JPH10255979A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an element having a high luminous intensity and exhibiting stable performance even by repeated use by using a specified compound as positive hole injection layer. SOLUTION: In an electroluminescent element having at least a positive electrode, a positive hole injection layer, a positive hole transport layer and a negative electrode, the positive hole injection layer contains any one of compounds represented by the formulae I, II and/or III. In the formula I, Ar11 and Ar13 are divalent group of aromatic hydrocarbon; and Ar12 is aryl or heterocyclic group; Ar14 -Ar17 are H, alkyl, aralkyl, aryl, or heterocyclic group. In the formula II, Ar21 -Ar23 are divalent group of aromatic hydrocarbon or heterocycle; and AC24 -AC29 are H, alkyl, aralkyl, aryl or heterocyclic group. In the formula III, Ar31 -Ar34 are aryl or heterocyclic group, and at least one of Ar31 -Ar34 has disubstituted amino group; and (n) is 0 or 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an organic electroluminescence device.

[0002]

2. Description of the Related Art An organic electroluminescence element is an element which emits light in response to an electric signal and is constituted by using an organic compound as a light emitting substance. The organic electroluminescence element basically includes an organic light emitting layer and a pair of counter electrodes sandwiching the organic light emitting layer. In the light emission, electrons are injected from one of the electrodes and holes are injected from the other electrode, so that the luminescent material in the luminescent layer is excited to a higher energy level, and the excited luminescent material is returned to its original base. When returning to the state, the extra energy is emitted as light.

In order to increase the luminous efficiency, in addition to the above-described basic structure, a structure in which a hole injection layer is further provided for an electrode for injecting holes, and an electron transport layer is provided for an electrode for injecting electrons. Has been taken.

[0004] As an example of an organic electroluminescence device, a device using single crystal anthracene or the like as a light emitting body is described in US Pat. No. 3,530,325. In addition, Japanese Patent Application Laid-Open No. 59-194393 proposes a combination of a hole injection layer and an organic luminescent layer. JP-A-63-295695 proposes a combination of an organic hole injection / transport layer and an organic electron injection / transport layer. These laminated electroluminescent elements have a structure in which an organic phosphor, a charge transporting organic substance (charge transporting material) and electrodes are laminated, and holes and electrons injected from the respective electrodes are contained in the charge transporting material. Move
They emit light when they recombine. As the organic phosphor, an organic dye which emits fluorescence such as an 8-quinolinol aluminum complex or a coumarin compound is used. Examples of the charge transport material include N, N′-di (m-tolyl) N, N′-diphenylbenzidine,
Diamino compounds such as 1,1-bis [N, N-di (p-tolyl) aminophenyl] cyclohexane,
(N, N-diphenyl) aminobenzaldehyde-N,
And N-diphenylhydrazone compounds. Further, porphyrin compounds such as copper phthalocyanine have been proposed. However, although the organic electroluminescence device has high emission characteristics, it is not sufficient in terms of stability during light emission and storage stability, and has not been put to practical use. It has been pointed out that the stability of the charge transporting material is one of the problems in the light emission stability and storage stability of the device. A layer formed of an organic material of an electroluminescent device is very thin, one hundred to several hundred nanometers, and a voltage applied per unit thickness is very high. In addition, there is heat by light emission and electricity,
Therefore, the charge transporting material is required to have electrical, thermal or chemical stability.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an organic electroluminescent device having a high emission intensity and exhibiting stable performance even when used repeatedly. An object of the present invention is to provide a luminescence element.

[0006]

The present invention relates to an organic electroluminescence device provided with at least an anode, a hole injection layer, a hole transport layer, a light emitting layer and a cathode, wherein the hole injection layer has the following general formula [I ], An organic electroluminescent device comprising any one of the compounds represented by [II] and [III];

[0007]

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In the above formula, Ar ₁₁ and Ar ₁₃ each independently represent a divalent group of an aromatic hydrocarbon which may have a substituent, for example, phenylene. The substituent may be an alkyl group such as a methyl group, an ethyl group or propyl.

