Hole transport material and its use

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to a hole transport material having a phthalocyanine structure. The phthalocyanine compound can be used as a photosensitive material or an organic conductive material, and more specifically, it can be used as a hole transport material for an organic electroluminescence (EL) element or an electrophotographic photosensitive member used for a planar light source or a display.

【0002】

[Conventional technology]

Organic photoconducting materials developed as photosensitive materials and hole transporting materials have many advantages such as low cost, various processability, and pollution-free properties, and many compounds have been proposed. For example, oxaziazole derivative (US Pat. No. 3,189,447), oxazole derivative (US Pat. No. 3,257,203), hydrazone derivative (US Pat. No. 3,717,462, JP-A-54-59,143, US Pat. No. 4,150,978), triaryl. Pyrazoline 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. 4,232,103, JP-A-55-144,250) , Japanese Patent Application Laid-Open No. 56-119,132), Stillben Derivatives (Japanese Patent Laid-Open No. 58-190,953, Japanese Patent Application Laid-Open No. 59-195,658) and other organic photoconductive materials are disclosed.

【0003】

One of the technologies using the hole transport material is an organic EL device. EL devices using organic substances are expected to be used as solid-state light-emitting inexpensive large-area full-color display devices, and many developments have been made. Generally, EL is composed of a light emitting layer and a pair of counter electrodes sandwiching the 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 these electrons recombine with holes in the light emitting layer and emit energy as light when the energy level returns from the conduction band to the valence band.

【0004】

The conventional organic EL element has a higher drive voltage and lower emission brightness and luminous efficiency than the inorganic EL element. In addition, the deterioration of characteristics has not been significantly put into practical use. In recent years, organic EL devices in which thin films containing organic compounds with high fluorescence quantum efficiency that emit light at a low voltage of 10 V or less have been laminated have been reported and are attracting attention (Applied Physics Letters, Vol. 51, p. 913). , 1987). In this method, a metal chelate complex is used for the phosphor layer and an amine compound is used for the hole injection layer to obtain high-intensity green light emission, and the brightness is several hundred cd / m at a DC voltage of 6 to 7 V.², The maximum luminous efficiency is 1.5lm / W, which is close to the practical range.

【0005】

However, although the emission intensity of organic EL devices up to now has been improved by improving the configuration, they still do not have sufficient emission brightness. In addition, it has a big problem that it is inferior in stability during repeated use. Therefore, in order to develop an organic EL device having a larger emission brightness and excellent stability during repeated use, it is desired to develop a hole transporting material having excellent hole transporting ability and durability. It is rare.

【0006】

Further, as a technique using a hole transport material, an electrophotographic photosensitive member can be mentioned. The electrophotographic method is one of the image forming methods invented by Carlson. In this method, after charging the photoconductor by corona discharge, an optical image is exposed to obtain an electrostatic latent image on the photoconductor, and toner is adhered to the electrostatic latent image for development, and the obtained toner image is printed on paper. It consists of transferring to. The basic characteristics required for a photoconductor in such an electrophotographic method are that an appropriate potential is maintained in a dark place, that the electric charge is discharged in a small amount in a dark place, and that the electric charge is quickly discharged by light irradiation. And so on. Conventional electrophotographic photosensitive members have used inorganic photoconductors such as selenium, selenium alloy, zinc oxide, cadmium sulfide, and tellurium. These inorganic photoconductors have advantages such as high durability and a large number of printed sheets, but problems such as high manufacturing cost, inferior workability, and toxicity have been pointed out. .. Organic photoconductors have been developed to overcome these drawbacks, but conventional electrophotographic photosensitive members using organic photoconducting materials as hole transport materials have such characteristics as chargeability, sensitivity, and residual potential. At present, the electrophotographic characteristics are not always satisfied, and the development of a hole transporting material having excellent charge transporting ability and durability has been desired.

【0007】

[Problems to be Solved by the Invention]

An object of the present invention is to provide a hole transporting material having excellent hole transporting ability and durability, and further, excellent stability in repeated use using the hole transporting material. An object of the present invention is to provide an organic EL element and an electrophotographic photosensitive member. As a result of diligent studies by the present inventors, an organic EL device or an electrophotographic photosensitive member using at least one kind of hole transporting material represented by the general formula [1] has a large hole transporting ability and is used repeatedly. We have found that the stability is also excellent, and have reached the present invention. In the case of an organic EL device, it is difficult to form a uniform thin layer with the phthalocyanines described in JP-A-57-51781, JP-A-63-264692, etc. because the particle size of the pigment is too large. It was. Therefore, by introducing a soluble substituent into phthalocyanine, it became soluble in an organic solvent, and it became possible to form a thin uniform film by coating. Further, also in the vapor-deposited film, the introduction of a bulky substituent makes it difficult to aggregate after forming the thin film, so that deterioration of the device can be prevented. For the above reasons, stable hole transport characteristics were obtained.

