JP2001064640A - Material for organic electroluminescence element and organic electroluminescence element by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new compound having a dicyanoethenyl group and a specific amino group, providing a luminescent color from yellow to red, having a high luminescent brightness and long emitting life, and useful for an organic EL element. SOLUTION: This new compound is represented by formula I [A1 and A2 are each H, cyano, an alkyl, an aryl or a substituent of formula II (A3 is a divalent substituent containing an aryl ring; A4 and A5 are each an alkyl or an aryl, and both thereof may be integrated), with the proviso that at least one thereof is the substituent of formula II], e.g. a compound of formula III. The compound of formula I is obtained by condensing a compound of formula IV with malononitrile through dehydration in a high-boiling solvent (e.g. n- propanol) by using a base (e.g. piperidine) as a catalyst. The A3 of formula II is preferably a substituent of the formula A6-A7 (A6 and A7 are each an arylene).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting material for an organic electroluminescence (EL) device used for a flat light source or display and a light emitting device having a high luminance.

[0002]

2. Description of the Related Art An EL device using an organic substance is expected to be used as an inexpensive, large-area, full-color display device of a solid light emitting type, and many developments have been made. Generally, an EL element includes a light-emitting layer and a pair of opposed electrodes sandwiching the light-emitting layer. In light emission, when an electric field is applied between both electrodes, electrons are injected from the cathode side, holes are injected from the anode side, the electrons recombine with holes in the light emitting layer, and the energy level is changed from the conduction band. This is a phenomenon in which energy is emitted as light when returning to the valence band. The conventional organic EL element has a higher driving voltage and lower light emission luminance and light emission efficiency than the inorganic EL element. In addition, the characteristic deterioration was remarkable, and it had not been put to practical use. In recent years, an organic EL device formed by laminating a thin film containing an organic compound having a high fluorescence quantum efficiency and emitting light at a low voltage of 10 V or less has been reported and attracted attention (Applied Physics Letters, vol. 51, p. 913). 1987). This method uses a metal chelate complex for a light emitting layer and an amine compound for a hole injection layer to obtain high-luminance green light emission. The luminance is several thousand cd / m ² at a DC voltage of 6 to 7 V. The luminous efficiency is 1.5 lm /
It achieves W and has performance close to the practical range. However, organic EL devices up to now have improved light emission luminance due to an improved configuration, but do not yet have sufficient light emission luminance. In addition, there is a major problem that the stability upon repeated use is poor. This is because, for example, a metal chelate complex such as a tris (8-hydroxyquinolinato) aluminum complex is chemically unstable during electroluminescence, has poor adhesion to a cathode, and is greatly deteriorated by short-time light emission. I was For the above reasons, an organic EL having high luminous brightness and luminous efficiency and excellent stability when repeatedly used
For the development of the device, development of a durable light emitting material having excellent light emitting ability is desired.

[0003]

An object of the present invention is to provide a light emitting material for an organic EL device having a light emission color from yellow to red, having a high light emission luminance and a long light emission life, and an organic EL device using the same. is there. As a result of intensive studies by the present inventors, an organic EL device using a light emitting material for an organic EL device represented by the general formula [1] in a light emitting layer emits yellow to red light, has high light emission luminance and light emission efficiency, It was also found that the luminescence life was excellent.

[0004]

Means for Solving the Problems The present invention relates to a material for an organic electroluminescence device represented by the following general formula [1]. General formula [1]

[0005]

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[Wherein A ¹ and A ² represent a hydrogen atom, a cyano group, an alkyl group, an aryl group, or the following general formula [2]
Wherein at least one of the substituents is a substituent represented by the following general formula [2]. General formula [2]

[0007]

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[Wherein A ³ represents a divalent substituent containing at least one aryl ring, A ⁴ and A ⁵ represent an alkyl group or an aryl group, and A ⁴ and A ⁵ are united. May be. The present invention also relates to the material for an organic electroluminescence device according to claim 1, wherein A ³ is represented by the following general formula [3]. General formula [3]

[0009]

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[Wherein A ⁶ and A ⁷ represent an arylene group. Further, the present invention provides an organic electroluminescent element in which a light-emitting layer or a plurality of organic compound thin films including a light-emitting layer is formed between a pair of electrodes. An organic electroluminescent device characterized in that it is contained alone or as a mixture.

The present invention also relates to an organic electroluminescence device comprising a light emitting layer or a plurality of organic compound thin films including the light emitting layer formed between a pair of electrodes, wherein the light emitting layer is made of the above-mentioned organic electroluminescent device material alone. Alternatively, the organic electroluminescence device is characterized by being contained as a mixture.

Further, the present invention is the above-described organic electroluminescent device, wherein a hole injection layer is formed between the anode and the light emitting layer.

