JPH10226785A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an organic electroluminescent element being capable of high-luminance emission and having heat resistance and a long lifetime by incorporating a triamine compound having a specified structure as a hole injection material or a hole transport material in an organic compound layer. SOLUTION: In an organic electroluminescent element composed of a pair of electrodes and an organic compound layer having at least an organic luminescent layer and sandwiched between the electrodes, a triamine compound represented by the formula [wherein Ar<1> is an aryl having 6-18 nucleus carbon atoms; X<1> to X<3> are each a single bond, -O-, -S-, -(CH2 )n - or -C(CH2 )2 ; n is 1-6; and X<1> may be null] is incorporated in the organic compound layer. It is desirable that the triamine compound is added to the organic luminescent layer or the organic compound layer (hole injection layer or hole transport layer) intervening between the anode and the organic luminescent layer, and it is particularly advantageous that it is added as a hole injection material to the hole injection layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device. The present invention relates to an organic electroluminescent device having a long life and, more particularly, to a triamine compound effectively used in the organic electroluminescent device.

[0002]

2. Description of the Related Art An electroluminescent device utilizing electroluminescence has characteristics such as high visibility due to self-luminescence and excellent impact resistance because it is a completely solid-state device. Attention has been focused on its use as an element. The electroluminescent device includes an inorganic electroluminescent device using an inorganic compound as a light emitting material and an organic electroluminescent device using an organic compound. Among these, the organic electroluminescent device has a significantly lower applied voltage. It is easy to reduce the size and thickness, and it has features such as low power consumption, surface light emission, and easy emission of three primary colors. It is being actively developed for application to car navigation and the like.

[0003] Regarding the configuration of this organic electroluminescent element,
A structure based on an anode / organic light emitting layer / cathode, which is provided with a hole transport layer and an electron injection layer as appropriate, such as an anode / hole transport layer / organic light emitting layer / cathode and an anode / hole transport layer. Structures such as / organic light emitting layer / electron injection layer / cathode are known. The hole transport layer has a function of transmitting holes injected from the anode to the light emitting layer, and the electron injection layer has a function of transmitting electrons injected from the cathode to the organic light emitting layer. . Then, by interposing the hole transport layer between the organic light emitting layer and the anode, many holes are injected into the organic light emitting layer at a lower electric field. It is known that the injected electrons are accumulated at the interface between the hole transport layer and the organic light emitting layer because the hole transport layer does not transport the electrons, thereby increasing the luminous efficiency.

There is also known an organic electroluminescent device in which a hole injection layer is provided between an anode and a hole transport layer as a layer receiving holes. In this case, by providing the hole injection layer, the energy difference between the anode and the hole transport layer is reduced, and the hole injection property can be improved. Further, an organic electroluminescence device having a hole injection / transport layer using the same material and having the functions of a hole injection layer and a hole transport layer is also known. A hole injection transport material having both functions of the transport layer is also known.

However, such an organic electroluminescent device generally has a drawback that light emission abruptly attenuates during driving, and has been a major obstacle to practical use. In particular, it is known that light emission is easily attenuated when driven at a high temperature (for example, a temperature exceeding 80 ° C.). In order to overcome such disadvantages, it has been disclosed that, for example, a triamine compound or a tetraamine compound is used as a hole injecting / transporting material (Japanese Unexamined Patent Publication No.
JP-A-308688, JP-A-8-193191), and there is no description on heat resistance.

Further, an organic electroluminescent device (hereinafter, abbreviated as an organic EL device) capable of emitting high-luminance light using a diamine or triamine compound having two or three carbazolyl skeletons as a hole transport material is disclosed. (JP-A-7-90256, JP-A-8-90256)
No. 3547). However, the heat resistance of this organic EL device was not always satisfactory.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic electroluminescent device which can emit light with high luminance under such circumstances and has both heat resistance and long life. It is.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop an organic electroluminescent device capable of emitting light with high luminance and having both heat resistance and long life, and as a result, have developed a specific structure. The above object can be achieved by incorporating a triamine compound having the formula (I) in an organic compound layer of an organic electroluminescent device, particularly as a hole-injecting material or a hole-transporting material of the device, especially a hole-injecting layer material. I found that. The present invention has been completed based on such findings.

That is, the gist of the present invention is as follows. [1]. In an organic electroluminescent element comprising at least an organic compound layer having an organic light emitting layer sandwiched between a pair of electrodes,
In the organic compound layer, the compound represented by the general formula (I)

[0010]

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[In the formula, Ar ¹ is an aryl group having 6 to 18 nuclear carbon atoms, with or without a substituent, Ar ^{2 to} Ar
⁵ represents an arylene group having 6 to 18 nuclear carbon atoms each having or not having a substituent, and X ¹ represents a single bond,-
O -, - S -, - (CH 2) n - (n is an integer from 1 to 6) or -C (CH _{3) 2} - indicates a is linking group, there may of these linking groups, no X ² and X ³ may be
Each single bond, -O -, - S -, - (CH 2) n - (n
Represents an integer of 1 to 6) or —C (CH ₃ ) ₂ —, which may be the same or different. ] The organic electroluminescent element characterized by containing the triamine compound represented by these. [2]. The organic electroluminescent device according to [1], wherein the organic compound layer interposed between the anode and the organic light emitting layer contains the triamine compound represented by the general formula (I). [3]. The organic electroluminescent device according to [1] or [2], wherein the triamine compound represented by the general formula (I) is contained in an organic compound layer as a hole injection material or a hole transport material. [4]. General formula (I)