【0008】

[Means for solving problems]

That is, the first invention is a hole transport material represented by the following general formula [1].

[1] [Chemical 3]

<img file="JPH07331237A_D0001.tif" />[In the formula, ring A¹~ A⁴Are independently substituted or unsubstituted aliphatic ring groups, substituted or unsubstituted carbocyclic aromatic ring groups, substituted or unsubstituted heterocyclic aromatic ring groups, substituted or unsubstituted heterocyclic groups. Represents. Substituent Y is a substituent (R) represented by the following general formulas [2] to [5].¹~ R¹⁰Are independent hydrogen atoms (however, R¹, R²Except for the case of. ), Substituted or unsubstituted aliphatic group, substituted or unsubstituted aliphatic ring group, substituted or unsubstituted carbocyclic aromatic ring group, substituted or unsubstituted heterocyclic aromatic ring group, substituted or It is an unsubstituted heterocyclic group. ). Z stands for oxygen or sulfur. p indicates an integer of 1 or 2. M represents a trivalent or tetravalent metal atom.

[Chemical 4]

<img file="JPH07331237A_D0002.tif" />【0009】

The second invention is an organic electroluminescence device, which comprises at least one layer of the hole transporting material according to claim 1.

【0010】

The third invention is an electrophotographic photosensitive member, which comprises at least one layer of the hole transporting material according to claim 1.

【0011】

Ring A of the compound represented by the general formula [1] in the present invention.¹~ A⁴Independently represent a substituted or unsubstituted aliphatic ring, a substituted or unsubstituted carbocyclic aromatic ring, a substituted or unsubstituted heterocyclic aromatic ring, and a substituted or unsubstituted heterocycle. Specific examples of the aliphatic ring include a cyclopentane ring, a cyclohexyl ring, and the like, and specific examples of the carbocyclic aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and the like, and a heterocyclic aromatic ring. Specific examples of the above include a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a quinoxaline ring and the like, and specific examples of the heterocycle include a pyrrolidine ring, a dioxane ring, a piperidine ring, a morpholin ring and the like.

【0012】

Specific examples of the substituent on the ring include halogen atoms such as chlorine, bromine, iodine and fluorine, methyl group, ethyl group, propyl group, butyl group, sec-butyl group, tert-butyl group and pentyl. Substituent or unsubstituted alkyl groups such as groups, hexyl groups, heptyl groups, octyl groups, stearyl groups, trichloromethyl groups, phenyl groups, naphthyl groups, 3-methylphenyl groups, 3-methoxyphenyl groups, 3-fluorophenyl groups, 3 Substituent or unsubstituted aryl group such as -trichloromethylphenyl group, 3-trifluoromethylphenyl group, 3-nitrophenyl group, methoxy group, n-butoxy group, tert-butoxy group, trichloromethoxy group, trifluoroethoxy group, penta Fluoropropoxy group, 2,2,3,3-tetrafluoropropoxy group, 1,1,1,3,3,Substituent or unsubstituted alkoxy group such as 3-hexafluoro-2-propoxy group, 6- (perfluoroethyl) hexyloxy group, phenoxy group, p-nitrophenoxy group, p-tert-butylphenoxy group, 3-fluoro Substitution of phenoxy group, pentafluorophenyl group, 3-trifluoromethylphenoxy group, etc. or unsubstituted aryloxy group, methylthio group, ethylthio group, tert-butylthio group, hexylthio group, octylthio group, trifluoromethylthio group, etc. Alternatively, substitution of an unsubstituted alkylthio group, phenylthio group, p-nitrophenylthio group, p-tert-butylphenylthio group, 3-fluorophenylthio group, pentafluorophenylthio group, 3-trifluoromethylphenylthio group, etc. Alternatively, a mono or di-substituted amino group such as an unsubstituted arylthio group, a cyano group, a nitro group, an amino group, a methylamino group, a diethylamino group, an ethylamino group, a diethylamino group, a dipropylamino group, a dibutylamino group or a diphenylamino group. , Bis (acetoxymethyl) amino group, bis (acetoxyethyl) amino group, bisacetoxypropyl) amino group, acylamino group such as bis (acetoxybutyl) amino group, hydroxyl group, syroxy group, acyl group, methylcarbamoyl group, dimethylcarbamoyl Carbomoyl group such as group, ethylcarbamoyl group, diethylcarbamoyl group, propylcarbamoyl group, butylcarbamoyl group, phenylcarbamoyl group, carboxylic acid group, sulfonic acid group, imide group, cyclopentane group, cyclohexyl group and other aliphatic ring groups. , Carbocyclic aromatic groups such as phenyl group, naphthyl group, biphenyl group, pyridine group, pyrazine group, pyrimidine group, pyridazine group, triazine group, indol group, quinoline group, acrydin group and other heterocyclic aromatic groups, There are heterocyclic groups such as pyrrolidine group, dioxane group, piperidine group, morpholine group, piperazine group and trithian group.Carbamoyl groups such as lucarbamoyl group, butylcarbamoyl group and phenylcarbamoyl group, carboxylic acid group, sulfonic acid group, imide group, cyclopentane group, aliphatic ring group such as cyclohexyl group, phenyl group, naphthyl group, biphenyl group and other carbon Heterocyclic aromatic groups such as cyclic aromatic groups, pyridine groups, pyrazine groups, pyrimidine groups, pyridazine groups, triazine groups, indol groups, quinoline groups, acrydin groups, pyrrolidine groups, dioxane groups, piperidine groups, morpholin groups. , Piperazine group, trithian group and other heterocyclic groups.Carbamoyl groups such as lucarbamoyl group, butylcarbamoyl group and phenylcarbamoyl group, carboxylic acid group, sulfonic acid group, imide group, cyclopentane group, aliphatic ring group such as cyclohexyl group, carbon such as phenyl group, naphthyl group and biphenyl group. Heterocyclic aromatic groups such as cyclic aromatic groups, pyridine groups, pyrazine groups, pyrimidine groups, pyridazine groups, triazine groups, indol groups, quinoline groups, acrydin groups, pyrrolidine groups, dioxane groups, piperidine groups, morpholin groups. , Piperazine group, trithian group and other heterocyclic groups.

