JPH10265773A - Hole injection material for organic electroluminescence device and organic electroluminescence device using the same - Google Patents

Abstract

[PROBLEMS] To provide a hole injection material and an organic electroluminescence element for an organic electroluminescence element having high luminance, high luminous efficiency, long luminescence life and long storage life. SOLUTION: A hole injection material for an organic electroluminescence device represented by the general formula 1, for example, the formula 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescence (EL) device material and can be used as a device material for an organic EL device used for a flat light source or a display device.

[0002]

2. Description of the Related Art Organic photoconductive materials have many advantages such as various molecular modifications and no pollution, and many compounds have been proposed. For example, oxadiazole derivatives (U.S. Pat. No. 3,189,447), oxazole derivatives (U.S. Pat. No. 3,257,203), hydrazone derivatives (U.S. Pat. 5
9,143, U.S. Pat. No. 4,150,978), triarylpyrazoline derivatives (U.S. Pat.
No. 989, JP-A-51-93,224 and JP-A-55-93.
No. 108,667), arylamine derivatives (US Pat. No. 3,180,730, US Pat. No. 4,232,10).
3, JP-A-55-144250, JP-A-56-1
No. 19,132), stilbene derivatives (JP-A-58-1)
No. 90,953, JP-A-59-195,658) and the like.

[0003] One of the techniques using an organic photoconductive material is an organic EL element. 2. Description of the Related Art An EL element using an organic substance is expected to be used as an inexpensive, large-area, full-color display element of a solid light emitting type, and many developments have been made. In general, an EL is composed of a light emitting layer and a pair of counter electrodes sandwiching the light emitting layer. In light emission, when an electric field is applied between both electrodes, electrons are injected from the cathode side and holes are injected from the anode side. Further, the electrons are recombined with holes in the light emitting layer, and energy is emitted as light when the energy level returns from the conduction band to the valence band.

[0004] Conventional organic EL devices have a higher driving voltage and lower luminous luminance and luminous efficiency than inorganic EL devices.
In addition, the characteristic deterioration was remarkable, and it had not been put to practical use.
2. Description of the Related Art In recent years, an organic EL in which a thin film containing an organic compound having high fluorescence quantum efficiency that emits light at a low voltage of 10 V or less is laminated.
Devices have been reported and are of interest (see Applied Physics Letters, vol. 51, p. 913, 1987). This method uses a metal chelate complex for a phosphor layer and an amine compound for a hole injection layer to obtain high-luminance green light emission, and can be driven by a DC voltage of 6 to 7 V. It achieves a maximum luminance of 1000 (cd / m ² ) and a maximum luminous efficiency of 1.5 (lm / W), and has performance close to a practical range.

An organic EL device is a device having a light emitting layer containing an organic fluorescent compound between a metal cathode layer and a transparent anode layer. Also, in order to obtain high-luminance light emission at low voltage,
An element is formed by adding an electron injection layer and a hole injection layer. In these organic EL elements, excitons are generated by recombination of electrons injected from the cathode and holes injected from the anode, and light is emitted in the process of extinguishing the excitons (Japanese Patent Application Laid-Open No. H10-163,197). 5
9-194393, JP-A-63-295695). However, if light emission is continued for a long time by applying a DC voltage, crystallization of an organic compound or the like is promoted, a leak current easily flows through the element, and the element is destroyed. Therefore, as a hole injection material used for the hole injection layer, 4,4 ′, 4 ″ -tris (N, N′-diphenylamino) triphenylamine (TDATA), 4,4 ′,
It is improved by using a compound such as 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) (JP-A-4-30868).
No. 8). These compounds have a three-dimensional coordination structure and are therefore difficult to be crystallized and have excellent thin film forming properties, but are still insufficient as organic thin films constituting organic EL devices. Therefore, there is a problem that the element is easily deteriorated during light emission.

As described above, the organic EL devices up to now are:
Luminous luminance and luminous stability during repeated use are not yet sufficient. For the development of an organic EL device having higher luminous luminance, high luminous efficiency, and excellent stability during light emission and storage, an excellent positive It is desired to develop a durable material having a hole injection ability.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly durable organic EL device material having excellent hole injecting ability, good adhesion to metals and organic compounds when formed into a thin film. It is another object of the present invention to provide an organic EL device that can be stored for a long time and has a long light-emitting life by using the organic EL device material.

[0008]

Means for Solving the Problems As a result of diligent studies by the present inventors, an organic EL device manufactured using at least one material represented by the general formula [1], the general formula [6] or the general formula [7] is obtained. The inventors have found that the element characteristics, long-term light emission and storage life of the element are excellent, and have reached the present invention. That is, the present invention is a hole injection material for an organic EL device represented by the following general formula [1]. General formula [1]

[0009]

Embedded image

Wherein R ^{1 to} R ²⁰ are each independently:
Hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted thioalkoxy group, mono- or disubstituted amino group, substituted or unsubstituted monocyclic group, substituted or unsubstituted Represents a substituted fused polycyclic group, a group represented by the following general formula [2], provided that at least one of R ^{1 to} R ²⁰ is a substituent represented by the general formula [2]. Further, R ^{1 to} R ⁵ , R
^A substituted or unsubstituted cycloalkyl ring between adjacent substituents of ^{6 to} R ¹⁰ , R ^{11 to} R ¹⁵ or R ^{16 to} R ²⁰ ;
A substituted or unsubstituted aryl ring may be formed. General formula [2]

[0011]

