JPH0973180A - Photoconductive body and photosensitive body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photoconductive body which a high charge generating efficiency can be obtd. by irradiation of light and a large difference in conductivity is obtd. between the states during irradiation of light and no irradiation of light by incorporating at least one kind of amorphous fullerene or its deriv. SOLUTION: Among fullerenes which are one kind of carbon clusters, a fullerene having no crystallinity or low crystallinity gives a high charge generating efficiency by irradiation of light, and therefore, this photoconductive material contains at least one kind of amorphous fullerene or its deriv. The photosensitive body using this photoconductive body is produced by forming the photoconductive body 15 on an electrode substrate 11 as a conductive substrate. The photoconductive body 15 contains dispersion of a charge generating material 13 and a charge transfer material 14 in a matrix polymer 12. Thereby, the photoconductive body containing a fullerene in which a high charge generating efficiency can be obtd. by irradiation of light can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor, and more particularly to a photoconductor having a good charge generation efficiency.

[0002]

2. Description of the Related Art In recent years, it has become clear that fullerenes such as C _{60 and} C ₇₀ have various characteristics, and the research thereof has been actively conducted. For example USP
In 5,250,378, one of the properties of the fullerenes is that they have a function as a photoconductor. Specifically, in a polymer forming a charge transfer complex with a fullerene, a saturated amount of fullerene or more is mixed, or a charge transfer complex composed of a donor compound and a fullerene is mixed and then mixed into the polymer to obtain a charge of the fullerene. It has been reported that a photoconductor having a high charge transporting ability was formed as a result of using a photoconductor made of a transfer complex as a photoconductor.

However, for example, [J. Mort, M. Mu
chorkin, R. Ziolo, and I. Chen, Appl. Phys. Left.,
61, 1829 (1992)],
Photoconductors using fullerenes have lower photocarrier generation efficiency than conventionally used charge generating materials,
The photoconductor described in Japanese Patent No. 5,250,378 still has insufficient charge generation efficiency, and is far from practical use as an electrophotographic photoconductor, for example.

[0004]

As described above, conventional photoconductors using fullerenes have low charge generation efficiency by light irradiation and are not suitable for practical use as charge generation materials. The present invention has been made in view of the problems as described above, and it is possible to obtain high charge generation efficiency by light irradiation,
It is an object to provide a photoconductor having a large difference in conductivity between light irradiation and non-irradiation.

[0005]

The first aspect of the present invention is a photoconductor containing at least one of amorphous fullerene and its derivatives. A second invention of the present application is at least one of fullerene having a crystal structure and a derivative thereof, in which a two-body distribution function g (R) obtained from a structural analysis is 0.7 to 1.3 in a region having a distance of 30 Å or more. A photoconductor containing a seed.

The third invention of the present application is a photoconductor containing at least one of fullerene and its derivatives, in which a boson peak is observed in a region of inelastic neutron scattering of 5 meV or less at a temperature below the glass transition point.

According to a fourth aspect of the present invention, the dark conductivity is 5 × 10 ¹⁴ or less under a voltage of 50V.
The photoconductor according to any one of 1 to 3. A fifth invention of the present application is the photoconductor according to any one of the first to third inventions, wherein 50 wt% or more of at least one of the fullerenes and derivatives thereof is a carbon cluster having a basic skeleton having 70 or more carbon atoms. .

The sixth invention of the present application is the photoconductor according to the first invention, wherein at least one of the fullerenes and derivatives thereof is molecularly dispersed in a matrix polymer. A seventh invention of the present application is that the film thickness is 5 μm or more and 300 μm.
The photoconductor according to the fifth aspect of the invention described below.

An eighth invention of the present application is the photoconductor according to the first invention, which is substantially composed of a charge generating material.
The ninth invention of the present application is the photoconductor according to the eighth invention, wherein the film thickness is 1 μm or less.

The tenth invention of the present application comprises a conductive support and a charge transport layer formed on the conductive support and a charge generation layer comprising the photoconductor described in the first invention. This is a photoconductor.

The eleventh invention of the present application is a photoconductor containing at least one of fullerene and its derivative, wherein (1) the crystal structure of at least one of fullerene and its derivative is amorphous; (2) fullerene and The two-body distribution function g (R) obtained from the structural analysis of at least one of the derivatives has a distance of 30.
At least one in the range of 0.7 to 1.3 in the region above angstrom; and (3) boson peaks are observed in the region below 5 meV inelastic neutron scattering at temperatures below the glass transition point. It is a photoconductor that satisfies the conditions.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention can obtain a high charge generation efficiency by light irradiation when a fullerene of one kind of carbon cluster has no crystallinity or has low crystallinity. The present invention was found out and the present invention was completed.

The fullerene used in the present invention is a carbon cluster having a three-dimensional structure in which the basic skeleton is often composed only of carbon and is composed of a 5-membered ring or a 6-membered ring. For example, C ₆₀ , which is a soccer ball-like molecule with 60 carbon atoms attached. C
₆₀ is called Buckminster fullerene or bucky ball.

