JP3498533B2 - Light emitting material for organic electroluminescent device and organic electroluminescent device using the same - Google Patents

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) element used for a flat light source or a display, and a high brightness light emitting element.

[0002]

2. Description of the Related Art An EL element using an organic substance is expected to be used as a solid-state light emitting type inexpensive large area full color display element, and many developments have been made. Generally EL
Is composed of a light emitting layer and a pair of counter 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 and holes are injected from the anode side. Further, this is a phenomenon in which 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.

A conventional organic EL element has a higher driving voltage and lower emission brightness and emission efficiency than an inorganic EL element.
In addition, the deterioration of the characteristics was remarkable and it was not put to practical use.
In recent years, an organic EL in which thin films containing an organic compound having a high fluorescence quantum efficiency that emits light at a low voltage of 10 V or less are laminated
The device has been reported and is of great interest (see Applied Physics Letters, 51, 913, 1987). This method uses a metal chelate complex as a light emitting layer and an amine compound as a hole injecting layer to obtain high-intensity green light emission, and a direct current voltage of 6 to 7 V produces a brightness of several thousand c.
d / m ² , maximum luminous efficiency of 1.5 lm / W is achieved,
It has the performance close to the practical range.

However, the organic EL devices to date have been improved in the emission intensity due to the improved structure, but still do not have sufficient emission brightness. Further, it has a big problem that it is inferior in stability when repeatedly used. 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 the cathode, and is greatly deteriorated by light emission in a short time. Was there. For the above reasons, in order to develop an organic EL element having high emission brightness and emission efficiency and excellent stability in repeated use, development of a light emitting material having excellent emission ability and durability Is desired.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides an organic EL device having high emission brightness and excellent stability during repeated use. As a result of diligent studies by the present inventors, the light emission of the organic EL device using the light emitting material for organic EL device represented by any one of the general formula [1], the general formula [3] or the general formula [4] in the light emitting layer. The inventors have found that the present invention has high brightness and high luminous efficiency and is excellent in stability even after repeated use, and thus has completed the present invention.

[0006]

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

[Chemical 5] [Wherein 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 homologous thereof. Or 2 to 15 different ring structural units of 2 or more types directly, or an oxygen atom, a nitrogen atom, a sulfur atom, a chain structural unit having 1 to 20 carbon atoms and optionally a hetero atom, or a non-aromatic ring structural unit It represents a trivalent to 15-valent group linked through at least one (except for 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 condensed aromatic ring group. X ¹ and X ²
Are each independently -O-, -S-,> C = O,> S
_{O 2, - (C x H} 2x) -O- (C y H 2y) -, the number of carbon atoms of the substituted or unsubstituted 1-20 alkylidene group or an alkylene group, a divalent aliphatic ring substituted or unsubstituted Represents a group (where x and y represent an integer of 0 to 20,
x + y = 0 is never achieved. ). R ^{1 to} R ¹⁰ are each independently 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 or a substituted or unsubstituted amino group (R ^{1 to} R ⁵ or R ^{6 to} R ¹⁰ may combine with adjacent substituents to form a new ring). ] General formula [2]

[Chemical 6]

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

[Chemical 7] [In the formula, A, X ¹ , X ² and R ^{1 to} R ¹⁰ each have the same meaning as defined in the general formula [1]. ]

Furthermore, the present invention relates to a light emitting material for an organic electroluminescence device represented by the following general formula [4]. General formula [4]

[Chemical 8] [Wherein A and R¹~ R^TenAre respectively represented by the general formula [1]
Has the same meaning as defined in. Y¹~ Y^FourReplace
Alternatively, an unsubstituted alkyl group having 1 to 20 carbon atoms and a substituted group
Or an unsubstituted aromatic ring group having 6 to 16 carbon atoms (Y
¹And Y²And Y ³And Y^FourWith substituted or unsubstituted charcoal
An aliphatic ring group having a prime number of 5 to 7 may be formed. ). ]

The present invention further 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 above light emitting material for organic electroluminescent devices. It is an organic electroluminescence element which is a layer.

