JPH09255949A - Organic electroluminescence element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an organic electroluminecence element which has excellent electroluminescent properties, is not problematic in the crystallization of the specified constituent compound, has good heat stability and excellent film thinness by incorporating a compound having a specified structure in at least one of a luminescent layer, an electron injection layer and a hold injection transport layer. SOLUTION: This element contains a compound represented by the formula (Ar<1> and Ar<2> are each a 6-20C monovalent aromatic group or a 2-18C monovalent heterocyclic group; Ar<3> is a 6-20C divalent aromatic group; R is H, a 1-6C alkyl or a 6-20C monovalent aromatic group; X is O, S or an N atom bonded to a 6-20C monovalent aromatic group; Q is a 6-20C divalent aromatic group or a 1-6C almlene; and (n) is 0 or 1).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescence device, and more specifically, it has excellent electroluminescence, does not crystallize even when made into a device, has good thermal stability, and has a thin film property. The present invention relates to an excellent organic electroluminescence device.

[0002]

2. Description of the Related Art Generally, an electroluminescence device utilizing electroluminescence (hereinafter abbreviated as an EL device) has high visibility because it self-luminesces and is excellent in impact resistance because it is a completely solid-state device. It is used for thin display devices, liquid crystal display backlights, flat light sources, and so on. The EL element currently in practical use is an inorganic EL element. However, since this inorganic EL element requires an alternating voltage of several tens of volts and 10 kHz or more, the driving circuit is complicated and
It has drawbacks such as high manufacturing cost and insufficient brightness and durability.

On the other hand, the organic thin film EL element has a driving voltage of 1
In order to be able to reduce the voltage to 0 V and to emit light with high brightness, research has been actively conducted in recent years, and many organic thin film E
L elements have been developed, for example, “Appl. Phy
s. Lett. 151, pp. 913-915 (1987), JP-A-59-194393.
U.S. Pat. No. 4,539,507, JP-A-63-29
5695, U.S. Pat. No. 4,720,432,
JP-A-63-264692 has been reported or proposed. In these, the anode, hole injection transport layer,
An electroluminescent device comprising a light emitting layer and a cathode is shown,
Specifically, aromatic tertiary amines are cited as typical examples of hole injecting and transporting materials, and aluminum chelate complexes are cited as typical examples of light emitting materials. In addition, as a technique closest to the present invention, there are examples in which an oxadiazole compound described in JP-A-5-502140 and JP-A-6-314594 is used in an electron injection layer. However, these techniques have a drawback that they are not sufficiently satisfactory in terms of brightness and durability.

[0004]

Under the above circumstances, the present invention is excellent in electroluminescence, does not crystallize even when formed into an element, has good thermal stability, and has durability and thin film property. It is an object of the present invention to provide an excellent organic EL device.

[0005]

DISCLOSURE OF THE INVENTION As a result of intensive studies conducted by the present inventors to develop an organic EL device having the above-mentioned preferable properties, an organic EL device containing a distyryl compound having a specific structure, particularly a light emitting device. It was found that at least one of the electron injecting layer and the hole injecting and transporting layer can achieve the object by an organic EL device containing the distyryl compound. The present invention has been completed based on such findings. That is, the present invention provides a compound represented by the general formula (I):

[0006]

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(In the formula, Ar ¹ and Ar ² each represent a monovalent substituted or unsubstituted aromatic group having 6 to 20 carbon atoms or a heterocyclic group having 2 to 18 carbon atoms. They may be the same or different, Ar ³ is a divalent substituted or unsubstituted aromatic group having 6 to 20 carbon atoms, R is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent substituted or unsubstituted group. C6-20 aromatic group, X is an oxygen atom, a sulfur atom, or a monovalent substituted or unsubstituted C6-20.
Nitrogen atom to which the aromatic group of is bonded, Q is a divalent substituted or unsubstituted aromatic group having 6 to 20 carbon atoms or 1 to 6 carbon atoms.
And an alkylene group of n is 0 or 1. The present invention provides an organic EL device characterized by containing a compound represented by the formula (1).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The organic EL device of the present invention has the general formula (I)

[0009]

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It contains a compound represented by:
In the above general formula (I), Ar ¹ and Ar ² each represent a monovalent substituted or unsubstituted aromatic group having 6 to 20 carbon atoms or a heterocyclic group having 2 to 18 carbon atoms. here,
Examples of the monovalent aromatic group having 6 to 20 carbon atoms include phenyl group, biphenyl group, terphenyl group, naphthyl group,
Examples thereof include anthracenyl group, binaphthyl group and pyrenyl group, and examples of monovalent heterocyclic group having 2 to 18 carbon atoms include pyridyl group, quinolyl group, carbazolyl group, oxadiazolyl group, thiazolyl group and triazolyl group. Is mentioned. The aromatic group and the heterocyclic group are
It may be unsubstituted or may have one or more substituents described below on the ring. The Ar
¹ and Ar ² may be the same or different from each other.

Ar ³ represents a divalent aromatic group having 6 to 20 carbon atoms. Examples of the divalent aromatic group include phenylene group, biphenylene group, terphenylene group, naphthylene group, anthracenylene group, Examples thereof include binaphthylene group and pyrenylene group. This aromatic group may be unsubstituted and may have one or two substituents described below on the ring.
It may have more than one. R represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent aromatic group having 6 to 20 carbon atoms. Here, as the alkyl group having 1 to 6 carbon atoms, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, Examples thereof include neopentyl group, n-hexyl group, and isohexyl group. Examples of the monovalent aromatic group having 6 to 20 carbon atoms include phenyl group, biphenyl group, terphenyl group, naphthyl group, anthracenyl group, binaphthyl group, Examples thereof include a pyrenyl group. This aromatic group may be unsubstituted or may have one or more substituents described below on the ring.