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(Where R^{twenty one}~ R^{twenty five}Are, independently of each other,
Hydrogen atom, halogen atom, substituted or unsubstituted alkyl
A substituted or unsubstituted alkoxy group, substituted or unsubstituted
Is an unsubstituted thioalkoxy group, mono- or di-substituted amino
Group, substituted or unsubstituted monocyclic group, substituted or unsubstituted
Represents a condensed polycyclic group. R^{twenty one}~ R²⁶Is an adjacent substituent
With a substituted or unsubstituted cycloalkyl ring,
Alternatively, an unsubstituted aryl ring may be formed. X¹Is straight
Tangent bond, substituted or unsubstituted alkylene group,-[CR
²⁶(R²⁷)] X-O- [CR²⁸(R²⁹)] Y-,-[C
R³⁰(R³¹)] XS- [CR³²(R³³)] Y-, -O
-, -S-,> C = O,> SO_Two,> SiR ³⁴(R³⁵)
−,> NR³⁶-,> PR³⁷−,> P = O (R³⁸)
You. R²⁶~ R³⁹Is a substituted or unsubstituted alkyl group,
Substituted or unsubstituted monocyclic group, substituted or unsubstituted condensed
Represents a polycyclic ring group. x and y each represent an integer of 0 to 8
However, both x and y do not become 0. ) Z¹Is below
The general formula [3], the following general formula [4] or the following general formula
Represents a substituent represented by [5]. General formula [3]

[0013]

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(Ar ¹ represents a substituted or unsubstituted arylene group.) [4]

[0015]

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(Ar ² or Ar ³ represents a substituted or unsubstituted arylene group. R ⁴⁰ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted monocyclic group, a substituted or unsubstituted fused polycyclic group Represents a group.) General formula [5]

[0017]

Embedded image

(Ar ^{4 to} Ar ⁶ represent a substituted or unsubstituted arylene group. R ⁴¹ or R ⁴² represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted monocyclic group, a substituted or unsubstituted Represents a condensed polycyclic group.)]

Further, the present invention provides a compound represented by the general formula [1]
^The hole for an organic electroluminescent element, wherein at least one of ^{1 to} R ⁵ , R ^{6 to} R ¹⁰ , R ^{11 to} R ¹⁵ , and R ^{16 to} R ²⁰ is a substituent represented by the general formula [2]. For injection material. Further, the present invention provides the following general formula [6]
And a hole injecting material for an organic electroluminescence element described above. General formula [6]

[0020]

Embedded image

Wherein R ^{43 to} R ⁷⁸ are each independently
Hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted thioalkoxy group, mono- or disubstituted amino group, substituted or unsubstituted monocyclic group, substituted or unsubstituted Represents a substituted fused polycyclic group. R ⁴³ and R ⁴⁴ , R ^{45 to} R ⁴⁹ ,
R ⁵⁰ and R ^51, R ⁵² and ^{R 53, R 54 ~R 58,} R 59 and R ^60, R
⁶¹ and ^{R 62, R 63 ~R 67,} R 68 and R ^69, R ⁷⁰ and R ^71, R ⁷²
To R ⁷⁶ , and adjacent substituents of R ⁷⁷ and R ⁷⁸ may form a substituted or unsubstituted cycloalkyl ring or a substituted or unsubstituted aryl ring. Z ² has the same meaning as Z ¹ described above. ]

Further, the present invention relates to a hole injection material for an organic electroluminescence device according to any one of claims 1 to 3, represented by the following general formula [7]. General formula [7]

[0023]

Embedded image

[Wherein, R⁷⁹~ R¹¹⁴Is a hydrogen atom, halo
Gen atom, substituted or unsubstituted alkyl group,
Or unsubstituted alkoxy group, substituted or unsubstituted thio
Alkoxy, mono- or di-substituted amino, substituted or
Represents an unsubstituted monocyclic group or a substituted or unsubstituted fused polycyclic group.
Represent. Also, R⁷⁹And R⁸⁰, R⁸¹~ R⁸⁵, R⁸⁶And R⁸⁷, R
⁸⁸And R⁸⁹, R⁹⁰~ R⁹⁴, R⁹⁵And R⁹⁶, R⁹⁷And R⁹⁸, R⁹⁹
~ R¹⁰³, R¹⁰⁴And R ¹⁰⁵, R¹⁹⁶And R¹⁰⁷, R¹⁰⁸~
R¹¹², R¹¹³And R^{1 14}Between adjacent substituents of
Or unsubstituted cycloalkyl ring, substituted or unsubstituted
A substituted aryl ring may be formed. R¹¹⁵~ R¹²²Is
Hydrogen atom, substituted or unsubstituted alkyl group,
Or unsubstituted monocyclic group, substituted or unsubstituted fused polycyclic group
Represents a cycloalkyl ring between adjacent substituents
You may. Y¹~ Y^FourIs a carbon or silicon atom
Represents Z^ThreeIs Z¹Has the same meaning as ]

Further, the present invention provides an organic electroluminescence device having a light-emitting layer comprising one or more organic compound thin films between a pair of electrodes, wherein at least one layer contains the above hole injection material for an organic electroluminescence device. The present invention relates to an organic electroluminescence device characterized by being a layer to be formed.

Further, the present invention relates to an organic electroluminescent device having a light emitting layer comprising a plurality of organic compound thin films between a pair of electrodes, wherein at least one layer between the anode and the light emitting layer is used for the organic electroluminescent device. The present invention relates to an organic electroluminescence device, which is a layer containing a hole injection material.

Further, the present invention provides an organic electroluminescence device comprising a plurality of organic compound thin films including a light emitting layer between a pair of electrodes, wherein at least two hole injection layers are provided between the anode and the light emitting layer. And a hole injection layer in contact with the anode is a layer containing the above-described hole injection material for an organic electroluminescence element.

