JPH08314169A - Hole transport material and its use - Google Patents

Abstract

(57) [Summary] (Modified) [Structure] A hole transport material represented by the following general formula [1]. [A represents a diamine derivative residue represented by the following general formula [2], and B represents a residue represented by the following general formula [3]. n is an integer of 1 or more and 5000 or less. ] [R ^{1 to} R ¹⁰ are hydrogen atom, halogen atom, alkyl group, alkoxy group, thioalkoxy group, cyano group, amino group, hydroxyl group, mercapto group, aryloxy group, arylthio group, aromatic ring group, heterocyclic group Etc. X represents an oxygen atom, a sulfur atom, or a selenium atom. Y and Z represent a hydrogen atom, a halogen atom, an alkyl group, an aromatic ring group, and a heterocyclic group, respectively. [Effect] Compared with conventional ones, the organic EL device has high luminous efficiency, high brightness, and long life, and has excellent electrophotographic properties such as sensitivity, hole transport properties, initial surface potential, dark decay rate, etc. An electrophotographic photoreceptor having less fatigue can be obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a hole transporting material having a diphenylamine structure. The diphenylamine compound can be used as a light-sensitive material or an organic photoconductive material, and more specifically, it is used for a flat light source or display. It can be used as a hole transport material for an organic electroluminescence (EL) element or an electrophotographic photoreceptor.

[0002]

2. Description of the Related Art Organic photoconductive materials which have been developed as photosensitive materials and hole transport materials have many advantages such as low cost, various processability and no pollution, and many compounds have been proposed. ing. 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. No. 3,717,462, JP-A-54- 5
9,143, US Pat. No. 4,150,978), triarylpyrazoline derivatives (US Pat. No. 3,820,
989, JP-A-51-93,224, JP-A-55-
108,667), arylamine derivatives (US Pat. No. 3,180,730, US Pat. No. 4,232,10).
3, JP-A-55-144,250, and JP-A-56-1.
19,132), stilbene derivatives (JP-A-58-1)
No. 90,953, JP-A-59-195,658) and other organic photoconductive materials are disclosed.

As one of the technologies utilizing the hole transport material, there is an organic EL element. E using organic substances
The L element is promising for use as a solid-state light emitting inexpensive large area full color display element, and many developments have been made. Generally, 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, this is a phenomenon in which the electrons are recombined with holes in the light emitting layer, and energy is emitted as light when the energy level returns from the conduction band to the valence band.

The conventional organic EL element has a higher driving voltage and lower emission brightness and emission efficiency than the inorganic EL element.
In addition, the deterioration of the characteristics was remarkable and it was not put to practical use.
In recent years, an organic EL in which thin films containing an organic compound having a high fluorescence quantum efficiency that emits light at a low voltage of 10 V or less are laminated
The device has been reported and is of great interest (see Applied Physics Letters, 51, 913, 1987). In this method, a metal chelate complex is used for a phosphor layer and an amine compound is used for a hole injection layer to obtain high-luminance green light emission, and the luminance is 100 cd at a DC voltage of 6 to 7V.
/ M ₂ and the maximum luminous efficiency of 1.5 lm / W, which is close to the practical range.

However, the organic EL devices to date have not been sufficient in the emission brightness and the emission stability during repeated use. Therefore, in order to develop an organic EL device having higher emission brightness, high emission efficiency and excellent stability during repeated use, a hole transport material having excellent hole transport ability and durability. Development is desired.

Further, as a technique utilizing the hole transport material, there is an electrophotographic photoreceptor. The electrophotographic method is
It is one of the image forming methods invented by Carlson.
In this method, after the photoconductor is charged by corona discharge, it is exposed to a light image to obtain an electrostatic latent image on the photoconductor, toner is attached to the electrostatic latent image for development, and the obtained toner image is printed on a paper. Consists of transferring to. The basic characteristics required for such an electrophotographic photosensitive member are that an appropriate electric potential is maintained in a dark place, that there is little discharge of electric charge in a dark place, and that electric charge is quickly discharged by light irradiation. And so on. Conventional electrophotographic photoreceptors have used inorganic photoconductors such as selenium, selenium alloys, zinc oxide, cadmium sulfide and tellurium. These inorganic photoconductors are
Although it has advantages such as high durability and a large number of printable sheets, it has been pointed out that there are problems such as high manufacturing cost, poor workability, and toxicity. In order to overcome these drawbacks, a photoconductor using an organic compound has been developed. However, an electrophotographic photoconductor using a conventional organic photoconductive material as a hole transporting material has a chargeability, sensitivity and At present, electrophotographic properties such as residual potential are not always satisfied, and development of a hole transport material having excellent charge transport ability and durability has been desired.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hole transport material having excellent hole transport ability and durability, and further using this hole transport material. The organic E has excellent stability when used repeatedly.
An object is to provide an L element, an electrophotographic photosensitive member, and the like.

