of the present invention is preferably 0.5 wt% or more. Usually, the thickness of the light-emitting layer of the organic EL element is 10 to 100 nm, but generally it is often 50 nm or more. When the film thickness is less than 50 nm, problems such as a decrease in light emission performance and a large color tone deviation occur. In order to easily form a film thickness of 50 nm or more, the solution concentration is preferably 0.5 wt% or more. When the concentration is lower than 0.5 wt%, it is difficult to form a thick film.

  In addition to the organic EL element material and solvent described above, a known additive may be added to the ink composition for an organic EL element of the present invention as necessary.

    The ink composition for an organic EL device of the present invention is a known wet film forming method, for example, a coating method, an inkjet method, a dip coating method, a die coating method, a spray coating method, a spin coating method, a roll coater method, a dipping coating method. Can be formed by screen printing, flexographic printing, screen printing, LB method, etc.

  Here, the organic EL element which can be produced using the organic EL element material of the present invention will be described in detail.

  The organic EL 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, the single layer type organic EL element is an element composed of only a light emitting layer between an anode and a cathode. Point to. On the other hand, the multilayer organic EL element facilitates 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 the purpose of this, it refers to a layer in which a hole injection layer, a hole transport layer, a hole blocking layer, an electron injection layer, and the like are laminated. Further, an interlayer that is adjacent to the light emitting layer between the light emitting layer and the anode and has a role of separating the light emitting layer and the anode or the light emitting layer from the hole injection layer or the hole transport layer. Layers may be inserted. Therefore, typical element configurations of the multilayer organic EL element 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 / positive 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) Anode / light emitting layer / hole blocking layer / electron injection layer / cathode, (8) anode / light emitting layer / electron injection layer / cathode, etc. (9) Anode / hole injection layer / hole transport layer / interlayer layer / light emission Layer / cathode, (10) anode / hole injection layer / interlayer layer / light emitting layer / electron injection layer / cathode, (11) anode / hole injection layer / hole transport layer / in Chromatography / light-emitting layer / electron injection layer / cathode, it is considered elements formed by laminating a multilayer structure of.

  Moreover, each organic layer mentioned above may be formed by the layer structure of two or more layers, respectively, and several layers may be laminated | stacked repeatedly. As such an example, an element configuration called “multi-photon emission” in which a part of the above-described multilayer organic EL element is multilayered has been proposed in recent years for the purpose of improving light extraction efficiency. For example, in an organic EL device composed of a glass substrate / anode / hole transport layer / electron transporting light emitting layer / electron injection layer / charge generating layer / light emitting unit / cathode, the charge generating layer and the light emitting unit There is a method of laminating a plurality of portions.

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 EL device 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 EL device material of the present invention are not particularly limited as long as they have the above-mentioned preferable properties. Any material can be selected and used from those commonly used as charge transport materials for holes in a conductive material and known materials used for hole injection layers of organic EL devices.

  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.

  The above-mentioned materials can be used as the hole injection material and the hole transport material, but aromatic tertiary amine compounds and styrylamine compounds (US Pat. No. 4,127,412, JP-A-53). No. -27033, No. 54-58445, No. 54-149634, No. 54-64299, No. 55-79450, No. 55-144250, No. 56-119132, No. 61- 295558, 61-98353, 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, etc. These inorganic compounds can also be used as hole injection materials and hole transport materials.

Further, materials that can be used for the hole injection layer include molybdenum oxide (MnO _x ), vanadium oxide (VO _x ), ruthenium oxide (RuO _x ), copper oxide (CuO _x ), tungsten oxide (WO _x ), and iridium oxide. Inorganic oxides such as (IrO _x ) are also included.

  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.

  Particularly preferred examples of the hole injection material are shown in Table 4.

  Moreover, as a hole transport material which can be used with the compound (material for organic EL elements) of this invention, the compound shown in following Table 5 is also mentioned.

  In order to form the hole injection layer described above, the above-mentioned compound is thinned by a known method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. The thickness of the hole injection layer is not particularly limited, but is usually 5 nm to 5 μm.

  Examples of the material used for the interlayer layer include polymers containing aromatic amines such as polyvinylcarbazole and derivatives thereof, polyarylene derivatives having aromatic amines in the side chain or main chain, arylamine derivatives, and triphenyldiamine derivatives. In addition, as a method for forming the interlayer layer, when a high molecular weight material is used, a method by film formation from a solution is exemplified.