DETAILED DESCRIPTION OF THE INVENTION

A of the compound represented by the general formula [1], the general formula [3] or the general formula [4] in the present invention is a substituted or unsubstituted aromatic ring group, a substituted or unsubstituted condensed aromatic ring group, a substituted Or an unsubstituted heteroaromatic ring group, a substituted or unsubstituted condensed heteroaromatic ring group, or 2 to 15 ring structural units of the same or different types thereof, directly or with an oxygen atom, a nitrogen atom, a sulfur atom, 1 to 2 carbon atoms
3 to 15 linked through at least one of a chain structure unit which may contain 0 heteroatoms and a non-aromatic ring structure unit
Represents a valence group. Here, the site | part which couple | bonds with the nitrogen atom of A has a ring structure. Specific examples of A include benzene, toluene,
Xylene, ethylbenzene, naphthalene, anthracene, phenanthrene, fluorene, pyrene, chrysene,
Residue of substituted or unsubstituted aromatic ring 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, diphenyl ether, methyldiphenylamine, benzophenone, phenyl benzoate, diphenylurea, diphenyl sulfide, diphenyl sulfone, diphenoxybiphenyl, bis (phenoxyphenyl) sulfone, bis (phenoxyphenyl) propane, di Two or more ring structures of the same kind or different kinds such as phenoxybenzene, ethylene glycol diphenyl ether, neopentyl glycol diphenyl ether, dipicolylamine, dipyridylamine, hexahydrotriphenyltriazine, tripyridyltriazine, triphenylamine and tris (diphenylamino) benzene. A residue of a compound having a skeleton in which two or more units are linked.

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

[0012]

[Table 1]

[0013]

[0014]

[0015]

[0016]

[0017]

The compound represented by the general formula [1] in the present invention
Ar compound¹And Ar²Are each independently
More specifically, it represents an unsubstituted divalent aromatic ring group or a condensed aromatic ring group.
Ar ¹And Ar²Examples of are benzene, toluene,
Xylene, ethylbenzene, naphthalene, anthracene
, Phenanthrene, fluorene, pyrene, chrysene,
Substitution or no placement of naphthacene, perylene, azulene, etc.
It is a divalent residue of a substituted aromatic ring or a condensed aromatic ring.
In addition, the general formula [1], the general formula [3], or the general formula [4]
R of the compound represented by¹~ R^TenEach independently, water
Elemental atom, halogen atom, substituted or unsubstituted alkyl
Group, substituted or unsubstituted alkoxy group, substituted or
Unsubstituted aryl group, substituted or unsubstituted amino group
Represent

Substituents which A or Ar ¹ and Ar ² have, and specific examples of R ^{1 to} R ¹⁰ include fluorine, chlorine, bromine and iodine as the halogen atom, and a methyl group as the substituted or unsubstituted alkyl group. , Ethyl group, propyl group, butyl group, sec-butyl group, tert-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,
There is an α-benzyloxybenzyl group and the like. As the substituted or unsubstituted alkoxyl group, 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,
Examples include 1,1,1-tetrafluoroethoxy group, phenoxy group, benzyloxy group, octylphenoxy group and the like. As the substituted or unsubstituted aryl group, 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 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 and a dibenzylamino group. In addition, adjacent substituents, each bonded to each other, 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, a quinoxaline ring, a xanthene ring, a carbazole ring, an acridine ring, a phenanthroline ring or the like may be newly formed.