[0012]

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[In the formula, Ar ¹ is an aryl group having 6 to 18 nuclear carbon atoms, with or without a substituent, Ar ^{2 to} Ar
⁵ represents an arylene group having 6 to 18 nuclear carbon atoms each having or not having a substituent, and X ¹ represents a single bond,-
O -, - S -, - (CH 2) n - (n is an integer from 1 to 6) or -C (CH _{3) 2} - indicates a is linking group, there may of these linking groups, no X ² and X ³ may be
Each single bond, -O -, - S -, - (CH 2) n - (n
Represents an integer of 1 to 6) or —C (CH ₃ ) ₂ —, which may be the same or different. ] The triamine compound represented by these.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The triamine compound of the present invention has the general formula (I)

[0015]

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A compound having a structure represented by the following formula: In the general formula (I), Ar ¹ represents an aryl group having 6 to 18 nuclear carbon atoms, with or without a substituent;
r ^{2 to} Ar ⁵ each represent an arylene group having 6 to 18 nuclear carbon atoms, each having or not having a substituent. here,
Examples of the aryl group having 6 to 18 nuclear carbon atoms include a phenyl group, a biphenyl group, a naphthyl group, a terphenyl group, an anthranyl group, a phenanthryl group, and a pyrenyl group. Examples thereof include a phenylene group, a biphenylene group, a naphthylene group, a terphenylene group, an anthranylene group, a phenanthrylene group and a pyrenylene group.

Examples of the substituent which can be introduced into the aryl group or the arylene group include an alkyl group, an alkoxy group and a phenyl group. As the alkyl group, those having 1 to 6 carbon atoms are preferable. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group,
Examples include a tert-butyl group, an n-pentyl group, an isopentyl group, a cyclopentyl group, an n-hexyl group, an isohexyl group, and a cyclohexyl group. As the alkoxy group, those having 1 to 6 carbon atoms are preferable. For example, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, n -Pentoxy, isopentoxy, cyclopentoxy, n-hexoxy, isohexoxy, cyclohexoxy and the like. The position and number of these substituents are not particularly limited. Ar ^{2 to} Ar ⁵ may be the same or different.

On the other hand, X ¹ is a single bond, -O-, -S-,
_{- (CH 2) n - (} n is an integer from 1 to 6) or -C (CH ₃₎
Denotes a linking group that is _2- , which may or may not be present. X ² and X ³ are each a single bond, —O
-, - S -, - ( CH 2) n - (n is an integer from 1 to 6) or -C (CH _{3) 2} - indicates a is linking group, which may be the same or different.

Examples of the amine compound represented by the general formula (I) include:

[0020]

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[0021]

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[0022]

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[0023]

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[0024]

Embedded image

[0025]

Embedded image And the like.

The organic electroluminescent device of the present invention comprises at least an organic compound layer having an organic light emitting layer sandwiched between a pair of electrodes, and has a structure of anode / organic light emitting layer / cathode, anode / Hole transport layer / organic light emitting layer / cathode, anode / organic light emitting layer / electron injection layer / cathode, anode /
Hole transport layer / organic light emitting layer / electron injection layer / cathode, anode /
/ Hole injection layer / Hole transport layer / Organic light emitting layer / Electron injection layer /
There is a cathode or the like, but an organic compound layer sandwiched by a pair of electrodes (anode and cathode) (organic light-emitting layer in the device having the above structure, and hole transport layer and organic light-emitting layer in the device having the structure). Organic light emitting layer in the device of
In the device having the structure of the hole transport layer and the organic light emitting layer,
In at least one of the hole injecting layer, the hole transporting layer and the organic light emitting layer in the device having the above structure, the triamine compound represented by the general formula (I) may be used. There may be. In addition, it is preferable that all of the organic electroluminescent elements having these configurations are supported by the substrate. The substrate is not particularly limited, and a substrate commonly used in conventional organic electroluminescent elements, for example, a substrate made of glass, transparent plastic, quartz, or the like can be used. Further, the triamine compound represented by the general formula (I) may include only one kind, or may include two or more kinds.

In the organic electroluminescent device of the present invention, the triamine compound is contained in an organic light emitting layer or an organic compound layer (a hole injection layer, a hole transport layer, etc.) interposed between the anode and the organic light emitting layer. In particular, it is advantageous that the compound is contained in the hole injecting layer as a hole injecting material or is contained in the hole transporting layer as a hole injecting material. Above all, it is advantageous to include it in the hole injection layer as a hole injection material.

The hole injection layer containing the triamine compound may have a single-layer structure composed of the triamine compound alone, or may contain a material conventionally used as a material for the hole injection layer of the organic electroluminescent device. And a multi-layer structure with the above layer. Further, it may have a single-layer structure or a multi-layer structure including a layer made of a mixture of the triamine compound and a substance conventionally used as a material for a hole injection layer of an organic electroluminescent device. As such a material, any one of conventionally known electron transfer compounds can be selected and used. When a hole injection layer having a multilayer structure is employed, it is preferable that the hole injection layer made of the triamine compound of the present invention or the hole injection layer containing the triamine compound of the present invention be located on the side in contact with the anode.