  For the formation of an interlayer layer from a solution, a known wet film forming method, for example, a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, Coating methods such as a dip coating method, a spray coating method, a screen printing method, a flexographic printing method, an offset printing method, an ink jet printing method, a capillary coating method, and a nozzle coating method can be used.

  The thickness of the interlayer layer varies depending on the material to be used, and may be selected so that the driving voltage and the light emission efficiency are appropriate values. Usually, the thickness is 1 nm to 1 μm, preferably 2 to 500 nm. More preferably, it is 5-200 nm.

  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. However, a thin film necessary for device fabrication can be formed, electrons from the cathode can be injected, and electrons can be transported. If it is material, it will not specifically limit to these.

  Preferable examples of the electron injection material 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 ] Quinolinato) metal complex compounds such as beryllium, bis (8-hydroxyquinolinato) zinc, 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- Bis (1-naphthyl) -1,3,4-triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like can be mentioned.

  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) ( Examples include gallium complex compounds such as 4-phenylphenolate) gallium and nitrogen-containing condensed aromatic compounds such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

The light emitting layer of the organic EL device of the present invention preferably has the following functions.
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.

  The material for an organic EL device of the present invention can be suitably used as a light emitting layer. The organic EL device material of the present invention can be used as a dopant material in the light emitting layer and combined with other compounds to form the light emitting layer.

  In order to obtain blue light emission using the organic EL device material of the present invention, in addition to the anthracene compounds shown in Table 2, fluorescent whitening agents such as benzothiazole, benzimidazole, and benzoxazole, Metal chelated oxinoid compounds and styrylbenzene compounds can be used. Specific examples of these compounds include compounds disclosed in, for example, 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 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 Conductor (JP-A-2-220394), cyclopentadiene derivative (JP-A-2-289675), pyrrolopyrrole derivative (JP-A-2-29691), styrylamine derivative (Appl. Phys. Lett., 56th) Vol. L799 (1990), coumarin compounds (Japanese Patent Laid-Open No. 2-191694), International Patent Publications WO 90/13148 and Appl. Phys. Lett., Vol 58, 18, P1982 (1991). Examples of the polymer compound, PPV (polyparaphenylene vinylene) derivative, polyfluorene derivative, and copolymers thereof include those having the structures of the following general formulas [5] to [7].

General formula [5]

(In the formula, R ^x1 and R ^X2 each independently represent an aliphatic hydrocarbon group, and n1 represents an integer of 3 to 100.)

General formula [6]

(In the formula, R ^x3 and R ^X4 each independently represent an aliphatic hydrocarbon group, and n2 and n3 each independently represent an integer of 3 to 100.)

General formula [7]

(In the formula, R ^X5 and R ^X6 each independently represent an aliphatic hydrocarbon group, and n4 and n5 each independently represent an integer of 3 to 100. Ph represents a phenyl group.)

In addition, the general formula (Rs-Q) _2- Al-O-L3 (wherein L3 is a hydrocarbon having 6 to 24 carbon atoms including a phenyl moiety) 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 a bis (2-methyl-8-quinolinolato) (para-phenylphenolato) aluminum (III) compound, which represents an 8-quinolinolato ring substituent selected to interfere. ), Bis (2-methyl-8-quinolinolato) (1-naphtholato) aluminum (III) and the like.

Although there is no restriction | limiting in particular as a light emitting layer in the case of obtaining white light emission, The following can be used.
The energy level of each layer of the organic EL 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, the material used for the anode of the organic EL 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 substance. Specific examples of such an electrode substance include metals such as Au and conductive materials such as CuI, ITO, 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 EL device of the present invention is a material having a small work function (4 eV or less) metal, alloy, electrically conductive compound and a mixture thereof as an electrode substance. 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 produced 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 EL 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. do it. Moreover, an organic EL element can also be produced from the cathode to the anode in the reverse order.

  This organic EL element is manufactured on a translucent substrate. This translucent substrate is a substrate that supports the organic EL element, and for the translucency, it is desirable that the transmittance of light in the visible region of 400 to 700 nm is 50% or more, preferably 90% or more, Further, it is preferable to use a smooth 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.