【0013】

The central metal M may be any trivalent or tetravalent metal atom, but Al, Ga, In, Si, Ge or Sn is preferable.

Substituents R constituting [2] to [5]¹~ R¹⁰Typical examples of are methyl group, ethyl group, n-butyl group, t-butyl group, stearyl group, trichloromethyl group, trifluoromethyl group, 2,2,2-trifluoroethyl group, 2,2,3. , 3-Tetrafluoropropyl group, 2,2,3,3,3-Pentafluoropropyl group, 1,1,1,3,3,3-Hexafluoro-2-propyl group, 2,2,3,3 , 4,4-Hexafluorobutyl group, 2-methoxyethyl group and other substituted or unsubstituted aliphatic group, cyclopentane group, cyclohexyl group and other substituted or unsubstituted aliphatic ring group, phenyl group, naphthyl group, Substituted or unsubstituted carbocyclic aromatic groups such as biphenyl group, p-nitrophenyl group, pt-butylphenyl group, pentafluorophenyl group, pyridine group, pyrazine group, pyrimidine group, pyridazine group, triazine group, indol group , A substituted or unsubstituted heterocyclic aromatic group such as a quinoline group or an acrydin group, a pyrrolidine group, a dioxane group, a piperidine group, a morpholine group, a piperazine group, a tritian group or the like. Yes, these substituents R¹~ R¹⁰As the substituent substituted with, a specific example may be shown as the substituent constituting the ring. Further, adjacent substituents may be integrated to form a 5-membered ring or a 6-membered ring which may contain a nitrogen atom.

【0014】

In the present invention, the compound represented by the general formula [1] can be produced, for example, by the following method. Phthalonitriles represented by the following general formula [6], or isoidrin compounds represented by the following general formula [7], or corresponding phthalic anhydrides and phthalimides represented by M in the general formula [1]. A phthalocyanine compound represented by the general formula [8] can be produced by a conventional method using various metal salts of the above metals as starting materials.

【0015】

General formula [6] [Chemical 5]

<img file="JPH07331237A_D0003.tif" />【0016】

General formula [7] [Chemical 6]

<img file="JPH07331237A_D0004.tif" />【0017】

General formula [8] [Chemical 7]

<img file="JPH07331237A_D0005.tif" />【0018】

Next, the obtained phthalocyanine compound represented by the general formula [8] is reacted with a chlorophosphine derivative having a linear, branched or cyclic alkyl group or aryl group which may have various substituents. , A phthalocyanine compound represented by the general formula [1] can be produced.