Further, X represents an oxygen atom, a sulfur atom or a nitrogen atom to which a monovalent aromatic group having 6 to 20 carbon atoms is bonded. Here, as the monovalent aromatic group having 6 to 20 carbon atoms bonded to the nitrogen atom, for example, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthracenyl group,
Examples thereof include binaphthyl group and pyrenyl group. This aromatic group may be unsubstituted or may have one or more substituents described below on the ring. On the other hand, Q is a divalent aromatic group having 6 to 20 carbon atoms or 1 carbon atom.
And 6 to 6 alkylene groups. Here, as the divalent aromatic group having 6 to 20 carbon atoms, for example, a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, an anthracenylene group, a binaphthylene group, a pyrenylene group, and further,

[0013]

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And the like. This aromatic group may be unsubstituted or may have one or more substituents described below on the ring. Examples of the alkylene group having 1 to 6 carbon atoms include methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group, isobutylene group, sec-butylene group, tert-butylene group, pentylene group, Examples include neopentylene group, n-hexylene group, isohexylene group and the like.

Further, examples of the substituent in the above aromatic or heterocyclic group include a halogen atom and a carbon number of 6 to 20.
Aryl group, C1-C6 alkyl group, C1-C1
Examples thereof include an alkoxy group having 6 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, an unsubstituted or hydrocarbon group-substituted amino group, and a hydroxyl group. Here, examples of the aryl group having 6 to 20 carbon atoms include phenyl group, biphenyl group, terphenyl group, naphthyl group, anthracenyl group, binaphthyl group, pyrenyl group and the like, and examples of the alkyl group having 1 to 6 carbon atoms. Examples include a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, n-hexyl group,
Examples of the alkoxy group having 1 to 6 carbon atoms such as isohexyl group are methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butyloxy group, sec-
A butyloxy group, a tert-butyloxy group, a pentyloxy group, a neopentyloxy group, an n-hexyloxy group, an isohexyloxy group and the like are examples of the aralkyl group having 7 to 20 carbon atoms, a phenylmethyl group, a biphenylmethyl group. , Naphthylmethyl group, binaphthylmethyl group, etc., examples of aryloxy group having 6 to 18 carbon atoms include phenoxy group, naphthoxy group, etc., examples of hydrocarbon group-substituted amino group include methylamino group, dimethylamino group. Group, phenylamino group, diphenylamino group and the like. N is 0 or 1.

The organic EL device of the present invention contains such a compound represented by the general formula (I). The inclusion here means that the compound of the general formula (I) itself is a thin film. In addition to the above, a thin film in which the compound of the general formula (I) is dispersed in a binder polymer, and further, having a structure of the general formula (I) as a side chain or containing a structure in a repeating structure of the main chain It also refers to containing a thin film of molecules. The compound represented by the general formula (I) can be produced by various known methods, but for example, it is advantageous to produce it by the following three methods. <Method 1> General formula (II)

[0017]

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(Wherein R ¹ represents an alkyl group having 1 to 4 carbon atoms or a phenyl group, and R, Ar ³ , X, Q and n are the same as above). ,
General formula (III)

[0019]

[Chemical 6]

A method in which a carbonyl compound represented by the formula (wherein Ar ¹ and Ar ² are the same as above) is condensed in the presence of a base (Wittig reaction or Witti reaction).
g-Hornor reaction). <Method 2> General formula (IV)

[0021]

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(In the formula, R, Ar ³ , X, Q and n are the same as above.) And the general formula (V).

[0023]

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(Wherein Ar ¹ , Ar ² and R ¹ are the same as above) and the phosphonate ester is condensed in the presence of a base (Wittig reaction or W
Ittig-Hornor reaction). In the above method 1 and method 2, a reaction solvent is usually used. As the reaction solvent, hydrocarbons, alcohols and ethers are preferable, and specifically, methanol; ethanol; isopropanol; butanol; 2-methoxyethanol; 1,2-dimethoxyethane; bis (2-methoxyethyl). Ether; dioxane; tetrahydrofuran; toluene; xylene and the like, and further dimethyl sulfoxide; N, N-dimethylformamide; N-methylpyrrolidone; 1,3-
Dimethyl-2-imidazolidinone and the like can also be used. Of these, tetrahydrofuran and dimethyl sulfoxide are particularly preferable.

As the base, for example, sodium hydroxide, potassium hydroxide, sodium amide, sodium hydride, n-butyllithium, sodium methylate,
Preferable examples include potassium t-butoxide,
Among these, especially n-butyl lithium and potassium t
-Butoxide is preferred. <Method 3> General formula (VI)

[0026]

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(Wherein Ar ¹ , Ar ² , Ar ³ , R,
X, Q and n are the same as above. It can be produced by subjecting the compound represented by the formula (4) to a cyclodehydration in the presence of a dehydrating agent. Examples of the dehydrating agent used in this method include phosphorus oxychloride, thionyl chloride, polyphosphoric acid, and toluenesulfonic acid. Also,
This reaction is carried out in the absence or presence of a solvent. When a solvent is used, preferable examples of the solvent include aromatic solvents such as chlorobenzene, dichlorobenzene, xylene and nitrobenzene, and halogen solvents such as trichloroethane and trichloroethylene. Examples of the compound represented by the above general formula (I) include:

[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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Examples include those represented by:

The present invention is an organic EL device containing a distyryl compound having a structure represented by the above general formula (I), and the device constitution is, for example, anode / hole injection / transport layer / light emitting layer / electron. Injection layer / cathode, anode / light emitting layer / electron injection layer / cathode, anode / hole injection / transport layer / light emitting layer / cathode,
Examples include an anode / light emitting layer / cathode type. The distyryl compound having the structure represented by the general formula (I) is preferably contained in at least one of the light emitting layer, the electron injecting layer and the hole injecting and transporting layer. In this element configuration,
The hole injecting and transporting layer and the electron injecting layer are not always necessary, but the element having these layers has an advantage of improving the light emitting performance. Further, the hole injecting and transporting layer, the light emitting layer, and the electron injecting layer may be sandwiched between a pair of electrodes.
Furthermore, in order to make each component exist stably, a mixed layer may be prepared using a binder such as a polymer compound.

Here, the organic EL device of the present invention will be described by taking an example of anode / hole injecting / transporting layer / light emitting layer / electron injecting layer / cathode type. The device of the present invention is preferably supported on a substrate. The substrate is not particularly limited as long as it is commonly used in conventional organic EL devices, and for example, a substrate made of glass, transparent plastic, quartz or the like can be used. The positive electrode of this EL element is a metal having a large work function (4 eV or more),
Those using an alloy, an electrically conductive compound, or a mixture thereof as an electrode material are preferably used. Specific examples of such an electrode material include a conductive transparent material such as metal such as Au, CuI, indium tin oxide (ITO), SnO ₂ and ZnO. The positive electrode can be manufactured by forming a thin film from these electrode substances by a method such as evaporation or sputtering. When light is extracted from this electrode, the transmittance is desirably higher than 10%, and the sheet resistance of the electrode is preferably several hundred Ω / □ or less.

Further, the film thickness depends on the material, but is usually 10 n.
m-1 μm, preferably 10-200 nm
It is. On the other hand, the cathode has a low work function (4 eV).
Below) metals, alloys, electrically conductive compounds and mixtures of these
A material is used as an electrode material. Such an electrode
Specific examples of the substance include sodium and sodium-potassium.
Um alloy, magnesium, lithium, magnesium / copper
Mixture, magnesium / silver mixture, Al / Al _TwoO_Three,
Examples include indium. The cathode is these electrodes
A thin film is formed by a method such as vapor deposition or sputtering of the substance.
It can be produced by forming it. Also,
Sheet resistance as an electrode is preferably several hundred Ω / □ or less,
The film thickness is usually 10 to 500 nm, preferably 50 to 200
It is selected in the range of nm. In addition, in order to transmit the light emission,
Either the anode or the cathode of the organic EL element is transparent or
If it is semi-transparent, the luminous efficiency is improved, which is convenient.

As the light emitting material of the light emitting layer of the present invention, a distyryl compound having a structure represented by the above general formula (I) is preferable. When the distyryl compound is used in a region other than the light emitting layer, the light emitting material of the light emitting layer is not particularly limited, and any conventionally known compound can be selected and used.

Examples of the light-emitting material other than the distyryl compound include polycyclic fused aromatic compounds, fluorescent brightening agents such as benzoxazole-based, benzothiazole-based and benzimidazole-based compounds, metal chelated oxanoide compounds,
A compound having a good thin film forming property such as a distyrylbenzene compound can be used. Here, examples of the above-mentioned polycyclic condensed aromatic compound include condensed ring luminescent substances containing anthracene, naphthalene, phenanthrene, pyrene, chrysene, and perylene skeletons.

As the above-mentioned fluorescent whitening agents of benzoxazole type, benzothiazole type, benzimidazole type and the like, for example, those described in JP-A-59-194393 can be used, and typical examples thereof are ,
2,5-bis (5,7-di-t-pentyl-2-benzoxazolyl) -1,3,4-thiadiazole; 4,
4'-bis (5,7-t-pentyl-2-benzooxazolyl) stilbene; 4,4'-bis (5,7-di-
(2-methyl-2-butyl) -2-benzoxazolyl) stilbene; 2,5-bis (5,7-di-t-pentyl-2-benzoxazolyl) thiophene; 2,5-
Bis (5- (α, α, -dimethylbenzyl) -2-benzoxazolyl) thiophene; 2,5-bis (5,7-
Di- (2-methyl-2-butyl) -2-benzoxazolyl) -3,4-diphenylthiophene; 2,5-bis (5-methyl-2-benzooxazolyl) thiophene;
4,4'-bis (2-benzoxazolyl) biphenyl; 5-methyl-2- (2- (4- (5-methyl-2-
Benzoxazolyl) phenyl) vinyl) benzoxazole; benzoxazoles such as 2- (2- (4-chlorophenyl) vinyl) naphtho (1,2-d) oxazole, 2,2 ′-(p-phenylenedivinylene) ) -Bisbenzothiazole and other benzothiazoles, 2-
Fluorescent whitening agents such as (2- (4- (2-benzimidazolyl) phenyl) vinyl) benzimidazole; benzimidazole-based fluorescent agents such as 2- (2- (4-carboxyphenyl) vinyl) benzimidazole.

