JPH10302960A - Luminescent material for organic electroluminescent element and organic electroluminescent element using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL element with high luminescent luminance and excellent stability during repetitive use by using luminescent material formed of compound containing plural aromacyclic groups for a luminescent layer. SOLUTION: Compound used for luminescent material is as shown in a formula. In the formula. A is a substituted or unsubstituted aromacyclic group, a condensed aromacyclic group, a hetero-aromacyclic group, a condensed hetero- aromacyclic group or at least two same or different types 3-15 valence groups with 2-15 cyclic structure units connected directly or via at least one chain structure unit or non-aromacyclic structure unit. Ar<1> , Ar<2> are independently substituted or unsubstituted aromacyclic groups, condensed aromacyclic groups. X<1> , X<2> are independently -O-, -S-, etc. R<1> -R<10> are independently hydrogen atoms, substituted or unsubstituted alkyl groups, alkoxy groups, aromacyclic groups, hetero-aromacyclic groups, amino groups.

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 EL
Is composed of a light-emitting layer and a pair of opposed electrodes sandwiching the layer. In light emission, when an electric field is applied between both electrodes, electrons are injected from the cathode side and holes are injected from the anode side. Further, the electrons are recombined with holes in the light emitting layer, and energy is emitted as light when the energy level returns from the conduction band to the valence band.

[0003] Conventional organic EL devices have a higher driving voltage and lower luminous brightness and luminous efficiency than inorganic EL devices.
In addition, the characteristic deterioration was remarkable, and it had not been put to practical use.
2. Description of the Related Art In recent years, an organic EL in which a thin film containing an organic compound having high fluorescence quantum efficiency that emits light at a low voltage of 10 V or less is laminated.
Devices have been reported and are of interest (see 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-intensity green light emission.
d / m ² and maximum luminous efficiency of 1.5 lm / W,
Has performance close to the practical range.

[0004] However, organic EL devices up to now have improved luminous intensity due to the improved structure, but do not yet have sufficient luminous brightness. 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, in order to develop an organic EL device having high luminous luminance and luminous efficiency and excellent stability in repeated use, development of a durable luminescent material having excellent luminous ability has been required. Is desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic EL device having a high emission luminance and excellent stability when used repeatedly. As a result of intensive studies by the present inventors, light emission of an organic EL element using a light emitting material for an organic EL element represented by any of the general formulas [1], [3] and [4] in a light emitting layer The inventors have found that the luminance and the luminous efficiency are high and the stability upon repeated use is excellent, and the present invention has been accomplished.

[0006]

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

Embedded image [In the formula, A is a substituted or unsubstituted aromatic ring group, a substituted or unsubstituted fused aromatic ring group, a substituted or unsubstituted heteroaromatic ring group, a substituted or unsubstituted fused heteroaromatic ring group, or a homolog thereof. Or two or more different ring structural units may be 2 to 15 directly or an oxygen atom, a nitrogen atom, a sulfur atom, a chain structural unit which may contain a heteroatom with 1 to 20 carbon atoms, and a non-aromatic ring structural unit. It represents a trivalent to pentavalent group linked via at least one group (excluding the case of the following general formula [2]). Ar ¹ and Ar ² are
Each independently represents a substituted or unsubstituted aromatic ring group or a substituted or unsubstituted fused aromatic ring group. X ¹ and X ²
Is independently -O-, -S-,> C = O,> S
O ₂ , — (C _x H _2x ) —O— (C _y H _2y ) —, a substituted or unsubstituted alkylidene group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted divalent aliphatic ring (Where x and y represent an integer of 0 to 20,
x + y = 0 never occurs. ). R ^{1 to} R ¹⁰ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aromatic ring group, a substituted or unsubstituted heteroaromatic ring Represents a group, a substituted or unsubstituted amino group (R ^{1 to} R ⁵ or R ^{6 to} R ¹⁰ may be bonded to adjacent substituents to form a new ring). General formula [2]

Embedded image

Further, the present invention relates to a light emitting material for an organic electroluminescence device represented by the following general formula [3]. General formula [3]

Embedded image [Wherein, A, X ¹ , X ² and R ^{1 to} R ¹⁰ each have the same meaning as defined in the general formula [1]. ]

Further, the present invention relates to a luminescent material for an organic electroluminescent device represented by the following general formula [4]. General formula [4]

Embedded imageWherein A and R¹~ R^TenIs represented by the general formula [1]
Represents the same meaning as defined in Y¹~ Y^FourReplace
Or an unsubstituted alkyl group having 1 to 20 carbon atoms,
Or an unsubstituted aromatic ring group having 6 to 16 carbon atoms (Y
¹And Y^TwoAnd Y ^ThreeAnd Y^FourWith substituted or unsubstituted charcoal
An aliphatic cyclic group having a prime number of 5 to 7 may be formed. ). ]