Preferred examples of the above known electron transfer compounds include, for example,

[0030]

Embedded image The compound represented by these is mentioned.

The hole injection layer containing the triamine compound of the present invention can be formed by vacuum deposition, casting, coating, spin coating using the triamine compound and, if necessary, other materials for the hole injection layer. And the like.
Furthermore, a transparent polymer such as polycarbonate, polyurethane, polystyrene, polyarylate, or polyester is cast, coated or spin-coated using a solution in which the triamine compound is dispersed, or is co-evaporated with the transparent polymer. Can also be formed.

The hole transport layer containing the triamine compound of the present invention may have a single-layer structure composed of the triamine compound alone, or may be used together with the triamine compound as a material for the hole transport layer of an organic electroluminescent device. It may have a multilayer structure with a layer of a substance. Further, it may have a single-layer structure or a multi-layer structure including a layer made of a mixture of the triamine compound and a substance conventionally used as a material for a hole injection layer of an organic electroluminescent device. As such a material, any one of conventionally known electron transfer compounds can be selected and used. The hole transport layer containing the triamine compound of the present invention, for example, the triamine compound,
It can be formed by a vacuum evaporation method, a casting method, a coating method, a spin coating method, or the like using other hole injection layer materials as necessary.

The organic light emitting layer containing the triamine compound of the present invention is preferably a layer containing both the triamine compound and an organic light emitting layer material conventionally used as an organic light emitting layer material of an organic electroluminescent device. Although preferred, a multilayer structure of a layer made of the triamine compound and a layer of a conventionally used substance may be used. Further, it may have a multilayer structure including a layer made of a mixture of the triamine compound and a substance conventionally used as a material for an organic light emitting layer of an organic electroluminescent device. The organic light emitting layer containing the triamine compound can be formed by using the triamine compound and another organic light emitting layer material by a vacuum deposition method, a casting method, a coating method, a spin coating method, or the like.

In the organic electroluminescent device of the present invention, the triamine compound represented by the general formula (I) may be contained in the organic compound having the organic light emitting layer. Specifically, it is sufficient that at least one of the organic light emitting layer, the hole transport layer, and the hole injection layer contains the triamine compound. In this case, when the layer containing the triamine compound represented by the general formula (I) is an organic light emitting layer, a layer containing the triamine compound is used for the hole transport layer and / or the hole injection layer. Is preferred.

The organic electroluminescent device of the present invention can be formed using the same materials as those of the conventional organic electroluminescent device except for the layer containing the triamine compound of the present invention.
For example, as a material for the anode, a material having a large work function (4e
V or more) Metals, alloys, electrically conductive compounds or mixtures thereof are preferably used. Specific examples include metals such as Au, CuI, indium tin oxide (ITO),
A dielectric transparent material such as SnO ₂ or ZnO is used.
The anode can be manufactured by forming a thin film of the above material by a method such as a vapor deposition method or a sputtering method. When light emitted from the organic light emitting layer is taken out from the anode, the transmittance of the anode is desirably greater than 10%. The sheet resistance of the anode is preferably several hundred Ω / □ or less. The thickness of the anode depends on the material, but is usually 10 nm to
It is selected in the range of 1 μm, preferably 10-200 nm.

On the other hand, as a material of the cathode, a metal, an alloy, an electrically conductive compound or a mixture thereof having a small work function (4 eV or less) is preferably used. Specific examples of the cathode material include sodium, lithium and magnesium.
Copper mixture, magnesium / silver mixture, Al / Al
₂ O ₃ , Al-Li, indium and the like can be mentioned. This cathode can be manufactured by forming a thin film of the above material by a method such as an evaporation method or a sputtering method. When light emitted from the organic light emitting layer is taken out from the cathode, it is desirable that the transmittance of the cathode is greater than 10%. The sheet resistance of the cathode is preferably several hundred Ω / □ or less. Although the thickness of the cathode depends on the material, it is usually 10 nm to 1 nm.
μm, preferably in the range of 50 to 200 nm.

From the viewpoint of efficiently extracting light emitted from the organic light emitting layer, it is preferable that at least one of the anode and the cathode is formed of a transparent or translucent substance. The electron injection layer includes a conventionally known Si-based, SiC-based,
A crystalline or non-crystalline material such as a CdS-based material can be used.

When the organic light emitting layer in the organic electroluminescent device of the present invention is formed of the triamine compound of the present invention and another substance, the organic light emitting layer other than the triamine compound may be, for example, a polycyclic condensation material. Aromatic compounds,
Benzoxazole, benzothiazole, benzimidazole and other fluorescent brighteners, metal chelated oxanoid compounds, distyrylbenzene compounds and other compounds having good thin film forming properties can be used.