【0019】

The representative examples of the compounds of the present invention are specifically illustrated in Table 1 below, but the present invention is not limited to the following representative examples.

【0020】

[table 1]

<img file="JPH07331237A_D0006.tif" />【0021】

<img file="JPH07331237A_D0007.tif" />【0022】

<img file="JPH07331237A_D0008.tif" />【0023】

<img file="JPH07331237A_D0009.tif" />【0024】

<img file="JPH07331237A_D0010.tif" />【0025】

<img file="JPH07331237A_D0011.tif" />【0026】

<img file="JPH07331237A_D0012.tif" />【0027】

<img file="JPH07331237A_D0013.tif" />【0028】

The hole transporting material of the present invention may be used alone or in combination. Further, it may be used in combination with other hole or electron transporting compounds. Since the compound of the present invention has excellent hole-transporting properties, it can be used extremely effectively as a hole-transporting material.

【0029】

First, a case where the compound represented by the general formula [1] is used as a hole transport material for an organic EL device will be described. Figures 1 to 3 show an example of a schematic diagram of the organic EL device used in the present invention. In the figure, 2 which is an electrode A is generally an anode, and 6 which is an electrode B is a cathode. Further, there is also an organic EL device laminated with a layer structure of (electrode A / light emitting layer / electron injection layer / electrode B), and the compound of the general formula [1] can be suitably used in any device structure.

Since the compound of [1] has a large carrier transport capability, it can be used as a carrier transport material in any of the hole injection layer 3, the light emitting layer 4, and the electron injection layer 5.

【0030】

For the light emitting layer 4 of FIG. 1, in addition to the compound of the general formula [1] of the present invention, a light emitting substance, a light emitting auxiliary material, a hole transporting material for carrier transporting, and an electron transporting material are used, if necessary. You can also do it. The structure of FIG. 2 separates the light emitting layer 4 and the hole injection layer 3. With this structure, the hole injection efficiency from the hole injection layer 3 to the light emitting layer 4 is improved, and the luminous brightness and the luminous efficiency can be increased. In this case, in order to achieve luminous efficiency, the light emitting substance itself used in the light emitting layer may be electron transportable, or an electron transporting material may be added to the light emitting layer to make the light emitting layer electron transportable. desirable.

【0031】

The structure of FIG. 3 has an electron injection layer 5 in addition to the hole injection layer 3 to improve the efficiency of hole-electron recombination in the light emitting layer 4. By forming the organic EL element into a multi-layer structure in this way, it is possible to prevent a decrease in brightness and life due to quenching. In the elements of FIGS. 2 and 3, if necessary, a luminescent substance, a luminescent auxiliary material, a hole transport material for carrier transport, and an electron transport material can be used in combination. Further, the hole injection layer, the light emitting layer, and the electron injection layer may each be formed by a layer structure of two or more layers.

【0032】

As the conductive material used for the anode of the organic EL element, a material having a work function larger than 4 eV is preferable, and carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, platinum, palladium, etc. And their alloys, ITO substrates, NESA substrates, metals such as tin oxide and indium oxide, and organic conductive resins such as polythiophene and polypyrrole are used. As the conductive substance used for the cathode, a substance having a work function smaller than 4 eV is preferable, and magnesium, calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese and the like and alloys thereof are used. , Not limited to these. The anode and cathode may be formed by a layer structure of two or more layers, if necessary.

【0033】

The organic EL element, in order to efficiently emit light, among the electrodes B indicated by the electrode A or 6 indicated by 2, and least one also is desirably sufficiently transparent in the emission wavelength region of the device. It is also desirable that the substrate 1 is also transparent. The transparent electrode is set so as to secure a predetermined translucency by a method such as thin film deposition or sputtering using the above-mentioned conductive substance. It is desirable that the electrode that extracts light emission has a light transmittance of 10% or more.

【0034】

The substrate 1 is not limited as long as it has mechanical and thermal strength and is transparent, but for example, a transparent resin such as a glass substrate, a polyethylene plate, a polyether sulfone plate, or a polypropylene plate may be used. can give.

【0035】

For the formation of each layer of the organic EL device according to the present invention, any method such as a dry film forming method such as vacuum deposition or sputtering or a wet film forming method such as spin coating or 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. The usual film thickness is preferably in the range of 5 nm to 10 μm, but more preferably in the range of 10 nm to 0.2 μm.