Further, the present invention provides an organic electroluminescent 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 contains the light emitting material for an organic electroluminescent device. This is an organic electroluminescence element which is a layer to be formed.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, A of the compound represented by the general formula [1], [3] or [4] represents a substituted or unsubstituted aromatic ring group, a substituted or unsubstituted fused aromatic ring group, Or unsubstituted heteroaromatic ring group, substituted or unsubstituted fused heteroaromatic ring group, or two or more of the same or different two or more ring structural units directly or oxygen atom, nitrogen atom, sulfur atom, Carbon number 1-2
3 to 15 linked via at least one of a chain structural unit which may contain a hetero atom and a non-aromatic ring structural unit
Represents a valence group. Here, the site bonded to the nitrogen atom of A has a ring structure. Specific examples of A include benzene, toluene,
Xylene, ethylbenzene, naphthalene, anthracene, phenanthrene, fluorene, pyrene, chrysene,
A residue of a substituted or unsubstituted aromatic or condensed aromatic ring such as naphthacene, perylene, triphenylene, azulene, fluorenone, anthraquinone, dibenzosuberenone, tetracyanoquinodimethane, or furan, thiophene, pyrrole, pyridine, pyrone , Oxazole, pyrazine, pyrimidine, melamine, oxadiazole, triazole, thiadiazole, indole, quinoline, isoquinoline, carbazole, acridine, thioxanthone, coumarin, acridone, diphenylene sulfone, quinoxaline, benzothiazole, phenazine,
It is a residue of a heteroaromatic ring or a condensed heteroaromatic ring such as phenanthroline, phenothiazine, quinacridone, flavanthrone, and indanthrone. Furthermore, biphenyl,
Terphenyl, binaphthyl, triphenylbenzene, diphenylanthracene, rubrene, bifluorenylidene, bipyridine, biquinoline, flavone, phenyltriazine, bisbenzothiazole, bithiophene, phenylbenzotriazole, phenylbenzimidazole,
Phenylacridine, bis (benzoxazolyl) thiophene, bis (phenyloxazolyl) benzene, biphenylylphenyloxadiazole, diphenylbenzoquinone, diphenylisobenzofuran, diphenylpyridine, stilbene, dibenzyl, diphenylmethane, bis (phenylisopropyl) benzene , Diphenylfluorene, diphenylhexafluoropropane, dibenzylnaphthyl ketone, dibenzylidenecyclohexanone,
Distyrylnaphthalene, (phenylethyl) benzylnaphthalene, diphenylether, methyldiphenylamine, benzophenone, phenylbenzoate, diphenylurea, diphenylsulfide, diphenylsulfone, diphenoxybiphenyl, bis (phenoxyphenyl) sulfone, bis (phenoxyphenyl) propane, Two or more kinds of the same or different ring structures such as phenoxybenzene, ethylene glycol diphenyl ether, neopentyl glycol diphenyl ether, dipicolylamine, dipyridylamine, hexahydrotriphenyltriazine, tripyridyltriazine, triphenylamine, tris (diphenylamino) benzene, etc. It is a residue of a compound having a skeleton in which two or more units are connected.

In the following, typical examples of the structure of A of the compound of the general formula [1], [3] or [4] of the present invention are specifically shown in Table 1. However, the present invention is not limited to this representative example.

[0012]

[Table 1]

[0013]

[0014]

[0015]

[0016]

[0017]

In the present invention, the compound represented by the general formula [1]
Compound Ar¹And Ar^TwoAre, independently of each other,
Or an unsubstituted divalent aromatic ring group or condensed aromatic ring group.
Ar ¹And Ar^TwoExamples of benzene, toluene,
Xylene, ethylbenzene, naphthalene, anthrace
, Phenanthrene, fluorene, pyrene, chrysene,
Substitution or substitution of naphthacene, perylene, azulene, etc.
It is a divalent residue of a substituted aromatic ring or a condensed aromatic ring.
In addition, general formula [1], general formula [3] or general formula [4]
R of the compound represented by¹~ R^TenAre each independently water
Elemental atom, halogen atom, substituted or unsubstituted alkyl
Group, substituted or unsubstituted alkoxy group, substituted or
An unsubstituted aryl group or a substituted or unsubstituted amino group
Represent.