General formula [1] or general formula in the present invention
X of the compound represented by [3]¹And X²Respectively
Independently, -O-, -S-,> C = O,> SO₂,-(C
_xH _2x)-O- (C_yH_2y)-, Substituted or unsubstituted
Alkylidene group or alkylene group, substituted or unplaced
Represents a divalent group of another aliphatic ring. Where x and y
Represents a positive integer from 0 to 20, but x + y = 0
Not. The compound represented by the general formula [4] in the present invention
Thing Y¹~ Y^FourIs a substituted or unsubstituted C1 to C2
0 alkyl group, substituted or unsubstituted carbon number 6 to 16
Represents an aromatic ring group. Also, Y¹And Y²Or Y³And Y
^FourAnd a substituted or unsubstituted alicyclic group having 5 to 7 carbon atoms
May be formed. Specific examples of alkyl group and aromatic ring group
Examples are the above R¹~ R^TenAnd the alkyl groups described in
An aromatic ring group is mentioned. Also, the number of carbon atoms that can be formed is 5
The aliphatic ring group of ~ 7 is cyclopentyl group, cyclohexyl
Group, 4-methylcyclohexyl group, cycloheptyl group
Etc.

The groups outside the nitrogen atom of the compound of the general formula [1], the general formula [3] or the general formula [4] of the present invention (the substituted or unsubstituted benzene ring in the general formula [1] -X ⁿ -Ar ⁿ -, a representative example of the portion) will be specifically exemplified in Table 2, the present invention is not limited to the representative examples.

[0022]

[Table 2]

[0023]

[0024]

Since the compound in the present invention has a large number of bulky groups having a large molecular weight, it has a high glass transition point and a high melting point. 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 the Joule heat generated in the organic layer during the electroluminescence, between the organic layers or between the organic layer and the metal electrode is improved, and when used as a light emitting material of an organic EL device, high light emission is obtained. It exhibits brightness and is also advantageous when emitting light for a long time.

A general method for synthesizing the compound represented by the general formula [1], the general formula [3] or the general formula [4] of the present invention is shown below. A polyhalide of a trivalent or higher-valent residue corresponding to A in general formula [1], general formula [3], or general formula [4], general formula [1], general formula [3] or general formula [4]
2 is a structure in which the bond between the nitrogen atom of A and A is replaced with hydrogen.
A compound of the general formula [1], general formula [3] or general formula [4] can be synthesized by reacting a primary amine derivative, potassium carbonate and a catalyst in a solvent. Some compounds can be synthesized from a polycarbonyl compound having an A structure instead of the polyhalide having an A structure. Further, it can be similarly synthesized from a polyamine compound having an A structure 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. The solvent is benzene, toluene or xylene. The above synthesis method is an example and is not particularly limited.

Representative examples of the compounds of the general formula [1], general formula [3] or general formula [4] of the present invention are specifically shown in Table 3 below. It is not limited to.

[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], the general formula [3] or the general formula [4] of the present invention is a compound having strong fluorescence in a solid state and is excellent in electroluminescence. Further, 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 material, electron injecting material or doping material may be used.

The organic EL element is an element in which a single-layer or multi-layer organic thin film is formed between the anode and the cathode. In the case of the single layer type, a light emitting layer is provided between the anode and the cathode. The light emitting layer contains a light emitting material, and may further contain a hole injecting material or an electron injecting material for transporting holes injected from the anode or electrons injected from the cathode to the light emitting material. However, the luminescent material of the present invention is
Since it is possible to form a uniform thin film having extremely high emission quantum efficiency, high hole transporting ability and electron transporting ability, it is also possible to form a light emitting layer using only the light emitting material of the present invention. The multilayer type is (anode / hole injection zone / emission layer / cathode), (anode / emission layer / electron injection zone / cathode),
(Anode / hole injection zone / light emitting layer / electron injection zone / cathode)
There is an organic EL element laminated in a multilayer structure. The compound of the general formula [1], the general formula [3] or the general formula [4] is
Since it has a high light emitting property and a hole injecting property, a hole transporting property, an electron injecting property, and an electron transporting property, it can be used as a light emitting material in a light emitting layer.