[0008]

As a result of intensive investigations by the present inventors, at least one hole-transporting material represented by the general formula [1] has a large hole-transporting ability. The inventors have found that the element characteristics of EL elements or electrophotographic photoreceptors or the stability upon repeated use are excellent, and the present invention has been completed. That is, the present invention relates to a hole transport material represented by the following general formula [1]. General formula [1]

[Chemical 4] [In the formula, A represents a diamine derivative residue represented by the following general formula [2], and B represents a bonding group represented by the following general formula [3]. n is an integer of 1 or more and 5000 or less. ] General formula [2]

Embedded image [Wherein, R ^{1 to} R ¹⁰ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group,
Cyano group, amino group, mono- or di-substituted amino group, hydroxyl group, mercapto group, substituted or unsubstituted aryloxy group, substituted or unsubstituted arylthio group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted Represents a heterocyclic group (adjacent substituents may form a substituted or unsubstituted aliphatic ring, a substituted or unsubstituted aromatic ring, or a substituted or unsubstituted heterocycle). X represents an oxygen atom, a sulfur atom, or a selenium atom. ] General formula [3]

[Chemical 6] [In the formula, Y and Z are a hydrogen atom, a halogen atom, and
It represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aromatic ring group, or a substituted or unsubstituted heterocyclic group.
Further, X and Y may form a substituted or unsubstituted aliphatic ring, a substituted or unsubstituted aromatic ring, or a substituted or unsubstituted heterocycle. ]

Furthermore, the present invention is an organic electroluminescence device comprising a light emitting layer composed of one or a plurality of organic compound thin films between a pair of electrodes, at least one layer containing the hole transport material. The present invention relates to an organic electroluminescence device characterized by the above.

Furthermore, the present invention is an electrophotographic photosensitive member comprising a charge generating material and a hole transporting material on a conductive support, wherein the hole transporting material is the above hole transporting material. And an electrophotographic photoreceptor.

Among R ^{1 to} R ¹⁰ of the compound represented by the general formula [2] in the present invention, the halogen atom is fluorine,
There are chlorine, bromine and iodine. The substituted or unsubstituted alkyl group includes a methyl group, an ethyl group, a propyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a stearyl group and a trichloromethyl group. , Trifluoromethyl group, cyclopropyl group, cyclohexyl group, 1,3-cyclohexadienyl group, 2-cyclopenten-1-yl group,
2,4-cyclopentadiene-1-yridenyl group and the like. As the substituted or unsubstituted alkoxy group, a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group,
Examples include sec-butoxy group, tert-butoxy group, pentyloxy group, hexyloxy group, stearyloxy group and trifluoromethoxy group. Examples of the substituted or unsubstituted thioalkoxy group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a sec-butylthio group, a tert-butylthio group, a pentylthio group, a hexylthio group, a heptylthio group and an octylthio group.