Specific examples of the substituents of A or Ar ¹ and Ar ² and R ^{1 to} R ¹⁰ include fluorine, chlorine, bromine, iodine as a halogen atom, and methyl as a substituted or unsubstituted alkyl group. , Ethyl, propyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, stearyl, 2-phenylisopropyl, trichloromethyl, trifluoromethyl, 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. Examples of the substituted or unsubstituted alkoxyl group include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, a t-butoxy group, an n-octyloxy group, a t-octyloxy group,
There are 1,1,1-tetrafluoroethoxy group, phenoxy group, benzyloxy group, octylphenoxy group and the like. Examples of the substituted or unsubstituted aryl group include a phenyl group, a 2-methylphenyl group, a 3-methylphenyl group,
4-methylphenyl group, 4-ethylphenyl group, biphenyl group, 4-methylbiphenyl group, 4-ethylbiphenyl group, 4-cyclohexylbiphenyl group terphenyl group, 3,5-dichlorophenyl group, naphthyl group, 5-methylnaphthyl Group, anthryl group, pyrenyl group and the like.
Examples of the substituted or unsubstituted amino group include an amino group, a dimethylamino group, a diethylamino group, a phenylmethylamino group, a diphenylamino group, a ditolylamino group, a dibenzylamino group, and the like. In addition, adjacent substituents are bonded to each other to form a substituted or unsubstituted,
Cyclopentene ring, cyclohexene ring, phenyl ring, naphthalene ring, anthracene ring, pyrene ring, fluorene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, pyridine ring, pyrazine ring, pyrroline ring, pyrazoline ring , Indole ring,
A quinoline ring, quinoxaline ring, xanthene ring, carbazole ring, acridine ring, phenanthroline ring or the like may be newly formed.

In the present invention, the general formula [1] or the general formula
X of the compound represented by [3]¹And X^TwoRespectively
Independently, -O-, -S-,> C = O,> SO_Two,-(C
_xH _2x)-O- (C_yH_2y)-, Substituted or unsubstituted
Alkylidene or alkylene, substituted or unsubstituted
Represents a divalent group of a substituted aliphatic ring. Where x and y
Represents a positive integer of 0 to 20, but x + y = 0.
And not. The compound represented by the general formula [4] in the present invention
Object Y¹~ Y^FourIs a substituted or unsubstituted carbon number of 1 to 2
0 alkyl group, substituted or unsubstituted carbon number of 6 to 16
Represents an aromatic ring group. Also, Y¹And Y^TwoOr Y^ThreeAnd Y
^FourA substituted or unsubstituted aliphatic cyclic group having 5 to 7 carbon atoms
May be formed. Specific examples of alkyl group and aromatic ring group
An example is R¹~ R^TenThe alkyl group described in and
And aromatic ring groups. In addition, the number of carbon atoms that can be formed is 5
To 7 are a cyclopentyl group, a cyclohexyl group;
Group, 4-methylcyclohexyl group, cycloheptyl group
And the like.

The group outside the nitrogen atom of the compound of the general formula [1], [3] or [4] of the present invention (substituted or unsubstituted benzene ring in the general formula [1]) -X ⁿ -Ar ^n- ) are specifically shown in Table 2, but the present invention is not limited to these representative examples.

[0022]

[Table 2]

[0023]

[0024]

Since the compound of the present invention has many bulky groups having a large molecular weight, the glass transition point and the melting point are high. Further, the compound in which the adjacent substituents of R ^{1 to} R ¹⁰ form an aromatic ring has a higher glass transition point and a higher melting point. Therefore, 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 at the time of electroluminescence is improved. It shows brightness and is advantageous when emitting light for a long time.

A general method for synthesizing the compound represented by the general formula [1], [3] or [4] of the present invention is shown below. A polyhalide of a trivalent or higher valent residue corresponding to A in the general formula [1], the general formula [3] or the general formula [4], the general formula [1], the general formula [3] or the general formula [4]
Is a structure in which the bond between nitrogen atom and A is replaced with hydrogen.
The compound of the general formula [1], the general formula [3] or the general formula [4] can be synthesized by reacting a secondary amine derivative, potassium carbonate and a catalyst in a solvent. Some can be synthesized from a polycarbonyl compound having an A structure instead of a polyhalide having an A structure. It can also be synthesized from a polyamine compound having the structure A and a halide of the group shown in Table 2. Instead of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, aqueous ammonia or the like can be used. As the catalyst, copper powder, cuprous chloride,
There are tin, stannous chloride, pyridine, aluminum trichloride or titanium tetrachloride. Solvents include benzene, toluene or xylene. The above synthesis method is an example and is not particularly limited.

Hereinafter, typical examples of the compound represented by the general formula [1], [3] or [4] of the present invention are specifically shown in Table 3. However, the present invention is not limited to this.

[0028]

[Table 3]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

The compound represented by the general formula [1], [3] or [4] of the present invention is a compound having strong fluorescence in a solid state and excellent in electroluminescence. In addition, since it has both excellent hole injecting property and hole transporting property from the metal electrode, and excellent electron injecting property and electron transporting property from the metal electrode, it can be effectively used as a light emitting material, Further, other hole injecting materials, electron injecting materials or doping materials may be used.

The organic EL device is a device in which one or more organic thin films are 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 general formula [1], the general formula [3] or the general formula [4]
Since it has high light-emitting properties and has hole-injecting properties, hole-transporting properties, electron-injecting properties, and electron-transporting properties, it can be used as a luminescent material in a luminescent layer.