In the light emitting layer, if necessary, in addition to the compound of the general formula [1], the general formula [3] or the general formula [4] of the present invention, further known light emitting materials, doping materials, holes An injection material or an electron injection material can also be used. When the organic EL element has a multi-layered structure, it is possible to prevent deterioration in brightness and life due to quenching. If necessary, a light emitting material, a doping material, a hole injecting material, and an electron injecting material can be used in combination. Further, by using the doping material, it is possible to improve emission brightness and emission efficiency and obtain red and blue emission. Further, the hole injection zone, the light emitting layer, and the electron injection zone may each be formed by a layer structure of two or more layers. In that case, in the case of the hole injection zone, the layer that injects holes from the electrode is the first hole injection layer, and the layer that receives holes from the hole injection layer and injects holes into the light emitting layer is the second positive hole injection layer. It is called a hole injection layer. Similarly, in the electron injection zone, the layer that injects electrons from the electrode is called a first electron injection layer, and the 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 according to factors such as the energy level of the material, heat resistance, and adhesion to the organic layer or the metal electrode.

As the light emitting material or the doping material which can be used in the light emitting layer together with the compound of the general formula [1], the general formula [3] or the general formula [4], 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 laser. There are fluorescent dyes for whitening, but the invention is not limited to these.

The abundance ratio of the compound of the general formula [1], the general formula [3] or the general formula [4] and the above compound which can be used together in the light emitting layer in the light emitting layer may be any main component. . That is, by the respective combinations of the above compounds and the compound of the present invention, the compound of the present invention can be a main material forming a light emitting layer or a dope pink material in another main material.

The hole-injecting material has the ability to transport holes, has the effect of injecting holes from the anode, and has an excellent effect of injecting holes into the light-emitting layer or the light-emitting material. Examples thereof include compounds that prevent excitons from moving to the electron injection zone or the electron injection material and have excellent thin film forming ability. Specifically, phthalocyanine derivative, naphthalocyanine derivative, porphyrin derivative, 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 their derivatives, and polyvinylcarbazole. Polymer materials such as polysilane and conductive polymers are available, but are not limited thereto.

Among the hole injecting materials that can be used in the organic EL device of the present invention, the more effective hole injecting material is
It is an aromatic tertiary amine derivative or a phthalocyanine derivative. Specific examples of the aromatic tertiary amine derivative include triphenylamine, tritolylamine, tolyldiphenylamine, 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 thereof, but not limited to these. It is not something that will be done.

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

The electron injecting material has an ability to transport electrons, has a hole injecting effect from the cathode, and an excellent electron injecting effect to the light emitting layer or the light emitting material. Examples thereof include compounds that prevent migration to the hole injection zone and have excellent thin film forming ability. For example, fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole,
Triazole, imidazole, perylene tetracarboxylic acid, fluorenylidene methane, anthraquinodimethane,
Examples include, but are not limited to, anthrone and derivatives thereof. It is also possible to sensitize the hole injecting material by adding an electron accepting substance and the electron injecting material by adding an electron donating substance.

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, metal complex compounds include 8-hydroxyquinolinato lithium and bis (8
-Hydroxyquinolinato) zinc, bis (8-hydroxyquinolinate) copper, bis (8-hydroxyquinolinato) manganese, tris (8-hydroxyquinolinate)
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) phenolato gallium, bis (o- (2-benzoxazolyl) phenolato) zinc, bis (o- (2-benzothiazolyl) phenolato) zinc, bis (o- (2-benzotriazolyl) ) Phenolate) zinc and the like, but not limited thereto. Further, 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)
] Benzene, etc., but are not limited thereto.

In the present organic EL device, in the light emitting layer,
In addition to the compound of the general formula [1], the general formula [3] or the general formula [4], at least one kind of a light emitting material, a doping material, a hole injecting material and an electron injecting material may be contained in the same layer. . Further, in order to improve the stability of the organic EL device obtained by the present invention against temperature, humidity, atmosphere, etc., a protective layer is provided on the surface of the device, silicone oil,
It is also possible to protect the entire element with resin or the like.

As the conductive material used for the anode of the organic EL element, one having a work function larger than 4 eV is suitable, and carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, platinum. , Palladium and their alloys, metal oxides such as tin oxide and indium oxide used for ITO substrates and NESA substrates,
Furthermore, organic conductive resins such as polythiophene and polypyrrole are used.