Further, the present invention provides an organic electroluminescence device having a light-emitting layer composed of a plurality of organic compound thin films between a pair of electrodes, wherein at least one of the light-emitting layers is made of the above-mentioned hole injection material for an organic electroluminescence device. An organic electroluminescent device, characterized in that it is a layer containing.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION

The halogen atom of the compound of the above general formula includes fluorine, chlorine, bromine and iodine. Examples of the substituted or unsubstituted alkyl group include a methyl group, an ethyl group,
Propyl group, butyl group, sec-butyl group, tert-
There are linear and branched groups such as butyl group, pentyl group, hexyl group, heptyl group, octyl group, stearyl group, trichloromethyl group, trifluoromethyl group and benzyl group.

The substituted or unsubstituted alkoxy group includes methoxy, ethoxy, propoxy, n-butoxy, sec-butoxy, tert-butoxy,
Examples include a pentyloxy group, a hexyloxy group, a stearyloxy group, and a trifluoromethoxy group.

Examples of the substituted or unsubstituted thioalkoxy group include a methylthio group, an ethylthio group, a propylthio group, an n-butylthio group, a sec-butylthio group,
t-butylthio group, pentylthio group, hexylthio group,
Heptylthio group, octylthio group, stearylthio group,
And a trifluoromethylthio group.

The mono- or di-substituted amino group includes methylamino, dimethylamino, ethylamino, diethylamino, dipropylamino, dibutylamino, diphenylamino, ditolylamino, dibiphenylamino, bis ( Acetooxymethyl) amino group,
Bis (acetooxyethyl) amino group, bis (acetooxypropyl) amino group, bis (acetooxybutyl)
There are an amino group, a benzylphenylamino group, a dibenzylamino group and the like.

As the monocyclic group, a monocyclic cycloalkyl group,
There are a monocyclic aryl group and a monocyclic heterocyclic group. Examples of the monocyclic cycloalkyl group include a cycloalkyl group having 4 to 8 carbon atoms such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

The monocyclic aryl group includes a phenyl group. Monocyclic heterocyclic groups include thionyl, thiophenyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, pyridyl, pyrazyl, pyrazinyl, pyrimidyl, pyridazinyl, oxazolyl, thiazolyl, oxadiazolyl Group, thiadiazolyl group, imidadiazolyl group and the like.

Examples of the condensed polycyclic group include a condensed polycyclic aryl group, a condensed polycyclic heterocyclic group and a condensed polycyclic cycloalkyl group. Examples of the condensed polycyclic aryl group include a naphthyl group, an anthranyl group, a benzoanthranyl group, a phenanthrenyl group, a fluorenyl group, an acenaphthyl group, an azulenyl group,
Examples include a heptalenyl group, an acenaphthylenyl group, a pyrenyl group, and a triphenylene group.

Examples of the condensed polycyclic heterocyclic group include indolyl, quinolyl, isoquinolyl, phthalazinyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenazinyl, furfuryl, isothiazolyl, isoxazolyl, and furzanyl. Phenoxazinyl group, benzoxazolyl group, benzothiazolyl group, benzimidazolyl group and the like. Other fused polycyclic groups include a 1-tetralyl group, a 2-tetralyl group, a tetrahydroquinolyl group, and the like.

Examples of the substituted or unsubstituted cycloalkyl ring which may form a ring between adjacent substituents include a cyclobutyl ring, a cyclopentyl ring, a cyclohexyl ring, a cycloheptyl ring, a cyclooctyl ring and the like. Examples of the substituted or unsubstituted aryl ring which may form a ring between adjacent substituents include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a fluorene ring, an acenaphthalene ring, an azurenium ring, a heptalene ring, and an acenaphthalene ring , A pyrene ring, a biphenyl ring, a 4-ethylbiphenyl ring, a terphenyl ring, a quarterphenyl ring, a benz [a] anthracene ring, a triphenylene ring, a 2,3-benzofluorene ring, and a 3,4-benzopyrene ring.

As the substituent of the above-mentioned monocyclic group or condensed polycyclic group, the above-mentioned halogen atom, alkyl group, alkoxy group, alkylthio group, mono- or di-substituted amino group,
A monocyclic group or a condensed polycyclic group can be exemplified.

The arylene groups of Ar ^{1 to} Ar ⁶ include:
Examples include a phenylene group, a naphthylene group, an anthranylene group, a phenanthrylene group, a fluorenylene group, an acenaphthylene group, a pyrenylene group, a biphenylene group, a terphenylene group, and a quarterphenylene group.

Further, other arylene groups include divalent arylene groups which may contain oxygen, sulfur and nitrogen atoms. Representative examples include a fullerenylene group, a dibenzofuranylene group, a dibenzosuberonylene group,
Examples include a dibenzosuberenylene group, an anthronylene group, an anthraquinolylene group, a fluorenonylene group, a thiophenylene group, a dibenzothiophenylene group, a dibenzothiophenylene sulfone group, a carbazolylen group, and an iminostilbenylene group.

Further, a divalent arylene group which may be bonded through an alkylene group, an oxygen atom, a sulfur atom, a nitrogen atom and a silicon atom is also included. Representative examples include diphenylmethane, benzophenone, diphenylamine, diphenylether, diphenylsulfide, diphenylsulfone, diphenylsilane, bisphenylpropane, bisphenylhexafluoropropane, bisphenoxybenzene, bis (phenoxy) biphenyl, bis [(phenoxy) phenyl] propane And divalent organic residues such as bis [(phenoxy) phenyl] sulfone, bis (phenyl) diisopropylbenzene, bis (phenyl) fluorene and bis (phenyl) cyclohexane. The above-mentioned arylene group may have a group represented by R ^{1 to} R ²⁰ as a substituent.