Further, the present invention provides the organic electroluminescent device, wherein the hole injection layer is a layer containing at least one selected from the group consisting of an arylamine derivative, a phthalocyanine compound, and a triphenylene derivative. It is.

Further, the present invention is the above-described organic electroluminescence device, wherein an electron injection layer is formed between the cathode and the light emitting layer.

Further, the present invention is the above-described organic electroluminescence device, wherein the electron injection layer is a layer containing a metal complex compound or a nitrogen-containing aromatic ring compound.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is characterized in that a compound represented by the general formula [1] is used for an organic EL device. This compound is characterized in that the site of the dicyanoethenyl group in the molecule is electron-withdrawing and that the amino group in the general formula [2] is electron-donating, and therefore absorbs light on the long wavelength side. I will show you. For the relationship between absorption wavelength and chemical structure,
It is described in detail in Color Science (Mitsuhiko Hida, published by Maruzen Co., Ltd.).

The compound represented by the general formula [1] is
Since the individual has strong fluorescence, it is useful as a red fluorescent material. In addition, since the glass transition point and the melting point are high, the resistance (heat resistance) to Joule heat generated in the organic layer, between the organic layers, or between the organic layer and the metal electrode during electroluminescence is improved. If used,
It exhibits high light emission luminance and is advantageous when emitting light for a long time. The compound of the present invention represented by the general formula [1],
A ¹ and A ² are a hydrogen atom, a cyano group, an alkyl group, an aryl group, or a substituent represented by the following general formula [2].

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a sec-butyl group and a tert-butyl group.
t-butyl group, pentyl group, hexyl group, heptyl group,
Octyl group, stearyl group, 2-phenylisopropyl group, trichloromethyl group, trifluoromethyl group, benzyl group, α-phenoxybenzyl group, α, α-dimethylbenzyl group, α, α-methylphenylbenzyl group, α,
α-ditrifluoromethylbenzyl group, triphenylmethyl group, α-benzyloxybenzyl group and the like. The aryl group includes a monocyclic group or a condensed polycyclic group. The monocyclic group includes a monocyclic aromatic ring group and a monocyclic heterocyclic group. Examples of the condensed polycyclic group include a condensed aromatic ring group and a condensed heterocyclic group.

As the monocyclic aromatic ring group, there is a phenyl group.

Examples of the monocyclic heterocyclic group include a thienyl group, a thiophenyl group, a furyl group, a pyrrolyl group, an imidazolyl group,
Examples include a pyrazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a triazolyl group, an oxazolyl group, a thiazolyl group, an oxadiazolyl group, a thiadiazolyl group, and an imidadiazolyl group.

Examples of the condensed aromatic ring group include naphthyl group, anthranyl group, phenanthrenyl group, fluorenyl group, acenaphthyl group, azulenyl group, heptalenyl group, acenaphthylenyl group, pyrenyl group, perylenyl group, triphenylenyl group and the like.

Examples of the fused heterocyclic group include an indolyl group, a quinolyl group, an isoquinolyl group, a phthalazinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, an acridinyl group, a phenazinyl group, a furfuryl group, an isothiazolyl group, an isoxazolyl group, a furazanyl group, a phenoxazinyl group. Group, benzothiazolyl group, benzoxazolyl group,
Examples include benzimidazolyl, benzotriazolyl, and prenyl groups.

The aryl group may be substituted by halogen such as chlorine. A ^{3 in the} structural formula represented by the general formula [2] in the present invention is a divalent substituent containing at least one aryl ring. The aryl ring means a ring that is a basic skeleton of the aryl group.

A ³ is an alkylene group, an arylene group, or 2 selected from an alkylene group and an arylene group.
A group in which one or more groups are bonded directly or via an atom other than carbon. A ³ needs to contain an aryl ring in order to ensure heat resistance and stability.

Specifically preferred alkylene groups include
-CH = CH -, - CH = CH-CH = CH-, those having a polyene structure such as cyclohexadienyl Eni alkylene group, -C (= CPh ₂₎ -, and the like. Where P
h represents a phenyl group. As the alkylene group, an unsaturated alkylene group in which the conjugated system between the dicyanoethenyl group and the amino group is not cleaved is recommended. However, when A ³ consists only of an alkylene group, any carbon of the alkylene group must be substituted with an aryl group.

The arylene group corresponds to a divalent substituent of the aryl group.

As atoms other than carbon atoms, oxygen atoms,
Examples include a nitrogen atom, a sulfur atom, a neighboring atom, a boron atom, and a silicon atom. As A ³ , those in which two or more arylene groups are directly bonded are preferably used. One example of the general formula [3] is one in which two arylene groups are directly bonded. Here, A ⁶ and A ⁷ represent an arylene group,
It has the same meaning as the above-mentioned arylene group. In this case, it is a preferable embodiment that the arylene group adjacent to the dicyanoethenyl group is a heterocyclic ring.