Examples of the mono- or di-substituted amino group include methylamino group, dimethylamino group, ethylamino group, diethylamino group, dipropylamino group, dibutylamino group, diphenylamino group and bis (acetooxymethyl) group.
Examples include an amino group, a bis (acetooxyethyl) amino group, a bis (acetooxypropyl) amino group, a bis (acetooxybutyl) amino group, and a dibenzylamino group. Examples of the substituted or unsubstituted aryloxy group include a phenoxy group, a p-tert-butylphenoxy group and a 3-fluorophenoxy group. Examples of the substituted or unsubstituted arylthio group include a phenylthio group and a 3-fluorophenylthio group. As the substituted or unsubstituted aromatic ring group, a phenyl group, a biphenylenyl group, a triphenylenyl group, a tetraphenylenyl group, a 3-nitrophenyl group, a 4-methylthiophenyl group, a 3,5-dicyanophenyl group, o-, m- and p-tolyl group, xylyl group, o-, m- and p-cumenyl group, mesityl group, pentalenyl group, indenyl group, naphthyl group, azulenyl group, heptanenyl group, acenaphthylenyl group, phenalenyl group, fluorenyl group, anthryl group Group, anthraquinonyl group, 3-methylanthryl group, phenanthryl group, triphenylenyl group, pyrenyl group, chrysenyl group, 2-ethyl-1-chrysenyl group, picenyl group, perylenyl group,
Examples thereof include a 6-chloroperenyl group, a pentaphenyl group, a pentacenyl group, a tetraphenylenyl group, a hexaphenyl group, a hexacenyl group, a rubicenyl group, a coronenyl group, a trinaphthylenyl group, a heptaphenyl group, a heptaenyl group, a pyrantrenyl group and an ovarenyl group.

As the substituted or unsubstituted heterocyclic group,
Thionyl group, furyl group, pyrrolyl group, imidazolyl group,
Pyrazolyl group, pyridyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, indolyl group, quinolyl group, isoquinolyl group, phthalazinyl group, quinoxalinyl group, quinazolinyl group, carbazolyl group, acridinyl group, phenazinyl group, furfuryl group, isothiazolyl group, isoxazolyl group , A flazanyl group, a phenoxazinyl group, a benzothiazolyl group, a benzoxazolyl group, a benzimidazolyl group, a 2-methylpyridyl group, a 3-cyanopyridyl group, and the like, but the substituents are not specifically limited.

Further, adjacent substituents may form an aliphatic ring, aromatic ring or heterocycle, which may contain a 5- to 7-membered ring, such as an oxygen atom, a nitrogen atom or a sulfur atom, It may have a substituent at any position of the ring.

Representative examples of the substituted or unsubstituted aromatic amine derivative residue represented by A of the general formula [1] are specifically shown in Table 1, but not limited thereto.

[0016]

[Table 1]

[0017]

[0018]

[0019]

Typical examples of Y and Z represented by the general formula [3] are, independently, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aromatic ring group,
It represents a substituted or unsubstituted heterocyclic group or the like, and represents the substituent represented by R ^{1 to} R ¹⁰ . Further, Y and Z may form a substituted or unsubstituted aliphatic ring, a substituted or unsubstituted aromatic ring, or a substituted or unsubstituted heterocycle, and preferable examples include 1,1-cyclopropylene. Group, 1,1-cyclobutylene group, 1,1-cyclopentylene group, 1,1-
Cyclohexylene group, 1,1- (4-methyl) cyclohexylene group, 1,1- (3-methyl) cyclohexylene group, 1,1- (2-methyl) cyclohexylene group, 1,
1- (2,4-dimethyl) cyclohexylene group, 1,1
-Cycloheptylene group, 1,1-cyclooctylene group and the like. Representative examples are specifically shown in Table 2 below, but the present invention is not limited thereto.

[0021]

[Table 2]

[0022]

[0023]

The compound represented by the general formula [1] of the present invention can be synthesized, for example, by the following method. In an acetic acid solvent, a substituted or unsubstituted alicyclic carbonyl compound such as aldehyde or ketone is mixed with 0.5 to 4 times mol of a substituted or unsubstituted aromatic amine compound together with an acid catalyst such as methanesulfonic acid at 100 ° C. For 30 hours to synthesize an aromatic amine polymer represented by the general formula [1]. Further, the acid catalyst used in the present invention may be an organic acid such as trifluoroacetic acid or p-toluenesulfonic acid, or sulfuric acid, hydrochloric acid, Lewis acid or the like instead of methanesulfonic acid. In addition to acetic acid, 1,4-dioxane, ether, petroleum ether and the like can be used as the organic solvent.

Representative examples of the compounds of the present invention are shown in Table 3, but the present invention is not limited to the following representative examples.

[0026]

[Table 3]

The hole transporting material of the present invention may be used as a mixture with another hole or electron transporting compound in the same layer. Since the compound of the present invention has an excellent hole transporting property, it can be used very effectively as a hole transporting material.