The conductive material used for the cathode is 4
Those having a work function smaller than eV are suitable, and magnesium, calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese, aluminum and the like and alloys thereof are used, but are not limited thereto. . As an alloy, magnesium / silver,
Typical examples include magnesium / indium and lithium / aluminum, but the present invention is not limited thereto. The alloy ratio is controlled by the temperature of the vapor deposition source, the atmosphere, the degree of vacuum, etc., and is selected as an appropriate ratio. The anode and the cathode may be formed in a layered structure of two or more layers if necessary.

In the organic EL device, it is desirable that at least one of them is sufficiently transparent in the emission wavelength region of the device in order to emit light efficiently. It is also desirable that the substrate is transparent. The transparent electrode is made of the above-mentioned conductive material and is set by a method such as vapor deposition or sputtering so as to ensure a predetermined translucency. The electrode on the light emitting surface preferably has a light transmittance of 10% or more. The substrate has mechanical and thermal strength, and is not limited as long as it has transparency, but, for example, a glass substrate, a polyethylene plate, a polyethylene terephthalate plate, a polyether sulfone plate, Examples include transparent resins such as polypropylene plates.

Each layer of the organic EL element according to the present invention can be formed by any one 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 it needs to be set to an appropriate film thickness. If the film thickness is too thick, a large applied voltage is required to obtain a constant light output, resulting in poor efficiency. If the film thickness is too thin, pinholes and the like will occur, and even if an electric field is applied, sufficient emission brightness cannot be obtained. The normal film thickness is preferably in the range of 5 nm to 10 μm, more preferably in the range of 10 nm to 0.2 μm.

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

In the case of the wet film forming method, the material forming each layer is ethanol, chloroform, tetrahydrofuran,
A thin film is formed by dissolving or dispersing in a suitable solvent such as dioxane, and any solvent may be used. Further, in any of the organic thin film layers, an appropriate resin or additive may be used for improving the film forming property and preventing pinholes in the film. Examples of usable resins include insulating resins such as polystyrene, polycarbonate, polyarylate, polyester, polyamide, polyurethane, polysulfone, polymethylmethacrylate, polymethylacrylate and cellulose, and copolymers thereof, poly-N-vinyl. Examples thereof include photoconductive resins such as carbazole and polysilane, and conductive resins such as polythiophene, polypyrrole, and polyphenylene vinylene. However, in the case of the compound represented by the general formula [1], the general formula [3] or the general formula [4] of the present invention, since the amorphous property is high, a very good film is obtained without mixing a resin. Can be formed. Examples of the additives include antioxidants, ultraviolet absorbers, plasticizers and the like.

As described above, by using the compound of the present invention in the light emitting layer of an organic EL device, it was possible to improve the organic EL device characteristics such as luminous efficiency and maximum luminous brightness. In addition, this device is extremely stable against heat and current, and because it can obtain practically usable light emission brightness at a low driving voltage, it can significantly reduce deterioration, which was a major problem until now. I was able to.

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 light-emitting body.
It can be applied to light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display boards, marker lights, etc., and its industrial value is very large. In addition to the organic EL device, the material of the present invention can also be used in the fields of electrophotographic photoreceptors, photoelectric conversion devices, solar cells, image sensors and the like.

[0062]

The present invention will be described in more detail based on the following examples. Example 1 A compound (4) shown in Table 3, 2,5-bis (1-naphthyl)-, as a light emitting material was 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 light emitting layer having a thickness of 100 nm was obtained by spin coating. . An electrode having a film thickness of 150 nm was formed on the alloy by mixing magnesium and indium at a ratio of 10: 1 to obtain an organic EL device. The emission characteristics of this element are 130 (c
d / m ² ), maximum luminance of 1900 (cd / m ²⁾ and luminous efficiency of 0.6 (lm / W) were obtained.