[0028] Specifically the A ^3, other those shown in Table 1 below, binaphthyl, a biquinoline, flavone,
Phenyltriazine, bisbenzothiazole, bithiophene, phenylbenzotriazole, phenylbenzimidazole, phenylacridine, bis (benzoxazolyl) thiophene, bis (phenyloxazolyl) benzene, biphenylylphenyloxadiazole, diphenylbenzoquinone, diphenyliso Examples include residues having a skeleton of benzofuran, diphenylpyridine, stilbene, dibenzyl, diphenylmethane, bis (phenylisopropyl) benzene, diphenylfluorene, and diphenylhexafluoropropane. A general method for synthesizing the compound represented by the general formula [1] is shown below.

The compound represented by the general formula [4] and malononitrile are reacted in a high-boiling alcohol with a base as a catalyst.
By subjecting to dehydration condensation, the target compound can be synthesized. As the high boiling point solvent, n-propanol, i
Examples include so-propanol, n-butanol, tert-butanol, n-pentyl alcohol, and iso-pentanol. Examples of the base include piperidine, DBU and the like.

Alternatively, the desired compound can be synthesized by subjecting the compound represented by the general formula [4] and malononitrile to a substitution reaction in a halogen solvent using titanium tetrachloride and pyridine as catalysts. . Examples of the halogen solvent include 1,2-dichloroethane, chloroform,
There are dichloromethane and the like.

The above synthesis method is an example, and is not particularly limited. General formula [4]

[0032]

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Wherein A ¹ and A ² have the same meaning as A ¹ and A ² in the general formula [1]. Hereinafter, typical examples of the compound represented by the general formula [1] are specifically illustrated in Table 1, but the present invention is not limited to these typical examples.

[0034]