Further, the fullerene used in the present invention has a larger number of carbon atoms in addition to C ₆₀ ,
C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₇₂₀ , C ₉₆₀ , a cylindrical tube that extends long, a C ₅₀₀ , C ₅₄₀ called a nanotube, and a bucky ball are concentric burrs. Bucky onion is.

Further, the fullerenes include metal-encapsulated fullerenes in which carbon atoms are doped with metal atoms, for example, an alkali metal such as La, more specifically, La-doped C ₈₂ , Sc-doped C _{82 and the} like. Be done. That is, the fullerene used in the present invention is
Carbon clusters composed only of carbon-carbon bonds,
Alternatively, the carbon cluster contains a metal.

The fullerene derivative used in the present invention is obtained by adding or substituting a substituent consisting of various atoms or atomic groups to a fullerene only by either a covalent bond or a Van der Waals force bond.

Further, the fullerene derivative as referred to herein includes a fullerene derivative having a fullerene in its main chain or side chain as long as it does not form a complex. Specific examples of the fullerene derivative include C ₆₀ O, C ₆₀ -1,3, dioxolane, and partial substitution of a substituent such as an alkyl group such as a methyl group, a tert-butyl group or a benzyl group on a part of fullerene with a covalent bond. Dimerized or fullerene,
Examples include trimers, tetramers, and pentamers.

A compound in which an ionized fullerene and an ionized molecule having an opposite charge to each other, such as a charge transfer complex, is not a fullerene derivative. That is,
In the charge transfer complex, electrons and holes are separated into fullerene and host molecule, and they are bonded (ionic bond) by the Coulomb force between them, and as a result, there are many charges when light is not irradiated and the conductivity increases. Becomes higher. Therefore, the ratio (gain) of conductivity between light irradiation and non-light irradiation, which affects the performance of the device, becomes small. If this gain is small, the function as a photoconductor is significantly reduced, such as the initial charging potential (pre-exposure potential) is small when used for a photoconductor or the like. Therefore, in the present invention, ionized fullerene is used. It is not possible to use a product in which an ionized molecule having an opposite charge to this is combined with.

The details will be described below. These flags
Among fullerenes, fullerenes having a higher skeleton such as C ₇₀ as a basic skeleton have higher charge generation efficiency than fullerenes having C ₆₀ as a basic skeleton and are suitable as a charge generating agent. The amount of higher fullerenes in all fullerenes is 50w
It is desirable that the content be t% or more, and further 80 wt% or more.

Further, C ₆₀ is excellent in mass productivity because it has higher purification efficiency than high-order fullerenes. Therefore, by setting the amount of C _{60 in} all the fullerenes to 50 wt% or more, the mass productivity of photoconductors can be improved.

Fullerenes, which are photoconductors, generate excitons by light irradiation and the like, and as a result, carriers are generated and function as photoconductors. The excitons include Frenkel excitons and charge transfer excitons. Compared to Frenkel excitons, charge transfer excitons quickly become self-confined, emit light or heat, and return to the ground state to be deactivated, that is, increase the amount of Frenkel excitons and improve carrier generation efficiency. You can

Here, the fullerene, which is a photoconductor, has a high crystallinity so that charge transfer excitons are mainly generated and the amount of the Frenkel excitons is small, and the amount of the Frenkel excitons increases as the crystallinity disappears. I think that the. Based on such knowledge, the first invention of the present application was reached.

That is, the photoconductor in the first invention of the present application is a photoconductor containing an amorphous fullerene in which a peak peculiar to fullerene is not observed by X-ray diffraction. A photoconductor containing amorphous fullerenes can be obtained, for example, by molecularly dispersing fullerenes in a matrix polymer.

The photoconductor in which fullerene molecules are molecularly dispersed in a matrix polymer can be obtained, for example, by dissolving the fullerene and the matrix polymer in a solvent and drying the dissolved product by heating or the like.

At this time, if the amount of fullerenes is equal to or higher than the saturated solubility of the solvent, the fullerenes that are not completely dissolved in the solvent remain in the crystalline state, and
Crystals of fullerenes remain. The first invention of the present application may include a crystal of such fullerenes as long as it has a system in which fullerenes are molecularly dispersed. However, in order to improve the charge generation efficiency, It is desirable that the content of the fullerene crystals in the photoconductor be 10 wt%.
Below, it is more preferable that all fullerene in the photoconductor be amorphous. Therefore, when the method for producing a photoconductor as described above is used, it is desirable that the amount of fullerenes be not more than the saturated solubility of the solvent.

Furthermore, if there are many crystals of fullerenes,
Since the light transmittance is lowered, the light irradiation amount is reduced in proportion to the depth direction. From this point of view, the charge generation efficiency can be improved by not including crystals in the matrix polymer.