【0036】

In the case of the wet film formation method, a thin film is formed by using a liquid in which the material forming each layer is dissolved or dispersed in an appropriate solvent such as chloroform, tetrahydrofuran, dioxane, etc., and the solvent may be any. .. Further, in any of the organic layers, an appropriate resin or additive may be used in order to improve the film forming property and prevent pinholes in the film. Examples of such resins include insulating resins such as polystyrene, polycarbonate, polyallylate, polyester, polyamide, urethane, polysulfone, polymethylmethacrylate and polymethylacrylate, and photoconductive resins such as poly-N-vinylcarbazole and polysilane. , Polythiophene, polypyrrole and other conductive resins.

【0037】

In the light emitting layer, the hole injection layer, and the electron injection layer, this organic EL device can be used in addition to the compound of the general formula [1], as well as known light emitting substances, light emitting auxiliary materials, hole transporting materials, and electrons. Transport materials can also be used.

【0038】

Known luminescent substances or auxiliary materials for luminescent substances include anthracene, naphthalene, phenanthrene, pyrene, tetracene, coronene, chrysene, fluorescein, perylene, phthaloperylene, naphthaloperylene, perinone, phthaloperinone, naphthaloperinone, diphenylbutadiene, tetraphenylbutadiene, coumarin, Oxaziazole, aldazine, bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, oxine, aminoquinoline, imine, diphenylethylene, vinylanthracene, diaminocarbazole, pyrane, thiopyrene, polymethine, merocyanine, imidazole chelated oxinoid compound, quinacridone, There are, but are not limited to, rubrene and the like and derivatives thereof.

【0039】

As a hole transporting material that can be used in combination with the hole transporting material of the general formula [1], it has the ability to transport holes, has an excellent hole injection effect on the light emitting layer or the luminescent material, and emits light. Examples thereof include compounds that prevent the transfer of excitons generated in the layer to the electron injecting layer or the electron transporting material and have excellent thin film forming ability. Specifically, phthalocyanine compounds, naphthalocyanine compounds, porphyrin compounds, oxadiazole, triazole, imidazole, imidazolone, imidazolone, pyrazoline, pyrazolone, tetrahydroimidazole, oxazole, oxadiazol, hydrazone, acylhydrazone, poly. There are arylalkane, stillben, butadiene, benzidine type triphenylamine, styrylamine type triphenylamine, diamine type triphenylamine and their derivatives, and polymer materials such as polyvinylcarbazole, polysilane and conductive polymer. However, it is not limited to these.

【0040】

As an electron transporting material, it has an ability to transport electrons, has an excellent electron injecting effect on a light emitting layer or a luminescent material, and has excitons generated in the light emitting layer into a hole injecting layer or a hole transporting material. Examples thereof include compounds that prevent migration and have excellent thin film forming ability. For example, there are fluorenone, anthracinodimethane, diphenoquinone, thiopyrandioxide, oxadiazole, perylenetetracarboxylic dian, flaolenilidenemethane, anthracinodimethane, anthrone and their derivatives, but are limited thereto. It's not a thing. It is also possible to sensitize by adding an electron accepting substance to the hole transporting material and an electron donating substance to the electron transporting material.

【0041】

In the organic EL devices shown in FIGS. 1 to 3, 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 and light emitting material can be used. At least one of an auxiliary material, a hole transport material and an electron transport material may be contained in the same layer. Further, in order to improve the stability of the organic EL device obtained by 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, since the compound of the general formula [1] was used for the organic EL device in the present invention, the luminous efficiency and the luminous luminance could be increased. In addition, this element is extremely stable against heat and current, and since it is possible to obtain light emission brightness that can be practically used with a low drive voltage, deterioration, which has been a major problem in the past, can be significantly reduced. Was done.

【0042】

The organic EL element of the present invention is considered to be applied to a flat panel display such as a wall-mounted television, a light source such as a copier or a printer, a light source such as a liquid crystal display or an instrument, a display board, an indicator light or the like as a flat light emitter. , Its industrial value is very large.

【0043】

Next, a case where the compound represented by the general formula [1] of the present invention is used as an electrophotographic photosensitive member will be described. The compound represented by the general formula [1] of the present invention can be used in any layer of the electrophotographic photosensitive member, but it is desirable to use it as a hole transport material because it has high hole transport properties. The compound acts as a hole transporting substance, can transport the electric charge generated by absorbing light extremely efficiently, and can obtain a photoconductor having excellent high-speed response. Further, since the compound is excellent in ozone resistance and photostability, a photoconductor having excellent durability can be obtained.