If necessary, the light-emitting layer may further contain, in addition to the compound of the general formula [1], [3] or [4] of the present invention, further known light-emitting materials, doping materials and holes. An injection material or an electron injection material can also 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. Further, with the use of the doping material, emission luminance and emission efficiency can be improved, and red and blue light emission can be obtained. 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, the layer for injecting holes from the electrode is the first hole injection layer, and the layer for receiving holes from the hole injection layer and injecting holes into the light emitting layer is the second hole. It is called a hole injection layer. Similarly, in the case of the electron injection zone, a layer that injects electrons from the electrode is called a first electron injection layer, and a layer that receives electrons from the electron injection layer and injects electrons into the light emitting layer is called a second electron injection 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 which can be used in the light emitting layer together with the compound of the general formula [1], [3] or [4] includes anthracene, naphthalene, phenanthrene, pyrene, tetracene, coronene,
Chrysene, fluorescein, perylene, phthaloperylene, naphthaloperylene, perinone, phthaloperinone, naphthaloperinone, diphenylbutadiene, tetraphenylbutadiene, coumarin, oxadiazole, aldazine, bisbenzoxazoline, bisstyryl, pyrazine,
For cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, benzoquinoline metal complex, imine, diphenylethylene, vinylanthracene, diaminocarbazole, pyran, thiopyran, polymethine, merocyanine, imidazole chelated oxinoid compounds, quinacridone, rubrene and dye lasers Examples include, but are not limited to, fluorescent dyes for brightening.

The proportion of the compound of the general formula [1], the general formula [3] or the general formula [4] and the above compounds which can be used together in the light emitting layer in the light emitting layer may be any. . 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.

The hole injecting material has the ability to transport holes, has the effect of injecting holes from the anode, and has an excellent hole injecting effect on the light emitting layer or the light emitting material. Compounds that prevent excitons from migrating to an electron injection zone or an electron injection material and have excellent thin film forming ability can be used. Specifically, phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, oxazole, oxadiazole, triazole, imidazole, imidazolone, imidazolethione, pyrazoline, pyrazolone,
Tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acylhydrazone, polyarylalkane, stilbene, butadiene, benzidine-type triphenylamine, styrylamine-type triphenylamine, diamine-type triphenylamine, and derivatives thereof, and polyvinyl carbazole , Polysilane, and a polymer material such as a conductive polymer, but are not limited thereto.

Among the hole injecting materials that can be used in the organic EL device of the present invention, more effective hole injecting materials are
It is an aromatic tertiary amine derivative or a phthalocyanine derivative. Specific examples of the aromatic tertiary amine derivative include triphenylamine, tolylamine, tolylphenylamine, N, N'-diphenyl-N, N'-di (3-
Methylphenyl) -1,1′-biphenyl-4,4′-
Diamine, N, N, N ′, N′-tetra (4-methylphenyl) -1,1′-phenyl-4,4′-diamine;
N, N, N ', N'-tetra (4-methylphenyl)-
1,1′-biphenyl-4,4′-diamine, N, N ′
-Diphenyl-N, N'-di (1-naphthyl) -1,
1′-biphenyl-4,4′-diamine, N, N′-di (methylphenyl) -N, N′-di (4-n-butylphenyl) phenanthrene-9,10-diamine, 4,
4 ', 4 "-tris (N- (3-methylphenyl) -N
-Phenylamino) triphenylamine, 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane, and the like, or oligomers or polymers having an aromatic tertiary amine skeleton, but are not limited thereto. It is not something to be done.

Specific examples of the phthalocyanine (Pc) derivative include H ₂ Pc, CuPc, CoPc, NiPc, Z
nPc, PdPc, FePc, MnPc, ClAlP
c, ClGaPc, ClInPc, ClSnPc, Cl
₂ SiPc, (HO) AlPc, (HO) GaPc, V
OPc, TiOPc, MoOPc, GaPc-O-Ga
Examples include, but are not limited to, phthalocyanine derivatives such as Pc and naphthalocyanine derivatives.

The electron injecting material has the ability to transport electrons, has the effect of injecting holes from the cathode, and has an excellent electron injecting effect on the light emitting layer or the light emitting material. Compounds that prevent migration to the hole injection zone and have excellent thin film forming ability can be mentioned. For example, fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole,
Triazole, imidazole, perylenetetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane,
Examples include, but are not limited to, anthrones and derivatives thereof. 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 a metal complex compound or a nitrogen-containing five-membered ring derivative. Specifically, as the metal complex compound, lithium 8-hydroxyquinolinate, 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-quinolinato) chlorogallium, bis (2-methyl-8-quinolinato) (o-cresolate) gallium, bis (2-methyl-8-quinolinato) (1-naphtholate) aluminum , Bis (2-methyl-8-quinolinato) (2-naphtholate) gallium, bis (2-
Methyl-8-quinolinato) phenolate gallium, bis (o- (2-benzoxazolyl) phenolate) zinc, bis (o- (2-benzothiazolyl) phenolate) zinc, bis (o- (2-benzotriazolyl) ) Phenolates) zinc and the like, but are not limited thereto. As the nitrogen-containing five-membered derivative, an oxazole, thiazole, oxadiazole, thiadiazole or triazole derivative is preferable. In particular,
2,5-bis (1-phenyl) -1,3,4-oxazole, 1,4-bis (2- (4-methyl-5-phenyloxazolyl)) benzene, 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 '
-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)
], But not limited thereto.