The organic EL device is a device in which a single-layer or multi-layer organic thin film is formed between an anode and a cathode. In the case of the single layer type, a light emitting layer is provided between the anode and the cathode. The light emitting layer contains a light emitting material, and may further contain a hole transport material or an electron transport material for transporting holes injected from the anode or electrons injected from the cathode to the light emitting material. In some cases, the light emitting material has a hole transporting property or an electron transporting property. The multilayer type is (anode / hole injection layer / emission layer / cathode), (anode / emission layer / electron injection layer /
There is an organic EL element having a multilayer structure of (cathode) and (anode / hole injection layer / light emitting layer / electron injection layer / cathode). The compound of the general formula [1] can be preferably used in any device constitution. Since the compound of the general formula [1] has a large hole transporting ability, it can be used as a hole transporting material in any of the hole injecting layer and the light emitting layer.

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

Further, the three-layer structure has a light emitting layer, a hole injecting layer, and an electron injecting layer to improve the efficiency of recombination of holes and electrons in the light emitting layer. As described above, by forming the organic EL element into a multi-layer structure, it is possible to prevent a decrease in brightness and life due to quenching. Also in the device having such a multilayer structure, a light emitting substance, a doping material, a hole transporting material for transporting carriers, and an electron transporting material can be used in combination, if necessary. The hole injection layer, the light emitting layer, and the electron injection layer may each be formed of two or more layers.

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

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

For formation of each layer of the organic EL device according to the present invention, any of dry film forming methods such as vacuum deposition and sputtering and wet film forming methods such as spin coating and dipping can be applied. The film thickness is not particularly limited, but each layer needs to be set to an appropriate film thickness. If the film thickness is too thick, a large applied voltage is required to obtain a constant light output, resulting in poor efficiency. If the film thickness is too thin, pinholes and the like will occur, and even if an electric field is applied, sufficient emission brightness cannot be obtained. Normal film thickness is 5nm to 10μ
The range of m is preferred, but the range of 10 nm to 0.2 μm is more preferred.

In the case of the wet film forming method, the material for forming each layer is dissolved or dispersed in an appropriate solvent such as chloroform, tetrahydrofuran, dioxane to form a thin film.
The solvent may be any. Further, in any of the thin films, an appropriate resin or additive may be used in order to improve the film forming property and prevent pinholes in the film. Examples of the resin used in the present invention include insulating resins such as polystyrene, polycarbonate, polyarylate, polyester, polyamide, polyurethane, polysulfone, polymethylmethacrylate, polymethylacrylate and cellulose, poly-N-vinylcarbazole, polysilane and the like. Examples of the photoconductive resin include a conductive resin such as polythiophene and polypyrrole. Examples of the additives include antioxidants, ultraviolet absorbers, plasticizers and the like.

Examples of the light emitting material or doping material that can be used in 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, vinylanthracene , Diaminocarbazole, pyran, thiopyran, polymethine, merocyanine, imidazole chelated oxinoid compounds, quinacridone, rubrene, and the like, and derivatives thereof, but are not limited thereto.

The hole transporting material that can be used in combination with the hole transporting material of the general formula [1] has the ability to transport holes and has an excellent hole injecting effect on the light emitting layer or the light emitting material. However, compounds that can prevent excitons generated in the light emitting layer from moving to the electron injection layer or the electron transport material and have excellent thin film forming ability can be given. Specifically, phthalocyanine compounds, naphthalocyanine compounds, porphyrin compounds, oxadiazoles, triazoles, imidazoles,
Imidazolone, imidazolethione, pyrazoline, pyrazolone, tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acylhydrazone, polyarylalkane, stilbene, butadiene, benzidine type triphenylamine, styrylamine type triphenylamine, diamine type triphenylamine, etc. Examples thereof include, but are not limited to, derivatives thereof, and polymeric materials such as polyvinylcarbazole, polysilane, and conductive polymers.

The electron-transporting material has the ability to transport electrons, has an excellent electron-injecting effect on the light-emitting layer or the light-emitting substance, and has a hole-injecting layer or hole-transporting layer for excitons generated in the light-emitting layer. Examples thereof include compounds that prevent transfer to the material and have excellent thin film forming ability. For example, fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxadiazole, perylene tetracarboxylic acid, fluorenylidene methane, anthraquinodimethane,
Examples include, but are not limited to, anthrone and derivatives thereof. It is also possible to sensitize by adding an electron accepting substance to the hole transporting material and adding an electron donating substance to the electron transporting material.