When the amount of fullerenes is set to be equal to or higher than the saturated solubility of the matrix polymer, crystals of fullerenes may be formed in the matrix polymer, and those containing crystals of fullerenes are included. As mentioned above, it is not desirable. However, if the amount of fullerenes is equal to or lower than the saturated solubility of the solvent, the fullerenes are molecularly dispersed in the solvent, and even if the amount of fullerenes is equal to or higher than the saturated solubility of the matrix polymer, this solvent is used. If the fullerenes are rapidly dried before crystallizing, the precipitate of fullerenes becomes amorphous. Also,
Depending on the drying speed during rapid drying, some crystalline fullerenes may be precipitated, but even in this case, the amount of amorphous fullerene in the matrix polymer can be increased and the charge generation amount can be improved. It becomes possible.

As described above, the content of fullerenes may be appropriately selected according to need such as charge generation efficiency and charge generation amount. The rapid drying method is not particularly limited as long as it is a method of shortening the drying time compared to natural drying at room temperature and atmospheric pressure, and examples thereof include a vacuum drying method and a heat drying method. The vacuum drying method mentioned here is a method in which the solvent in the sample is evaporated and dried in a vacuum of 0.1 Torr or less for 10 seconds to 30 minutes. The heating and drying method is a method in which the substrate coated with the composition preparation solution is heated at a temperature equal to or lower than the boiling point of the solvent, and the solvent in the sample is evaporated and dried, for example, in 10 seconds to 30 minutes. Also, the drying time can be shortened by setting the atmosphere for drying to low humidity. Further, by using these drying methods together, it becomes possible to further shorten the drying time.

Examples of the solvent used in the above-mentioned production method include alcohols, ketones, amides, sulfoxides, esters, aromatic halogenated hydrocarbons, aromatics and the like. Among them, toluene, Carbon disulfide, benzene, methylene chloride, normal hexane and the like are suitable because they dissolve a large amount of fullerene.
Further, as described above, the function as a photoconductor is significantly deteriorated when a charge transfer complex is formed. Therefore, the solvent to be used must not be one that changes a fullerene into a charge transfer complex.

As the matrix polymer constituting the photoconductor, it is not possible to use a matrix polymer which is mixed with the fullerenes to change the structure thereof to a structure different from that of the fullerenes defined in the present invention. Specifically, a polysilane compound,
It is not possible to use polyvinyl carbazole and its derivatives, polyvinyl triphenylamine, and the like that form a charge transfer complex by mixing with fullerene. Further, the optically active polymer is preferably an optically inactive polymer because it may reduce the quantum efficiency of fullerenes. In order to further increase the charge generation amount, it is necessary to increase the amount of fullerenes contained in the matrix polymer. Therefore, it is desirable that the solubility of fullerenes is large. Specifically, the fullerenes are 0.1 wt% or more. It is desirable to use one that can be dissolved.

Specific examples of the matrix polymer used include polyethylene resin, nylon resin,
Polyester resin, polycarbonate resin, polyarylate resin, butyral resin, phenol resin, styrene-butadiene copolymer resin, polyvinyl acetal resin, diallyl phthalate resin, polysulfone resin, acrylic resin, vinyl acetate, polyphenylene oxide resin,
Examples thereof include alkyd resin, styrene-maleic anhydride copolymer resin, vinyl chloride-vinyl acetate copolymer resin, polyester carbonate, polyvinyl chloride, polyvinyl acetal, and polyarylate. These matrix polymers may be used alone or in combination of two or more.

The second and third inventions of the present application are based on the first invention. In the first invention of the present application, it is specified that an amorphous fullerene in which a peak specific to fullerene is not observed by X-ray diffraction specific to fullerene is contained, but the present inventors further proceed with research. As a result, the photoconductor of the present invention is excellent, that is, the photocarrier generation efficiency is high, unlike the crystal, the energy level fluctuates due to the interaction with the adjacent molecule, whereby the excited state of It was predicted that the service life would be extended. Therefore, if it is not a single crystal but an aggregate state in which the level fluctuates, it is not always amorphous or microcrystalline (a state in which a domain of fullerene which is a crystalline structure exists in an amorphous fullerene). ), And it is considered that a polycrystal may be used as long as the long-range order of the crystal structure is lacking, and the second and third inventions of the present application have been reached.

That is, a fullerene containing at least one of fullerene and a fullerene derivative is contained,
The crystalline state of the fullerenes is amorphous even for a photoconductor in which the two-body distribution function g (R) obtained from the structural analysis is 0.7 to 1.3 in the region where the distance is 30 Å or more. It is possible to increase the charge generation efficiency by the same mechanism as fullerenes.

FIG. 1 shows the two-body distribution function g with respect to the distance R.
It is a figure which shows (R). The 2-pair distribution function g (R) is the probability of finding another molecule at a point separated by R when there is one atom at the origin, and g (R ) = 1. Further, in the case of a molecular state having a perfect crystal structure, a peak exists only at the R position due to the grain system of the molecule, and g (R) becomes 0 at the other R positions. For example, in the case of C _{60 having} a hexagonal close-packed structure, the diameter of the molecule is 14.17 (A) and R is 14.17 (A), 20.
(A), 24.5 (A), 31.7 (A), 34.7
(A), 40.1 (A), 42.5 (A), 44.8
Peaks are observed only at the positions of (A), ... And g (R) becomes 0 except for these values. Then, as the crystallinity is lost, g (R) becomes a curve in which R converges to 1 while having a maximum value due to the position of the peak.