[Table 1]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

The compound of the present invention has strong fluorescence in a solid state and has excellent electroluminescence. In addition, since it has both excellent electron injecting property and electron transporting property from a metal electrode, it can be effectively used as a light emitting material, and further has another hole transporting material, an electron transporting material or Doping materials can be used. An organic EL device is a device in which a single or multilayer organic thin film is formed between an anode and a cathode. In the case of a single layer type, a light emitting layer is provided between an anode and a cathode. The light-emitting layer contains a light-emitting material and may further contain a hole-injection material or an electron-injection material for transporting holes injected from an anode or electrons injected from a cathode to the light-emitting material. However, the luminescent material of the present invention
Since it has extremely high emission quantum efficiency, high hole transport ability and electron transport ability and can form a uniform thin film, it is possible to form a light emitting layer using only the light emitting material of the present invention. The multilayer type includes (anode / hole injection zone / light-emitting layer / cathode), (anode / light-emitting layer / electron injection zone / cathode),
(Anode / Hole injection zone / Emitting layer / Electron injection zone / Cathode)
There is an organic EL element stacked in a multilayer structure of the above. The compound of the present invention has high light-emitting properties, and has a hole injection property, a hole transport property and an electron injection property, and an electron transport property.
It can be used in a light emitting layer as a light emitting material. In the light emitting layer, if necessary, in addition to the compound of the present invention, further known light emitting materials, doping materials, hole injection materials and electron injection materials can be used. When the organic EL element has a multilayer structure, it is possible to prevent a decrease in luminance and life due to quenching. If necessary, a combination of a light emitting material, a doping material, a hole injection material, and an electron injection material can be used. Also, depending on the doping material,
It is also possible to improve light emission luminance and light emission efficiency and obtain red and blue light emission. Further, each of the hole injection zone, the light emitting layer, and the electron injection zone may be formed by a layer structure of two or more layers. In that case, in the case of the hole injection zone, a layer for injecting holes from the electrode is a hole injection layer, and a layer for receiving holes from the hole injection layer and transporting holes to the light emitting layer is a hole transport layer. Call. Similarly, in the case of the electron injection zone, a layer that injects electrons from the electrode is called an electron injection layer, and a layer that receives electrons from the electron injection layer and transports electrons to the light emitting layer is called an electron transport layer. Each of these layers is selected and used depending on factors such as the energy level of the material, heat resistance, and adhesion to the organic layer or the metal electrode. The light-emitting material or doping material that can be used in the light-emitting layer together with the compound of the present invention includes anthracene, naphthalene, phenanthrene, pyrene, tetracene, coronene, chrysene, fluorescein, perylene, phthaloperylene, naphthaloperylene, perinone, phthaloperinone,
Naphthaloperinone, diphenylbutadiene, tetraphenylbutadiene, coumarin, oxadiazole, aldazine, bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, benzoquinoline metal complex, imine, diphenylethylene, vinyl anthracene , Diaminocarbazole, pyran, thiopyran, polymethine, merocyanine, imidazole chelated oxinoid compounds, quinacridone, rubrene, and fluorescent dyes for dye lasers and whitening, but are not limited thereto. The present compound and any of the above compounds which can be used together in the light-emitting layer may be present in the light-emitting layer in any proportion as the main component. That is, by the respective combinations of the above-mentioned compound and the compound of the present invention, the compound of the present invention can be used as a main material forming the light emitting layer or as a doping material into other main materials. As a hole injection material,
Has the ability to transport holes, the effect of hole injection from the anode,
Compounds that have an excellent hole injection effect on the light emitting layer or the light emitting material, prevent excitons generated in the light emitting layer from moving to the electron injection band or the electron injection material, and have excellent thin film forming ability. Can be Specifically, phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, oxazole, oxadiazole, triazole, imidazole, imidazolone, imidazolethione, pyrazoline, pyrazolone, tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acylhydrazone, polyaryl Alkanes, stilbenes, butadiene,
Benzidine-type triphenylamine, styrylamine-type triphenylamine, diamine-type triphenylamine and the like, and derivatives thereof, and polyvinyl carbazole,
Although there are polymer materials such as polysilane and conductive polymer,
It is not limited to these. Among the hole injection materials that can be used in the organic EL device of the present invention, more effective hole injection materials are arylamine derivatives, phthalocyanine compounds, or triphenylene derivatives. Specific examples of the arylamine derivative include triphenylamine, tolylamine, tolylphenylamine,
N, N'-diphenyl-N, N'-di-m-tolyl-
4,4'-biphenyldiamine, N, N, N ', N'-
Tetra (p-tolyl) -p-phenylenediamine, N,
N, N ′, N′-tetra-p-tolyl-4,4′-biphenyldiamine, N, N′-diphenyl-N, N′-di (1-naphthyl) -4,4′-biphenyldiamine,
N, N'-di (4-n-butylphenyl) -N, N'-
Di-p-tolyl-9,10-phenanthylenediamine,
4,4 ′, 4 ″ -tris (N-phenyl-Nm-tolylamino) triphenylamine, 1,1-bis [4-
(Di-p-tolylamino) phenyl] cyclohexane and the like, or oligomers or polymers having an aromatic tertiary amine skeleton, but are not limited thereto. Specific examples of the phthalocyanine (Pc) compound include H ₂ Pc, CuPc, CoPc, NiP
c, ZnPc, PdPc, FePc, MnPc, ClA
lPc, ClGaPc, ClInPc, ClSnPc,
Cl ₂ SiPc, (HO) AlPc, (HO) GaP
c, VOPc, TiOPc, MoOPc, GaPc-O
Examples include, but are not limited to, phthalocyanine derivatives such as -GaPc and naphthalocyanine derivatives. Specific examples of the triphenylene derivative include hexamethoxy triphenylene, hexaethoxy triphenylene, hexahexyloxy triphenylene, hexabenzyloxy triphenylene, trimethylene dioxy triphenylene, hexaalkoxy triphenylenes such as triethylene dioxy triphenylene, hexaphenoxy triphenylene, hexanaphthyl Examples include, but are not limited to, hexaaryloxytriphenylenes such as oxytriphenylene, hexabiphenylyloxytriphenylene, and triphenylenedioxytriphenylene, and hexaacyloxytriphenylenes such as hexaacetoxytriphenylene and hexabenzoyloxytriphenylene. As an electron injection material, it has the ability to transport electrons, has a hole injection effect from the cathode, and has an excellent electron injection effect on the light emitting layer or the light emitting material,