Ar ₁₂ represents an optionally substituted aryl group such as phenyl or naphthyl, or a heterocyclic group such as pyridyl. The substituent may be an alkyl group such as a methyl group, an ethyl group or propyl, or an alkoxy group such as a methoxy group or an ethoxy group.

Ar _{14 to} Ar ₁₇ each independently represent a hydrogen atom, an alkyl group which may have a substituent,
For example, a methyl group, an ethyl group, a propyl or butyl group, an aralkyl group, for example, a benzyl group, an aryl group,
For example, it represents a phenyl group, a diphenyl group or a naphthyl group, or a heterocyclic group such as thienyl or furyl. The substituent may be an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, or an alkoxy group such as a methoxy group or an ethoxy group. Ar ₁₄ and Ar ₁₅ and Ar ₁₆ and Ar ₁₇ do not simultaneously become hydrogen atoms, and Ar ₁₄ and Ar ₁₅ , Ar ₁₆
And Ar ₁₇ together form a ring with carbon atoms, for example:

Embedded image May be formed.

[0011]

Embedded image In the above formula, Ar _{21 to} Ar ₂₃ each independently represent a divalent group of an aromatic hydrocarbon which may have a substituent, for example, a phenylene group or a divalent group of a heterocyclic ring such as thiophene. . These groups may have a substituent, and the substituent may be an alkyl group such as a methyl group, an ethyl group or propyl.

Ar _{24 to} Ar ₂₉ each independently represent a hydrogen atom, an alkyl group which may have a substituent,
For example, a methyl group, an ethyl group, a propyl group or a butyl group, an aralkyl group such as a benzyl group, an aryl group such as a phenyl group, a diphenyl group or a naphthyl group, or a heterocyclic group such as a thienyl group or a furyl group. . As a substituent, a methyl group, an ethyl group,
It may be an alkyl group such as a propyl group or a butyl group.

Ar ₂₄ and Ar ₂₅ together form a ring together with a carbon atom, for example,

Embedded image May be formed.

However, Ar ₂₄ and Ar ₂₅ and Ar ₂₆
And Ar ₂₇ , and Ar ₂₈ and Ar ₂₉ are not simultaneously hydrogen atoms.

[0015]

Embedded image In the above formula, Ar _{31 to} Ar ₃₄ each independently represent an optionally substituted aryl group such as a phenyl group, a diphenyl group or a naphthyl group, or a heterocyclic group such as a thienyl group or a furyl group. . The substituent methyl group may be ethyl, propyl, or similar alkyl groups or butyl group, a methoxy group or an alkoxy group such as ethoxy group or a di-substituted amino group,, Ar ₃₁ ~
At least one of Ar ₃₄ has a disubstituted amino group.
The disubstituted amino group may be a dimethylamino group, a diethylamino group, a dibutylamino group, a diphenylamino group, a dibenzylamino group or a ditolylamino group.

Further, Ar ₃₃ and Ar ₃₄ are integrally formed as a ring, for example,

Embedded image May be formed.

N represents a number of 0 or 1.

The organic electroluminescent device of the present invention comprises at least a hole injecting layer, a hole transporting layer and a photosensitive layer between the electrodes, and the above general formula [I] is added to the hole injecting layer of the organic electroluminescent device. ], [II] or [I
II] as a basic feature.

The compounds represented by the general formulas [I], [II] and [III] can be produced by a known method,
For example, it can be easily produced by a Wittig reaction by condensation of a corresponding aldehyde compound and a phosphorus ylide compound.

Specific examples of the compounds represented by the above general formulas [I], [II] and [III] include the following, but their illustrations do not limit the scope of the present invention. This is not an example.

[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[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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FIGS. 1 to 4 schematically show possible configurations of the electroluminescent device of the present invention. In FIG.
(1) is an anode, on which a hole injection layer (2), a hole transport layer (3), an organic light emitting layer (4) and a cathode (5) are sequentially laminated, The hole injection layer contains the compound represented by the general formulas [I], [II] and / or [III].

In the configuration shown in FIG. 2, (1) is an anode, on which a hole injection layer (2), a hole transport layer (3),
Organic light emitting layer (4) and electron transport layer (6), cathode (5)
Are sequentially laminated, and the hole injection layer contains the compound represented by the general formulas [I], [II] and / or [III].