That is, in the second invention of the present application, even if the fullerenes are polycrystals, the maximum and minimum values of g (R) are 0.7 to 7 in the region where R is 30 (A). 1.
If the crystallinity is lost to such an extent that it falls within the range of 3, it is possible to increase the charge generation efficiency by the same mechanism as that of the amorphous fullerenes.

Further, the fluctuation of the energy level due to the interaction with the adjacent molecule also exists in the following cases. For example, for photoconductors in which the crystalline state of fullerenes is such that a boson peak is observed in the region of neutron inelastic scattering of 5 meV or less at a temperature below the glass transition point, a charge is generated by a mechanism similar to that of amorphous fullerenes. It is possible to increase efficiency.

A method for producing fullerenes in an aggregated state of any of amorphous, microcrystalline or polycrystalline lacking long-range order of crystal structure will be described below. For example, it can be manufactured through the following two processes.

(1) First, the system is brought into a high energy state by some method. (2) Next, energy is rapidly taken from the system. The high energy state here includes liquid, gas, plasma state and the like. In order to rapidly remove heat from these high energy systems, they are brought into contact with cold objects or deposited on the substrate. Specifically, there are quenching of liquid, physical vapor deposition of gas, etc., usable methods are
There are a vacuum vapor deposition method, a sputtering method, a quenching method and the like.

As another method, there is a method of adding energy to a certain aggregated state to change the aggregated state. In the case of fullerenes, the crystal structure is based on the Van der Waals force, and thus the assembly state desired by the present invention can be achieved relatively easily by this method. Examples of such a method include a treatment method using mechanical stress, a treatment method of immersing in a solvent, neutron irradiation, electron beam irradiation, and laser ablation.

Next, a specific method for forming the aggregated state of fullerenes used in the present invention will be described.
The former typical method by thermal evaporation is as follows. First, the substrate is first incorporated into the vapor deposition device. At this time, as the temperature of the substrate is lower, the long-range order of the obtained polycrystalline crystal structure is lacking or becomes amorphous.
Specifically, 90 ° C. or lower is suitable, and preferably 10
It is desirable to set the temperature to 50 ° C to 50 ° C. Next, the fullerene to be vapor deposited is held on the vapor deposition board.

Subsequently, vapor deposition is performed using, for example, a fullerene film having a C ₆₀ concentration of 99% or more. At this time, it is desirable to pretreat by heating or the like to remove impurities having a low boiling point. Therefore, while the substrate is masked, the atmosphere in the vapor deposition apparatus is removed by a rotary pump or a diffusion pump to achieve a vacuum degree of 5 × 10 ⁻⁷ Pa and the vapor deposition board temperature is 320 ° C. to 550 ° C. It is desirable to heat to a moderate temperature.

Then, 0.1 [angstrom / mi
n] or more. As a result, an amorphous C ₆₀ film can be obtained. Even if the temperature of the substrate is controlled to a predetermined temperature, the temperature may temporarily become higher than that temperature, but it does not matter even if such a case occurs. Further, the temperature of the vapor deposition board depends on the structure of the fullerenes to be vapor deposited, the shape of the board, the degree of vacuum, etc., and therefore may be set to an appropriate temperature. For example, the vapor deposition source is set to C ₆₀ under the above conditions.
When the temperature is changed from C ₇₀ to C ₇₀ , the temperature of the vapor deposition board is 420 ° C to 6
It is suitable to set the temperature to about 80 ° C.

The vapor deposition rate is preferably high,
The range of 0.1 to 10 ² [Angstrom / min] is preferable. Next, the sputtering method will be described.
First, fullerenes are placed on the target, the substrate is held, and the degree of vacuum is set within the range of 10 Pa to 10 ⁻³ Pa by introducing an inert gas while reducing the pressure in the sputtering apparatus. After that, voltage is applied, plasma discharge is made, charged particles are hit on the fullerene which is the target,
Attach to substrate. At this time, the charged particles in the sputtering apparatus are not particularly limited as long as they are atoms such as Ar, N and Xe which are normally used for sputtering in addition to inert gas such as O.

The quenching method is a method of quenching fullerenes in a liquid or gas state. As an example, the inside of the apparatus is decompressed to a degree of vacuum of, for example, 10 ⁻⁴ Pa to 100 Pa, and C ₆₀ on the board is heated to a temperature equal to or higher than the melting point in the apparatus to be in a liquid state. After this, the temperature of each board is 50K
Transfer to 150K metal and cool. Then, an amorphous bulky fullerene class aggregate is generated. The lower the temperature of the metal at this time, the lower the crystallinity of the obtained fullerene.

The latter method, which is one of methods for applying energy to the fullerene aggregate to change the aggregate state, is a method of applying mechanical stress in a solvent. This will be specifically described as follows. First, as a method of applying the mechanical stress, there is a method of using a ball mill. This is a container containing balls in a container made of ceramic, metal, glass, polymer or the like. There are various sizes of containers, for example, a volume of 0.5 ml to 1000 ml. The ball is contained in a single or multiple containers, for example, 30% of the container including the volume of voids.
Try to fit in ~ 70% capacity.