Compounds that prevent the exciton generated in the light emitting layer from moving to the hole injection zone and have excellent thin film forming ability can be cited. For example, there are fluorenone, anthraquinodimethane, diphenoquinone, thiopyrandioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane, anthrone and the like and derivatives thereof. ,
It is not limited to these. In addition, sensitization can be performed by adding an electron accepting substance to the hole injecting material and adding an electron donating substance to the electron injecting material. In the organic EL device of the present invention, a more effective electron injection material is
It is a metal complex compound or a nitrogen-containing five-membered ring derivative. Specifically, as the metal complex compound, lithium 8-hydroxyquinolinato, bis (8-hydroxyquinolinato) zinc, bis (8-hydroxyquinolinato) copper, bis (8-hydroxyquinolinato) manganese , Tris (8-hydroxyquinolinato) aluminum, tris (2-methyl-8-hydroxyquinolinato) aluminum, tris (8-hydroxyquinolinato) gallium, bis (10-hydroxybenzo [h] quinolinato) beryllium , Bis (10-hydroxybenzo [h]
(Quinolinato) zinc, bis (2-methyl-8-hydroxyquinolinato) chlorogallium, bis (2-methyl-
8-hydroxyquinolinato) (o-cresolate) gallium, bis (2-methyl-8-hydroxyquinolinate) (1-naphtholate) aluminum, bis (2-methyl-8-hydroxyquinolinate) (2- Naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinato) phenolate gallium, bis (o- (2-benzoxazolyl) phenolate) zinc, bis (o-
(2-benzothiazolyl) phenolate) zinc, bis (o- (2-benzotriazolyl) phenolate) zinc and the like, but are not limited thereto. Also,
As the nitrogen-containing five-membered derivative, an oxazole, thiazole, oxadiazole, thiadiazole or triazole derivative is preferable. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, dimethyl POPOP, 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-butylbenzene], 2- (4'-ter
t-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, but are not limited thereto. Book organic e
In the L element, at least one of a light emitting material, a doping material, a hole injection material, and an electron injection material may be contained in the same layer in the light emitting layer in addition to the compound of the present invention. In order to improve the stability of the organic EL device obtained according to the present invention with respect to temperature, humidity, atmosphere, and the like, a protective layer may be provided on the surface of the device, or the entire device may be protected with silicon oil, resin, or the like. Is also possible. Organic EL
As the conductive material used for the anode of the element, those having a work function of more than 4 eV are suitable, such as carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, platinum, palladium and the like. Alloys, metal oxides such as tin oxide and indium oxide used for ITO substrates and NESA substrates, and organic conductive resins such as polythiophene and polypyrrole.
As the conductive material used for the cathode, those having a work function smaller than 4 eV are suitable, and magnesium, calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese, aluminum, and the like and alloys thereof are used. However, the present invention is not limited to these. Representative examples of the alloy include magnesium / silver, magnesium / indium, and lithium / aluminum, but are not limited thereto. The ratio of the alloy is controlled by the temperature, atmosphere, degree of vacuum, and the like of the evaporation source, and is selected to be an appropriate ratio. The anode and cathode are
If necessary, it may be formed by a two or more layer structure. In organic EL devices, in order to emit light efficiently,
At least one of them is desirably sufficiently transparent in the emission wavelength region of the device. Further, it is desirable that the substrate is also transparent. The transparent electrode uses the above conductive material,
It is set so as to secure a predetermined translucency by a method such as vapor deposition or sputtering. The electrode on the light emitting surface has a light transmittance of 10%
It is desirable to make the above. The substrate is not limited as long as it has mechanical, thermal strength and transparency, but, for example, a glass substrate, a polyethylene plate,
Transparent resins such as polyethylene terephthalate plate, polyethersulfone plate and polypropylene plate can be used. Each layer of the organic EL device according to the present invention is formed by vacuum deposition,
Any of dry film forming methods such as sputtering, plasma, and ion plating and wet film forming methods such as spin coating, dipping, and flow coating can be applied. The film thickness is not particularly limited, but needs to be set to an appropriate film thickness. If the film thickness is too large, a large applied voltage is required to obtain a constant light output, resulting in poor efficiency. If the film thickness is too small, pinholes and the like are generated, and sufficient light emission luminance cannot be obtained even when an electric field is applied. The normal film thickness is suitably in the range of 5 nm to 10 μm, but is more preferably in the range of 10 nm to 0.2 μm. In the case of the wet film formation method, a material for forming each layer is dissolved or dispersed in an appropriate solvent such as ethanol, chloroform, tetrahydrofuran, dioxane or the like to form a thin film, and any solvent may be used. In any of the organic thin film layers, a suitable resin or additive may be used for improving film forming properties, preventing pinholes in the film, and the like. Examples of usable resins include insulating resins such as polystyrene, polycarbonate, polyarylate, polyester, polyamide, polyurethane, polysulfone, polymethyl methacrylate, polymethyl acrylate, and cellulose, and copolymers thereof, and poly-N-vinyl. Carbazole, photoconductive resin such as polysilane, polythiophene,
A conductive resin such as polypyrrole can be used. Examples of the additive include an antioxidant, an ultraviolet absorber, and a plasticizer. As described above, by using the compound of the present invention in the light emitting layer of the organic EL device, it was possible to improve the organic EL device characteristics such as the luminous efficiency and the maximum luminous brightness. In addition, this device is extremely stable against heat and current, and furthermore, it can emit light that can be practically used at a low driving voltage, so that the deterioration, which has been a major problem until now, can be significantly reduced. Was completed. The organic EL element of the present invention can be applied to a flat panel display such as a wall-mounted television, 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, or a sign lamp as a plane light emitter. , Its industrial value is very large. The material of the present invention is an organic EL device, an electrophotographic photosensitive member,
It can also be used in fields such as photoelectric conversion elements, solar cells, and image sensors.