  As a method for forming each layer of the organic EL element of the present invention, a dry film forming method such as vacuum deposition, electron beam irradiation, sputtering, plasma, ion plating, or a wet film forming method such as spin coating, dipping, or flow coating is used. Either method can be applied. In addition, Special Table 2002-53482, S.I. T.A. Lee, et al. , Proceedings of SID'02, p. LITI (Laser Induced Thermal Imaging) method described in 784 (2002), printing (offset printing, flexographic printing, gravure printing, screen printing), inkjet, and the like can also be applied.

  The organic 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. An organic layer can be formed. 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 EL element with respect to temperature, humidity, atmosphere and the like, 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 current applied to the organic EL 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 EL device driving method of the present invention can be driven not only by the passive matrix method but also by the active matrix method. Further, the method for extracting light from the organic EL device of the present invention is applicable not only to the method of bottom emission for extracting light from the anode side but also to the method of top emission for extracting 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).

  Examples of the main method of full colorization of the organic EL device of the present invention include a three-color coating method, a color conversion method, and a color filter method. In the three-color coating method, an evaporation method using a shadow mask, an ink jet method, and a printing method can be used. In addition, Special Table 2002-53482, S.I. T.A. Lee, et al. , Proceedings of SID'02, p. 784 (2002) can also be used. The laser thermal transfer method (also referred to as Laser Induced Thermal Imaging, LITI method) can also be used. In the color conversion method, a blue light emitting layer is used to convert green and red having a longer wavelength than blue through a color conversion (CCM) layer in which fluorescent dyes are dispersed. The color filter method uses a white light emitting organic EL element to extract light of three primary colors through a color filter for liquid crystal. In addition to these three primary colors, a part of white light is directly extracted and used for light emission. Thus, the luminous efficiency of the entire device can be increased.

  Furthermore, the organic EL element of the present invention may adopt a microcavity structure. This is because the organic EL element has a structure in which the light emitting layer is sandwiched between the anode and the cathode, and the emitted light causes multiple interference between the anode and the cathode, but the reflectance and transmission of the anode and the cathode. This is a technology that actively uses the multiple interference effect and controls the emission wavelength extracted from the device by appropriately selecting the optical characteristics such as the rate and the film thickness of the organic layer sandwiched between them. . 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, the organic EL element using the organic EL element material of the present invention can obtain blue light emission for a long time with a low driving voltage. Therefore, this organic EL device can be used as a flat panel display such as a wall-mounted television and various flat light emitters, as well as a light source such as a copying machine or a printer, a light source such as a liquid crystal display or an instrument, a display board, a marker lamp, etc. Can be applied.

  First, synthesis examples of the present invention will be described, but the present invention is not limited to these synthesis examples.

Synthesis example 1
Synthesis Method of Compound (1) Compound (1) was synthesized according to Reaction Formula 1 to Reaction Formula 2.

Reaction formula 1

  Hereinafter, the synthesis method will be described with reference to Reaction Scheme 1. Under nitrogen atmosphere at −78 ° C., 9.63 g (0.03 mol) of 3-bromo-9-phenylcarbazole (I) and 33 ml of n-butyllithium (1.52 M hexane solution) in tetrahydrofuran (100 ml). The reaction was performed to lithiate the 3-position of 3-bromo-9-phenylcarbazole. After stirring for 2 hours, 10.39 g (0.1 mol) of trimethyl borate was slowly added dropwise at −78 ° C., stirred at the same temperature for 2 hours, and further stirred at room temperature for 3 hours. Thereafter, 200 ml of 1% aqueous hydrochloric acid solution was added to the reaction product, stirred for 30 minutes, neutralized with 1% aqueous sodium hydroxide solution, extracted with ether, dried, concentrated by an evaporator, and 8.65 g of 9-phenyl. Carbazole-3-boronic acid (II) was obtained.