The compound of the general formula [1] of the present invention can be used in any layer, and in addition to the compound of the general formula [1], a light emitting substance, a light emission auxiliary material, a hole transporting material and an electron transporting material. At least one of the materials may be contained in the same layer. Further, in order to improve the stability of the organic EL element obtained by the present invention against temperature, humidity, atmosphere, etc., a protective layer is provided on the surface of the element or silicon oil or the like is enclosed to protect the entire element. It is also possible. As described above, in the present invention, since the compound of the general formula [1] is used for the organic EL device, the luminous efficiency and the luminous brightness can be increased. Also,
This device is extremely stable against heat and current, and because it can obtain practically usable light emission brightness at a low driving voltage, it is possible to greatly reduce deterioration, which was a big problem until now. It was INDUSTRIAL APPLICABILITY The organic EL device of the present invention may be applied to a flat panel display such as a wall-mounted TV, a light source for a copying machine, a printer, etc., a light source for a liquid crystal display, instruments, a display plate, a marker lamp, etc. , Its industrial value is very large.

Next, the case where the compound represented by the general formula [1] of the present invention is used as an electrophotographic photoreceptor will be described. The compound represented by the general formula [1] of the present invention can be used in any layer of an electrophotographic photoreceptor, but it is preferably used as a hole transport material because it has high hole transport properties. The compound acts as a hole-transporting material, can transport charges generated by absorbing light very efficiently, and can provide a photoreceptor having a high-speed response. Further, since the compound is excellent in ozone resistance and light stability, a photoreceptor having excellent durability can be obtained.

The electrophotographic photosensitive member is a single-layer type photosensitive member in which a charge generating material and, if necessary, a photosensitive layer in which a charge transporting material is dispersed in a binder resin are provided on a conductive substrate. An undercoat layer, a charge generation layer, and a hole transport layer in this order,
Alternatively, there is a laminated type photoreceptor in which a hole transport layer and a charge generation layer are laminated in this order on a conductive substrate or an undercoat layer. Here, the undercoat layer may not be used if not necessary. If necessary, the photoreceptor may be provided with an overcoat layer for the purpose of protecting the surface from active gas and preventing filming by toner.

As the charge generating material, bisazo, quinacridone, diketopyrrolopyrrole, indigo, perylene,
Examples thereof include organic compounds such as perinone, polycyclic quinone, squarylium salt, azurenium salt, phthalocyanine, and naphthalocyanine, and inorganic substances such as selenium, selenium-tellurium alloy, cadmium sulfide, zinc oxide, and amorphous silicon.

Each layer of the photoreceptor can be formed by vapor deposition or dispersion coating method. Dispersion coating is performed using a spin coater, an applicator, a spray coater, a dip coater, a roller coater, a curtain coater, a bead coater, etc., and drying is from room temperature to 200 ° C., 1
It is performed under static or blown conditions in the range of 0 minutes to 6 hours.
The film thickness of the photosensitive layer after drying is 5 μm to 50 μm in the case of a single-layer type photoconductor, and 0.0 in the case of a multilayer type photoconductor.
1 μm to 5 μm, preferably 0.1 μm to 1 μm, the hole transport layer is 5 μm to 50 μm, preferably 1
0 μm to 20 μm is preferable.

The resin used for forming the photosensitive layer of the single-layer type photoreceptor, the charge generation layer or the hole transport layer of the laminated type photoreceptor can be selected from a wide range of insulating resins. Also, poly-N
-Selectable from organic photoconductive polymers such as vinylcarbazole, polyvinylanthracene and polysilanes.
Preferably, polyvinyl butyral, polyarylate,
Insulating resins such as polycarbonate, polyester, phenoxy, acrylic, polyamide, urethane, epoxy, silicon, polystyrene, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, phenol and melamine resin can be mentioned. The resin used for forming the charge generation layer or the hole transport layer is preferably 100% by weight or less with respect to the charge generation material or the hole transport material, but is not limited thereto. You may use resin in combination of 2 or more types.
Further, if necessary, the resin may not be used. Also,
The charge generation layer can also be formed by a physical film forming method such as vapor deposition or sputtering. In the vapor deposition or sputtering method, it is desirable to form the film in a vacuum atmosphere of preferably 10 ⁻⁵ Toor or less. It is also possible to form a film in an inert gas such as nitrogen, argon, or helium.