Here, specific examples of the above-mentioned polycyclic fused aromatic compound include a fused ring luminescent material containing an anthracene, naphthalene, phenanthrene, pyrene, chrysene, perylene skeleton, and 8 to 20, preferably 8 Other condensed ring light-emitting substances containing condensed rings are exemplified. Examples of the above-mentioned benzoxazole-based, benzothiazole-based, benzimidazole-based fluorescent whitening agents include those disclosed in JP-A-59-194393. As a typical example, 2,5-bis (5,7-
Di-t-pentyl-2-benzoxazolyl) -1,
3,4-thiadiazole; 4,4′-bis (5,7-t
-Pentyl-2-benzoxazolyl) 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-benzoxazolyl) ) Thiophene; 4,4'-bis (2-benzoxazolyl) biphenyl; 5-methyl-2- (2-
Benzoxazoles such as (4- (5-methyl-2-benzoxazolyl) phenyl) vinyl) benzoxazole; 2- (2- (4-chlorophenyl) vinyl) naphtho (1,2-d) oxazole; And benzothiazoles such as 2,2 ′-(p-phenylenedivinylene) -bisbenzothiazole and benzimidazoles such as 2- (2- (4-carboxyphenyl) vinyl) benzimidazole. .

As the metal chelated oxanoid compound, for example, those disclosed 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 complexes such as quinolinonyl) methane) and dilithium epindridione.

As the distyrylbenzene compound, for example, those disclosed in European Patent No. 0 375 582 can be used. Typical examples thereof include 1,4-bis (2-methylstyryl) benzene; 1,4-bis (3-methylstyryl) benzene;
1,4-bis (4-methylstyryl) benzene; distyrylbenzene; 1,4-bis (2-ethylstyryl) benzene; 1,4-bis (3-ethylstyryl) benzene; 1,4-bis (2 -Methylstyryl) -2-methylbenzene; 1,4-bis (2-methylstyryl) -2-
Ethylbenzene and the like can be mentioned.

Further, a distyrylpyrazine derivative disclosed in JP-A-2-252793 can also be used as a material for the organic light emitting layer. As a typical example,
2,5-bis (4-methylstyryl) pyrazine; 2,5
-Bis (4-ethylstyryl) pyrazine; 2,5-bis [2- (1-naphthyl) vinyl] pyrazine; 2,5-bis (4-methoxystyryl) pyrazine; 2,5-bis [2- (4 -Biphenyl) vinyl] pyrazine; 2,5-
Bis [2- (1-pyrenyl) vinyl] pyrazine and the like can be mentioned.

In addition, dimethylidene derivatives disclosed in European Patent No. 0388768 and JP-A-3-231970 can be used as a material for the organic light emitting layer. Typical examples thereof are 1,4-phenylenedimethylidin; 4,4′-biphenylenedimethylidin; 2,5-xylylenedimethylidillin; 2,6-naphthylenedimethylidin; 1,4-biphenylene Dimethylidin; 1,4-p-terephenylenedimethylidin;
9,10-anthracenediyl dimethylidin; 4,
4 '-(2,2-di-t-butylphenylvinyl) biphenyl; 4,4'-(2,2-diphenylvinyl) biphenyl and the like, and derivatives thereof.

Further, coumarin derivatives disclosed in JP-A-2-191694 and JP-A-2-1968.
Patent No. 85,853, discloses a perylene derivative;
Naphthalene derivatives disclosed in JP-A-255789, JP-A-2-289676 and JP-A-2-8868.
The phthaloperinone derivative disclosed in JP-A No. 9 and the styrylamine derivative disclosed in JP-A-2-250292 can also be used as a material for the organic light emitting layer.

These organic light emitting layer materials are appropriately selected according to the desired light emission color and performance. The organic light emitting layer in the organic electroluminescent device of the present invention is described in US Pat.
As disclosed in the specification of Japanese Patent No. 69,292, a fluorescent material may be added. In this case, the base substance may be the triamine compound of the present invention or an organic light emitting layer material other than the triamine compound. Furthermore, a mixture of the triamine compound and the organic light emitting layer material may be used. When the organic light emitting layer is formed by adding a fluorescent substance, the amount of the fluorescent substance added is preferably several mol% or less. Since the fluorescent substance emits light in response to recombination of electrons and holes, it plays a part in the light emitting function.

The hole transport layer in the organic electroluminescent device of the present invention may be a layer containing the triamine compound if the hole injection layer or the organic light emitting layer contains the triamine compound of the present invention. The layer may not contain the triamine compound. As the hole transport layer material other than the triamine compound of the present invention, various substances conventionally used as the hole transport layer material of the organic electroluminescent device can be used.

Examples of such a hole transport material include a triazole derivative (see US Pat. No. 3,112,197) and an oxadiazole derivative (US Pat. No. 3,189,44).
No. 7, etc.), imidazole derivatives (JP-B-37)
), Polyarylalkane derivatives (U.S. Pat. Nos. 3,615,402, 3,820,989, 3,542,544, JP-B-45-555, JP-B-51-10983, Showa 51-932
No. 24, No. 55-17105, No. 56-41
Nos. 48, 55-108667 and 55-1
JP-A-56953, JP-A-56-36656 and the like, pyrazoline derivatives and pyrazolone derivatives (U.S. Pat. Nos. 3,180,729 and 4,278,746; JP-A-55-88064; JP-A-49-105537, JP-A-55-51086
JP-A-56-80051, JP-A-56-8814
No. 1, No. 57-45545, No. 54-112
637, 55-74546, etc.), phenylenediamine derivatives (U.S. Pat. No. 3,615,404, JP-B-51-10105, JP-B-46-3712).
JP-A-47-25336, JP-A-54-53
No. 435, No. 54-110536, No. 54-
No. 119925), arylamine derivatives (U.S. Pat. Nos. 3,567,450, 3,180,703, 3,240,597, 3,658,520,
4,232,103, 4,175,961 and 4,012,
No. 376, JP-B-49-35702, 39
-27577, JP-A-55-144250, JP-A-56-119132, and 56-22437.
No. 1,110,518, etc.), amino-substituted chalcone derivatives (see US Pat. No. 3,526,501), oxazole derivatives (US Pat. No. 3,257,203)
, Styrenane anthracene derivatives (see JP-A-56-46234, etc.), fluorenone derivatives (see JP-A-54-110837, etc.), and hydrazone derivatives (US Pat. No. 3,717,462). JP 5
JP-A-4-59143, JP-A-55-52063, JP-A-55-52064, JP-A-55-46760,
JP-A-55-85495, JP-A-57-1350, JP-A-57-148749, etc.), stilbene derivatives (JP-A-61-210363, JP-A-61-22)
No. 8451, No. 61-14642, No. 61-
Nos. 72255, 62-47646, 62
-36674, 62-10652, 6
Nos. 2-30255, 60-93445, 60-94462, 60-174949, 60-175052, etc.).