In FIG. 3, (1) is an anode, on which a hole injection layer (2) and a hole transport layer (3), an organic light emitting layer (4), an electron transport layer (6), The electron injection layer (7) and the cathode (5) are sequentially laminated, and the hole injection layer has the above general formula [I], [II] and / or [I
II].

In FIG. 4, (1) is an anode, on which a hole injection layer (2), a hole transport layer (3), an organic light emitting layer (4), a cathode (5), a sealing The film (8) is configured to be sequentially laminated, and the hole injection layer contains the compound represented by the general formula [I], [II] and / or [III].

In each of the electroluminescent elements having the above structure, the anode (1) and the cathode (5) are connected by a lead wire.
The organic light emitting layer (4) emits light by applying a voltage to the anode (1) and the cathode (5).

As the conductive material used as the anode (1) of the organic electroluminescence device, those having a work function larger than 4 eV are preferable, and carbon, aluminum, vanadium, iron, cobalt, nickel, copper, zinc,
Tungsten, silver, tin, gold, and alloys thereof, and conductive metal compounds such as tin oxide, indium oxide, antimony oxide, zinc oxide, and zirconium oxide are used.

The metal forming the cathode (5) is 4 eV
It is better to have a work function smaller than that of magnesium, calcium, titanium, yttrium lithium,
Gadolinium, ytterbium, ruthenium, manganese and their alloys are used.

In the organic electroluminescence element, at least the anode (1) or the cathode (5) needs to be a transparent electrode so that light emission can be seen. On this occasion,
When a transparent electrode is used for the cathode, it is liable to be oxidized and deteriorated in transparency, so that the anode is preferably a transparent electrode.

When forming a transparent electrode, on a transparent substrate,
Using a conductive material as described above, a device such as vapor deposition, sputtering, or a method such as a sol-gel method or a method of dispersing and applying in a resin or the like is used to secure desired translucency and conductivity. I just need.

The transparent substrate is not particularly limited as long as it has an appropriate strength, is not adversely affected by heat due to vapor deposition or the like when producing an organic electroluminescent element, and is transparent. It is also possible to use a glass substrate, a transparent resin such as polyethylene, polypropylene, polyethersulfone, polyetheretherketone, and the like. As a transparent electrode formed on a glass substrate, commercially available products such as ITO and NESA are known, but these may be used.

The production of an electroluminescent device having the structure shown in FIG. 1 using the above-described electrodes will be described as an example. First, a hole injection layer (2) is formed on the above-mentioned anode (1). The hole injection layer (2) may be formed by vapor deposition of the compound of the above general formulas [I], [II] and / or [III], or may be formed together with a solution in which the compound is dissolved or a suitable resin. The solution may be formed by dip coating or spin coating.

When the hole injection layer is formed by a vapor deposition method, the thickness is usually 1 to 30 nm. When the hole injection layer is formed by a coating method, the thickness may be about 1 to 50 nm. As the film thickness is larger, the applied voltage for emitting light needs to be higher, and the luminous efficiency is poor, and the organic electroluminescent element is likely to be deteriorated. When the film thickness is small, the luminous efficiency is improved, but the breakdown is easy and the life of the organic electroluminescent element is shortened.

The hole transport layer (3) is formed on the hole injection layer (2). As the hole transporting material used for the hole transporting layer, known materials can be used. For example, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,
1'-diphenyl-4,4'-diamine, N, N'-diphenyl-N, N'-bis (4-methylphenyl)-
1,1'-bis (3-methylphenyl) -4,4'-diamine, N, N'-diphenyl-N, N'-bis (4-
Methylphenyl) -1,1'-diphenyl-4,4'-
Diamine, N, N'-diphenyl-N, N'-bis (1
-Naphthyl) -1,1'-diphenyl-4,4'-diamine, N, N'-diphenyl-N, N'-bis (2-naphthyl) -1,1'-diphenyl-4,4'-diamine , N, N'-tetra (4-methylphenyl) -1,
1'-diphenyl-4,4'-diamine, N, N'-tetra (4-methylphenyl) -1,1'-bis (3-methylphenyl) -4,4'-diamine, N, N'- Diphenyl-N, N'-bis (3-methylphenyl) -1,
1'-bis (3-methylphenyl) -4,4'-diamine, N, N'-bis (N-carbazolyl) -1,1'-
Diphenyl-4,4′-diamine, 4,4 ′, 4 ″ -tris (N-carbazolyl) triphenylamine, N,
N ′, N ″ -triphenyl-N, N ′, N ″ -tris (3-methylphenyl) -1,3,5-tri (4-aminophenyl) benzene, 4,4 ′, 4 ″ -tris [ N,
N ′, N ″ -triphenyl-N, N ′, N ″ -tris (3-methylphenyl)] triphenylamine. These may be used as a mixture of two or more.