In the present organic EL device,
In addition to the compound of the general formula [1], the general formula [3] or the general formula [4], 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. . Further, in order to improve the stability of the organic EL device obtained according to the present invention with respect to temperature, humidity, atmosphere, etc., a protective layer may be provided on the surface of the device, or silicone oil,
It is also possible to protect the entire element with a resin or the like.

As the conductive material used for the anode of the organic EL device, those having a work function of more than 4 eV are suitable, and include carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, and platinum. , Palladium and their alloys, tin oxide used for ITO substrate, NESA substrate, metal oxide such as indium oxide,
Further, an organic conductive resin such as polythiophene or polypyrrole is used.

As the conductive material used for the cathode, 4
Suitable are those having a work function lower than eV, such as, but not limited to, magnesium, calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese, aluminum, and alloys thereof. . Alloys include magnesium / silver,
Representative examples include 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 the cathode may be formed by two or more layers if necessary.

In the organic EL device, at least one of them is desirably sufficiently transparent in the emission wavelength region of the device in order to emit light efficiently. Further, it is desirable that the substrate is also transparent. The transparent electrode is set using the above-described conductive material so as to secure a predetermined translucency by a method such as vapor deposition or sputtering. The electrode on the light emitting surface desirably has a light transmittance of 10% or more. The substrate is not limited as long as it has mechanical and thermal strength and transparency, but, for example, a glass substrate, a polyethylene plate, a polyethylene terephthalate plate, a polyether sulfone plate, A transparent resin such as a polypropylene plate can be used.

Each layer of the organic EL device according to the present invention may be formed by any of dry film forming methods such as vacuum deposition, 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.

The compound represented by the general formula [1], [3] or [4] of the present invention has a large overall molecular weight because a large number of groups having a large molecular weight are bonded to each other. The boiling point rises considerably. Therefore, some compounds are not suitable for film formation by vacuum deposition. On the other hand, since the bulky group having a large molecular weight has a high glass transition point, a high melting point, and a high amorphous property, it does not crystallize when the solvent is diluted after application, and a wet film forming method is suitable. .

In the case of the wet film forming method, a material for forming each layer is made of ethanol, chloroform, tetrahydrofuran,
The thin film is formed by dissolving or dispersing in a suitable solvent such as dioxane, 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. Examples thereof include photoconductive resins such as carbazole and polysilane, and conductive resins such as polythiophene, polypyrrole, and polyphenylenevinylene. However, in the case of the compound represented by the general formula [1], [3] or [4] of the present invention, since the compound is highly amorphous, a very good film can be obtained without mixing a resin. Can be formed. 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 characteristics of the organic EL device such as luminous efficiency and 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 device of the present invention can be used as a flat panel display such as a wall-mounted television or a flat luminous body.
It can be applied to light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display boards, and sign lamps, and its industrial value is extremely large. Further, the material of the present invention can be used in the fields of electrophotographic photoreceptors, photoelectric conversion elements, solar cells, image sensors, and the like, in addition to organic EL elements.

[0062]

The present invention will be described in more detail with reference to the following examples. Example 1 A compound (4) of Table 3 and 2,5-bis (1-naphthyl)-as a luminescent material were placed on a washed glass plate with an ITO electrode.
1,3,4-oxadiazole and a polycarbonate resin (Teijin Kasei: Panlite K-1300) were dissolved in tetrahydrofuran at a weight ratio of 5: 3: 2, and a 100 nm-thick light emitting layer was obtained by spin coating. . An electrode having a thickness of 150 nm was formed thereon by using an alloy in which magnesium and indium were mixed at a ratio of 10: 1 to obtain an organic EL device. The light emission characteristics of this element were 130 (c) at a DC voltage of 5 V.
d / m ² ), green light with a maximum luminance of 1900 (cd / m ²⁾ and a luminous efficiency of 0.6 (lm / W) were obtained.

Example 2 A compound of Table 3 was placed on a washed glass plate with an ITO electrode.
(5) is vacuum-deposited to form a 100 nm-thick light emitting layer
Then, magnesium and silver were mixed at a ratio of 10: 1.
An electrode with a thickness of 100 nm is formed of an alloy to produce an organic EL device.
Obtained. The light emitting layer is 10 ^-6Substrate temperature chamber in Torr vacuum
It was deposited under warm conditions. This element is 4
50 (cd / m^Two), Maximum brightness 780 (cd / m^Two),
Blue-green light emission with a light emission efficiency of 0.8 (lm / W) was obtained.