Further, silazane derivatives (US Pat. No. 4,955)
No. 0,950), polysilanes (JP-A-2-2049).
No. 96), an aniline-based copolymer (JP-A-2-282)
No. 263), a conductive polymer oligomer (Japanese Unexamined Patent Publication No.
No. 211399), and especially thiophene-containing oligomers.

The organic electroluminescent device of the present invention may have, besides the above-mentioned layers, a layer for improving the adhesion between the layers. Specific examples of the material of such a layer, for example, a layer for improving the adhesion between the organic light-emitting layer and the cathode include quinolinol metal complex-based materials such as tris (8-quinolinol) aluminum and tris (8-quinolinol) indium. Compounds can be mentioned.

The above-described organic electroluminescent device of the present invention can be manufactured, for example, as follows according to the configuration. (A) Production of organic electroluminescent device having a constitution of anode / organic light emitting layer (including triamine compound of the present invention) / cathode
1- First, a thin film made of a desired electrode material, for example, an anode material, is formed on a suitable substrate in a thickness of 1 μm or less, preferably 10 to 20 μm.
An anode is formed by a method such as vapor deposition or sputtering so as to have a thickness in a range of 0 nm. Next, an organic light emitting layer is provided by forming a thin film containing the triamine compound of the present invention on the anode. The thin film containing the triamine compound can be formed by a method such as a vacuum evaporation method, a spin coating method, and a casting method.
A vacuum deposition method is preferable because a uniform film is easily obtained and a pinhole is hardly generated.

When a vacuum deposition method is applied to form a thin film containing the triamine compound, the deposition conditions depend on the type of the triamine compound and other compounds used, the crystal structure and association structure of the intended organic light emitting layer, and the like. Although different, generally the boat heating temperature is 50 to 400 ° C and the degree of vacuum is 10
^-6 to 10 ^-3 Pa, deposition rate 0.01 to 50 nm / sec,
It is preferable to appropriately select the substrate temperature in the range of −50 to + 300 ° C. and the film thickness of 5 nm to 5 μm.

After forming the organic light emitting layer in this manner, a thin film made of a cathode material is formed on the organic light emitting layer by 1 μm.
Hereinafter, the cathode is formed by a method such as vapor deposition or sputtering so as to have a thickness preferably in the range of 10 to 200 nm. Thereby, a desired organic electroluminescent device is obtained. In the production of the organic electroluminescent device, it is also possible to reverse the production order and produce the cathode / organic luminescent layer / anode on the substrate in this order.

(B) Manufacture of an organic electroluminescent device having a constitution of anode / organic light emitting layer (including the triamine compound of the present invention) / cathode-2-First, on a suitable substrate, Similarly, an anode is manufactured. Next, an organic light emitting layer is provided by applying a solution containing a hole transport layer material, an organic light emitting layer material, an electron injection layer material, a binder (such as polyvinyl carbazole), etc. on the anode.

Next, a thin film made of a cathode material is formed on the organic light-emitting layer in the same manner as in the above (a) to produce a cathode. Thereby, a desired organic electroluminescent device is obtained. The organic light emitting layer may have a multilayer structure by forming a thin film of a desired organic light emitting layer material on the layer formed as described above by a vacuum deposition method or the like. Alternatively, the organic light emitting layer material may be formed by co-evaporating the organic light emitting layer material together with the hole transport layer material and the electron injection layer material.

(C) Manufacture of an organic electroluminescent device having the constitution of anode / hole transport layer (including the triamine compound of the present invention) / organic light emitting layer / cathode First, the above-mentioned (a) An anode is manufactured in the same manner as in the case. Next, a hole transport layer is provided by forming a thin film of the triamine compound of the present invention on the anode. The formation of the hole transport layer can be performed in the same manner as the formation of the organic light emitting layer (including the triamine compound of the present invention) in the above (a).

Next, an organic light emitting layer is provided on the hole transport layer using a desired organic light emitting layer material. The organic light emitting layer can be formed by thinning the organic light emitting layer material by a method such as a vacuum deposition method, a spin coating method, a casting method, etc. However, a uniform film is easily obtained and pinholes are generated. A vacuum deposition method is preferable because it is difficult. Thereafter, a thin film made of a cathode material is formed on the organic light-emitting layer in the same manner as in the above (a) to produce a cathode. Thereby, a desired organic electroluminescent device is obtained. In the production of the organic electroluminescent device, it is possible to reverse the production order and produce the cathode, the organic luminescent layer, the hole transport layer, and the cathode on the substrate in this order.