[0044]

The present invention will be described in more detail with reference to the following examples. Synthesis method of compound (2) In 50 ml of isopropyl alcohol, 3.4 g of 5- (4-diphenylaminophenyl) furfural, 1.0 g of malononitrile, and 4.8 g of piperidine were added, and the mixture was heated at 50 ° C.
For 1 hour. Thereafter, the mixture was diluted with 100 ml of methanol, and the precipitated red solid was filtered off with suction, separated and purified by column chromatography, and recrystallized twice with n-butanol to obtain 1.8 g of red crystals.
I got It was confirmed to be Compound (2) by analysis of molecular weight, NMR spectrum and the like by FD-MS. Infrared absorption spectrum of this compound (KBr tablet method)
Is shown in FIG. FIG. 2 shows the fluorescence spectrum of this compound. Method for synthesizing compound (35) In 225 ml of 1,2-dichloroethane, N, N,
4.9 g of N ′, N′-tetrakis {p- (α, α-dimethylbenzyl) phenyl} -4,4′-benzophenonediamine and 16 g of malononitrile were added and cooled to 5 ° C. under nitrogen. Then, 20 ml of titanium tetrachloride and 40 ml of pyridine were added dropwise, and the mixture was heated and stirred for 10 hours. Thereafter, the precipitate was filtered off with suction and extracted with chloroform to obtain 4 g of a red solid. For purification, the solid was dissolved in chloroform, diluted with methanol, and the precipitated red solid was separated by suction filtration, dried, and purified by column chromatography using silica gel to obtain 3 g of a powder having red fluorescence. . Molecular weight analysis by FD-MS, NMR
Analysis of the spectrum and the like confirmed that the product was the compound (35). The infrared absorption spectrum of this compound (KBr
The tablet method is shown in FIG. FIG. 4 shows the fluorescence spectrum of this compound. Example 1 Compound (2) of Table 1 and 2,5-bis (1-naphthyl)-as a luminescent material were placed on a washed glass plate with an ITO electrode.
1,2,10: 1,3,4-oxadiazole, polycarbonate resin (Teijin Chemical: Panlite K-1300)
Was dissolved in tetrahydrofuran at a weight ratio of, and a light-emitting layer having a thickness of 100 nm was obtained by spin coating. An electrode having a thickness of 150 nm was formed thereon with an alloy of magnesium and silver mixed at a ratio of 10: 1 to obtain an organic EL device. The light emission characteristics of this element are such that the light emission luminance at a DC voltage of 5 V is 60.
(Cd / m ² ), a maximum emission luminance of 800 (cd / m ² ), and red light emission with a luminous efficiency of 0.10 (lm / W) were obtained. Example 2 N, N ′-(3
-Methylphenyl) -N, N'-diphenyl-1,1 '
-Biphenyl-4,4'-diamine (TPD) was vacuum-deposited to obtain a 20-nm-thick hole injection layer. Next, the compound (4) was vapor-deposited to form a light-emitting layer having a thickness of 40 nm, and then tris (8-hydroxyquinolinato) aluminum complex (Alq3) was vapor-deposited to obtain a 30-nm-thick electron injection layer. An electrode having a thickness of 100 nm was formed thereon using an alloy in which magnesium and silver were mixed at a ratio of 10: 1 to obtain an organic EL device. The hole injection layer and the light emitting layer were deposited in a vacuum of 10 ^-6 Torr at a substrate temperature of room temperature. This device has a luminance of 80 (cd / m ² ) at a DC voltage of 5 V, a maximum luminance of 2500 (cd / m ² ), and a luminous efficiency of 0.2 (l).
m / W). Example 3 A compound (7) was dissolved in methylene chloride on a cleaned glass plate with an ITO electrode, and a hole injection type light emitting layer having a thickness of 50 nm was obtained by a spin coating method. Next, bis (2-methyl-8-hydroxyquinolinate) (1-naphtholate) gallium complex was vacuum-deposited to a thickness of 40 nm.
An electron injection layer was formed, and an electrode having a thickness of 100 nm was formed on the electron injection layer using an alloy in which magnesium and silver were mixed at a ratio of 10: 1 to obtain an organic EL device. The light emitting layer and the electron injection layer are 1
Vapor deposition was performed at a substrate temperature of room temperature in a vacuum of 0 ^-6 Torr. This device has an emission luminance of 50 (c) at a DC voltage of 5 V.
d / m ² ), red-orange emission with a maximum emission luminance of 2200 (cd / m ² ) and a luminous efficiency of 0.20 (lm / W) was obtained. Example 4 Compound (6) was vacuum-deposited on a cleaned glass plate with an ITO electrode to obtain a hole-injection type luminescent layer having a thickness of 50 nm.
Next, a bis (2-methyl-8-hydroxyquinolinato) (phenolate) gallium complex was vacuum-deposited to form an electron injection layer having a thickness of 30 nm, and magnesium and silver were mixed at a ratio of 10: 1. An electrode having a thickness of 100 nm was formed from the alloy to obtain an organic EL device. The light emitting layer and the electron injection layer were deposited in a vacuum of 10 ^-6 Torr at a substrate temperature of room temperature. This device has a light emission luminance of 80 (cd / m ² ) at a DC voltage of 5 V and a maximum light emission luminance of 3200 (cd / m ² ).
m ² ), and orange luminescence with a luminous efficiency of 0.3 (lm / W) was obtained. Examples 5 to 14 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) was vacuum-deposited on a washed glass plate with an ITO electrode to form a 30 nm-thick film. A hole injection layer was formed. Next, the compounds shown in Table 1 were vacuum-deposited as light-emitting materials to obtain a light-emitting layer having a thickness of 30 nm. Then, bis (2-methyl-8-hydroxyquinolinate)
(Phenolate) gallium complex is vacuum deposited to a thickness of 30