Specifically, a diameter of 5 m in a 100 ml container
Introduce 400 m balls. For example, 20 ml of toluene as a solvent, 1 g of fullerene C ₇₀ and 2 g of polystyrene as a binder polymer are put in a container containing a ball, and the container is rotated by a ball milling device.
Add energy to the fullerene while hitting the ball with the container. By continuing this treatment for 2 hours or more, preferably about 50 hours, an aggregated state in which the long-range order of the crystal structure is lacking can be formed. By increasing this processing time, it becomes possible to further reduce the crystallinity and make it amorphous.

As the method for applying energy to the fullerenes, other methods such as stirring with a shaker, crushing with ultrasonic waves, and hitting or rubbing a fluid such as a homogenizer with a rigid body There are a method of pulverizing by applying pressure with a nanomizer or the like through a narrow space, a method of irradiating an infrared laser to partially add energy, a method of irradiating with an electron beam or the like.

In addition, the fullerene is dissolved in a solvent such as toluene, the solution is applied onto a substrate, and then the solvent is evaporated to accelerate the drying rate of the solution when a fullerene film is formed on the substrate surface. In this way, it becomes possible to reduce the crystallinity, and to make polycrystal, which lacks the long-range order of the crystal structure, and further amorphous.

To increase the drying speed, for example, 13P
The solution may be dried within 10 minutes under a vacuum of a or less, and more preferably within 5 minutes.

The photoconductor obtained as described above is mainly composed of fullerenes, but in order to utilize the high charge generation efficiency of fullerenes, the amount of fullerenes in the photoconductor is 90 wt%. It is desirable to set the above.

Further, as described in the description of the first invention of the present application, the fullerene group is made to be in a state in which the long-range order of the crystal structure is lacking by molecularly dispersing the fullerene group in the matrix polymer. Is also possible.

As described in the first invention of the present application,
The exciton generated by irradiating the fullerene with light diffuses on the crystal surface of the fullerene, and the exciton is deactivated in the process.

The seventh and ninth inventions of the present application are basically intended to improve the charge generation efficiency by reducing the film thickness of the photoconductor, that is, by allowing the excitons to reach the photoconductor surface before diffusing. I am trying.

That is, for example, when a photoconductor in which fullerene molecules are arranged in an orderly manner is formed on a conductor and this photoconductor is irradiated with light, the light absorption amount decreases as the depth of the photoconductor increases in the film thickness direction. Become. Therefore, the number of excited excitons is highest near the photoconductor surface. However, the excitons generated near the surface of the photoconductor have a longer distance to reach the conductor, so the excitons are deactivated in the process, and if the exciton travels longer, electric charges are generated. It will not come. Therefore, the total amount of charges generated in the entire film is reduced. That is, the charge generation efficiency can be improved by shortening the distance from the vicinity of the surface of the photoconductor having high charge generation efficiency to the surface receiving the charge.

Specifically, when the photoconductor is substantially composed of only fullerenes, the film thickness of fullerenes is 1 μm.
It may be thin as m or less. However, if it is less than 0.01 μm, it is difficult to form a uniform film. In addition, in a system in which fullerenes are dispersed in a matrix polymer, it is desirable that the film thickness be 300 μm or less, and usually the content of fullerenes in the photoconductor is 5 wt% or less in consideration of charge generation efficiency. In order to suppress the charge generation amount, the film thickness is preferably 5 μm or more in order to increase the absolute amount of charge generation.

The photoconductor of the present invention is a photoconductor of a copying machine or a printer using an electrophotographic system, a holographic element, a photoconductive toner, a resist, an optical memory, an optical sensor, an optical switch, a solar cell, a photoelectric converter. It can be applied to devices that utilize the photoconductive phenomenon, such as conversion devices.

The photoconductor of the present invention has a low dark conductivity, and is particularly effective in applications such as photoconductors where the surface is charged. The photoconductor of the present invention obtained by the above-described manufacturing method has a lower crystallinity to have a dark conductivity of 5 × 10 ^-14 Ω ^-1 m ^-1 or less when 50 V is applied. Is desirable.

Application examples of the photoconductor of the present invention will be described below. For example, when used as a photoreceptor, the charge generation layer and the charge transport layer may be formed in a single layer or a laminated structure on the surface of the conductive support.

For example, in the case of dispersing fullerenes in a polymer, a charge-transporting agent may be added to the polymer, but fullerenes themselves have a charge-transporting function in addition to a charge-generating function. Need not be formed. When forming a single-layer type photoreceptor using only fullerenes, it is preferable that C ₇₀ having a high charge generating function and C ₆₀ having a high charge transporting function are mixed and dispersed in a matrix polymer.

When the photoconductor has a small film thickness as in the ninth invention of the present application, when the photoconductor is used as a photoconductor,
Since the capacitance of the photoconductor itself is small, the surface potential becomes small and the potential contrast may not be sufficiently obtained. Therefore, it is desirable to provide a charge transport layer separately from the photoconductor of the present invention to form a laminated type.