Example 3 A compound (6) shown in Table 3 was dissolved in methylene chloride on a washed glass plate with an ITO electrode, and a 50 nm-thick light emitting layer was obtained by spin coating. Next, bis (2-methyl-8-quinolinato) (2-naphtholate) aluminum is vacuum-deposited to form a 10-nm-thick electron injection layer, on which an alloy obtained by mixing magnesium and aluminum at a ratio of 10: 1. An organic EL device was obtained by forming an electrode having a thickness of 100 nm. The electron injection layer is 10 ^-6 Torr
The film was deposited under the condition of room temperature and substrate temperature in a vacuum of r. This device has a DC voltage of 5 V at 850 (cd / m ² ), a maximum luminance of 18400 (cd / m ² ), and a luminous efficiency of 1.8 (lm / m ² ).
Blue light emission of W) was obtained.

Example 4 A compound (11) shown in Table 3 was vacuum-deposited on a washed glass plate with an ITO electrode to form a light-emitting layer with a thickness of 50 nm. Then, tris (8-hydroxyquinolinate)
Aluminum was vacuum-deposited to form an electron injection layer having a thickness of 10 nm, and aluminum and lithium were further deposited thereon by 50:
An electrode having a thickness of 100 nm was formed from the alloy mixed in Step 1 to obtain an organic EL device. Each layer is placed in a vacuum of 10 ^-6 Torr,
The deposition was performed at a substrate temperature of room temperature. This element is about 180 (cd / m ² ) at a DC voltage of 5 V and has a maximum luminance of 7800.
(Cd / m ² ) and orange luminescence with a luminous efficiency of 0.9 (lm / W) were obtained.

Example 5 On a washed glass plate with ITO electrodes, 2, 3, 6,
7,10,11-hexamethoxytriphenylene was vacuum-deposited to obtain a 30-nm-thick hole injection layer. Then
The compound (13) in Table 3 was vacuum-deposited to obtain a light-emitting layer having a thickness of 30 nm. Further, bis (2-methyl-8-quinolinato) (1-naphtholate) gallium was vacuum-deposited to form an electron injection layer having a thickness of 30 nm, and an indium and lithium mixed alloy of 50: 1 was further formed thereon. Film thickness 100n
An organic EL element was obtained by forming an electrode having a thickness of m. Each layer was deposited at a substrate temperature of room temperature in a vacuum of 10 ^-6 Torr. This element is about 280 (cd /
m ² ), blue light emission having a maximum luminance of 35000 (cd / m ² ) and a luminous efficiency of 3.9 (lm / W) was obtained.

Examples 6 to 43 One of the light emitting materials shown in Table 3 was dissolved in methylene chloride on a washed glass plate with an ITO electrode, and a light emitting layer having a thickness of 50 nm was obtained by spin coating. Then
One of the electron injecting materials shown in Table 4 was vacuum-deposited to a film thickness of 3
An electron injection layer having a thickness of 0 nm was formed, and an electrode having a thickness of 150 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 electron injection layer is 1
Vapor deposition was performed at a substrate temperature of room temperature in a vacuum of 0 ^-6 Torr. Table 5 shows the materials used for each element and the light emission characteristics of this element. All of the organic EL elements of this embodiment have a maximum luminance of 5
000 (cd / m ² ) or more.

[0068]

[Table 4]

[0069]

[Table 5]

Examples 44 to 59 N, N'-diphenyl-N, N'-di (1-naphthyl) -1,1'-biphenyl-4,4'-diamine was placed on a washed glass plate with an ITO electrode. Is vacuum-deposited to a thickness of 3
A hole injection layer of 0 nm was obtained. Next, one of the light-emitting materials in Table 3 was vacuum-deposited to obtain a light-emitting layer having a thickness of 30 nm. Further, one of the electron injection materials shown in Table 4 was vacuum-deposited to obtain an electron injection layer having a thickness of 30 nm. in addition,
An alloy of magnesium and silver mixed at a ratio of 10: 1 with a film thickness of 15
An 0 nm electrode was formed to obtain an organic EL device. Each layer is 1
Vapor deposition was performed at a substrate temperature of room temperature in a vacuum of 0 ^-6 Torr. Table 6 shows the materials used for each element and the light emission characteristics of this element. All of the organic EL elements of this embodiment have a maximum luminance of 5
000 (cd / m ² ) or more.

[0071]

[Table 6]

Example 60 4,4 ′, 4 ″ was placed on a washed glass plate with ITO electrodes.
-Tris (N- (3-methylphenyl) -N-phenylamino) triphenylamine was vacuum deposited to a thickness of 25
nm of the first hole injection layer was obtained. Further, N, N'-diphenyl-N, N'-di (3-methylphenyl) -1,
1′-biphenyl-4,4′-diamine was vacuum-deposited to obtain a 5 nm-thick second hole injection layer. Next, the compound (30) is vacuum-deposited as a light emitting material to a thickness of 20 nm.
Was obtained. Further, the electron injection material (E-1) was vacuum-deposited to obtain an electron injection layer having a thickness of 30 nm. 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. This device has a DC voltage of 5 V, 530 (cd / m ² ), a maximum luminance of 25200 (cd / m ² ), and a luminous efficiency of 3.2 (lm / m ² ).
Light emission of W) was obtained.