The compound represented by the general formula [1], [6] or [7] of the present invention can be synthesized, for example, by the following method. In a flask, a polar solvent, a halogenoamine compound, a 5- to 8-fold molar amount of a substituted aromatic amine compound, an alkali, a catalyst such as a metal atom or a metal compound are added, and the mixture is reacted at 200 ° C. or higher for 5 to 50 hours. An aromatic amine compound represented by the formula [1], the general formula [6] or the general formula [7] is synthesized.

Representative examples of the compound represented by the general formula [1], [6] or [7] are specifically shown in Table 1, but are not limited thereto.

[0045]

[Table 1]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

The charge injection material of the present invention may be used in a mixture with other hole or electron injection compounds in the same layer. Since the compound of the present invention is excellent in hole injectability, it can be used very effectively as a hole injectable material.

The organic EL device is a device in which one or more organic thin films are formed between an anode and a cathode. In the case of a single layer type, a light emitting layer is provided between an anode and a cathode. The light-emitting layer contains a light-emitting material, and may further contain a hole-injection material or an electron-injection material for injecting holes injected from an anode or electrons injected from a cathode into the light-emitting material. The light emitting material itself may have a hole injecting property or an electron injecting property. The multilayer type includes (anode / hole injection layer / light emitting layer / cathode), (anode / light emitting layer / electron injection layer / cathode), (anode / hole injection layer / light emitting layer / electron injection layer /
There is an organic EL element stacked in a multilayer structure of (cathode). The compound of the general formula [1], the general formula [6] or the general formula [7] can be used in any device configuration. The compound represented by the general formula [1], the general formula [6] or the general formula [7] can be used as a hole injection material in any of the hole injection layer and the light emitting layer. The hole injection material of the present invention has a function of injecting holes from the anode into the organic layer, and a function of transporting the injected holes and injecting them into the light emitting layer. May be used for any of the hole injection layers. Since the thin film formed of the compound of the general formula [1], [6] or [7] is amorphous and has good heat resistance, it can be stored for a long time when the thin film is formed. It is also advantageous in light emission lifetime when the element is driven. Further, the compound of the general formula [1], the general formula [6] or the general formula [7] has good adhesion to a metal electrode such as ITO, and has a low ionization potential of the film. Since it is advantageous for hole injection, when two or more hole injection layers are used, the general formulas [1] and [6]
Alternatively, it is more advantageous to use the compound of the general formula [7] for the hole injection layer on the metal electrode (anode) side.

In the light emitting layer, if necessary, in addition to the compound of the general formula [1] of the present invention, a light emitting material, a doping material, a hole injection material for carrier injection, or an electron injection material may be used. it can. In the case of a two-layer structure, the light emitting layer and the hole injection layer are separated. With this structure, the efficiency of hole injection from the hole injection layer to the light emitting layer is improved, and the light emission luminance and the light emission efficiency can be increased. In this case, for light emission, it is desirable that the light emitting material used for the light emitting layer itself has an electron injecting property, or that the electron injecting material is added to the light emitting layer. Another layer configuration includes a two-layer structure including a light emitting layer and an electron injection layer. In this case, it is desirable that the light emitting material itself has a hole injecting property, or that the hole injecting material is added to the light emitting layer.

The three-layer structure has a light-emitting layer, a hole injection layer, and an electron injection layer to improve the efficiency of recombination of holes and electrons in the light-emitting layer. In this manner, by making the organic EL element have a multilayer structure, it is possible to prevent a decrease in luminance and life due to quenching. In such an element having a multilayer structure, a light emitting material, a doping material, a hole injection material for injecting carriers, and an electron injection material can be used in combination, if necessary. In addition, each of the hole injection layer, the light emitting layer, and the electron injection layer may be formed of two or more layers.

As the conductive material used for the anode of the organic EL device, those having a work function of more than 4 eV are suitable, and include carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, and platinum. , Palladium and the like, alloys thereof, metal oxides such as tin oxide and indium oxide called ITO substrates and NESA substrates, and organic conductive resins such as polythiophene and polypyrrole are used. As the conductive material used for the cathode, those having a work function smaller than 4 eV are preferable, and magnesium, calcium, tin, lead, titanium,
Yttrium, lithium, ruthenium, manganese and the like and alloys thereof are used. Examples of the alloy include magnesium / silver, magnesium / indium, and lithium / aluminum, but are not limited thereto, and the metal ratio of the alloy is not limited. Also,
The anode and the cathode may be formed of two or more layers if necessary.

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

Each layer of the organic EL device according to the present invention can be formed by any of dry film forming methods such as vacuum evaporation and sputtering and wet film forming methods such as spin coating and dipping. The thickness is not particularly limited, but each layer needs to be set to an appropriate thickness. If the film thickness is too large, a large applied voltage is required to obtain a constant light output, resulting in poor efficiency. If the film thickness is too small, pinholes and the like are generated, and sufficient light emission luminance cannot be obtained even when an electric field is applied. Normal thickness is 5nm to 10μ
The range of m is suitable, but the range of 10 nm to 0.2 μm is more preferable.