Example 2 On the washed glass plate with ITO electrode, the compounds of Table 3
(5) is vacuum-deposited to form a light emitting layer with a thickness of 100 nm.
And then mixed magnesium and silver 10: 1.
An organic EL element is formed by forming an electrode with a thickness of 100 nm from an alloy.
Obtained. Emitting layer 10 ^-6Substrate temperature chamber in Torr vacuum
Deposition was carried out under warm conditions. This element is 4 at a DC voltage of 5V.
50 (cd / m²), Maximum brightness 780 (cd / m²),
Blue-green light emission with a luminous efficiency of 0.8 (lm / W) was obtained.

Example 3 Compound (6) 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 film thickness of 50 nm was obtained by spin coating. Then, bis (2-methyl-8-quinolinato) (2-naphtholate) aluminum is vacuum-deposited to form an electron injection layer having a thickness of 10 nm, and an alloy in which magnesium and aluminum are mixed at a ratio of 10: 1 is formed on the electron injection layer. An electrode having a film thickness of 100 nm was formed to obtain an organic EL device. The electron injection layer is 10 ^-6 Tor
In a vacuum of r, vapor deposition was performed at a substrate temperature of room temperature. This device has a direct current voltage of 5 V, 850 (cd / m ² ), a maximum brightness of 18400 (cd / m ² ), and a luminous efficiency of 1.8 (lm / m ² ).
A blue light emission of W) was obtained.

Example 4 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 is vacuum-deposited to form an electron injection layer having a film thickness of 10 nm, on which aluminum and lithium are added in an amount of 50:
An electrode having a thickness of 100 nm was formed from the alloy mixed in 1 to obtain an organic EL device. Each layer is in a vacuum of 10 ^-6 Torr,
Deposition was carried out under the condition that the substrate temperature was room temperature. This element has a maximum brightness of 7800 at a DC voltage of 5V of approximately 180 (cd / m ² ).
(Cd / m ² ) and an emission efficiency of 0.9 (lm / W) were obtained.

Example 5 On a washed glass plate with an ITO electrode, 2, 3, 6,
7,10,11-Hexamethoxytriphenylene was vacuum-deposited to obtain a hole injection layer having a film thickness of 30 nm. Then
The compound (13) in Table 3 was vacuum-deposited to obtain a light emitting layer having a film thickness of 30 nm. Further, bis (2-methyl-8-quinolinato) (1-naphtholate) gallium was vacuum-deposited to form an electron injection layer having a film thickness of 30 nm, and an alloy in which indium and lithium were mixed at a ratio of 50: 1 was formed thereon. Film thickness 100n
An electrode having a thickness of m was formed to obtain an organic EL device. Each layer was vapor-deposited in a vacuum of 10 ⁻⁶ Torr at a substrate temperature of room temperature. This device has a DC voltage of 5 V and a capacitance of about 280 (cd /
m ² ), a maximum luminance of 35000 (cd / m ² ), and a luminous efficiency of 3.9 (lm / W) were 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 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 on the alloy by mixing magnesium and silver at a ratio of 10: 1 to obtain an organic EL device. 1 electron injection layer
Deposition was performed under the conditions of 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. The organic EL devices of this example all have a maximum brightness of 5
It had high luminance characteristics of 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. Vacuum deposited to a film thickness of 3
A 0 nm hole injection layer was obtained. Then, one of the light emitting materials shown in Table 3 was vacuum deposited to obtain a light emitting layer having a film 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 film 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 electrode of 0 nm was formed to obtain an organic EL device. Each layer is 1
Deposition was performed under the conditions of a substrate temperature of room temperature in a vacuum of 0 ^-6 Torr. Table 6 shows the materials used for each element and the emission characteristics of this element. The organic EL devices of this example all have a maximum brightness of 5
It had high luminance characteristics of 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 give a film thickness of 25
A first hole injection layer of nm was obtained. Furthermore, N, N'-diphenyl-N, N'-di (3-methylphenyl) -1,
1'-biphenyl-4,4'-diamine was vacuum-deposited to obtain a second hole injection layer having a film thickness of 5 nm. Then, the compound (30) as a light emitting material is vacuum-deposited to a film thickness of 20 nm.
To obtain a light emitting layer. Furthermore, the electron injection material (E-1) was vacuum-deposited to obtain an electron injection layer having a film thickness of 30 nm. An electrode having a film thickness of 150 nm was formed on it with an alloy in which magnesium and silver were mixed at a ratio of 10: 1 to obtain an organic EL element. This device has a DC voltage of 5 V, 530 (cd / m ² ), a maximum brightness 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 was vacuum-deposited to give a film thickness of 25 nm.
The first hole injection layer of was obtained. Furthermore, 2, 3, 6, 7, 1
0,11-hexaphenoxytriphenylene was vacuum-deposited to obtain a second hole injection layer having a film thickness of 5 nm. Then, the compound (24) as a light emitting material is vacuum-deposited to a film thickness of 20 n.
A light emitting layer of m was obtained. Furthermore, the electron injection material (E-5) was vacuum-deposited to obtain an electron injection layer having a film thickness of 30 nm. An electrode having a film thickness of 150 nm was formed on it with an alloy in which magnesium and silver were mixed at a ratio of 10: 1 to obtain an organic EL element. This device has a direct current voltage of 5 V, 260 (cd / m ² ), a maximum brightness of 30500 (cd / m ² ), and a luminous efficiency of 5.6 (lm).
/ W) emission was obtained.