Reaction formula 2

Hereinafter, the synthesis method will be described with reference to Reaction Scheme 2. Under a nitrogen atmosphere, 5.17 g (0.01 mol) of 1,3,6,8-tetrabromopyrene, 14.35 g (0.05 mol) of 9-phenylcarbazole-3-boronic acid (II), tetrakis (triphenyl) Phosphine) palladium 0.5 g, potassium carbonate (2M aqueous solution) 50 g, and dioxane 200 g were added to a four-necked flask and heated to reflux for 5 hours. Thereafter, the reaction solution was poured into 400 ml of methanol, and the precipitated solid was collected by filtration and dried in a hot vacuum to obtain 10.20 g of (Compound (1)) as a crude product. The obtained crude product was purified by silica gel column chromatography, and further sublimation purification was performed. Compound (1) was identified by mass spectrum (manufactured by Bruker Daltonics, Autoflex II), ¹ H-NMR, and ¹³ C-NMR (manufactured by JEOL, ECX-400P). The UV spectrum and fluorescence (PL) spectrum of the compound (1) are shown in FIGS. The UV spectrum was measured with a photometer (U-3500) manufactured by Hitachi Spectro Co., Ltd., and the fluorescence (PL) spectrum was measured with a fluorescence spectrophotometer (FP-6500) manufactured by JASCO Corporation.

  The 3-bromo-9-phenylcarbazole (I) used for the synthesis of compound (1) was synthesized according to the method described in WO2007 / 43484. A commercially available reagent was used for 1,3,6,8-tetrabromopyrene (III).

Synthesis Examples 2-60
The compounds shown in Table 1 were synthesized by combining the following reaction formula (3) and reaction formula (4).

Reaction formula 3

In Reaction Scheme 3, A ¹ represents a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, or a substituted or unsubstituted aromatic group. R ^{1 to} R ⁷ represent a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, Represents a cyclic group, a substituted or unsubstituted aromatic heterocyclic group, a substituted silyl group, a cyano group, an alkoxyl group, an aryloxy group, or a substituted amino group, and R ^{1 to} R ⁴ are bonded to each other adjacent groups. Thus, a ring may be formed.

As a synthesis method, Li-lithium produced by reacting 3-bromo-9-phenylcarbazole derivative (IV) with n-butyllithium (n-BuLi) at −78 ° C. under a nitrogen stream in accordance with a conventional method, was produced. The derivative was reacted with B (OMe) ₃ to synthesize the desired boronic acid derivative (V) form.

Reaction formula 4

In Reaction Scheme 4, A ¹ represents a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, or a substituted or unsubstituted aromatic group. R ^{1 to} R ⁷ represent a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, Represents a cyclic group, a substituted or unsubstituted aromatic heterocyclic group, a substituted silyl group, a cyano group, an alkoxyl group, an aryloxy group, or a substituted amino group, and R ^{1 to} R ⁴ are bonded to each other adjacent groups. Thus, a ring may be formed.

  The synthesis method is the same as in Synthesis Example 1 except that 5 equivalents of the boronic acid derivative (V) is used per 1 equivalent of the 1,3,6,8-tetrabromopyrene derivative (III). Compound (VI) can be obtained.

About the structure of the compound of this invention obtained by combining the above Reaction Formula 3 and Reaction Formula 4, like the synthesis example 1, it identified by the mass spectrum, < ¹ > H-NMR, < ¹³ > C-NMR. The measurement results of the mass spectrum of the synthesized compound are shown in Table 6. The compound numbers are the same as those described in Table 1 in this specification.

Hereinafter, although the organic EL element using the organic EL element material of the present invention will be described with reference to the following examples, the present invention is not limited to the following examples. In the examples, all mixing ratios are weight ratios unless otherwise specified. Vapor deposition (vacuum deposition) was performed in a vacuum of 10 ⁻⁶ Torr under conditions where temperature control such as heating and cooling of the substrate was not performed. The light emission characteristics of the element were measured using an organic EL element having a light emitting element area of 2 mm × 2 mm.

Example 1
On the cleaned glass plate with an ITO electrode, HTM4 of Table 4 was vacuum-deposited to obtain a hole injection layer having a thickness of 60 nm. Subsequently, the compound (1) in Table 1 of this invention was vacuum-deposited, and the light emitting layer with a film thickness of 20 nm was obtained. Furthermore, tris (8-hydroxyquinolino) aluminum complex (Alq3) was vacuum-deposited to form an electron injection layer having a thickness of 20 nm, on which first lithium fluoride was deposited to 1 nm and then aluminum (Al) was deposited to 150 nm. Thus, an electrode was formed to obtain an organic EL element. The chromaticity when this device was driven to 6 V was blue light emission of CIE (x, y) = (0.14, 0.15). The luminance half life when this device was driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ) was measured. In addition, initial luminance when driven at a current density of 12.5 mA / cm ² and luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 7.