When the hole transporting layer is formed by a vapor deposition method, its thickness is usually 30 to 100 nm, and when it is formed by a coating method, the thickness may be about 50 to 200 nm. As the film thickness is larger, the applied voltage for emitting light needs to be higher, and the luminous efficiency is poor, and the organic electroluminescent element is likely to be deteriorated. When the film thickness is small, the luminous efficiency is improved, but the breakdown is easy and the life of the organic electroluminescent element is shortened.

An organic light emitting layer is formed on the hole transport layer (3). As the organic luminescent material used in the organic luminescent layer, known luminescent materials can be used, for example, epidolidine, 2,5-
Bis [5,7-di-t-pentyl-2-benzoxazolyl] thiophene, 2,2 ′-(1,4-phenylenedivinylene) bisbenzothiazole, 2,2 ′-(4
4′-biphenylene) bisbenzothiazole, 5-methyl-2- {2- [4- (5-methyl-2-benzooxazolyl) phenyl] vinyl} benzoxazole, 2,
5-bis (5-methyl-2-benzoxazolyl) thiophene, anthracene, naphthalene, phenanthrene,
Pyrene, chrysene, perylene, perinone, 1,4-diphenylbutadiene, tetraphenylbutadiene, coumarin, acridine, stilbene, 2- (4-biphenyl)
-6-phenylbenzoxazole, aluminum trisoxine, magnesium bisoxin, bis (benzo-8-quinolinol) zinc, bis (2-methyl-8-quinolinolalto) aluminum oxide, indium trisoxin, aluminum tris (5-methyloxin) , Lithium oxine, gallium tris oxine,
Calcium bis (5-chlorooxin), polyzinc-bis (8-hydroxy-5-quinolinolyl) methane, dilithium epindridione, zinc bisoxin, 1,2-
Examples thereof include phthaloperinone and 1,2-naphthaloperinone.

In addition, common fluorescent dyes such as fluorescent coumarin dyes, fluorescent perylene dyes, fluorescent pyran dyes, fluorescent thiopyran dyes, fluorescent polymethine dyes, fluorescent methyanine dyes, fluorescent imidazole dyes and the like are also used. it can. this house,
Particularly preferred are chelated oxinoid compounds.

The organic light-emitting layer may have a single-layer structure of the above-described light-emitting substance, or may have a multi-layer structure in order to adjust characteristics such as light emission color and light emission intensity. Further, two or more kinds of light-emitting substances may be mixed or the light-emitting layer may be doped.

When formed by the vapor deposition method, the thickness is usually 1 to 200 nm, and when formed by the coating method, the thickness is 5 to 200 nm.
The thickness may be about 500 nm. As the film thickness is larger, the applied voltage for emitting light needs to be higher, and the luminous efficiency is poor, and the organic electroluminescent element is likely to be deteriorated. When the film thickness is small, the luminous efficiency is improved, but the breakdown is easy and the life of the organic electroluminescent element is shortened. Next, on the organic light emitting layer,
The above-mentioned cathode is formed.

A pair of transparent electrodes, a cathode and an anode, are connected to a suitable lead wire (9) such as a nichrome wire, a gold wire, a copper wire, a platinum wire, etc., and the organic luminescence device is suitable for both electrodes. Light is emitted by applying an appropriate voltage (Vs).