The charge-transporting substance includes a hole-transporting substance and an electron-transporting substance, but any substance commonly used can be used without particular limitation. As an example of the hole transport material,
Hydrazone compounds, pyrazoline compounds, oxazole compounds, oxadiazole compounds, thiazole compounds, thiadiazole compounds, imino compounds, ketazine compounds,
Enamine compounds, amidine compounds, stilbene compounds,
A low molecular weight compound such as a butadiene compound and a carbazole compound, and a high molecular weight compound in which these are introduced into the main chain or side chain of a high molecular weight compound can be mentioned.

Further, specific examples of the electron transport material include, for example, chloroanyl, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro. -9-Tetrafluorenone, 2,4,7-trinitro-
9-dicyanomethylenefluorenone, 2,4,5,7-
Electron withdrawing substances such as tetranitroxanthone, 2,4,9-trinitrothioxanthone, N, N-bis (3,5-dimethylphenyl) -3,4,9,10-perylenetetracarboximide, or electron withdrawing substances thereof A polymer compound in which a substance is introduced into the main chain or side chain of a polymer can be mentioned.

Furthermore, semiconductors having irregular structure such as Si, Ge, Se, S, Te, B, As and Sb known as amorphous semiconductors, SiC, InSb, GaAs, GaS.
_{b, CdGe x As 2, Cd} , Si x P 2, CdSn x
As ₂ , As ₂ Se ₃ , As ₂ S ₃ , Ge-Sb-S
e, Si-Ge-As-Te, Ge-As-Se, As
₂ Se ₃ -As ₂ Te ₃ , As-Se-Te, Tl ₂ S
e-As ₂ , (Cu 1- _x Au _x ) Te ₂ , V ₂ O ₅ -P _{2
O 5, MnO-Al 2 O} 3 -SiO 2, V 2 O 5 -P 2
_{O 5 -BaO, CoO-Al 2} O 3 -SiO 2, V 2
_{O 5 -GeO 2 -BaO, FeO-} Al 2 O 3 -SiO
_{2, V 2 O 5 -PbO-} Fe 2 O 3, TiO 2 -B 2 O
_{3 -BaO, SiO x, Al 2} O 3, ZrO 2, Ta 2
Semiconductors having irregular composition such as O ₃ , Si ₃ N ₄ and BN, π-conjugated polymers and oligomers such as polyacetylene, polypyrrole, polythiophene and polyaniline, σ-conjugated polymers and oligomers such as polygermane, anthracene , A polycyclic aromatic compound such as pyrene, phenanthrene, coronene or a compound having a nitrogen-containing cyclic compound such as indole, carbazole, oxazole, inoxazole, thiazole, imidazole, pyrazole, oxadiazole, pyrazoline, thiadiazole, triazole, or Compounds having these in the main chain or side chain,
Hydrazone compounds, triphenylamines, triphenylmethanes, butadienes, stilbenes, TCNQ,
Derivatives such as anthraquinone and diphenoquinone can be used.

The thickness of the charge transport layer is usually 5 to 50 μm, preferably 10 to 30 μm. Also,
The photoconductor of the present invention may include those generally known as polymeric antioxidants and ultraviolet absorbers. Specifically, as usually used as a photoreceptor, for example, hindered phenols, aromatic amines, organic sulfur compounds,
Phosphite, chelating agent, benzophenone,
Examples include benzotriazole type and nickel complexes.

In the production of a photoreceptor using the photoconductor of the present invention, a photosensitive layer can be formed by applying and drying a solvent in which fullerene is dissolved on a conductive substrate. For that purpose, various organic solvents can be used. As specific organic solvents, alcohols, ketones, amides, sulfoxides, ethers, esters, aromatic halogenated hydrocarbons, aromatic hydrocarbons and the like can be used.

The photoconductor of the present invention is usually formed on a conductive substrate and used in many cases. Specific examples of the conductive substrate used include aluminum, nickel, copper and brass. Conductive substances such as aluminum, nickel, chromium, palladium, graphite, indium oxide, tin oxide, etc. are vapor deposited, sputtered and applied onto metal plates or metal foils such as, or plastic sheets, plastic plates, glass, cloth, paper, etc. It is possible to use those subjected to various conductive coating treatments such as.

When a photoconductor is used as the electrophotographic photosensitive member, it is particularly desirable among the above-mentioned conductive substrates, for example, a plastic sheet such as polyethylene terephthalate (PET) sheet, although it depends on the purpose of use. Such as aluminum evaporated on the surface of
The thing which consists of aluminum can be mentioned. Further, as the conductive substrate, for example, brass, aluminum, gold,
The surface of a metal material such as silver is coated with a plastic thin film; metal-coated paper, metal-coated plastic sheet, chromium oxide, tin oxide, etc., glass coated with a conductive polymer, plastic sheet and the like. These are used as a cylindrical sheet thin plate having appropriate thickness, hardness and flexibility, and whether the substrate itself has conductivity or
Alternatively, it is preferable that the surface thereof has conductivity and has sufficient strength for handling.