Examples 2 to 26
A device was prepared in the same manner as in Example 1 except that the light emitting layer was formed using the compounds shown in Table 7 among the compounds shown in Table 1 instead of the compound (1). The luminance half life when this device was driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ) was measured. Further, the initial luminance when driven at a current density of 15 mA / cm ² and the luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 7.

Comparative Example 1
A device was prepared in the same manner as in Example 1 except that a light emitting layer was prepared using the compound (A) shown below. The chromaticity when this element was driven to 6 V was blue light emission of CIE (x, y) = (0.28, 0.30). The device was measured for luminance and half-life when the device was driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ). In addition, initial luminance when driven at a current density of 12.5 mA / cm ² and luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 7.

  As is clear from Table 7, all the elements using the organic EL element material of the present invention had a longer life and higher luminance than the element prepared in Comparative Example 1.

Example 27
On the glass plate with an ITO electrode, HIM4 of Table 3 was vacuum-deposited to obtain a 60 nm-thick hole injection layer. Next, an 85:15 mixture of the compound (1) in Table 1 and the compound (3) in Table 1 was deposited to form a light-emitting layer having a thickness of 40 nm. Further, Alq3 was deposited to form an electron injection layer having a thickness of 15 nm. A cathode was formed thereon by vapor deposition of 0.1 nm of lithium fluoride (LiF) and 200 nm of Al to obtain an organic EL device. When this device was driven at a direct current of 10 V, the external quantum efficiency was 5.0%. Further, the luminance half life when driving at constant current with emission luminance of 500 (cd / m ² ) was measured. Further, the initial luminance when driven at a current density of 13.5 mA / cm ² and the luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 8.

Examples 28-40
Instead of forming a light-emitting layer having a thickness of 40 nm by vapor-depositing a mixture in which two kinds of compounds in Table 1 (compound (a) and compound (b)) were mixed at a ratio shown in Table 8, a light-emitting layer having a thickness of 40 nm was formed. A device was prepared in the same manner as in Example 27 except that the compounds and the compounds shown in Table 1 were used. All of these devices exhibited an external quantum efficiency of 4% or more at a DC voltage of 10V. Further, the luminance half life when driving at constant current with emission luminance of 500 (cd / m ² ) was measured. In addition, initial luminance when driven at a current density of 12.5 mA / cm ² and luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 8.

  As is apparent from Table 8, all the elements using the organic EL element material of the present invention had a longer life and higher luminance than the element prepared in Comparative Example 2.

Example 41
On the glass plate with an ITO electrode, HIM2 of Table 3 was vacuum-deposited to obtain a hole injection layer having a thickness of 70 nm. Next, the compound (2) in Table 1 and the compound (H-45) in Table 2 were co-evaporated at a composition ratio of 5:95 to form a light-emitting layer having a thickness of 40 nm. Further, Alq3 was deposited to form an electron injection layer having a thickness of 20 nm. A cathode was formed thereon by vapor deposition of 1 nm of lithium oxide (Li ₂ O) and 100 nm of Al to obtain an organic EL device. When this device was driven at a direct current of 10 V, the external quantum efficiency was 4.5%. Further, the luminance half life when driving at constant current with emission luminance of 500 (cd / m ² ) was measured. Further, the initial luminance when driven at a current density of 13.5 mA / cm ² and the luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 9.

Examples 42-66
Instead of co-evaporating the compound of Table 1 and the compound of Table 2 at a composition ratio of 5:95 to form a light-emitting layer having a thickness of 40 nm, among the compounds of Table 1 and Table 2, the compounds shown in Table 9 A device was fabricated in the same manner as in Example 27 except that was used. All of these devices exhibited an external quantum efficiency of 4% or more at a DC voltage of 10V. Further, the luminance half life when driving at constant current with emission luminance of 500 (cd / m ² ) was measured. In addition, initial luminance when driven at a current density of 12.5 mA / cm ² and luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 9.

Comparative Example 2
A device was prepared in the same manner as in Example 41 except that the compound (A) was used instead of the compound (2) in Table 1. The initial luminance when driven at a current density of 12.5 mA / cm ² and the luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 9.

  As is apparent from Table 9, all the elements using the organic EL element material of the present invention had a longer life and higher luminance than the element prepared in Comparative Example 2.