The solvent used when forming each layer of the electrophotographic photosensitive member is preferably selected from those which do not affect the undercoat layer and other photosensitive layers. Specifically, aromatic hydrocarbons such as benzene and xylene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, alcohols such as methanol and ethanol, esters such as ethyl acetate and methyl cellosolve, carbon tetrachloride, chloroform and dichloromethane. However, aliphatic halogenated hydrocarbons such as dichloroethane and trichloroethylene, aromatic halogenated hydrocarbons such as chlorobenzene and dichlorobenzene, and ethers such as tetrahydrofuran and dioxane are used, but not limited thereto.

The hole-transporting layer is formed by applying only a hole-transporting material, or by applying a coating solution in which the hole-transporting material is dissolved in an insulating resin, or by a dry film-forming method such as vapor deposition.
The hole transport material used in the present photoreceptor may be used in combination with other hole transport materials in addition to the compound of the general formula [1]. Since the compound of the general formula [1] has a high molecular weight, it is not necessary to use another insulating resin, but in addition, an insulating resin was used in combination to improve heat resistance and abrasion resistance. Even in such a case, the compatibility with other resins is good, and the formed thin film does not easily precipitate as crystals,
It is advantageous for improving sensitivity and durability.

In order to improve electrophotographic characteristics, image characteristics, etc., an undercoat layer can be provided between the substrate and the organic layer, if necessary. As the undercoat layer, polyamides, casein, polyvinyl alcohol, gelatin are used. Resins such as polyvinyl butyral and metal oxides such as aluminum oxide are used. The material of the present invention can be suitably used not only as a hole transport material for an organic EL element or an electrophotographic photoreceptor but also in any field of an organic photoconductive material such as a photoelectric conversion element, a solar cell, an image sensor.

[0047]

The present invention will be described in more detail based on the following examples. Method for synthesizing compound (3) In 40 parts of acetic acid, 11 parts of cyclohexanone and 4,4′-
18 parts of dimethoxydiphenyl-p, p′-diaminodiphenyl ether and 0.5 part of methanesulfonic acid were added, and the mixture was heated with stirring at 100 ° C. for 20 hours. Then 50
It was diluted with 0 part of water and neutralized with dilute aqueous sodium hydroxide solution. After that, extraction was performed with ethyl acetate, the mixture was concentrated, and purified by column chromatography using silica gel to obtain 15 parts of a powder having white fluorescence. FD-MS
It was confirmed to be the compound (3) by the molecular weight analysis.

Example 1 On a washed glass plate with an ITO electrode, tris (8-hydroxyquinoline) aluminum complex, compound (1),
Polycarbonate resin (Teijin Kasei: Panlite L-12
50) was dissolved and dispersed in chloroform at a ratio of 3: 2: 5, and a light emitting layer having a film thickness of 100 nm was obtained by a spin coating method. On top of that, add magnesium and silver 10:
An electrode having a thickness of 150 nm was formed from the alloy mixed in 1 to obtain an organic EL device. With this device, an emission luminance of 100 cd / m ² and an emission efficiency of 0.9 lm / W were obtained at a DC voltage of 5V.

Example 2 Compound (2) was vacuum-deposited on a washed glass plate with an ITO electrode to obtain a hole injection layer having a film thickness of 30 nm. Then, a tris (8-hydroxyquinoline) aluminum complex is vacuum-deposited to form a light emitting layer having a thickness of 50 nm, and an electrode having a thickness of 150 nm is formed on the light emitting layer having a thickness of 50: 1. Thus, an organic EL device was obtained.
The hole injection layer and the light emitting layer are in a vacuum of 10 ⁻⁶ Torr,
Deposition was carried out under the condition that the substrate temperature was room temperature. This device has a luminance of about 420 cd / m ² at a DC voltage of 5 V and a luminous efficiency of 3.2.
lm / W was obtained.