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

Examples 63 to 65 As the light emitting layer, one of the compounds (2) in Table 3 and one of the compounds in Table 7 was vapor-deposited at a weight ratio of 100: 1 to a film thickness of 30 nm.
An organic EL device was produced in the same manner as in Example 44, except that the light emitting layer of was used. Table 8 shows the emission characteristics of this device. The organic EL devices of this example all have a maximum brightness of 200.
It had a high luminance property of 00 (cd / m ² ) or more and was able to obtain a desired luminescent color.

[0076]

[Table 7]

[0077]

[Table 8]

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

Example 70 In the light emitting layer, the compound (37) shown in Table 3 and the compounds (D-2), (D-4) and (D-6) shown in Table 6 were prepared 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 element is 890 (cd /
m ² ), a maximum brightness of 30600 (cd / m ² ), and a luminous efficiency of 2.6 (lm / W) were obtained.

Example 71 On the washed glass plate with ITO electrodes, N, N'-dim
Tylphenyl-N, N'-di (4-n-butylphenyi
Vacuum) vapor deposition of phenanthrene-9,10-diamine
Thus, a hole injection layer having a film thickness of 30 nm was obtained. Then Tris
(8-Hydroxyquinolinate) aluminum and
Compound (16) was 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. Furthermore, the electron injection material (E
-2) is vacuum-deposited to form an electron injection layer with a thickness of 30 nm.
And then mixed magnesium and silver 10: 1.
An electrode with a thickness of 150 nm is formed from an alloy to form an organic EL device.
Obtained. 10 for each layer^-6Substrate temperature at room temperature in Torr vacuum
It vapor-deposited on condition of. This device has a DC voltage of 5 V
40 (cd / m²), Maximum brightness 26900 (cd /
m ²), Emission efficiency of 2.7 (lm / W) was obtained.
It was Example 72 On the washed glass plate with ITO electrode, 2, 3, 6,
Vacuuming 7,10,11-hexaethoxytriphenylene
By vapor deposition, a hole injection layer having a film thickness of 30 nm was obtained. Then
N, N'-diphenyl-N, N'-di (1-naphthyl)
-1,1'-biphenyl-4,4'-diamine and
Compound (7) was vacuum-deposited at a weight ratio of 100: 5 to form a film.
A 30 nm light emitting layer was obtained. Further, an electron injection material (E-
5) is vacuum-deposited to form an electron injection layer with a thickness of 30 nm.
And then mixed magnesium and silver 10: 1.
An electrode with a thickness of 150 nm is formed from an alloy to form an organic EL device.
Obtained. 10 for each layer^-6Substrate temperature at room temperature in Torr vacuum
It vapor-deposited on condition of. This element has a DC voltage of 5V
40 (cd / m²), Maximum brightness 33500 (cd /
m²), Light emission with a light emission efficiency of 3.2 (lm / W) was obtained.
It was