In the case of the wet film forming method, a material for forming each layer is dissolved or dispersed in an appropriate solvent such as chloroform, tetrahydrofuran, dioxane or the like to form a thin film.
The solvent may be any. In any of the thin films, a suitable resin or additive may be used to improve film forming properties, prevent pinholes in the film, and the like. Examples of the resin used in the present invention include insulating resins such as polystyrene, polycarbonate, polyarylate, polyester, polyamide, polyurethane, polysulfone, polymethyl methacrylate, polymethyl acrylate, and cellulose, poly-N-vinyl carbazole, and polysilane. And a conductive resin such as polythiophene and polypyrrole. Examples of the additive include an antioxidant, an ultraviolet absorber, and a plasticizer.

Examples of the light emitting material or doping material usable for the organic EL device of the present invention include anthracene, naphthalene, phenanthrene, pyrene, tetracene, coronene, chrysene, fluorescein, perylene, phthaloperylene, naphthaloperylene, perinone, phthaloperinone,
Naphthaloperinone, diphenylbutadiene, tetraphenylbutadiene, coumarin, oxadiazole, aldazine, bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, benzoquinoline metal complex, imine, diphenylethylene, vinyl anthracene , Diaminocarbazole, triphenylamine, benzidine-type triphenylamine, styrylamine-type triphenylamine, diamine-type triphenylaminepyran, thiopyran, polymethine, merocyanine, imidazole chelated oxinoid compounds, quinacridone, rubrene, and derivatives thereof. However, the present invention is not limited to these.

The hole injecting material which can be used in combination with the hole injecting material of the general formula [1], [6] or [7] has the ability to transport holes, and has a light emitting layer or a light emitting layer. Compounds that have an excellent hole injection effect on the material, prevent excitons generated in the light emitting layer from migrating to the electron injection layer or the electron transport material, and have excellent thin film forming ability. Specifically, phthalocyanine compounds, naphthalocyanine compounds, porphyrin compounds, oxadiazole, triazole, imidazole, imidazolone, imidazolethione, pyrazoline, pyrazolone, tetrahydroimidazole, oxazole, oxadiazole,
Hydrazone, acylhydrazone, polyarylalkane, stilbene, butadiene, benzidine-type triphenylamine, styrylamine-type triphenylamine, diamine-type triphenylamine, and derivatives thereof, and polyvinyl carbazole, polysilane, conductive polymer, etc. Examples include, but are not limited to, polymeric materials.

The electron injecting material has a capability of transporting electrons, has an excellent electron injecting effect on the light emitting layer or the light emitting material, and has a hole injecting layer or hole injection of excitons generated in the light emitting layer. Compounds that prevent transfer to a material and have excellent thin film forming ability are exemplified. For example, fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxadiazole, perylenetetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane,
Examples include, but are not limited to, anthrones and derivatives thereof. Alternatively, an electron accepting material may be added to the hole injecting material and an electron donating material may be added to the electron injecting material to sensitize the material.

The compound represented by the general formula [1], [6] or [7] of the present invention can be used for any of the layers. In addition to the compound of the formula [7], at least one of a light emitting material, a doping material, a hole injection material and an electron injection material may be contained in the same layer. In order to improve the stability of the organic EL device obtained according to the present invention with respect to temperature, humidity, atmosphere, etc., a protective layer is provided on the surface of the device, or silicon oil or the like is sealed to protect the entire device. It is also possible. As described above, in the present invention, the compound of the general formula [1], the general formula [6] or the general formula [7] is used for the organic EL device, so that the luminous efficiency and the luminous brightness can be increased. Also,
This element is stable against heat and current, and can obtain practically usable emission luminance at a low drive voltage. I was able to. The organic EL element of the present invention can be used for flat panel displays such as wall-mounted televisions,
The flat illuminant can be applied to light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display boards, and sign lamps, and its industrial value is very large.

The material of the present invention can be used not only as an organic EL device but also as a hole transport material in any field of an organic photoconductive material such as a photoelectric conversion device, a solar cell, and an image sensor.

[0088]

The present invention will be described below in more detail with reference to examples. According to the DSC analysis, many of the compounds represented by the general formulas [1], [6] and [7] of the present invention have been conventionally used as non-crystalline hole injection materials. 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine has a higher glass transition temperature, melting point and decomposition point, and is a hole injection material for organic EL devices. The compounds represented by the general formulas [1], [6] and [7] of the present invention have low crystallinity and non-crystallinity. Since it is a compound, it has good adhesion to the anode substrate and the organic thin film layer, and has great advantages in terms of resistance to the environment as an organic thin film, light emission lifetime when an organic EL element is driven, and storage stability of the element. is there.

Example 1 Compound (12) was placed on a washed glass plate with an ITO electrode.
Was vacuum-deposited to obtain a hole injection layer having a thickness of 30 nm. Next, a tris (8-hydroxyquinoline) aluminum complex was vacuum-deposited to form a 50-nm-thick light-emitting layer, on which a 150-nm-thick electrode was formed using an alloy of magnesium and silver mixed at a ratio of 10: 1. Thus, an organic EL device was obtained. The hole injection layer and the light emitting layer were deposited in a vacuum of 10 ^-6 Torr at a substrate temperature of room temperature. This device has a light emission luminance of 240 (cd / m ² ) at a DC voltage of 5 V, a maximum light emission luminance of 16500 (cd / m ² ), and a light emission efficiency of 1.9 (lm).
/ W) green light emission was obtained.

Example 2 Compound (36) in which the hole injection layer was dissolved in chloroform
An organic EL device was produced in the same manner as in Example 1, except that was formed by spin coating. This device has a light emission luminance of 220 (cd / m ² ) at a DC voltage of 5 V and a maximum light emission luminance of 1
8000 (cd / m ² ), luminous efficiency 2.0 (lm / W)
Green light emission was obtained.