As the metal chelated oxanoide compound, for example, those described in JP-A-63-295695 can be used. Representative examples are tris (8-quinolinol) aluminum, bis (8-quinolinol) magnesium, bis (benzo (f) -8-quinolinol) zinc, bis (2-methyl-
8-quinolinolate) aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) aluminum, lithium 8-quinolinol, tris (5-chloro-8-quinolinol) gallium, bis (5-chloro- 8-quinolinol) calcium, poly (zinc (II) -bis (8-hydroxy-5-
Examples thereof include 8-hydroxyquinoline-based metal chain bodies such as quinolinonyl) methane) and dilithium epindridione.

In addition, a distyrylbenzene derivative described in European Patent No. 0373582, 038876.
Dimethylidene derivatives described in JP-A No. 8 (1994) -108,
No. 91694, coumarin derivative, JP-A-2-252
No. 793, distyrylpyrazine derivatives;
No. 196885, perylene derivatives disclosed in JP-A-2-25
No. 5789, naphthalene derivative, JP-A-2-289
The phthaloperinone derivative of JP-A No. 676 and JP-A No. 2-88689, the styrylamine derivative of JP-A No. 2-250292, and the cyclopentadiene derivative of JP-A No. 2-289675 are appropriately selected from the desired emission color and performance. be able to.

The light emitting layer made of the above organic compound may have a laminated structure of two or more layers as desired.
It may be formed by adding a fluorescent substance as disclosed in Japanese Patent No. 769,292. In this case, the organic compound is a thin film-like layer and has a part of the injection function and the light emitting function of the function of the light emitting region, while the fluorescent substance is present in the layer of the organic compound in a trace amount (several mol% or less). It plays a part of a light emitting function of emitting light in response to recombination of electrons and holes. Further, the organic compound used in the light emitting region may be a compound having no thin film property, and examples of such a compound include 1,4-diphenyl-1,3-butadiene; 4-tetraphenyl-1,3-
Butadiene; tetraphenylcyclopentadiene and the like. However, these materials that do not have a thin film property have a shortcoming that the life of the device is short.

The light emitting layer may be composed of a single layer made of one or more of these light emitting materials, or may be a laminate of light emitting layers made of a compound different from the light emitting layer. Good. Next, the hole injecting / transporting layer of the organic EL device of the present invention is made of a hole transferring compound and has a function of transferring the holes injected from the anode to the light emitting layer. By interposing the transport layer between the anode and the light emitting layer, many holes are injected into the light emitting layer at a lower electric field, and moreover, the electrons injected from the cathode or the electron injection layer into the light emitting layer become Due to the barrier of electrons existing at the interface of the hole injecting and transporting layer, the device is excellent in light emission performance because it is accumulated at the interface in the light emitting layer to improve the light emission efficiency.

The hole transfer compound used in the hole injecting and transporting layer is disposed between two electrodes to which an electric field is applied, and when the hole is injected from the anode, the hole is appropriately emitted. Can be transmitted to the layers, for example 10 ⁴ -10 ⁶ V
Those having a hole mobility of at least 10 ⁻⁶ cm ² / V · sec when an electric field of / cm is applied are preferable. The hole transporting compound is not particularly limited as long as it has the above-mentioned preferable properties, and is conventionally used as a charge injecting / transporting material for holes in an optical transmission material or EL.
Any known material used for the hole injecting and transporting layer of the device can be selected and used.

Examples of the hole transfer compound include distyryl compounds represented by the general formula (I), triazole derivatives, oxadiazole derivatives (US Pat. No. 3,1).
89,447), imidazole derivative, polyarylalkane derivative, pyrazoline derivative and pyrazolone derivative, phenylenediamine derivative, arylamine derivative, amino-substituted chalcone derivative, oxazole derivative, styrylanthracene derivative, fluorenone derivative, hydrazone derivative. , Stilbene derivatives and the like. Examples of the charge injection / transport material include silazane derivatives, polysilane-based and aniline-based copolymers, and conductive polymer oligomers, especially thiophene oligomers.

In the present invention, the above hole transfer compound or charge injecting / transporting material can be used as the hole injecting material, and the porphyrin compound shown below (described in JP-A-63-295965). ) And aromatic tertiary amine compounds and styrylamine compounds (US Pat. No. 4,127,412, JP-A-53-27033).
Gazette, JP-A-54-58445, JP-A-54-1496
Nos. 34, 54-64299, 55-79
Nos. 450, 55-144250, 56-
119132, 61-295558, 61-98353, 63-295695 and the like), and particularly preferably the aromatic tertiary amine compound.

As typical examples of the porphyrin compound,
Porphine, 1,10,15,20-tetraphenyl-
21H, 23H-porphine copper (II); 1,10,1
5,20-Tetraphenyl 21H, 23H-porphine zinc (II); 5,10,15,20-Tetrakis (pentafluorophenyl) -21H, 23H-porphine;
Silicon phthalocyanine oxide; aluminum phthalocyanine chloride; phthalocyanine (metal-free); dilithium phthalocyanine; copper tetramethyl phthalocyanine;
Copper phthalocyanine; chromium phthalocyanine; zinc phthalocyanine; lead phthalocyanine; titanium phthalocyanine oxide; magnesium phthalocyanine; copper octamethylphthalocyanine and the like.