Example 67
On the glass plate with an ITO electrode, HIM3 of Table 3 was vacuum-deposited to obtain a hole injection layer having a thickness of 70 nm. Next, the compound (4) in Table 1 and the compound (H-46) in Table 2 were co-evaporated at a composition ratio of 3:97 to form a light-emitting layer having a thickness of 40 nm. Further, the compound (B) was deposited to form an electron injection layer having a thickness of 20 nm. A cathode was formed thereon by vapor deposition of 1 nm of lithium oxide (Li ₂ O) and 100 nm of Al to obtain an organic EL device. When this device was driven at a direct current of 10 V, the external quantum efficiency was 4.6%. Further, the luminance half life when driving at constant current with emission luminance of 500 (cd / m ² ) was measured. Further, the initial luminance when driven at a current density of 13.5 mA / cm ² and the luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 10.

Examples 68-79
Instead of co-evaporating the compound of Table 1 and the compound of Table 2 at a composition ratio of 3:97 to form a light-emitting layer having a thickness of 40 nm, among the compounds of Table 1 and Table 2, the compounds shown in Table 10 A device was prepared in the same manner as in Example 67 except that was used. All of these devices exhibited an external quantum efficiency of 4% or more at a DC voltage of 10V. In addition, initial luminance when driven at a current density of 12.5 mA / cm ² and luminance after continuous driving for 100 hours in an environment of 80 ° C. were measured. The results are shown in Table 10.

  As can be seen from Table 10, all the elements using the organic EL element material of the present invention had a long life and high luminance.

  Hereinafter, although the organic EL element using the ink composition for organic EL elements which consists of a compound of the present invention and an organic solvent is explained, the present invention is not limited to the following example. The spin coating was rotated for 1 minute at a rotational speed between 500 rpm and 2500 rpm in accordance with the solvent type and the target film thickness. The light emission characteristics of the element were measured using an organic EL element having a light emitting element area of 2 mm × 2 mm.

Example 80
PEDOT / PSS (poly (3,4-ethylenedioxy) -2,5-thiophene / polystyrene sulfonic acid, BAYTRON P VP CH8000 manufactured by Bayer) manufactured on a cleaned glass plate with an ITO electrode by a spin coating method A hole injection layer having a thickness of 40 nm was obtained. Subsequently, 60% of PVK (polyvinylcarbazole), 3% of the compound (27) in Table 1 and 37% of the electron transporting material (compound (C)) were dissolved in toluene at a concentration of 2.0 wt%, and the spin coating method was performed. As a result, a light emitting layer having a thickness of 70 nm was obtained. Furthermore, after depositing 20 nm of Ca thereon, 200 nm of Al was deposited to form an electrode to obtain an organic EL device. When this device was subjected to an energization test, blue light emission with a maximum light emission luminance of 830 cd / m ² was obtained.

Examples 81-100
PEDOT / PSS (poly (3,4-ethylenedioxy) -2,5-thiophene / polystyrene sulfonic acid, BAYTRON P VP CH8000 manufactured by Bayer) manufactured on a cleaned glass plate with an ITO electrode by a spin coating method A hole injection layer having a thickness of 40 nm was obtained. Next, 60% of PVK (polyvinylcarbazole), 3% of the light-emitting material in which the combinations shown in Table 11 among the compounds of Table 1 and Table 2 were mixed at a ratio of 3:97, and an electron transport material (Compound (D)) 37% was dissolved in toluene at a concentration of 2.0 wt%, and a light emitting layer having a thickness of 70 nm was obtained by a spin coating method. Furthermore, after depositing 20 nm of Ca thereon, 200 nm of Al was deposited to form an electrode to obtain an organic EL device. When this device was subjected to an energization test, blue light emission with a maximum light emission luminance of 610 cd / m ² was obtained. The initial luminance when driven at a current density of 12.5 mA / cm ² and the luminance after continuous driving for 100 hours in an environment of 40 ° C. were measured. The results are shown in Table 11.

  As can be seen from Table 11, all the elements using the organic EL element material of the present invention had a long lifetime and high luminance.