Example 61 4,4 ′, 4 ″ was placed on a washed glass plate with ITO electrodes.
-Tris (N- (1-naphthyl) -N-phenylamino) triphenylamine is vacuum-deposited to a thickness of 25 nm.
Was obtained. Furthermore, 2,3,6,7,1
0,11-hexaphenoxytriphenylene was vacuum-deposited to obtain a 5 nm-thick second hole injection layer. Next, the compound (24) was vacuum-deposited as a light emitting material to a thickness of 20 n.
m light emitting layers were obtained. Further, an electron injection material (E-5) was vacuum-deposited to obtain an electron injection layer having a thickness of 30 nm. 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. This device has a DC voltage of 5 V, 260 (cd / m ² ), a maximum luminance of 30,500 (cd / m ² ), and a luminous efficiency of 5.6 (lm).
/ W).

Example 62 9,9-Bis (4- (N, N-di- (3-methylphenyl) amino) was placed on a washed glass plate with an ITO electrode.
(Phenyl) fluorene was vacuum-deposited to obtain a 20-nm-thick hole injection layer. Next, the compound (5) was vacuum-deposited as a light emitting material to obtain a light emitting layer having a thickness of 20 nm. Further, the electron injecting material (E-2) is vacuum-deposited to a thickness of 2
A 0 nm second electron injection layer was obtained. Next, an electron injection material (E-5) was vacuum-deposited to obtain a first electron injection layer having a thickness of 10 nm. An electrode having a thickness of 150 nm is formed thereon by using an alloy in which magnesium and silver are mixed at a ratio of 10: 1.
An L element was obtained. This element is 450 (c) at a DC voltage of 5V.
d / m ² ), a maximum luminance of 39700 (cd / m ² ), and a light emission efficiency of 4.2 (lm / W) were obtained.

Examples 63 to 65 One of the compound (2) in Table 3 and one of the compounds in Table 7 was deposited at a weight ratio of 100: 1 to form a light emitting layer having a thickness of 30 nm.
An organic EL device was produced in the same manner as in Example 44 except that the light-emitting layer was used. Table 8 shows the emission characteristics of this device. All of the organic EL elements of this embodiment have a maximum brightness of 200
It has a high luminance characteristic of 00 (cd / m ² ) or more, and a desired emission color can be obtained.

[0076]

[Table 7]

[0077]

[Table 8]

Examples 66 to 69 The light-emitting layer was coated with a methylene chloride solution in which a compound (18) in Table 3 and one of the compounds in Table 7 were mixed at a weight ratio of 100: 1 to a thickness of 50 nm. An organic EL device was produced in the same manner as in Example 6, except that the light-emitting layer was used. Table 8 shows the emission characteristics of this device. All of the organic EL elements of this embodiment have a maximum luminance of 15000 (cd)
/ M ² ) or more, and a desired emission color could be obtained.

Example 70 The compound (37) in Table 3 and the compounds (D-2), (D-4) and (D-6) in Table 6 were used as the light-emitting layers in the ratio of 100: 2:
An organic EL device was produced in the same manner as in Example 6, except that a 50 nm-thick light emitting layer coated with a methylene chloride solution mixed at a weight ratio of 0.5: 0.2 was used. This device has a DC voltage of 5 V and 890 (cd /
m ² ), white light with a maximum luminance of 30600 (cd / m ² ) and a luminous efficiency of 2.6 (lm / W) were obtained.

Example 71 N, N'-dimension was placed on a washed glass plate with an ITO electrode.
Tylphenyl-N, N'-di (4-n-butylphenyl
F) Phenanthrene-9,10-diamine is vacuum-deposited
Thus, a hole injection layer having a thickness of 30 nm was obtained. Then Tris
(8-Hydroxyquinolinate) aluminum and Table 3
Compound (16) is vacuum-deposited at a weight ratio of 100: 3 to form a film
A light emitting layer having a thickness of 30 nm was obtained. Further, the electron injection material (E
-2) is vacuum-deposited to form a 30-nm-thick electron injection layer
Then, magnesium and silver were mixed at a ratio of 10: 1.
An electrode with a thickness of 150 nm is formed of an alloy to produce an organic EL device.
Obtained. Each layer is 10^-6Substrate temperature room temperature in Torr vacuum
Under the following conditions. This element has a DC voltage of 5 V and
40 (cd / m^Two), Maximum brightness 26900 (cd /
m ^Two), Light emission having a luminous efficiency of 2.7 (lm / W) was obtained.
Was. Example 72 On a cleaned glass plate with an ITO electrode,
7,10,11-hexaethoxytriphenylene is evacuated
By evaporation, a hole injection layer having a thickness of 30 nm was obtained. Then
N, N'-diphenyl-N, N'-di (1-naphthyl)
-1,1'-biphenyl-4,4'-diamine and Table 3
Compound (7) is vacuum-deposited at a weight ratio of 100: 5 to form a film
A 30 nm light emitting layer was obtained. Further, the electron injection material (E-
5) Vacuum evaporation to create a 30 nm thick electron injection layer
Then, magnesium and silver were mixed at a ratio of 10: 1.
An electrode with a thickness of 150 nm is formed of an alloy to produce an organic EL device.
Obtained. Each layer is 10^-6Substrate temperature room temperature in Torr vacuum
Under the following conditions. This element is about 4 at DC voltage 5V.
40 (cd / m^Two), Maximum brightness 33500 (cd /
m^Two), Light emission with a luminous efficiency of 3.2 (lm / W) was obtained.
Was.