Typical examples of the aromatic tertiary amine compound and styrylamine compound include N, N, N ',
N'-tetraphenyl-4,4'-diaminophenyl;
N, N'-diphenyl-N, N'-di (3-methylphenyl) -4,4'-diaminobiphenyl (TPDA);
2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ', N'-tetra-
p-tolyl-4,4'-diaminobiphenyl; 1,1-
Bis (4-di-p-tolylaminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-
Methylphenyl) phenylmethane; bis (4-di-p-
Trilylaminophenyl) phenylmethane; N, N'-diphenyl-N, N'-di (4-methoxyphenyl)-
4,4'-diaminobiphenyl; N, N, N ', N'-
Tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4-
(Di-p-tolylamino) -4 '-[4 (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-
Methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole and the like. In addition, crystals of inorganic semiconductors such as Si, SiC, CdS,
Amorphous materials can also be used.

The hole injecting and transporting layer may be composed of one or more of these hole injecting materials, or a single layer of a compound different from the hole injecting and transporting layer. It may be a stack of injecting and transporting layers.
The electron injection layer of the organic EL element used in the present invention is made of an electron injection material and has a function of transmitting electrons injected from the cathode to the light emitting layer. In the case of the present invention, the compound represented by the above general formula (I) is preferable.
When this distyryl compound is used in a layer other than the electron injecting layer, the electron injecting material is not particularly limited, and any one of conventionally known compounds can be selected and used.

This electron injection layer may be composed of one or more of these electron injection materials, or may be composed of a single layer.
Alternatively, an electron injection layer made of a compound different from the above layer may be laminated. Furthermore, it is an inorganic substance, p
-Si, p-SiC hole injection material, n-type α-
An electron injection material made of Si, n-type α-SiC can be used as the electron injection material. For example, international publication WO9
Inorganic semiconductors disclosed in 0/05998 and the like can be mentioned.

Next, a suitable example for producing the organic EL device of the present invention will be described. As an example, a method of manufacturing an EL device composed of the above-mentioned anode / hole injecting / transporting layer / light emitting layer / electron injecting layer / cathode will be described. First, a desired electrode material, for example, an anode material is formed on a suitable substrate. A thin film is formed by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably in the range of 10 to 200 nm, to prepare an anode. Next, a thin film made of the materials of the hole injecting and transporting layer, the light emitting layer, and the electron injecting layer, which are element materials, is formed on this. As the thinning method, there are the spin coating method, the casting method, the vapor deposition method and the like as described above, but the vacuum vapor deposition method is preferable from the viewpoint that a uniform film is easily obtained and pinholes are hard to be generated. . For this thinning,
When this vapor deposition method is adopted, the vapor deposition conditions vary depending on the type of compound used, the desired crystal structure of the molecular deposited film, the association structure, etc.
400 ° C., vacuum degree 10 ⁻⁶ to 10 ⁻³ Pa, vapor deposition rate 0.01
~ 50 nm / sec, substrate temperature -50 ~ 300 ° C, film thickness 5n
It is desirable to appropriately select in the range of m to 5 μm.

After forming these layers, a thin film made of a substance for the cathode is formed thereon and has a thickness of 1 μm or less, preferably 50 to 200 n.
A desired EL element can be obtained by forming a film having a thickness in the range of m by, for example, a method such as vapor deposition or sputtering and providing a cathode. In the production of this EL element, it is possible to reverse the production order and produce the cathode, the electron injection layer, the light emitting layer, the hole injection transport layer, and the anode in this order. In addition, a hole injecting and transporting layer between the pair of electrodes,
Anode sandwiching a mixture of a light emitting layer and an electron injection layer /
As a method for producing an element composed of a light emitting layer / cathode, for example, a thin film made of a material for an anode is formed on an appropriate substrate,
A solution containing a hole injecting material, a light emitting material, an electron injecting material, a binder such as polyvinylcarbazole, polycarbonate, polyarylate, polyester, or polyether is applied, or a thin film is formed from this solution by a dip coating method. There is a light emitting layer on which a thin film made of a substance for a cathode is formed. Here, an element material which is a material for the light emitting layer or the electron injection layer may be further vacuum-deposited on the produced light emitting layer, and a thin film made of a substance for a cathode may be formed thereon.

When a DC voltage is applied to the EL device thus obtained, light emission can be observed by applying a voltage of about 5 to 40 V with the anode having a positive polarity and the cathode having a negative polarity. Also, even if a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the positive electrode becomes + and the negative electrode becomes-. The waveform of the applied alternating current may be arbitrary.

[0055]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Production Example 1 Compound (1) was produced according to the reaction formula shown below.

[0056]

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0.35 g (1.70 mmol) of carboxylic acid [A] was dissolved in 2 ml of thionyl chloride and heated under reflux for 3 hours, and then unreacted thionyl chloride was distilled off to give 0.52 g of acid chloride (1 .60 mmol, yield 95%) was obtained.
0.52 g (1.60 mmol) of this acid chloride was added to pyridine 2
It was dissolved in milliliter, 0.04 ml of anhydrous hydrazine was added, and the mixture was heated under reflux for 6 hours. The reaction solution was poured into ice water, the precipitate formed was collected by filtration, and hydrazide [B] 0.7 was added.
7 g (yield 85%) was obtained. The nuclear magnetic resonance spectrum [ ¹ H-NMR, reference: tetramethylsilane (TMS), solvent: CDCl ₃ ] of this hydrazide [B] was measured and found to be δ = 9.0 to 7.0 ppm (15 H, m). there were.