(D) Manufacture of an organic electroluminescent device having the structure of anode / hole transport layer (including the triamine compound of the present invention) / organic light emitting layer / electron injection layer / cathode First, on an appropriate substrate, Anode and hole transport layer (including the triamine compound of the present invention) in the same manner as in (c).
And an organic light emitting layer.

After the formation of the organic light emitting layer, a thin film made of an electron transfer compound is formed on the organic light emitting layer by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably in the range of 5 to 100 nm. Then, an electron injection layer is formed. Thereafter, the thin film made of the cathode material is applied to the above (c).
The cathode is formed on the electron injection layer in the same manner as in the above case. Thereby, a desired organic electroluminescent device is obtained. In the production of this organic electroluminescent device,
The production order can be reversed, and a cathode / electron injection layer / organic light emitting layer / hole transport layer / anode can be formed on the base electrode in this order.

(E) Manufacture of an organic electroluminescent device having the structure of anode / hole injection layer (including the triamine compound of the present invention) / hole transport layer / organic light emitting layer / electron injection layer / cathode An anode is formed on a substrate in the same manner as in the above (a). Next, a hole injection layer is provided by forming a thin film of the triamine compound of the present invention on the anode. The thin film made of the triamine compound can be prepared by a method such as a vacuum deposition method, a spin coating method, a casting method, or the like.However, a uniform film is easily obtained and a pinhole is hardly formed. The method is preferred. When the vacuum deposition method is used, a thin film can be formed by the same method as in the case (a).

After forming the hole injection layer, a hole transport layer, an organic light emitting layer, an electron injection layer and a cathode are formed on this layer in the same manner as in the above (d). According to this method, the organic electroluminescent device of the present invention is obtained. In the production of this organic electroluminescent device, the production order may be reversed, and the cathode / electron injection layer / organic light emitting layer / hole transport layer / hole injection layer / anode may be produced on the substrate in this order. It is possible.

The organic electroluminescent device of the present invention, which can be manufactured as described above, emits light by applying a DC voltage of 5 to 40 V with the anode having a positive polarity and the cathode having a negative polarity. Even if a voltage is applied with the opposite polarity, no current flows,
No light emission occurs. When an AC voltage is applied, light emission occurs only when the anode has a positive polarity and the cathode has a negative polarity. When an AC voltage is applied, the waveform of the AC may be arbitrary.

[0062]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Example 1 A transparent support substrate was formed by forming an ITO electrode with a thickness of 100 nm on a glass substrate having a size of 25 mm x 75 mm x 1.1 mm. This was subjected to ultrasonic cleaning with isopropyl alcohol for 5 minutes, followed by cleaning with pure water for 5 minutes, and finally ultrasonic cleaning with isopropyl alcohol again for 5 minutes. This transparent support substrate was fixed to a substrate holder of a vacuum evaporation apparatus (manufactured by Japan Vacuum Engineering Co., Ltd.), and three molybdenum resistance heating boats were prepared, each of which was TA-1 (Tg = 108 ° C.).
Of NPD (N, N'-di- (1-naphthyl) -N, N'-diphenyl-4,4 'having the following structure
-Benzidine) and finally 200 mg of tris (8-hydroxyquinoline) aluminum (Alq)
The pressure inside the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa.

[0063]

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Then, the boat containing TA-1 was heated to deposit TA-1 on the substrate, thereby forming a hole injection layer having a thickness of 60 nm. Next, the boat containing the NPD was heated to evaporate the NPD, thereby forming a hole transport layer having a thickness of 20 nm. Further, Alq (organic light emitting layer) was deposited to a thickness of 60 nm from the last boat. Next, this was taken out of the vacuum chamber, and a stainless steel mask was placed on the light emitting layer, and fixed again to the substrate holder. Further, 0.5g of silver (Ag) wire is placed in a tungsten basket.
Then, 1 g of a magnesium (Mg) ribbon was put into another molybritene boat. 1 × 10 ^-4 P in vacuum chamber
The pressure was reduced to a, and Mg was vapor-deposited at a rate of 1.8 nm / s and Ag was vapor-deposited at a rate of 0.1 nm / s at the same time to produce a negative electrode.

The obtained device was treated with ITO as an anode, Mg: A
When g was used as a cathode and a voltage of 6 V was applied, green uniform light emission was obtained. Initial performance is 6 mA and current density is 4.2 mA / c
m ² , luminance 148 cd / m ² , efficiency 1.8 lumen / W
Met. When the constant current is continuously driven in dry nitrogen at an initial 300 cd / m ² , the half life (time when the luminance is reduced to half) is 4
It was 300 hours. Even when this device was stored in a thermostat at 100 ° C. for 20 hours, the initial efficiency did not change at all.

Example 2 In Example 1, TA-2 (Tg = 1) was used instead of TA-1.
12 ° C.), and an organic electroluminescent device was prepared and evaluated in the same manner. The obtained device was treated with ITO as an anode, M
g: When a voltage of 6 V was applied using Ag as a cathode, uniform light emission was performed in green. Initial performance is 6 mA at a current density of 3.7 mA /
cm ² , luminance 124 cd / m ² , efficiency 1.8 lumen /
W. When the device was continuously driven in dry nitrogen at a constant current of 300 cd / m ² , the half-life was 3900 hours. Even when this device was stored in a thermostat at 100 ° C. for 20 hours, the initial efficiency did not change at all.