Example 3 Compound (34) was placed on a washed glass plate with an ITO electrode.
Was vacuum-deposited to obtain a first hole injection layer having a thickness of 40 nm. Then, 4,4'-bis [N- (1-naphthyl)-
[N-phenylamino] biphenyl was vacuum-deposited to obtain a second hole-injection layer having a thickness of 10 nm. In addition, Tris (8
-Hydroxyquinoline) aluminum complex was vacuum-deposited to form a 40-nm-thick electron-injection light-emitting layer, and a 150-nm-thick electrode was formed thereon by using an alloy of magnesium and silver mixed at a ratio of 10: 1. An organic EL device was obtained. The hole injection layer and the light emitting layer were deposited in a vacuum of 10 ^-6 Torr at a substrate temperature of room temperature. This device has a light emission luminance of 370 (cd / m ² ) at a DC voltage of 5 V and a maximum light emission luminance of 2
2000 (cd / m ² ), luminous efficiency 2.1 (lm / W)
Green light emission was obtained.

Examples 4 to 93 The compounds shown in Table 1 were vacuum-deposited on the cleaned glass plate with ITO electrodes to obtain a first hole injection layer having a thickness of 40 nm. Then, 4,4′-bis [N- (1-naphthyl)
[N-phenylamino] biphenyl was vacuum-deposited to obtain a second hole injection layer having a thickness of 10 nm. Further, a tris (8-hydroxyquinoline) aluminum complex was vacuum-deposited to form a 50-nm-thick light-emitting layer.
-Methyl-8-hydroxyquinolinato) (1-phenolate) gallium complex was vacuum-deposited to form an electron injection layer having a thickness of 30 nm, on which an aluminum and lithium alloy mixed at a ratio of 25: 1 was used. An 150 nm electrode was formed to obtain an organic EL device. The hole injection layer and the light emitting layer were deposited in a vacuum of 10 ^-6 Torr at a substrate temperature of room temperature. In these devices, green light emission shown in Table 2 was obtained.

[0093]

[Table 2]

[0094]

[0095]

[0096]

Example 94 Compound (35) was placed on a washed glass plate with an ITO electrode.
Was vacuum-deposited to obtain a first hole injection layer having a thickness of 40 nm. Then, 4,4'-bis [N- (1-naphthyl)-
[N-phenylamino] biphenyl was vacuum-deposited to obtain a second hole-injection layer having a thickness of 10 nm. Further, N, N,
N ′, N ′-[4- (α, α′-dimethylbenzyl) phenyl] -anthranyl-9,10-diamine was vacuum-deposited to form a 50 nm-thick light-emitting layer, and tris (8-hydroxyquinoline) ) Vacuum evaporation of an aluminum complex to form an electron injection layer having a thickness of 40 nm,
An alloy of magnesium and silver mixed at a ratio of 10: 1 with a film thickness of 15
An 0 nm electrode was formed to obtain an organic EL device. The hole injection layer and the light emitting layer were deposited in a vacuum of 10 ^-6 Torr at a substrate temperature of room temperature. This element has a DC voltage of 5 V
, The emission luminance is 570 (cd / m ² ), and the maximum emission luminance is 660
Green light having a luminance of 00 (cd / m ² ) and a luminous efficiency of 5.5 (lm / W) was obtained.

Example 95 Example 94 was repeated except that the compound (56) was used in the second hole injection layer instead of 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl. An organic EL device was produced in the same manner as in the above. This device has a light emission luminance of 600 (cd / m ² ) at a DC voltage of 5 V and a maximum light emission luminance of 69000.
(Cd / m ² ) and green light emission with a luminous efficiency of 6.0 (lm / W).

Example 96 A compound (34) was used in the first hole injection layer instead of the compound (35), and 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl was used instead of the compound (34). An organic EL device was produced in the same manner as in Example 94, except that the compound (12) was used for the second hole injection layer. This element has a DC voltage of 5
At V, light emission luminance 720 (cd / m ² ), maximum light emission luminance 73
Green light emission of 000 (cd / m ² ) and luminous efficiency of 6.3 (lm / W) was obtained.

Example 97 Compound (66) was used for the first hole injection layer, and the compound (66) was used for the second hole injection layer.
Except for using the compound (56), a method similar to that of Example 94 was used.
To produce an organic EL device. This element has a DC voltage of 5 V
620 (cd / m^Two), Maximum emission luminance 730
00 (cd / m ^Two), Green with luminous efficiency of 6.3 (lm / W)
Color emission was obtained.

Example 98 Bis (2-methyl-8-hydroxyquinolinato) was used in place of the tris (8-hydroxyquinoline) aluminum complex
An organic EL device was manufactured in the same manner as in Example 94 except that the (1-phenolate) gallium complex was used for the electron injection layer. This device has a luminance of 820 at a DC voltage of 5 V.
(Cd / m ² ), maximum emission luminance 102000 (cd / m ² )
² ) Green light emission with a luminous efficiency of 10.5 (lm / W) was obtained.

Example 99 A compound (74) was placed on a washed glass plate with an ITO electrode.
Was vacuum-deposited to obtain a hole injection layer having a thickness of 40 nm. Next, the compound (34) and rubrene are vacuum-deposited at a weight ratio of 20: 1 to form a 50-nm-thick light-emitting layer, and a tris (8-hydroxyquinoline) aluminum complex is further vacuum-deposited to inject a 40-nm-thick electron. A layer was formed, and an electrode having a thickness of 150 nm was formed thereon using an alloy in which magnesium and silver were mixed at a ratio of 10: 1 to obtain an organic EL device. The hole injection layer and the light emitting layer were deposited in a vacuum of 10 ^-6 Torr at a substrate temperature of room temperature. This device has a light emission luminance of 420 (cd / m ² ) at a DC voltage of 5 V and a maximum light emission luminance of 4
5000 (cd / m ² ), luminous efficiency 4.2 (lm / W)
Yellow light emission was obtained.