Example 3 Compound (3) was vacuum-deposited on a washed glass plate with an ITO electrode to obtain a hole injection layer having a film thickness of 30 nm. Then, a 20-nm-thick light-emitting layer of tris (8-hydroxyquinoline) aluminum complex was formed by a vacuum evaporation method, and then [2- (4-tert-butylphenyl) -5- (biphenyl) -1 was formed by a vacuum evaporation method. , 3,4-Oxadiazole] having a thickness of 20 nm was obtained.
An electrode having a film thickness of 150 nm was formed on it with an alloy in which magnesium and silver were mixed at a ratio of 10: 1 to obtain an organic EL element. This device has a luminance of about 360 cd at a DC voltage of 5V.
/ M ² and a luminous efficiency of 2.9 lm / W were obtained.

Examples 4 to 25 The compounds shown in Table 2 were dissolved in chloroform on a washed glass plate with an ITO electrode, and a hole injection layer having a thickness of 50 nm was obtained by spin coating. Then, a tris (8-hydroxyquinoline) aluminum complex is vacuum-deposited to form a light-emitting layer having a thickness of 30 nm, and an alloy in which magnesium and silver are mixed at a ratio of 10: 1 has a thickness of 100 nm.
An electrode of nm was formed to obtain an organic EL device. 1 light emitting layer
Deposition was performed under the conditions of a substrate temperature of room temperature in a vacuum of 0 ^-6 Torr. The device obtained the emission luminance shown in Table 4 at a DC voltage of 5V.

[0052]

[Table 4]

Comparative Example 1 N, N '-(4-methylphenyl)-was added to the hole injection layer.
An organic EL device was produced in the same manner as in Example 2 except that N, N ′-(4-n-butylphenyl) -phenanthrene-9,10-diamine was used. With this device, a luminescent brightness of about 390 cd / m ² and a luminous efficiency of 2.0 lm / W were obtained at a DC voltage of 5V.

When all the organic EL elements shown in this example were continuously made to emit light at 3 mA / cm ² , 10
Although the luminance of 50% or more of the initial luminance could be observed for 00 hours or more, when the element of Comparative Example 1 was continuously emitted under the same conditions, the luminance became 50% or less of the initial luminance in 100 hours, and the number of dark spots was decreased. Also became extremely large. Organic EL of the present invention
The device achieves improvement in luminous efficiency, luminous brightness, and long life, and is used together with a light emitting substance, a light emission auxiliary material, a hole transport material, an electron transport material, a sensitizer, a resin, an electrode material, etc. The method for manufacturing the device is not limited.

Next, examples in which the hole transport material of the present invention is used as an electrophotographic photosensitive material are shown below.

Example 26 4 g of ε-type copper phthalocyanine, 2 g of compound (6) and 14 g of a polyester resin (Toyobo: Byron 200) were dispersed with 80 g of tetrahydrofuran in a ball mill for 5 hours. This dispersion was applied onto an aluminum substrate and dried to prepare a single-layer type electrophotographic photoreceptor having a film thickness of 20 μm.

Example 27 6 g of dibromoanthanthrone, 2 g of compound (8) and 12 g of a polyester resin (Toyobo: Byron 200) were dispersed together with 80 g of tetrahydrofuran in a ball mill for 5 hours. This dispersion was applied onto an aluminum substrate and dried to prepare a single-layer type electrophotographic photoreceptor having a film thickness of 20 μm.

Example 28 N, N'-bis (2,6-dichlorophenyl) -3,
2 g of 4,9,10-perylenedicarboximide and 2 g of polyvinyl butyral resin (Sekisui Chemical: BH-3) were dispersed together with 96 g of tetrahydrofuran in a ball mill for 2 hours. This dispersion was applied onto an aluminum substrate and dried to form a charge generation layer having a film thickness of 0.3 μm. Next, 10 g of compound (25) and a polycarbonate resin (Teijin Kasei:
Panlite L-1250) 10 g dichloromethane 80
dissolved in g. This coating liquid was applied onto the charge generating layer and dried to form a hole transporting layer having a film thickness of 20 μm, to prepare a laminated electrophotographic photoreceptor.

Examples 29 to 53 2 g of τ-type metal-free phthalocyanine and 2 g of polyvinyl butyral resin (Sekisui Chemical Co., Ltd .: BH-3) were dispersed with 96 g of tetrahydrofuran in a ball mill for 2 hours. This dispersion is applied on an aluminum substrate and dried to give a film thickness of 0.3 μm.
m charge generating layer was prepared. Next, the compound 1 shown in Table 3
0g, polycarbonate resin (Teijin Kasei: Panlite L
-1250) was dissolved in 80 g of dichloromethane. This coating solution is applied onto the charge generation layer and dried to give a film thickness of 2
A hole transport layer having a thickness of 0 μm was formed to prepare a laminated electrophotographic photosensitive member.