Further, as shown in FIG. 3, an electron transport layer (6) is further provided between the organic light emitting layer (4) and the cathode (5).
When forming the electron injecting layer, a known material can be used as the electron transporting material used for the electron transporting layer. For example, 2- (4-biphenylyl) -5-
(4-tert-butylphenyl) -1,3,4-oxadiazole, 2- (1-naphthyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole,
4-bis {2- [5- (4-tert-butylphenyl)-
1,3,4-oxadiazolyl]} benzene, 1,3-
Bis {2- [5- (4-tert-butylphenyl) -1,
3,4-oxadiazolyl] {benzene, 4,4′-bis} 2- [5- (4-tert-butylphenyl) -1,
3,4-oxadiazolyl]} biphenyl, 2- (4-
Biphenylyl) -5- (4-tert-butylphenyl)
-1,3,4-thiodiazole, 2- (1-naphthyl)
-5- (4-tert-butylphenyl) -1,3,4-thiodiazole, 1,4-bis {2- [5- (4-tert-
[Butylphenyl) -1,3,4-thiodiazolyl] {benzene, 1,3-bis {2- [5- (4-tert-butylphenyl) -1,3,4-thiodiazolyl]} benzene, 4,4 ′ -Bis {2- [5- (4-tert-butylphenyl) -1,3,4-thiodiazolyl]} biphenyl, 3- (4-biphenylyl) -4-phenyl-5-
(4-tert-butylphenyl) -1,2,4-triazole, 3- (1-naphthyl) -4-phenyl-5- (4
-Tert-butylphenyl) -1,2,4-triazole, 1,4-bis {3- [4-phenyl-5- (4-te
rt-butylphenyl) -1,2,4-triazolyl]}
Benzene, 1,3-bis {3- [4-phenyl-5-
(4-tert-butylphenyl) -1,3,4-oxadiazolyl] {benzene, 4,4′-bis} 2- [4-phenyl-5- (4-tert-butylphenyl) -1,3,3
4-oxadiazolyl] {biphenyl, 1,3,5-tris} 2- [5- (4-tert-butylphenyl) -1,
3,4-oxadiazolyl] @benzene. These may be used as a mixture of two or more.

The electron transporting layer may be formed by vapor deposition of an electron transporting material, or may be dip-coated or spin-coated with a solution in which the electron-transporting material is dissolved or a solution in which a suitable resin is dissolved.

When formed by a vapor deposition method, the thickness is usually 1
To 500 nm, and 5 to 1 when formed by a coating method.
The thickness may be about 000 nm.

If the film thickness is large, the applied voltage must be increased, which is disadvantageous for the life. If the film thickness is small, the film is liable to be deteriorated by an electric field and a dark spot is easily generated.

The electron injection layer is made of, for example, an electron transporting material and a metal material of a cathode, and is co-evaporated to have a thickness of 1 to 20 n.
m. If the thickness is too large, the transport of electrons is insufficient or the electron transport deteriorates. If the thickness is too small, the function as a film cannot be achieved. Further, when the sealing film (8) is formed as shown in the configuration of FIG. 8, SiO ₂ , SiO, GeO, MgF ₂ or the like is used for the purpose of preventing the organic layer and the electrode from oxidation and moisture.
By forming a vapor deposition film, it is formed to a thickness of about 5 to 1000 nm. If the thickness is too large, it takes time to form or the electrode peels off. If it is too thin, a problem arises that the function as a sealing film is not achieved.

The organic electroluminescent device of the present invention is applicable to various display devices, display devices, and the like. Hereinafter, the present invention will be described with reference to Examples.

Example 1 Compound (2) was deposited as a hole injection layer on a substrate of indium tin oxide-coated glass to form a thin film having a thickness of 10 nm. Next, on the hole injection layer, N,
N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-diphenyl-4,4′-diamine was deposited to form a thin film having a thickness of 50 nm. A thin film was formed thereon as an organic light emitting layer by vapor deposition of aluminum trisoxine to a thickness of 60 nm. Next, a thin film was formed as a cathode by evaporation of magnesium to have a thickness of 200 nm. Thus, an organic electroluminescence device was manufactured.