An electron injection layer having a thickness of 100 nm was formed, and an electrode having a thickness of 100 nm was formed on the electron injection layer using an alloy in which magnesium and silver were mixed at a ratio of 10: 1 to obtain an organic EL device. The hole injection layer and the light emitting layer were deposited in a vacuum of 10 ^-6 Torr at a substrate temperature of room temperature. Table 2 shows the light emission characteristics of this device. The emission luminance here is the luminance when a DC voltage of 5 V is applied. The organic EL device of this example was able to obtain emission colors from yellow to red. Table 2 化合物 Examples Compounds in Table 1 Luminance Luminance Maximum Luminance Luminous Efficiency (Cd / m ² ) (cd / m ² ) (lm / W) ───────────────────────────────── ── 5 (1) 150 2000 0.36 (2) 110 1800 0.27 (4) 190 2200 0.38 (5) 150 2000 0.29 (7) 110 3000 0.4 10 (8) ) 190 5000 0.5 11 (12) 150 3000 0.2 12 (16) 110 2500 0.313 (20) 120 3000 0.214 (34) 190 4000 0.6は Above light emission luminance and light emission efficiency are DC 5V applied It shows the measured values. Example 15 4,4 ′, 4 ″ was placed on a washed glass plate with an ITO electrode.
-Tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine was vacuum deposited to a film thickness of 40
As a result, a hole injection layer having a thickness of nm was obtained. Next, α-NPD was vacuum-deposited to obtain a 10-nm-thick second hole injection layer. Further, the compound (12) was vacuum-deposited to form a light-emitting layer having a thickness of 30 nm, and a bis (2-methyl-8-hydroxyquinolinate) (1-phenolate) gallium complex was further vacuum-deposited to form a film. An electron injection layer having a thickness of 30 nm was formed, and an electrode having a thickness of 150 nm was formed thereon using an alloy in which aluminum and lithium were mixed at a ratio of 25: 1 to obtain an organic EL device. The hole injection layer and the light emitting layer were deposited in a vacuum of 10 ^-6 Torr at a substrate temperature of room temperature. This element
Emission luminance 110 (cd / m ² ) at a DC voltage of 5 V, maximum emission luminance 4000 (cd / m ² ), luminous efficiency 0.4 (l)
m / W). Example 16 Example 3 was repeated except that a hole injection layer of copper phthalocyanine having a thickness of 5 nm was provided between the ITO electrode and the compound (15).
An organic EL device was produced in the same manner as in the above. This element
DC voltage 5V in emission luminance 120 (cd / m ^2), the maximum emission luminance 3000 (cd / m ^2), luminous efficiency 0.4 (lm
/ W). Example 17 4,4 ', 4 "-tris [N- (3-methylphenyl)
An organic EL device was produced in the same manner as in Example 15 except that a hole injection layer of metal-free phthalocyanine having a thickness of 20 nm was provided instead of [-N-phenylamino] triphenylamine. This device has an emission luminance of 15 at a DC voltage of 5 V.
0 (cd / m ² ), maximum emission luminance 4000 (cd / m ² )
m ² ) and red luminescence with a luminous efficiency of 0.4 (lm / W) was obtained. Example 18 Compound (20): α-NPD was used as a light-emitting layer at 1:10.
An organic EL device was manufactured in the same manner as in Example 5, except that a thin film having a thickness of 30 nm deposited at a rate of 0 was provided.
This device has an emission luminance of 120 (cd /
m ² ) Yellow light emission having a maximum light emission luminance of 8000 (cd / m ² ) and a light emission efficiency of 1.0 (lm / W) was obtained. Example 19 Compound (23): bis (2-methyl-8) was used as a light emitting layer.
An organic EL device was manufactured in the same manner as in Example 5, except that a 30-nm-thick thin film obtained by vapor-depositing -hydroxyquinolinato) (phenolate) gallium complex at a ratio of 1: 100 was provided. This device has an emission luminance of 2 at a DC voltage of 5 V.
00 (cd / m ² ), maximum emission luminance 11000 (cd / m ² )
m ² ), and orange luminescence with a luminous efficiency of 1.0 (lm / W) was obtained. Example 20 The same method as in Example 5 except that a thin film having a thickness of 30 nm in which compound (35): tris (8-hydroxyquinolinato) aluminum complex was deposited at a ratio of 1: 100 was provided as a light emitting layer. To produce an organic EL device. This device has an emission luminance of 250 (cd / m ² ) at a DC voltage of 5 V, a maximum emission luminance of 10100 (cd / m ² ), and an emission efficiency of 1.1.
(Lm / W) yellow light emission was obtained. Example 21 As a light emitting layer, compound (1): compound (37) was mixed with 50:
An organic EL device was manufactured in the same manner as in Example 5, except that a thin film having a thickness of 30 nm deposited at a ratio of 50 was provided.
This device has an emission luminance of 250 (cd /
m ² ) Red light emission having a maximum light emission luminance of 7100 (cd / m ² ) and a light emission efficiency of 0.7 (lm / W) was obtained. Example 22 α-NPD: Compound (4) was used as the light emitting layer in a ratio of 100: 5.
Except that a thin film having a thickness of 30 nm deposited at a ratio of
An organic EL device was manufactured in the same manner as in Example 15. This device has an emission luminance of 240 (cd / m) at a DC voltage of 5 V.
² ) Maximum luminous luminance 9500 (cd / m ² ), luminous efficiency 1.
0 (lm / W) orange light emission was obtained. Example 23 Film thickness of compound (1): 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM) deposited at a ratio of 50:50 as a light emitting layer. A thin film of 30 nm is provided, and tris (8-
An organic EL device was produced in the same manner as in Example 15 except that a hydroxyquinolinato) aluminum complex was vacuum-deposited to form an electron injection layer having a thickness of 30 nm. This device has a light emission luminance of 200 (cd / m ² ) at a DC voltage of 5 V.
Maximum light emission luminance 12500 (cd / m ² ), light emission efficiency 1.
1 (lm / W) red light emission was obtained. The organic EL device shown in this embodiment has a two-layer or more device configuration,
High luminous efficiency could be obtained. When the organic EL device shown in this example was continuously emitted at 3 (mA / cm ² ), stable emission could be observed for 1000 hours or more.