【0044】

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

【0045】

Charge generating materials include bisazo, quinacridone, indigo, perylene, perinone, polycyclic quinone, squarylium salt, azulenium salt, phthalocyanine, naphthalocyanine and other organic compounds, or selenium, selenium-tellu alloy, cadmium sulfide, zinc oxide, etc. Examples include inorganic substances such as amorphous silicon.

【0046】

Each layer of the photoconductor can be formed by a vapor deposition or dispersion coating method. Dispersion coating is performed using a spin coater, applicator, spray coater, immersion coater, roller coater, curtain coater, bead coater, etc., and drying is performed under static or blowing conditions in the range of room temperature to 200 ° C. for 10 minutes to 6 hours. Do it with. The film thickness of the photosensitive layer after drying is 5 microns to 50 microns in the case of a single-layer type photosensitive member, and the charge generation layer is 0.01 to 5 microns, preferably 0.1 to 1 micron in the case of a laminated type photosensitive member, and holes. The transport layer is preferably 5 to 50 microns, preferably 10 to 20 microns.

【0047】

The resin used for forming the photosensitive layer of the single-layer type photoconductor, the charge generation layer of the laminated photoconductor, or the hole transport layer can be selected from a wide range of insulating resins. Further, it can be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polysilanes. Preferably, insulating resins such as polyvinyl butyral, polyarylate, polycarbonate, polyester, phenoxy, acrylic, polyamide, urethane, epoxy, silicon, polystyrene, polyvinyl chloride, salt and vinegar copolymer, phenol and melamine resin are mentioned. Can be done. The resin used to form 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 this is not the case. Two or more types of resins may be used in combination. Moreover, if necessary, resin may not be used. Further, the charge generation layer can be formed by a physical film forming method such as thin film deposition or sputtering. In the vapor deposition and sputtering methods, preferably 10^-5It is desirable to form a film in a vacuum atmosphere below the Toor. It is also possible to form a film in an inert gas such as nitrogen, argon or helium.

【0048】

The solvent used when forming each layer of the electrophotographic photosensitive member is preferably selected from those that 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. , Dichloroethane, trichloroethylene and other aliphatic halogenated hydrocarbons, chlorobenzene, dichlorobenzene and other aromatic halogenated hydrocarbons, tetrahydrofuran, dioxane and the like ethers and the like are used, but are not limited thereto.

【0049】

The hole transport layer is formed by applying only the hole transport material or a coating liquid in which the hole transport material is dissolved in a resin. The hole transporting material used in this photoconductor can be used in combination with other hole transporting materials in addition to the compound of the general formula [1].

The compound of [1] has good compatibility with the resin and crystals are less likely to precipitate, which is advantageous for improving sensitivity and durability.

【0050】

In order to improve electrophotographic characteristics, image characteristics, etc., an undercoat layer can be provided between the substrate and the organic layer if necessary, and the undercoat layers include polyamides, casein, polyvinyl alcohol, gelatin, and polyvinyl butyral. Resins such as, and metal oxides such as aluminum oxide are used. The material of the present invention is suitable as a hole transport material for electrophotographic photosensitive members for copiers and printers.

【0051】

[Example]

Hereinafter, the present invention will be described in more detail based on examples. Method for synthesizing compound (9) Add 10 parts of 4- (2,2-bis (trifluoromethyl) propyl) oxy-1,3-diiminoisoindoline and 15 parts of silicon tetrachloride to 100 parts of o-dichlorobenzene and 30 parts of tri-n-butylamine. After heating and stirring at 160 to 170 ° C for 8 hours, the mixture was cooled and diluted with 500 parts of methanol. The precipitated precipitate was separated by filtration, washed with a mixed solution of methanol / water (4/1), and dried to obtain 10 parts of a green powder. As a result of molecular weight analysis, this powder was dihydroxysilicon phthalocyanine of the general formula [8]. After stirring and dissolving 5 parts of the dihydroxysilicon phthalocyanine obtained above in 100 parts of pyridine and 25 parts of n-tributylamine, 10 parts of chlorodiphenylphosphine is added while cooling, and the mixture is heated and stirred at 100 ° C for 2 hours before precipitation. The precipitate was separated by filtration, washed with water and dried to obtain 4 parts of a phthalocyanine compound (9). As a result of molecular weight analysis, it was confirmed that this powder was a phthalocyanine compound (9). The results of elemental analysis of the product are shown below. Elemental analysis results C₇₆H₅₂F₂₄N₈O₈P₂As Si Calculated value (%): C: 52.11 H: 2.97 N: 6.40 Measured value (%): C: 52.42 H: 2.51 N: 6.27 [0052]

Example 1 Compound (4), tris (8-hydroxyquinolin) aluminum complex, and polycarbonate resin (PC-A) were dissolved in tetrahydrofuran at a ratio of 3: 2: 5 on a washed glass plate with ITO electrode, and the spin coating method was used. A light emitting layer having a film thickness of 100 nm was obtained. An electrode having a film thickness of 150 nm was formed on the electrode with a 10: 1 mixture of magnesium and silver to obtain the organic EL device shown in FIG. This element is 180 cd / m at a DC voltage of 10 V.²Luminescence was obtained.