Examples 2 to 4 In Example 1, instead of using the compound (2),
An organic electroluminescent device was manufactured in exactly the same manner as in Example 1 except that the compounds (5), (7) and (9) were used instead.

Example 5 A compound (10) was deposited as a hole injection layer on a glass substrate coated with indium tin oxide to form a thin film having a thickness of 5 nm. Next, on the hole injection layer, as a hole transport layer,
N, N'-diphenyl-N, N'-bis (1-naphthyl) -1,1'-diphenyl-4,4'-diamine was deposited to form a thin film having a thickness of 55 nm. Next, aluminum trisoxine was vapor-deposited as an organic light emitting layer to a thickness of
A thin film was formed to have a thickness of.

Next, a thin film having a thickness of 40 nm was formed by vapor deposition of the following oxadiazole compound (A) as an electron transport layer.

Embedded image Next, magnesium was evaporated to 200 nm as a cathode.
A thin film was formed to have a thickness of. In this way,
An organic electroluminescence device was manufactured.

Examples 6 to 8 The procedure of Example 5 was repeated, except that Compound (10) was replaced by Compounds (11), (16) and (17). A luminescence device was manufactured.

Example 9 A compound (20) was deposited as a hole injecting layer on a glass substrate coated with indium tin oxide to form a thin film having a thickness of 15 nm. Next, on the hole injection layer, N, N'-diphenyl-N, N'-bis (4-methylphenyl) -1,1'-bis (3-methylphenyl)-was formed as a hole transport layer.
4,4′-Diamine was deposited to form a thin film having a thickness of 45 nm. An organic light-emitting layer was co-evaporated with aluminum trisoxin doped with 5% by weight of rubrene to form a thin film having a thickness of 30 nm. Next, a thin film having a thickness of 30 nm was formed by vapor deposition of the following oxadiazole compound (A) as an electron transport layer.

Embedded image Next, as a cathode, Mg and Ag having an atomic ratio of 10: 1 were evaporated to form a thin film having a thickness of 200 nm.
Thus, an organic electroluminescence device was manufactured.

Examples 10 to 12 The same procedure as in Example 10 was carried out except that the compound (20) was replaced by the compounds (25), (30) and (36). A luminescence device was manufactured.

Example 13 Compound (3) was coated on a glass substrate coated with indium tin oxide.
8) was vacuum-deposited to obtain a 20-nm-thick hole injection layer. Further, N, N'-diphenyl-N, N '-(3-
Methylphenyl) -1,1′-biphenyl-4,4′-
Diamine was vacuum deposited to obtain a hole transport layer having a thickness of 40 nm. Next, a tris (8-hydroxyquinoline) aluminum complex was evaporated to form a thin film having a thickness of 50 nm. Next, as a cathode, Mg and Ag having an atomic ratio of 10: 1 were evaporated to form a thin film having a thickness of 200 nm. Finally, a 300-nm sealing film was formed by vacuum evaporation of a resistance heating method using silicon oxide as an evaporation source. Thus, an organic electroluminescence device was manufactured.

Examples 14 to 16 The procedure of Example 13 was repeated, except that the compound (38) was replaced by the compounds (42), (50) and (53). A luminescence device was manufactured.

Comparative Example 1 N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'-diphenyl-4, N, N'-diphenyl-N, N'-bis (3-methylphenyl) 4′-diamine was deposited to form a thin film having a thickness of 60 nm. Aluminum trisoxine was deposited thereon as an organic light emitting layer to form a thin film having a thickness of 60 nm. Next, magnesium was deposited as a cathode to form a thin film having a thickness of 200 nm. Thus, an organic electroluminescence device was manufactured.

COMPARATIVE EXAMPLE 2 N, N′-diphenyl-N, N′-bis (1-
Naphthyl) -1,1′-diphenyl-4,4′-diamine was deposited to form a thin film having a thickness of 60 nm. Next, a thin film having a thickness of 20 nm was formed as an organic light emitting layer by vapor deposition of aluminum trisoxine. next,
The following oxadiazole compound (A) as an electron transport layer
Was formed to a thickness of 40 nm by vapor deposition. Next, magnesium was vapor-deposited for 200 as a cathode.
A thin film was formed to have a thickness of nm. Thus, an organic electroluminescence device was manufactured.