The organic EL device of the present invention achieves improvement of luminous efficiency, luminous luminance and long life, and is used together with a luminescent material, a doping material, a hole injection material, an electron injection material, and a sensitizer. It does not limit the agent, resin, electrode material and the like, and the element manufacturing method.

[0046]

The organic EL device using the organic EL device material of the present invention as a light emitting material emits light from yellow to red, has higher luminous efficiency, higher luminance, and has a longer luminous life as compared with the prior art. The device was obtained.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of compound (2).

FIG. 2 is a fluorescence spectrum diagram of compound (2).

FIG. 3 is an infrared absorption spectrum of compound (35).

FIG. 4 is a fluorescence spectrum diagram of compound (35).

Claims (8)

[Claims] 1. A material for an organic electroluminescence device represented by the following general formula [1]. General formula [1] [In the formula, A ¹ and A ² represent a hydrogen atom, a cyano group, an alkyl group, an aryl group or a substituent represented by the following general formula [2], and at least one of them is represented by the following general formula [2]. Substituent. General formula [2] Wherein A ³ is a group containing at least one aryl ring
A ⁴ and A ⁵ represent an alkyl group or an aryl group, and A ⁴ and A ⁵ may be integrated. ] 2. The material for an organic electroluminescence device according to claim 1, wherein A ³ is represented by the following general formula [3]. General formula [3] Wherein A ⁶ and A ⁷ represent an arylene group. ] 3. An organic electroluminescence device comprising a light-emitting layer or a plurality of organic compound thin films including a light-emitting layer formed between a pair of electrodes, wherein one of the layers is the organic electroluminescence element according to claim 1 or 2. An organic electroluminescence device comprising the device material alone or as a mixture. 4. The organic electroluminescence device material according to claim 1, wherein the light-emitting layer is an organic electroluminescence device in which a light-emitting layer or a plurality of organic compound thin films including the light-emitting layer is formed between a pair of electrodes. Or a mixture thereof. 5. The organic electroluminescence device according to claim 3, wherein a hole injection layer is further formed between the anode and the light emitting layer. 6. The method according to claim 1, wherein the hole injection layer is an arylamine derivative,
The organic electroluminescent device according to claim 5, wherein the organic electroluminescent device is a layer containing at least one selected from the group consisting of a phthalocyanine compound and a triphenylene derivative. 7. The organic electroluminescence device according to claim 3, wherein an electron injection layer is further formed between the cathode and the light emitting layer. 8. The organic electroluminescence device according to claim 7, wherein the electron injection layer is a layer containing a metal complex compound or a nitrogen-containing aromatic ring compound.