Example 100 Tris (8-hydroxyquinoline) aluminum complex and quinacridone were deposited in a weight ratio of 40: 1 to form a film having a thickness of 40 n.
An organic EL device was produced in the same manner as in Example 94 except that a m light-emitting layer was obtained. This device has a light emission luminance of 510 (cd / m ² ) at a DC voltage of 5 V and a maximum light emission luminance of 49000.
(Cd / m ² ) and green luminescence with a luminous efficiency of 4.2 (lm / W) were obtained.

Example 101 An alloy obtained by mixing magnesium and silver at a ratio of 10: 1 to a film thickness of 15
An organic EL device was manufactured in the same manner as in Example 94 except that a cathode having a thickness of 150 nm was obtained using an alloy in which aluminum and lithium were mixed at a ratio of 10: 1 instead of obtaining a cathode having a thickness of 0 nm. This device has a light emission luminance of 620 at a DC voltage of 5 V.
(Cd / m ² ), maximum light emission luminance 72000 (cd / m ² )
m ² ) and green light emission with a luminous efficiency of 5.2 (lm / W) was obtained.

Comparative Example 1 In place of the compound (12) in the hole injection layer, 4,4 ′, 4 ″ was used.
An organic EL device was prepared in the same manner as in Example 1, except that -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine was used. This device has a light emission luminance of about 160 (cd / m ² ) at a DC voltage of 5 V,
Light emission characteristics of a light emission efficiency of 1.2 (lm / W) were obtained.

Comparative Example 2 Instead of the compound (35) in the hole injection layer, 4,4 ′, 4 ″ was used.
An organic EL device was prepared in the same manner as in Example 94, except that -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine was used. This device has a light emission luminance of about 560 (cd / m ² ) at a DC voltage of 5 V,
Light emission characteristics of a light emission efficiency of 3.3 (lm / W) were obtained.

For all the organic EL devices shown in this example, continuous emission was performed at 3 (mA / cm ² ).
Although luminance of 50% or more of the initial luminance could be observed for 10,000 hours or more, the devices of Comparative Example 1 and Comparative Example 2 were continuously emitted under the same conditions. The number of dark spots, which are non-light emitting portions of the device, also increased. The reason for the above results is that since the compound of the present invention is a non-planar compound, it is possible to form a non-crystalline thin film when forming a thin film, and that many condensed aromatic compounds are contained in the compound. The presence of the ring improves the hole injecting property of the organic EL element and improves the hole injecting property of the organic EL element. Furthermore, since the heat resistance of the compound was also improved, it was confirmed that the resistance of the element to heat generation during continuous light emission was also improved. Further, after the organic EL device was manufactured, it was stored in a nitrogen stream, and a time-dependent deterioration test was performed at room temperature. The organic E of the present invention using the general formula [1], the general formula [6] or the general formula [7]
The L element maintained a transparent and uniform film even after storage for 1000 hours and had the same initial organic EL element characteristics as the initial characteristics before storage, whereas the elements of Comparative Examples 1 and 2 , The organic layer was partially clouded and crystallized,
In the initial organic EL device characteristics after storage for 00 hours, the emission luminance at 5 V DC was less than half, and the luminous efficiency and the maximum emission luminance were also deteriorated to 30% of the initial value.

The organic EL device of the present invention achieves an improvement in luminous efficiency, luminous brightness, and a long life, and is used together with a luminescent material, a doping material, a hole injection material, an electron injection material, It does not limit the sensitizer, resin, electrode material, and the like, and the element manufacturing method.

According to the present invention, a compound having excellent hole injecting ability and having stable properties even when stored or driven for a long time or at a high temperature can be obtained. By using the compound provided by the present invention, an organic EL device having high luminous efficiency and high luminance and having a longer life during storage and driving than before can be obtained.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Satoshi Okutsu 2-3-113 Kyobashi, Chuo-ku, Tokyo Toyo Ink Manufacturing Co., Ltd.

Claims (8)