Example 3 In Example 1, TA-3 (Tg = 1) was used instead of TA-1.
10 ° C.), and an organic electroluminescent device was prepared and evaluated in the same manner. The obtained device was treated with ITO as an anode, M
g: When a voltage of 6 V was applied using Ag as a cathode, uniform light emission was performed in green. Initial performance is 3.9 mA / current density at 6V.
cm ² , luminance 127 cd / m ² , efficiency 1.7 lumen /
W. When the device was continuously driven in dry nitrogen at a constant current of 300 cd / m ² , the half-life was 3700 hours. Even when this device was stored in a thermostat at 100 ° C. for 20 hours, the initial efficiency did not change at all.

Example 4 In Example 1, TA-43 (Tg =
138 ° C.), and an organic electroluminescent device was produced and evaluated in the same manner. The obtained device was treated with ITO as an anode, M
g: When a voltage of 6 V was applied using Ag as a cathode, uniform light emission was performed in green. Initial performance is 6 mA at a current density of 4.0 mA /
cm ² , luminance 139 cd / m ² , efficiency 1.8 lumen /
W. When the device was continuously driven in dry nitrogen at a constant current of 300 cd / m ² , the half-life was 4100 hours. Even when this device was stored in a thermostat at 100 ° C. for 20 hours, the initial efficiency did not change at all.

Comparative Example 1 In Example 1, an MT having the following structure was used instead of TA-1.
An organic electroluminescent device was fabricated in the same manner except that DATA (4,4 ′, 4 ″ -tris {N- (3-methylphenyl) -N-phenylamino} triphenylamine, Tg = 78 ° C.) was used. And evaluated. When a voltage of 6 V was applied to the obtained device using ITO as an anode and Mg: Ag as a cathode, the device emitted uniform green light. Initial performance is 6 V, current density is 3.8 mA / cm ² , luminance is 154 cd / m ² , and efficiency is 2.
It was 1 lumen / W. When the device was continuously driven in dry nitrogen at a constant current of 300 cd / m ² , the half life was 4,200 hours. However, this device was placed in a thermostat at 100 ° C. for 2 hours.
After storing for 0 hours, the current density was 1.2 mA / cm ² and the luminance was 22 cd /
m ² , efficiency is 1.0 lumen / W, and performance is greatly reduced,
It was confirmed that the heat resistance was poor.

[0070]

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Comparative Example 2 In Example 1, the following TCP was used in place of TA-1.
An organic electroluminescent device was prepared and evaluated in the same manner except that B (1,3,5-tris {4- (N-carbazolyl) phenyl} benzene, Tg = 147 ° C.) was used. When a voltage of 6 V was applied to the obtained device using ITO as an anode and Mg: Ag as a cathode, the device emitted uniform green light. Initial performance is 6
Current density at 2.9 mA / cm ² , luminance 107 cd / m
^{2. The} efficiency was 1.9 lumens / W, which was inferior in luminance. In addition, it was confirmed that the half life was 1300 hours when the constant current driving was continuously performed in dry nitrogen at 300 cd / m ^2, which is a short life.

[0072]

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Comparative Example 3 In Example 1, the following PC-
3 (N-phenylcarbazole trimer, Tg = 142
° C) to produce and evaluate an organic electroluminescent device in the same manner. The obtained device was coated with ITO as an anode and Mg: A.
When g was used as a cathode and a voltage of 6 V was applied, green uniform light emission was obtained. Initial performance is 6 mA and current density is 3.0 mA / c
m ² , luminance 110 cd / m ² , efficiency 1.9 lumen / W
And the luminance was inferior. In addition, initial 300 cd / m
^{When the} constant current is continuously driven in dry nitrogen in ² , the half life is 70
It was confirmed that the life was 0 hours and the life was short.

[0074]

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Next, production examples of the triamine compounds used in Examples 1 to 4 will be described. Reference Example 1 Synthesis of TA-1 0.5 g of 4,4'-dibromo-triphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in a 300 ml three-necked flask.
g, carbazole 0.5 g, potassium carbonate 1 g, copper powder 1 g, and nitrobenzene 200 ml, and the mixture was stirred at 200 ° C. for 48 hours under a nitrogen stream.

Thereafter, the inorganic substances were filtered off, and the mother liquor was distilled off under reduced pressure. The residue was separated and purified using a column supporting silica gel. The obtained purified product was recrystallized using acetonitrile to obtain 0.24 g of a white powder. When this white powder was analyzed by FD-MS (field diffusion mass spectrum), TA-1 was obtained.
With respect to the molecular weight of (C ₄₂ H ₂₉ N ₃ = 575), m / z = 5
Since only the peak of 75 was observed, it was identified as TA-1. The absorption in the infrared absorption spectrum (unit: cm ^-1 ) of this product was 3420, 3040, 1590, 1
505, 1500, 1270, 830, 740, 690
cm ^-1 appeared.

Reference Example 2 Synthesis of TA-2 The reaction, purification and recrystallization were carried out in the same manner as in Reference Example 1, except that 0.7 g of phenoxazine (manufactured by Tokyo Kasei) was used instead of carbazole. This gave 0.21 g of a pale yellow powder.