【0053】

Example 2 Compound (1) was dissolved in tetrahydrofuran on a washed glass plate with an ITO electrode, and a hole injection layer having a film thickness of 50 nm was obtained by a spin coating method. Next, a tris (8-hydroxyquinoline) aluminum complex was vacuum-deposited to form a light emitting layer having a thickness of 30 nm, and an electrode having a thickness of 100 nm was formed on the light emitting layer with a mixture of magnesium and silver at a ratio of 10: 1. The organic EL device shown in Fig. 2 was obtained. 10 hole injection layer and light emitting layer^-6Deposition was performed in Torr's vacuum under the conditions of substrate temperature and room temperature. This element is about 250 cd / m at a DC voltage of 10 V.²Luminescence was obtained.

【0054】

Example 3 Compound (10) was dissolved in tetrahydrofuran on a washed glass plate with an ITO electrode, and a hole injection layer having a film thickness of 50 nm was obtained by a spin coating method. Next, a tris (8-hydroxyquinoline) aluminum complex was vacuum-deposited to form a light emitting layer having a thickness of 30 nm, and an electrode having a thickness of 100 nm was formed on the light emitting layer with a mixture of magnesium and silver at a ratio of 10: 1. The organic EL device shown in Fig. 2 was obtained. Light emitting layer is 10^-6Deposition was performed in Torr's vacuum under the conditions of substrate temperature and room temperature. This element is about 410 cd / m at a DC voltage of 10 V.²Luminescence was obtained.

【0055】

Example 4 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 20 nm. Further, N, N'-diphenyl-N, N'-(3-methylphenyl) -1,1'-biphenyl-4,4'-diamine was vacuum-deposited to obtain a hole transport layer having a film thickness of 30 nm. It was. Next, a tris (8-hydroxyquinoline) aluminum complex was vacuum-deposited to form a light emitting layer having a thickness of 30 nm, and an electrode having a thickness of 100 nm was formed on the light emitting layer with a mixture of magnesium and silver at a ratio of 10: 1. Obtained an organic EL element. 10 hole injection layer and light emitting layer^-6Deposition was performed in Torr's vacuum under the conditions of substrate temperature and room temperature. This element is about 310 cd / m at a DC voltage of 10 V.²Luminescence was obtained.

【0056】

Example 5 N, N'-diphenyl-N, N'-(3-methylphenyl) -1,1'-biphenyl-4,4'-diamine is vacuum-deposited on a cleaned glass plate with ITO electrode to form a film. A 50 nm hole injection layer was obtained. Next, a tris (8-hydroxyquinoline) aluminum complex and compound (2) were vacuum-deposited at a ratio of 3: 1 to form a light emitting layer having a film thickness of 50 nm, on which magnesium and silver were mixed at a ratio of 10: 1. An electrode having a film thickness of 150 nm was formed from the alloy, and the organic EL element shown in FIG. 2 was obtained. 10 hole injection layer and light emitting layer^-6Deposition was performed in Torr's vacuum under the conditions of substrate temperature and room temperature. This element is about 270 cd / m at a DC voltage of 10 V.²Luminescence was obtained.

【0057】

Example 6 Compound (13) was dissolved in chloroform on a washed glass plate with an ITO electrode, and a hole injection layer having a film thickness of 50 nm was obtained by a spin coating method. Next, a light emitting layer having a thickness of 50 nm of a tris (8-hydroxyquinoline) aluminum complex was prepared by a vacuum deposition method, and then [2- (4-tert-butylphenyl) -5- (biphenyl) -1 was further produced by a vacuum deposition method. , 3,4-Oxadiazole] was obtained with an electron-injected layer having a film thickness of 20 nm. An electrode having a film thickness of 150 nm was formed on the electrode with a mixture of magnesium and silver at a ratio of 10: 1 to obtain an organic EL device shown in FIG. This element is about 290 cd / m at a DC voltage of 10 V.²Luminescence was obtained.