[Claims] An organic electro-chemical compound represented by the following general formula [1]:
Hole injection material for toroluminescence devices. General formula [1][Wherein, R¹~ R²⁰Are each independently a hydrogen atom,
A halogen atom, a substituted or unsubstituted alkyl group,
Or an unsubstituted alkoxy group, a substituted or unsubstituted
Alkoxyl group, mono- or di-substituted amino group,
Or unsubstituted monocyclic group, substituted or unsubstituted fused polycyclic
A group represented by the following general formula [2];
R¹~ R²⁰At least one is represented by the general formula [2]
Is a substituent. Also, R¹~ R^Five, R⁶~ R^Ten, R¹¹~
R^FifteenOr R¹⁶~ R²⁰Between adjacent substituents of
Or unsubstituted cycloalkyl ring, substituted or unsubstituted
A substituted aryl ring may be formed. General formula [2](Where R^{twenty one}~ R^{twenty five}Are each independently a hydrogen atom,
A halogen atom, a substituted or unsubstituted alkyl group,
Or an unsubstituted alkoxy group, a substituted or unsubstituted
Alkoxyl group, mono- or di-substituted amino group,
Or unsubstituted monocyclic group, substituted or unsubstituted fused polycyclic group
Represents R^{twenty one}~ R²⁶Is an adjacent substituent, which may be substituted or
Is an unsubstituted cycloalkyl ring, a substituted or unsubstituted
A reel ring may be formed. X¹Is a direct bond,
Or an unsubstituted alkylene group,-[CR²⁶(R²⁷)] X
-O- [CR²⁸(R²⁹)] Y-,-[CR³⁰(R³¹)]
x-S- [CR³²(R³³)] Y-, -O-, -S-,>
C = O,> SO_Two,> SiR ³⁴(R³⁵)-,> NR
³⁶-,> PR³⁷−,> P = O (R³⁸). R²⁶~ R
³⁹Is a substituted or unsubstituted alkyl group,
Shows unsubstituted monocyclic groups, substituted or unsubstituted fused polycyclic groups.
You. x and y each represent an integer of 0 to 8;
Are not both zero. ) Z¹Is represented by the following general formula [3], the following general formula [4] or
Represents a substituent represented by the general formula [5]. General formula [3](Ar¹Represents a substituted or unsubstituted arylene group
You. ) General formula [4](Ar^TwoOr Ar^ThreeIs a substituted or unsubstituted ant
Represents an allene group. R⁴⁰Is a substituted or unsubstituted alkyl
Group, substituted or unsubstituted monocyclic group, substituted or unsubstituted
Represents a substituted fused polycyclic group. ) General formula [5](Ar^Four~ Ar⁶Is a substituted or unsubstituted arylene
Represents a group. R⁴¹Or R⁴²Is a substituted or unsubstituted
Alkyl group, substituted or unsubstituted monocyclic group, substituted or
Represents an unsubstituted fused polycyclic group. )] 2. In the general formula [1], R ^{1 to} R ⁵ , R
^{6 ~R 10, R 11 ~R 15} , R 1 each of the at least one ⁶ to R ²⁰ has the general formula hole injecting material for an organic electroluminescent device according to claim 1, wherein the substituent represented by [2] . 3. The hole injection material for an organic electroluminescence device according to claim 1, which is represented by the following general formula [6]. General formula [6] [Wherein, R ^{43 to} R ⁷⁸ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group, a mono- or di-substituted group; Represents an amino group, a substituted or unsubstituted monocyclic group, or a substituted or unsubstituted fused polycyclic group. R ⁴³ and R ⁴⁴ , R ^{45 to} R ⁴⁹ , R ⁵⁰ and R ⁵¹ ,
R ⁵² and ^{R 53, R 54 ~R 58,} R 59 and R ^60, R ⁶¹ and R ^62, R
^{63 to} R ⁶⁷ , R ⁶⁸ and R ⁶⁹ , R ⁷⁰ and R ⁷¹ , R ^{72 to} R ⁷⁶ , R ⁷⁷
And the adjacent substituents to each other of R ^78, substituted or unsubstituted cycloalkyl ring, may form a substituted or unsubstituted aryl ring. Z ² has the same meaning as Z ¹ described above. ] 4. The method according to claim 1, which is represented by the following general formula [7].
4. The organic electroluminescent device according to claim 3,
Hole injection material for sensing elements. General formula [7][Wherein, R⁷⁹~ R¹¹⁴Is a hydrogen atom, a halogen atom,
Substituted or unsubstituted alkyl group, substituted or unsubstituted
Alkoxy group, substituted or unsubstituted thioalkoxy
Group, mono- or di-substituted amino group, substituted or unsubstituted
Represents a monocyclic group or a substituted or unsubstituted fused polycyclic group. Ma
R⁷⁹And R⁸⁰, R⁸¹~ R⁸⁵, R⁸⁶And R⁸⁷, R⁸⁸When
R⁸⁹, R⁹⁰~ R⁹⁴, R⁹⁵And R⁹⁶, R⁹⁷And R⁹⁸, R⁹⁹~ R
¹⁰³, R¹⁰⁴And R ¹⁰⁵, R¹⁹⁶And R¹⁰⁷, R¹⁰⁸~ R
¹¹², R¹¹³And R^{1 14}Between adjacent substituents of
Or unsubstituted cycloalkyl ring, substituted or unsubstituted
May form an aryl ring. R¹¹⁵~ R¹²²Is the water
An atom, a substituted or unsubstituted alkyl group, substituted or unsubstituted
Represents an unsubstituted monocyclic group or a substituted or unsubstituted fused polycyclic group.
Represents a cycloalkyl ring between adjacent substituents
May be. Y¹~ Y^FourRepresents a carbon atom or a silicon atom
Represent. Z^ThreeIs Z¹Has the same meaning as ] 5. An organic electroluminescence device comprising a light emitting layer composed of one or more organic compound thin films between a pair of electrodes, at least one of which is provided.
An organic electroluminescence device comprising a layer containing the hole injection material for an organic electroluminescence device according to claim 4. 6. An organic electroluminescence device comprising a light emitting layer composed of a plurality of organic compound thin films between a pair of electrodes, wherein at least one layer between the anode and the light emitting layer is provided. An organic electroluminescence device comprising a layer containing the hole injection material for an organic electroluminescence device according to the above. 7. An organic electroluminescence device comprising a plurality of organic compound thin films including a light emitting layer between a pair of electrodes, wherein at least two hole injection layers are provided between the anode and the light emitting layer. Claim 1 wherein the contacting hole injection layer is
An organic electroluminescence device comprising a layer containing the hole injection material for an organic electroluminescence device according to claim 4. 8. An organic electroluminescence device comprising a light emitting layer comprising a plurality of organic compound thin films between a pair of electrodes, wherein at least one of the light emitting layers is an organic electroluminescent element according to claim 1. An organic electroluminescence device comprising a layer containing a hole injection material for a device.