The pale yellow powder was analyzed by FD-MS.
And the molecular weight of TA-2 (C₄₂H₂₉O _TwoN_Three= 603)
On the other hand, only a peak at m / z = 607 was observed.
Therefore, it was identified as TA-2. Also, the infrared absorption of this thing
Spectrum (cm^-1) Are 3410, 304
0,1600,1500,1280,830,730c
m^-1Appeared.

Reference Example 3 Synthesis of TA-3 Instead of carbazole, 0.8 g of phenoxazine (E.
The same method as in Reference Example 1 was used, except that
The reaction, purification and recrystallization were carried out to obtain 0.18 g of pale yellow
A powder was obtained. This pale yellow powder was analyzed by FD-MS.
The molecular weight of TA-3 (C₄₂H₂₉N _ThreeS_Two= 639)
In contrast, only a peak at m / z = 639 was observed.
Therefore, it was identified as TA-3. Also, the infrared absorption of this thing
Spectrum (cm^-1) Is 3400, 304
0,1600,1490,1280,820,730c
m^-1Appeared.

REFERENCE EXAMPLE 4 Synthesis of TA-43 In a 300 ml three-necked flask, 20 g of 9-phenylcarbazole (manufactured by Aldrich), 19 g of potassium iodide and 250 ml of acetic acid were placed, and placed in a nitrogen stream. It melted by heating at ° C. afterwards,
After cooling to 60 ° C., 25 g of potassium iodate was added,
The mixture was heated and stirred at 120 ° C. for about 1 hour until the purple color disappeared.

After cooling to room temperature, 100 ml of water was added and the mixture was filtered and washed with water until the mother liquor became neutral. Thereafter, recrystallization was performed from acetone to obtain 37 g of 3,6-diiodo-9-phenylcarbazole. 300
3,6-diiodo-9 in a milliliter three-necked flask
-2 g of phenylcarbazole, 2 g of carbazole,
1 g of copper powder and 200 ml of nitrobenzene were added and heated and stirred at 200 ° C. for 48 hours under a nitrogen stream.

Thereafter, the inorganic substance was filtered off, and the mother liquor was removed under reduced pressure.
Distilled off. And using a column carrying silica gel
The residue was separated and purified. The purified product obtained is acetonitrile
Recrystallize using toril to obtain 0.8 g of pale yellow powder
Was. When this pale yellow powder was analyzed by FD-MS, T
Molecular weight of A-43 (C₄₂H ₂₇N_Three= 573), m
/ Z = 573 only, the TA
-1. In addition, the infrared absorption spectrum of this product
Le (unit: cm^-1) Is 3400, 3020, 15
90, 1500, 1290, 820, 720 cm^-1Present
Was.

[0083]

The organic electroluminescent device of the present invention is a device in which a specific triamine compound such as a carbazole compound is contained in an organic compound layer, in particular, a hole injecting layer or a hole transporting layer. And has a feature that it has an extremely long life and excellent heat resistance, and is suitably used as a light emitting element in various display devices.

When the amine compound of the present invention is used for an organic electroluminescent device or an electrophotographic photoreceptor, it can provide a device or a photoreceptor having an extremely long life and excellent heat resistance.

Claims (4)

[Claims] 1. An organic electroluminescent device comprising an organic compound layer having at least an organic light-emitting layer sandwiched between a pair of electrodes, wherein the organic compound layer contains a compound represented by the general formula (I): [In the formula, Ar ¹ represents an aryl group having 6 to 18 nuclear carbon atoms having or not having a substituent, and Ar ^{2 to} Ar ⁵ represents an arylene group having 6 to 18 nuclear carbon atoms each having or having no substituent. , X ¹ are a single bond, -O-, -S
_{-, - (CH 2) n} - (n is an integer from 1 to 6) or -C (C
A linking group that is H ₃ ) ₂ —; these linking groups may or may not be present, and X ² and X ³ are each a single bond, —O—, —S—, — (CH ₂ ) _n - (n is an integer from 1 to 6) or -C (CH _{3) 2} - indicates a is linking group, which may be the same or different. ] The organic electroluminescent element characterized by containing the triamine compound represented by these. 2. The organic electroluminescent device according to claim 1, wherein the triamine compound represented by the general formula (I) is contained in an organic compound layer interposed between the anode and the organic light emitting layer. 3. The organic electroluminescent device according to claim 1, wherein the triamine compound represented by the general formula (I) is contained in an organic compound layer as a hole injection material or a hole transport material. 4. A compound of the general formula (I) [In the formula, Ar ¹ represents an aryl group having 6 to 18 nuclear carbon atoms with or without a substituent, and Ar ^{2 to} Ar ⁵ represents an arylene group having 6 to 18 nuclear carbon atoms with or without a substituent. , X ¹ are a single bond, -O-, -S
_{-, - (CH 2) n} - (n is an integer from 1 to 6) or -C (C
A linking group which is H ₃ ) _2- ; these linking groups may or may not be present, and X ² and X ³ are each a single bond, -O-, -S-,-(CH ₂ ) _n - (n is an integer from 1 to 6) or -C (CH _{3) 2} - indicates a is linking group, which may be the same or different. ] The triamine compound represented by these.