Next, 0.77 g of the above-mentioned hydrazide [B] (1.
(30 mmol) was dissolved in 5.0 ml of phosphorus oxychloride and heated under reflux for 58 hours. Then, the reaction solution was poured into ice water, and the formed precipitate was collected by filtration and recrystallized from acetonitrile to give a white solid 0.3 g (0.52 mmol, yield 40)
%) Was obtained. Nuclear magnetic resonance spectrum of this white solid [ ¹
H-NMR, reference: tetramethylsilane (TMS), solvent: CDCl ₃ ] were measured, and δ = 8.5 to 7.0 p.
It was pm (30H, m).

The results of elemental analysis are as follows: C H 2 O 2 actual value (%) 87.27 5.43 5.04 Calculated value (%) 87.17 5.23 4.84 (as C ₄₂ H ₃₀ N ₂ O) Met. Furthermore, the result of mass spectrometry was m / z = 578. From the above results, it was confirmed that the target compound (1) was obtained.

Production Examples 2 to 12 Compounds (2) to (12) were prepared in the same manner as in Production Example 1 except that the carboxylic acid shown in Table 1 was used in place of the carboxylic acid [A]. Got The yield is shown in Table 1.

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3]

Production Example 13 Compound (13) was produced according to the reaction formula shown below.

[0065]

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Phosphorus oxychloride 0.31 g (2.0 mmol)
Dissolved in 5 ml of dichlorobenzene, aniline
0.56 g (6.0 mmol) was added, and the mixture was stirred at room temperature for 3 hours. Furthermore, 0.6 g (1.0 mmol) of hydrazide [B]
Was added and the mixture was heated under reflux for 36 hours. Then, the solvent was distilled off, and the residue was purified by a silica gel column to give a white solid (0.56 g).
(Yield 85%) was obtained. Nuclear magnetic resonance spectrum of this white solid [ ¹ H-NMR, reference: tetramethylsilane (T
MS), solvent: CDCl ₃ ], δ = 8.
It was 5 to 7.0 ppm (35 H, m).

The results of elemental analysis were as follows: C H N actual measurement value (%) 88.33 3.56 6.20 Calculated value (%) 87.18 3.40 6.43 (as C ₄₈ H ₃₅ N ₃ ). there were. Furthermore, the result of mass spectrometry was m / z = 653. From the above results, it was confirmed that the target compound (13) was obtained.

Production Examples 14 to 16 Compounds (14) to (16) were produced in the same manner as in Production Example 13 except that aromatic amines shown in Table 2 were used instead of aniline. did. Second yield
It is shown in the table.

[0069]

[Table 4]

Production Example 17 Compound (17) was produced according to the following reaction formula.

[0071]

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1.2 g (2.0 mmol) of hydrazide [B]
Is dissolved in 10 ml of pyridine, and P ₂ S ₅ 1.28 is added.
g was added and the mixture was heated under reflux for 16 hours. Ethyl alcohol 2
After adding 5 ml to stop the reaction, the reaction-terminated liquid was poured into water, and the formed precipitate was collected by filtration. Then
Recrystallization from acetonitrile gave 712 mg of a white solid. Nuclear magnetic resonance spectrum of this white solid [ ¹ H-NM
R, standard: tetramethylsilane (TMS), solvent: CD
Cl ₃ ], δ = 9.0-7.0 ppm (1
5H, m).

In addition, as a result of elemental analysis, C H N S measured value (%) 84.89 5.09 4.75 5.33 Calculated value (%) 84.93 5.09 4.72 5.39 (C ₄₂ H ₃₀ N ₂ S). Furthermore, the result of mass spectrometry was m / z = 594. From the above results, it was confirmed that the target compound (17) was obtained.

Production Example 18 Compound (19) was produced according to the reaction formula shown below.

[0075]

Embedded image 0.35 g (1.70 mmol) of carboxylic acid [A] was dissolved in 2 ml of thionyl chloride and heated under reflux for 3 hours, and then unreacted thionyl chloride was distilled off to give 0.52 g of acid chloride.
(1.60 mmol, yield 95%) was obtained. This acid chloride
0.52 g (1.60 mmol) was dissolved in 2 ml of pyridine, 0.02 ml of anhydrous hydrazine was added,
The mixture was refluxed for 6 hours. The reaction solution was poured into ice water and the formed precipitate was collected by filtration to give 0.45 g of compound [C] (yield 85
%) Was obtained.

Next, 0.45 g of this compound [C] (1.4
(Mmol) was dissolved in 5 ml of pyridine, 295 mg (0.7 mmol) of acid chloride [D] was added, and the mixture was heated under reflux for 3 hours. The reaction mixture was poured into ice water and the generated precipitate was collected by filtration to obtain 689 mg of the compound [E] (yield 100%). Next, 689 mg (0.7 mmol) of this compound [E] was dissolved in 4 ml of phosphorus oxychloride and heated under reflux for 58 hours. Then, the reaction solution was poured into ice water, the generated precipitate was collected by filtration, and recrystallized from acetonitrile to obtain 431 mg (yield 65%) of a white solid. The nuclear magnetic resonance spectrum [ ¹ H-NMR, reference: tetramethylsilane (TMS), solvent: CDCl ₃ ] of this white solid was measured and found to be δ = 8.5 to 7.0 ppm (38 H, m). .

The elemental analysis results are as follows: C H N measured value (%) 72.03 4.35 5.72 Calculated value (%) 71.94 4.30 5.69 (C ₅₉ H ₄₂ N ₄ O ₂ F _{Was 6} ). Furthermore, the result of mass spectrometry was m / z = 984. From the above results, it was confirmed that the target compound (19) was obtained.