Example 101
The following compound (E) and compound (F) are dissolved in toluene at a concentration of 0.5 wt% at a ratio of 9: 1 on a cleaned glass plate with an ITO electrode, and the film thickness is 40 nm by spin coating. A hole transport layer was formed and polymerized at 200 ° C. Next, the compound (11) in Table 1 and the compound (H-10) in Table 2 were mixed at a composition ratio of 2:98, dissolved in toluene at a concentration of 1.0 wt%, and a 60 nm film was formed by spin coating. A thick light emitting layer was formed. Dried at 100 ° C. Further, a compound (B) shown below is vacuum-deposited thereon to form an electron injection layer having a film thickness of 20 nm, and then 1 nm of lithium fluoride and then 150 nm of aluminum (Al) are vapor-deposited thereon. An electrode was formed to obtain an organic EL element. When this device was subjected to an energization test, blue light emission with a maximum light emission luminance of 580 cd / m ² was obtained. The chromaticity when this device was driven to 6 V was blue light emission of CIE (x, y) = (0.14, 0.14). The luminance half life when this device was driven at a constant current at room temperature with an emission luminance of 500 (cd / m ² ) was measured. Further, the initial luminance when driven at a current density of 12.5 mA / cm ² and the luminance after continuous driving for 100 hours in an environment of 60 ° C. were measured. The results are shown in Table 12.

Examples 102-110
The following compound (E) and compound (F) are dissolved in toluene at a concentration of 0.5 wt% at a ratio of 9: 1 on a cleaned glass plate with an ITO electrode, and the film thickness is 40 nm by spin coating. A hole transport layer was formed and polymerized at 200 ° C. Next, among the compounds in Table 1 and Table 2, the combinations shown in Table 12 were dissolved in toluene at a concentration of 1.0 wt% of the luminescent material mixed at a ratio of 2:98, and 60 nm in thickness was obtained by spin coating. A light emitting layer having a film thickness was formed. Dried at 100 ° C. Further, a compound (B) shown below is vacuum-deposited thereon to form an electron injection layer having a film thickness of 20 nm, and then 1 nm of lithium fluoride and then 150 nm of aluminum (Al) are vapor-deposited thereon. An electrode was formed to obtain an organic EL element. An energization test was performed on this element. The results are shown in Table 12.

  As is clear from Table 12, all the elements using the organic EL element material of the present invention had a long lifetime and high luminance.

Example 111
Solubility measurement of compound (1)

  The solubility of the compound (1) of the present invention in toluene was examined, and the results are shown in Table 13. As shown in Table 1, the compound (1) showed sufficient solubility for film formation in toluene.

Examples 112-176
Instead of the compound (1), the solubility in toluene was examined using the compounds shown in Table 1. The results are shown in Table 13.

Comparative Example 3
The solubility in toluene was examined using the compound (G). The results are shown in Table 13.

  As is clear from Table 13, all the organic EL device materials of the present invention showed high solubility.

  As described above, by using the organic EL element material of the present invention, a high performance EL element can be produced. It is clear that remarkably high performance is exhibited with respect to the comparative compound, and high emission efficiency, low drive voltage, long life, and high color purity blue light emission of the organic EL element can be achieved.

Claims (6)

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

(Wherein, A ^{1 to} A ⁴ each independently represents a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, or Represents a substituted or unsubstituted aromatic heterocyclic group,
R ^{1 to} R ²⁸ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, Represents a substituted or unsubstituted aromatic heterocyclic group, substituted silyl group, cyano group, alkoxyl group, aryloxy group, or substituted amino group, R ^{1 to} R ⁴ , R ^{11 to} R ¹⁴ , R ^{15 to} R ¹⁸ and R ^{25 to} R ²⁸ may be bonded to each other to form a ring. ) The organic electroluminescent element material according to claim 1, wherein A ^{1 to} A ⁴ are each independently a group represented by the following general formula [2].
General formula [2]

Wherein R ^{29 to} R ³³ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aliphatic Represents a heterocyclic group, a substituted or unsubstituted aromatic heterocyclic group, a substituted silyl group, a cyano group, an alkoxyl group, an aryloxy group, or a substituted amino group, and R ^{29 to} R ³³ represent groups adjacent to each other They may combine to form a ring.) 3. An organic electroluminescence device comprising a plurality of organic layers including a light emitting layer between a pair of electrodes, wherein the light emitting layer comprises the material for an organic electroluminescence device according to claim 1 or 2. element. The organic electroluminescent device according to claim 3, further comprising an anthracene derivative and a spiro derivative as a host material in the light emitting layer. The organic electroluminescent element according to claim 3 or 4, wherein the light emitting layer is formed by coating. The ink composition for organic electroluminescent elements which consists of the organic electroluminescent element material of Claim 1 or 2, and an organic solvent.