The organic EL element shown in this example has a luminous brightness of 5000 (cd / m ² ) or more, and all of them can obtain high luminous efficiency. When the organic EL device shown in this example was made to continuously emit light at 3 (mA / cm ² ), stable light emission could be observed for 1000 hours or longer, and dark spots were hardly observed. The organic EL device using the organic EL device material of the present invention as a light emitting material has a very high fluorescence quantum efficiency of the light emitting material. Therefore, in the device using this light emitting material, high brightness light emission in a low current application region is possible. In addition, 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. Furthermore, by adding a doping material having a different fluorescent color to the compound of the general formula [1], the general formula [3] or the general formula [4], a light emitting device having a different emission color could be obtained.

The organic EL device of the present invention achieves improvement of luminous efficiency, luminous brightness and prolongation of life, and is used together with a light emitting material, a doping material, a hole injecting material, an electron injecting material and a sensitizing material. There is no limitation on the agent, resin, electrode material, etc., and the method for producing the element.

[0083]

The organic EL device using the organic EL device material of the present invention as a light emitting material exhibits light emission with high luminous efficiency and high brightness as compared with the prior art, and an organic EL device having a long life could be obtained. . As described above, using the compound shown in the present invention in at least one layer of an organic EL device, and
With the organic EL element formed by the element structure of the present invention, it has become possible to easily produce an organic EL element having high brightness, high luminous efficiency, and long life.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-284252 (JP, A) JP-A-10-265773 (JP, A) JP-A-10-251633 (JP, A) JP-A-10- 233287 (JP, A) JP 10-88120 (JP, A) JP 10-88122 (JP, A) JP 10-72581 (JP, A) JP 10-72580 (JP, A) JP-A-10-72579 (JP, A) JP-A-9-268283 (JP, A) JP-A-9-222741 (JP, A) JP-A-8-87121 (JP, A) JP-A-7-316549 (JP, A) Special Table 2000-514591 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09K 11/06 H05B 33/14

Claims (4)

(57) [Claims] 1. A light emitting material for an organic electroluminescence device represented by the following general formula [1]. General formula [1] [Wherein 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 homologous thereof. Or 2 to 15 different ring structural units of 2 or more types directly, or an oxygen atom, a nitrogen atom, a sulfur atom, a chain structural unit having 1 to 20 carbon atoms and optionally a hetero atom, or a non-aromatic ring structural unit It represents a trivalent to 15-valent group linked through at least one (except for 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 condensed aromatic ring group. X ¹ and X ²
Are each independently -O-, -S-,> C = O,> S
_{O 2, - (C x H} 2x) -O- (C y H 2y) -, the number of carbon atoms of the substituted or unsubstituted 1-20 alkylidene group or an alkylene group, a divalent aliphatic ring substituted or unsubstituted Represents a group (where x and y represent an integer of 0 to 20,
x + y = 0 is never achieved. ). R ^{1 to} R ¹⁰ are each independently 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 or a substituted or unsubstituted amino group (R ^{1 to} R ⁵ or R ^{6 to} R ¹⁰ may combine with adjacent substituents to form a new ring). ] General formula [2] 2. The light emitting material for an organic electroluminescence device according to claim 1, which is represented by the following general formula [3]. General formula [3] [In the formula, 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, which is represented by the following general formula [4]. General formula [4] [In the formula, 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} have a substituted or unsubstituted carbon number of 5
The aliphatic ring group 7 may be formed. ). ] 4. 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 the light emitting layer is an organic electroluminescent device. An organic electroluminescence device, which is a layer containing a light emitting material for a luminescence device.