Production Examples 19 to 24 In Production Example 18, instead of the acid chloride [D], the third compound was used.
Compounds (18) and (20) to (24) were obtained in the same manner as in Production Example 18 except that the compounds shown in the table were used. The yield is shown in Table 3.

[0079]

[Table 5]

[0080]

[Table 6]

Example 1 A glass substrate having a size of 25 mm × 75 mm × 1.1 mm and an ITO film (corresponding to an anode) having a thickness of 100 nm provided on a glass substrate was used as a transparent supporting substrate. The transparent supporting substrate was ultrasonically cleaned with isopropyl alcohol for 5 minutes, further ultrasonically cleaned with pure water for 5 minutes, and then cleaned with a UV ion cleaner (manufactured by Samco International) at a substrate temperature of 150 ° C. for 20 minutes. This transparent support substrate is dried with dry nitrogen gas and fixed to a substrate holder of a commercially available vapor deposition apparatus [manufactured by Nippon Vacuum Technology Co., Ltd.], and a copper phthalocyanine complex (hereinafter abbreviated as CuPc) is placed in a molybdenum resistance heating boat. Two
00 mg was added. Next, after depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing CuPc is energized to heat it to 450 ° C., and CuPc is vapor-deposited at a vapor deposition rate of 0.1 to 0.3 nm / sec. A CuPc layer having a film thickness of 60 nm corresponding to the hole injection layer was provided.

Next, the resistance heating boat was taken out,
Three other resistance heating boats were fitted. Each of these three resistance heating boats had N, N'-bis (4-methylphenyl) -N, N'-bis (1-naphthyl)-[1,
1'-biphenyl] -4,4'-diamine (hereinafter referred to as NP
Abbreviated as D), compound (1) (hereinafter abbreviated as DPVOXD), and 4,4 ″ -bis [2-[4- (N, N ′
-Diphenylamino) phenyl] vinyl-1,1 ':
4, 1 ″] (hereinafter abbreviated as DPAVBi). First, the resistance heating boat containing NPD was energized and heated to deposit NPD at a deposition rate of 0.1 to 0.3 nm / sec.
An NPD layer with a thickness of 20 nm is provided, and then DPVOXD
And a DPAVBi-containing resistance heating boat are energized and heated, DPVOXD and DPAVBi are co-deposited at a deposition rate of 4 nm / sec and 0.1 nm / sec, respectively, and a DPV having a thickness of 40 nm containing DPAVBi as a charge injection auxiliary agent.
An OXD-DPAVBi layer was provided as a light emitting layer.

Then, the transparent supporting substrate having these three organic layers laminated was taken out from the vacuum chamber, a stainless steel mask was placed on the light emitting layer, and the substrate was again fixed to the substrate holder. Then, in a resistance heating boat made of molybdenum, tris (8-quinolinol) aluminum (hereinafter, referred to as Al
(abbreviated as q) 200 mg was put and attached to a vacuum chamber.
Further, a resistance heating boat containing 1 g of magnesium ribbon and a tungsten basket containing 500 mg of silver wire were attached to a vacuum chamber. After that, the vacuum chamber is 1 × 10
After the pressure was reduced to ^-4 Pa, the resistance heating boat containing Alq was heated to 270 ° C., and Alq was vapor-deposited on the light emitting layer at a vapor deposition rate of 0.1 to 0.3 nm / sec to form an Alq layer with a thickness of 20 nm ( Corresponding to the electron injection layer). Then, the basket containing the silver wire is energized to deposit silver at a deposition rate of 0.1 nm / sec, and at the same time the boat containing magnesium is energized to deposit magnesium at a deposition rate of 1.4 to 2.0 nm / sec. did.

By this binary simultaneous vapor deposition, a 160-nm-thick magnesium-silver layer (corresponding to the cathode) was formed on the Alq layer. When an ITO electrode of this device was used as an anode and a magnesium-silver electrode was used as a cathode and a direct current of 8.7 V was applied, a current of 13 mA / cm ² flowed and blue light emission was obtained. At this time, the emission luminance was 850 cd / cm ² and the emission efficiency was 2.4 lumen / W.

Examples 2 to 8 The same procedures as in Example 1 were carried out except that the compounds shown in Table 4 were used as the light emitting material instead of the compound (1). Table 4 shows the results. In addition, as a result of leaving the obtained devices in the air, no crystallization was visually observed even after 1 month.

[0086]

[Table 7]

Example 9 A transparent supporting substrate which has been subjected to the same washing treatment as in Example 1 is dried.
After drying with nitrogen gas, a commercially available vapor deposition device [Japan Vacuum Technology
Fixed to a substrate holder manufactured by KK
Alq 200 mg was put into the anti-heating boat. Also another
Hole injection and transport materials for molybdenum boats [compounds
(4)] Put 200 mg, and set the vacuum chamber to 4 × 10. ^-FourPa
The pressure was reduced to Then, a heating bowl containing compound (4)
Energize the chamber to heat up to 350 ° C, vapor deposition rate 0.1-0.3
Holes with a film thickness of 60 nm are obtained by depositing compound (4) at a rate of nm / sec.
An injecting and transporting layer was provided.