【0058】

1mA / cm for all organic EL devices shown in this example²When the light was continuously emitted at, stable light emission could be observed for 1000 hours or more. The organic EL device of the present invention achieves improved luminous efficiency, luminous brightness and extended life, and is used in combination with a luminous substance, a light emitting auxiliary material, a hole transporting material, an electron transporting material, a sensitizer, and the like. The resin, electrode material, etc. and the device manufacturing method are not limited.

【0059】

Example 7 4 g of ε-type copper phthalocyanine, 2 g of compound (4), and 14 g of polyester resin (Byron 200: manufactured by Toyoho Co., Ltd.) 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 electrophotographic photosensitive member having a film thickness of 15 microns as shown in FIG.

【0060】

Example 8 6 g of dibromoanthanthrone, 2 g of compound (11), and 12 g of polyester resin (Byron 200: manufactured by Toyo Defense Co., Ltd.) 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 electrophotographic photosensitive member having a film thickness of 15 microns as shown in FIG.

【0061】

Example 9 2 g of τ-type metal-free phthalocyanine and 2 g of polyvinyl butyral resin (BH-3: manufactured by Sekisui Chemical Co., Ltd.) 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 prepare a charge generation layer having a film thickness of 0.3 micron. Next, 10 g of compound (5) and 10 g of polycarbonate resin (L-1250; manufactured by Teijin Chemicals Ltd.) were dissolved in 80 g of dichloromethane. This coating liquid was applied onto the charge generation layer and dried to form a charge transport layer having a film thickness of 20 microns, and the laminated electrophotographic photosensitive member shown in FIG. 5 was prepared. Example 10 N, N'-bis (2-carbomethoxyphenyl) -3,4,9,10-perylene carboxyimide 2g, polyvinyl butyral resin (BH-3: manufactured by Sekisui Chemical Co., Ltd.) 2g with tetrahydrofuran 96g in a ball mill Dispersed for 2 hours. This dispersion was applied onto an aluminum substrate and dried to prepare a charge generation layer having a film thickness of 0.3 micron. Next, 10 g of compound (10) and 10 g of polycarbonate resin (L-1250; manufactured by Teijin Chemicals Ltd.) were dissolved in 80 g of dichloromethane. This coating liquid was applied onto the charge generation layer and dried to form a charge transport layer having a film thickness of 20 microns, and the laminated electrophotographic photosensitive member shown in FIG. 5 was prepared.

【0062】

The electrophotographic characteristics of the electrophotographic photosensitive member were measured by the following method. Electrostatic copying paper test equipment (EPA-8100; manufactured by Kawaguchi Electric Works, Ltd.) irradiates static mode 2, corona charging with white light of -5.2 (kV), 5 (lux), and initial surface potential ( V₀), V₀Surface potential (V) when left in the dark for 2 seconds₂) Ratio (dark attenuation: DDR₂= V₂/ V₀), Half exposure sensitivity (E) from the time when the charge amount decreases to 1/2 of the initial value after light exposure_1/2) And surface potential (VR) 3 seconds after light exposure₃) Was examined. Table 2 shows the electrophotographic characteristics of the electrophotographic photosensitive members of Examples 8 to 11.

【0063】

[Table 2]

<img file="JPH07331237A_D0014.tif" />【0064】

When the electrophotographic characteristics were measured repeatedly 10,000 times or more, stable surface potentials and sensitivities could be obtained for all the electrophotographic photosensitive members shown in this example.

[Effect of the invention]

According to the present invention, a compound having an excellent hole transporting ability could be obtained. The compound provided by the present invention has higher luminous efficiency and higher brightness than conventional compounds, and is excellent in long-life organic EL devices and initial electrophotographic characteristics such as sensitivity, hole transport characteristics, initial surface potential, and dark attenuation rate. It was possible to obtain an electrophotographic photosensitive member with less fatigue due to repeated use.

[Simple explanation of drawings]

[Figure 1]

Sectional drawing which shows the schematic structure of the organic EL element used in an Example. [Figure 2]

Sectional drawing which shows the schematic structure of the organic EL element used in an Example. [Fig. 3]

Sectional drawing which shows the schematic structure of the organic EL element used in an Example. [Fig. 4]

Sectional drawing which shows the schematic structure of the electrophotographic photosensitive member used in an Example. [Fig. 5]

Sectional drawing which shows the schematic structure of the electrophotographic photosensitive member used in an Example. [Explanation of symbols]

1. Board 2. Electrode A 3. Hole injection layer 4. Light emitting layer 5. Electron injection layer 6. Electrode B 7.Al substrate 8. Photosensitive layer 9. Charge generation layer 10. Hole transport layer