Evaluation The organic electroluminescent devices obtained in Examples 1 to 16 and Comparative Examples 1 and 2 were obtained by using the glass electrode as an anode and applying a voltage (V) to start light emission when a DC voltage was gradually applied. The emission luminance (cd / m ² ) when a DC voltage of 5 V was applied was measured. In addition, a decrease rate (%) (5) of the initial output when operated at a current density of 5 mA / cm ² for 5 hours.
Output after time (mW / cm ² ) is the initial output (mW / cm ² )
Divided by 100 and multiplied by 100). Table 1 summarizes the measurement results.

[0071]

[Table 1]

As can be seen from Table 1, the organic electroluminescent device of the present invention started to emit light at a low potential and exhibited good emission luminance. In addition, the organic EL element of the present invention was able to observe stable light emission having a small output and a long life.

The specific compound represented by the general formula [I], [II] or [III] has a low ionization potential,
Since the hole transporting ability is large, the light-emission starting voltage required for causing the organic electroluminescence device of the present invention to emit light may be low, and it is considered that light emission for a long time can be stably performed.

The organic electroluminescent device of the present invention achieves an improvement in luminous efficiency, luminous luminance and a long life, and also uses a luminescent substance, a luminescent auxiliary material, a charge transport material, The present invention is not limited to agents, resins, electrode materials, and the like, and the element manufacturing method.

[0075]

According to the present invention, it is possible to obtain an organic electroluminescence device having a high light emission intensity, a low light emission starting voltage and excellent durability by incorporating a specific compound into the hole injection layer of the organic electroluminescence device. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one configuration example of an electroluminescent element of the present invention.

FIG. 2 is a schematic cross-sectional view of one configuration example of the electroluminescent element of the present invention.

FIG. 3 is a schematic cross-sectional view of one configuration example of the electroluminescent element of the present invention.

FIG. 4 is a schematic cross-sectional view of one configuration example of the electroluminescent element of the present invention.

[Explanation of symbols]

 1: anode 2: hole injection layer 3: hole transport layer 4: organic light emitting layer 5: cathode 6: electron transport layer 7: electron injection layer 8: sealing film 9: lead wire

Claims (1)

[Claims] 1. An electroluminescence device provided with at least an anode, a hole injection layer, a hole transport layer, an organic light emitting layer, and a cathode, wherein the hole injection layer has the following general formula [I]:
An organic electroluminescent device comprising one of the compounds represented by [II] and / or [III]: (Wherein, Ar ₁₁ and Ar ₁₃ each independently represent a divalent group of an aromatic hydrocarbon which may have a substituent;
Ar ₁₂ represents an aryl group or a heterocyclic group which may have a substituent; Ar _{14 to} Ar ₁₇ each independently represent
A hydrogen atom, each of which may have a substituent, represents an alkyl group, an aralkyl group, an aryl group or a heterocyclic group, and Ar ₁₄ and Ar ₁₅ and Ar ₁₆ and Ar ₁₇ are not simultaneously hydrogen atoms, Ar ₁₄ and Ar ₁₅ , Ar ₁₆
And Ar ₁₇ may together form a ring; (Wherein, Ar _{21 to} Ar ₂₃ each independently represent a divalent aromatic hydrocarbon or heterocyclic group which may have a substituent; Ar _{24 to} Ar ₂₉ each independently represent a hydrogen atom; An atom, which may have a substituent, represents an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group, and Ar ₂₄ and Ar ₂₅ may form a ring together; Ar ₂₄ and Ar
₂₅ , Ar ₂₆ and Ar ₂₇ , and Ar ₂₈ and Ar ₂₉ are not hydrogen atoms at the same time); (Wherein, Ar _{31 to} Ar ₃₄ each independently represent an aryl group or a heterocyclic group which may have a substituent;
At least one of the r ₃₁ to Ar ₃₄ has a disubstituted amino group, also Ar ₃₃ and Ar ₃₄ may form a ring together; n represents 0 or the number 1).