The electrophotographic photosensitive member is usually exposed from the side of the conductive substrate on which the photosensitive layer is formed, but in the case of so-called backside exposure in which exposure is performed from the back side of the surface of the conductive substrate on which the photosensitive layer is formed, The conductive substrate used may be transparent in the wavelength range of the light source used, for example, 780 nm for a semiconductor laser, 630 nm for an LED, and 580 n for an EL.
m. 400 to 6 in the visible range for ordinary resins
800, which is transparent in the range of 00 nm and is in the long wavelength region
Many of them maintain transparency up to around nm. Therefore, polyvinyl chloride, polyvinylidene chloride, polyethylene, polycarbonate, polyester, polyamide, acrylic resin, polyimide and the like are preferable.

The conductive layer formed under the photosensitive layer and the conductive layer formed on the exposed surface may be transparent in the wavelength range of the light source used, like the substrate. Generally, metal or metal oxide vapor deposition or those What was fired after being applied in a shape of any kind, dispersed in such a binder fine powder having conductivity,
Examples include those that have been applied and dried. These conductive surfaces may be electrically conducted and may be grounded.

In the photoconductor of the present invention, a protective layer may be formed on the surface of the photosensitive layer, if necessary. The thickness of the protective layer is usually 5 to 50 μm, preferably 10 to 30 μm.
It is desirable to set to m. Any known substance may be used as the substance used for the protective layer. Examples of such substances include thermoplastic resins such as acrylic resins, fluororesins and silicone resins, thermosetting resins such as phenol resins and melamine resins, photocurable resins, EB curable resins, X-ray curable resins, UV curable resins, urethanes. Resin etc. are mentioned.

The protective layer includes an antioxidant, an ultraviolet absorber,
A small amount of additives such as an anti-aging agent may be added. Examples of such additives include hindered phenols, aromatic amines, organic sulfur compounds, phosphites, chelating agents, benzophenones, benzotriazoles, and nickel complexes.

When the photoconductor of the present invention is applied to an optical memory such as a photorefractive element or the like, a transparent conductive thin film is particularly preferable as the substrate, and for example, the surface of a plastic sheet such as a polyethylene terephthalate (PET) sheet is oxidized. Indium (ITO), tin oxide (NES
Examples thereof include those obtained by depositing a conductive substance such as A) and those obtained by depositing these on glass.

When the photoconductor of the present invention is used as an optical memory material, a nonlinear optical substance may be dispersed in addition to the composition of the present invention. As a non-linear optical material, for example,
4- (diethylamino)-, which is a third-order nonlinear optical material
β-nitrostyrene, 3-fluoro-4- (diethylamino) -β-nitrostyrene, (4-piperidinobenzylidene) malononitrile, 2-[(α-methylbenzyl)
Amino] -5-nitropyridine, 4-methoxy-2'-
(Trifluoromethyl) -4'-nitrostilbene, 4-
(Diethylamino) -β-methyl-β-nitrostyrene, 4- (diethylamino) -cinnamonitrile and the like can be mentioned.

[0074]

【Example】

Example 1 FIG. 2 is a schematic sectional view showing a photoconductor using the photoconductor of the present invention. In the photoreceptor shown in FIG. 2, a photoconductor 15 in which a charge generating substance 13 and a charge transporting substance 14 are molecularly dispersed in a matrix polymer 12 is formed on an electrode substrate 11 which is a conductive substrate.

High purity (99%) as the charge generating substance 13
0.0167g of C ₇₀ of the charge-transporting material (hole transporting material) 14 as N, N'-diphenyl -N, N'-bis (3-methylphenyl) - (1,1'-biphenyl) -
0.44 g of 4,4'-diamine (TPD) and 1.169 of polystyrene as the matrix polymer 12
g, each was dissolved in 35.6 g of toluene to prepare a toluene solution (mixing ratio of each component, charge generating substance: charge transporting substance: matrix polymer = 1: 29:
70% by weight). At this time, no precipitation of fullerene was found in the toluene solution.

Next, indium oxide (IT0) was formed on the glass.
The prepared solution is dropped on the electrode substrate 11 on which
It was sufficiently dried under the conditions to obtain a highly transparent photoconductor film having a film thickness of 25 μm.

The X-ray diffraction pattern of the obtained photoconductor was measured. The result is shown in FIG. As can be seen from FIG. 3, the photoconductor obtained in this example contains C ₇₀
It was confirmed that the fullerene was a photoconductor containing amorphous fullerene in which the fullerene was molecularly dispersed in the matrix polymer.

The absorption spectrum and quantum efficiency of this photoconductor film were measured. FIG. 4 shows the results. In the figure, white circles represent absorption spectra and black circles represent quantum efficiency. As can be seen from FIG. 4, the quantum efficiency was approximately constant η = 0.3 in the light absorbing region. This value was higher than the quantum efficiency of the organic pigments that have been put into practical use, and showed good photosensitivity.