The electrophotographic characteristics of the electrophotographic photosensitive member are as follows.
It was measured by the method. Electrostatic copying paper tester (Kawaguchi Electric Works:
According to EPA-8100), static mode 2,
Rona charging is -5.2 (kV), 5 (lux) white light
The initial surface potential (V ₀), V₀And release in the dark for 2 seconds
Surface potential (V₂) Ratio (dark decay rate: DD = V₂
/ V₀), The amount of charge decreases to half of the initial amount after light exposure
From time to half sensitivity (E_1/2) And 3 seconds after light exposure
Surface potential (VR₃) Was investigated. This example electrophotographic photosensitivity
The electrophotographic properties of the body are shown in Table 5.

[0061]

[Table 5]

All the electrophotographic photoconductors shown in this example have surface potentials before and after repeatedly used 10,000 times or more,
Since the rate of change in electrophotographic characteristics such as sensitivity and the image density is within 2%, it can be seen that the electrophotographic photoreceptor has stable electrophotographic characteristics and can retain high quality images.

Comparative Example 2 N, N '-(4-methylphenyl)-was added to the hole transport layer.
Example 29 except that N, N '-(4-n-butylphenyl) -phenanthrene-9,10-diamine was used.
An electrophotographic photosensitive member was produced by the same method as described above. The electrophotographic characteristics of this electrophotographic photosensitive member are as follows: initial potential (V ₀ ) =
-700 (V), potential holding ratio after 2 seconds (DDR ₂ ) = 9
0 (%), half exposure dose sensitivity (E _1/2 ) = 1.2 (lux
· S), the residual potential after 3 seconds (VR ₃₎ = - a 25 (V), was inferior to the hole transport material of the present invention. Further, the electrophotographic characteristics such as surface potential and sensitivity and the image density before and after the electrophotographic photosensitive member was repeatedly used 10,000 times or more showed a change rate of 10% or more. The rate of change of this big
It showed unstable electrophotographic characteristics and could not stably obtain high quality images.

[0064]

Industrial Applicability According to the present invention, a compound having an excellent hole transporting ability can be obtained. With the compound provided by the present invention, an organic EL device having higher luminous efficiency, higher brightness, and longer life than before, and excellent electrophotographic properties such as sensitivity, hole transport properties, initial surface potential, and dark decay rate. It was possible to obtain an electrophotographic photosensitive member with little fatigue against repeated use.

Claims (3)

[Claims] 1. A hole transport material represented by the following general formula [1]. General formula [1] [In the formula, A represents a diamine derivative residue represented by the following general formula [2], and B represents a bonding group represented by the following general formula [3]. n is an integer of 1 or more and 5000 or less. ] General formula [2] [Wherein, R ^{1 to} R ¹⁰ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group,
Cyano group, amino group, mono- or di-substituted amino group, hydroxyl group, mercapto group, substituted or unsubstituted aryloxy group, substituted or unsubstituted arylthio group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted Represents a heterocyclic group (adjacent substituents may form a substituted or unsubstituted aliphatic ring, a substituted or unsubstituted aromatic ring, or a substituted or unsubstituted heterocycle). X represents an oxygen atom, a sulfur atom, or a selenium atom. ] General formula [3] [In the formula, Y and Z are a hydrogen atom, a halogen atom, and
It represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aromatic ring group, or a substituted or unsubstituted heterocyclic group.
Further, X and Y may form a substituted or unsubstituted aliphatic ring, a substituted or unsubstituted aromatic ring, or a substituted or unsubstituted heterocycle. ] 2. An organic electroluminescence device comprising a light emitting layer composed of one or a plurality of organic compound thin films between a pair of electrodes, wherein at least one layer is provided.
An organic electroluminescence device, which is a layer containing the hole-transporting material described above. 3. An electrophotographic photoreceptor comprising a charge-generating material and a hole-transporting material on a conductive support,
An electrophotographic photoreceptor, wherein the hole transport material is the hole transport material according to claim 1.