The organic EL devices shown in this example had a light emission luminance of 5000 (cd / m ² ) or more, and all were able to obtain high light emission efficiency. When the organic EL device shown in this example was continuously emitted at 3 (mA / cm ² ), stable emission was observed for 1000 hours or more, and almost no dark spot was observed. An organic EL device using the organic EL device material of the present invention as a light-emitting material has extremely high fluorescence quantum efficiency of the light-emitting material. Therefore, in a device using this light-emitting material, high-luminance light emission in a low current application region is possible. By using a doping material in addition to the compound of the general formula [1], the general formula [3] or the general formula [4] in the light emitting layer,
The maximum luminous brightness and the maximum luminous efficiency could be improved. Further, by adding doping materials having different fluorescent colors to the compounds of the general formula [1], the general formula [3] or the general formula [4], light-emitting elements having different emission colors could be obtained.

The organic EL device of the present invention achieves an improvement in luminous efficiency, luminous brightness and a 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.

[0083]

According to the organic EL device using the organic EL device material of the present invention as a light-emitting material, the device emits light with high luminous efficiency and high luminance as compared with the prior art, and a long-life organic EL device can be obtained. . Using the compound shown in the present invention as described above in at least one layer of an organic EL device, and
With the organic EL device formed by the device configuration of the present invention, an organic EL device having high luminance, high luminous efficiency, and long life can be easily manufactured.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshio Enoda 2-3-13-1 Kyobashi, Chuo-ku, Tokyo Inside Toyo Ink Manufacturing Co., Ltd.

Claims (4)

[Claims] 1. A light-emitting material for an organic electroluminescence device represented by the following general formula [1]. General formula [1] [In the formula, A is a substituted or unsubstituted aromatic ring group, a substituted or unsubstituted fused aromatic ring group, a substituted or unsubstituted heteroaromatic ring group, a substituted or unsubstituted fused heteroaromatic ring group, or a homolog thereof. Or two or more different ring structural units may be 2 to 15 directly or an oxygen atom, a nitrogen atom, a sulfur atom, a chain structural unit which may contain a heteroatom with 1 to 20 carbon atoms, and a non-aromatic ring structural unit. It represents a trivalent to pentavalent group linked via at least one group (excluding the case of the following general formula [2]). Ar ¹ and Ar ² are
Each independently represents a substituted or unsubstituted aromatic ring group or a substituted or unsubstituted fused aromatic ring group. X ¹ and X ²
Is independently -O-, -S-,> C = O,> S
O ₂ , — (C _x H _2x ) —O— (C _y H _2y ) —, a substituted or unsubstituted alkylidene group or alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted divalent aliphatic ring (Where x and y represent an integer of 0 to 20,
x + y = 0 never occurs. ). R ^{1 to} R ¹⁰ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aromatic ring group, a substituted or unsubstituted heteroaromatic ring Represents a group, a substituted or unsubstituted amino group (R ^{1 to} R ⁵ or R ^{6 to} R ¹⁰ may be bonded to adjacent substituents to form a new ring). General formula [2] 2. The light emitting material for an organic electroluminescence device according to claim 1, represented by the following general formula [3]. General formula [3] [Wherein, A, X ¹ , X ² and R ^{1 to} R ¹⁰ each have the same meaning as defined above. ] 3. The light emitting material for an organic electroluminescence device according to claim 2, represented by the following general formula [4]. General formula [4] [Wherein, A and R ^{1 to} R ¹⁰ each have the same meaning as defined above. Y ^{1 to} Y ⁴ represent a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aromatic ring group having 6 to 16 carbon atoms (Y ¹ and Y ²
And Y ³ and Y ^{4 each} having 5 to 5 carbon atoms which are substituted or unsubstituted.
And 7 may form an aliphatic ring group. ). ] 4. An organic electroluminescent 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, wherein the light emitting layer is according to any one of claims 1 to 3. An organic electroluminescent device, which is a layer containing a luminescent material for a luminescent device.