Next, without taking this out from the vacuum chamber, Alq was deposited as a light emitting layer from another boat to a thickness of 50 nm on the hole injecting and transporting layer. At this time, the boat temperature was 250 ° C., the vapor deposition rate was 0.2 to 0.4 nm / sec, and the substrate temperature was room temperature. The thus laminated vapor-deposited product was taken out from the vacuum chamber, a stainless steel mask was placed, and the film was again fixed to the substrate holder. Next, put 1g of magnesium ribbon in a resistance heating boat made of molybdenum, and put a silver wire 5 in another tungsten basket.
00 mg was put and attached to a vacuum chamber. After that, the vacuum layer was decompressed to 1 × 10 ⁻⁴ Pa, and a basket containing silver wire was energized to deposit silver at a deposition rate of 0.1 nm / sec. Magnesium was vapor-deposited at 1.4 to 2.0 nm / sec.

By this binary simultaneous vapor deposition, a 160 nm-thickness magnesium-silver layer (corresponding to the cathode) was formed on the Alq layer. When an ITO electrode of this device was used as an anode and a magnesium-silver electrode was used as a cathode and a direct current of 8.7 V was applied, a current of 12.5 mA / cm ² flowed and green light emission was obtained. At this time, the emission luminance was 450 cd / cm ² .

Example 10 A transparent supporting substrate that had been subjected to the same cleaning treatment as in Example 1 was dried with dry nitrogen gas, and fixed on a substrate holder of a commercially available vapor deposition apparatus (manufactured by Nippon Vacuum Technology Co., Ltd.) to obtain molybdenum. Resistance heating boat made of N, N'-bis (3-methylphenyl)
-N, N'-diphenyl (1,1-biphenyl) -4,
200 mg of 4'-diamine (hereinafter abbreviated as TPD)
Put another 4 in another molybdenum resistance heating boat.
200 mg of 4'-bis [2,2'-diphenylvinyl) biphenyl (hereinafter abbreviated as DPVBi) was added,
The vacuum chamber was evacuated to 4 × 10 ⁻⁴ Pa. Then TPD
Was heated to 215 to 220 ° C. and vapor-deposited at a vapor deposition rate of 0.1 to 0.3 nm / sec on a transparent support substrate to form a hole injection layer having a film thickness of 60 nm. On this occasion,
The temperature on the substrate was room temperature. Next, without removing this from the vacuum chamber, 40 nm of DPVBi as a light emitting layer was laminated on the hole injection layer.

The thus-deposited layers are vacuum chambers.
Take out more and place a stainless steel mask
And again fixed to the substrate holder. Then made of molybdenum
Put 200 mg of Compound (8) in the resistance heating boat of
In addition to other molybdenum resistance heating boats,
Put 1g of Bonn into another tungsten basket
A silver wire (500 mg) was put in and attached to a vacuum chamber. That
Then, set the vacuum chamber to 1 x 10 ^-FourAfter reducing the pressure to Pa, the compound
Energize the resistance heating boat containing (8) to 300-31
Compound (8) is vapor-deposited at a rate of 0.1 to 0.3n by heating to 0 ° C.
Evaporation at m / sec, 20nm electron injection and transport layer on light emitting layer
Laminated. Next, energize the basket containing the silver wire
And deposit silver at a deposition rate of 0.1 nm / sec.
Deposition rate is 1.4 to 2.
Magnesium was vapor-deposited at 0 nm / sec.

This binary simultaneous vapor deposition formed a magnesium-silver layer (corresponding to the cathode) having a thickness of 160 nm on the electron injecting and transporting layer. The ITO electrode of this element is used as an anode,
When a direct current of 8.7 V was applied using the magnesium-silver electrode as a cathode, a current of 19 mA / cm ² flowed, and blue light emission was obtained. At this time, the emission luminance was 970 cd / cm ² .

Comparative Example 1 An organic EL device was prepared in the same manner as in Example 1 except that the compound [Z] having the following structure was used as the luminescent material in place of the compound (1). When a direct current of 8.7 V was applied, a current of 5.4 mA / cm ² flowed and the emission luminance was 180 cd / cm ² . The luminescent color at this time was blue. The luminous efficiency was 1.2 lumen / W, which was lower than the luminous efficiency of Example 1 of 2.4 lumen / W.

[0094]

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[0095]

INDUSTRIAL APPLICABILITY The organic EL device of the present invention exhibits high brightness and high luminous efficiency, is excellent in electroluminescence, does not crystallize even when formed into a device, has good thermal stability, and has durability and durability. It has features such as excellent thin film properties. Such an organic EL element of the present invention is suitably used, for example, as a display of information industrial equipment.

Claims (2)

[Claims] 1. A compound of the general formula (I) (In the formula, Ar ¹ and Ar ² are each a monovalent substituted or unsubstituted aromatic group having 6 to 20 carbon atoms or 2 to 2 carbon atoms.
18 heterocyclic groups, which may be the same or different from each other, Ar ³ is a divalent substituted or unsubstituted aromatic group having 6 to 20 carbon atoms, R is a hydrogen atom or 1 carbon atom
~ 6 alkyl group or a monovalent substituted or unsubstituted aromatic group having 6 to 20 carbon atoms, X is an oxygen atom, a sulfur atom or a monovalent substituted or unsubstituted aromatic group having 6 to 20 carbon atoms. A bonded nitrogen atom, Q is a divalent substituted or unsubstituted aromatic group having 6 to 20 carbon atoms or an alkylene group having 1 to 6 carbon atoms, and n is 0 or 1. ) The organic electroluminescent element containing the compound represented by these. 2. The organic electroluminescent device according to claim 1, wherein at least one of the light emitting layer, the electron injecting layer and the hole injecting and transporting layer contains a compound represented by the general formula (I).