Example 2 0.01% of high-purity (99%) C ₇₀ was used as a charge generating substance.
69 g, N, N′-diphenyl-as a hole transport material
N, N'-bis (3-methylphenyl)-(1,1'-
Biphenyl) -4,4'-diamine (TPD) 0.4
55 g, 0.0136 g of polystyrene as a matrix polymer, each of which was dissolved in 35.6 g of toluene to prepare a toluene solution (mixing ratio of each component,
Charge generating substance: Charge transporting substance: Matrix polymer =
22: 60: 18% by weight). At this time, no precipitation of fullerene was observed in the toluene solution.

Next, indium oxide (IT0) was formed on the glass.
The prepared solution was dropped on the electrode substrate 11 on which
The film was dried in a Pa vacuum chamber at a substrate temperature of 60 ° C. for 5 minutes to obtain a photoconductor film having a film thickness of 10 μm.

An X-ray diffraction pattern was measured for the obtained photoconductor film, but there was no peak as in Example 1, and fullerene was molecularly dispersed in a matrix polymer and was amorphous. It was confirmed that the photoconductor was a fullerene-containing photoconductor. The resulting photoconductor was poor in transparency.

The absorption spectrum and quantum efficiency of this photoconductor film were measured in the same manner as in Example 1. as a result,
In the light absorption region, the quantum efficiency is almost constant η =
0.3.

Example 3 FIG. 5 is a schematic sectional view of a photosensitive member of this example. As shown in the figure, the photoconductor has a photoconductive layer 3 formed on a conductive substrate having a support 1 made of a cylindrical polyester film and an electrode layer 2 formed on the surface of the support, and further transports charge on the surface of the photoconductive layer 3. Layer 4 has been formed.

A photoconductor as shown in FIG. 5 was prepared as follows. On both surfaces of a 100 μm-thick polyester film (240 mm × 200 mm) serving as a support, an aluminum film serving as an electrode layer having a surface resistance of 500 Ω / □ was formed. This polyester film is made into a cylindrical shape and the long sides on both sides of the aluminum coating are fused and the radius is 60 mm.
To form a cylinder having a length of 240 mm. A photoconductor was formed as a film on the outer surface of this cylinder as follows to form a photoconductor.

First, a water-soluble nylon film having a thickness of 0.2 μm was formed on the outer surface of the cylinder, and a photoconductor layer serving as a charge generating layer having a thickness of 1 μm was formed thereon by a spray coating method. In this charge generation layer, 90% by weight or more has a mixing ratio of a high-order fullerene having 70 or more carbon atoms and a butyral resin at a weight ratio of 1: 1.

Next, the cylindrical body on which the charge generation layer is formed is set to 4
-Dibenzylamino-2-methylbenzaldehyde-
2 parts by weight of 1,1-diphenyl-hydrazone, 2 parts by weight of 1,1 parts by weight of fullerene having a carbon number of 60 at 85% by weight or more, and 1 part by weight of polycarbonate (trade name: K-1300w, manufactured by Teijin Chemicals Ltd.) It was immersed in a dispersion solution dissolved and dispersed in 2-trichloroethane, taken out and dried to form a charge transport layer having a film thickness of 20 μm on the charge generation layer.

The sensitivity (half-exposure amount) of the photoconductor thus prepared was measured and found to be 0.3 (μJ ⁻¹ · c
m ² ) and high sensitivity. The half-dose exposure amount is an exposure amount required to reduce the surface potential of the photoconductor to half from the initial potential. In this example, the photoconductor charged to 500V was exposed to 250V. An electrostatic charging test device EPA-8100 (manufactured by Kawaguchi Denki Co., Ltd.) was used to measure the half-dose exposure amount.

Then, this photosensitive member was incorporated into an electrophotographic apparatus of a back exposure system. What is the back exposure system?
The light source is arranged inside the photoconductor cylinder. With this electrophotographic device, charging, exposure and development, and transfer are repeated,
When 100,000 images were output at a speed of 80 sheets per minute,
The image obtained did not change much compared to the initial image.

Comparative Example 1 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that copper phthalocyanine was used as the charge generating substance instead of fullerene and the fullerene was not contained in the charge generating layer. The performance was evaluated in the same manner as in Example 1. As a result, the sensitivity was as low as 1.5 (μJ ⁻¹ · cm ² ), and image formation could not be performed at a speed of 20 sheets per minute or more. Further, bleeding was observed in the print after forming an image on almost 100,000 sheets.

Examples 4 to 6 An aluminum coating film was formed on each surface of three drums made of paper having a diameter of 10 mm so that the surface resistance was 50Ω. A photoconductor was formed as a film on the outer surface of this drum as follows to form a photoconductor.

First, the outer surface of the drum has a thickness of 0.2 μm.
The water-soluble nylon film of No. 1 was formed, and a liquid in which 85% by weight or more of higher fullerene having 60 carbon atoms was mixed and dispersed with an organic solvent was spray-coated to form a charge generation layer. The average film thickness of this charge generation layer is 0.05 μm.
(Example 4), 0.15 μm (Example 5), 0.8 μm
(Example 6).

On the charge generation layer thus formed, 1,1-bis (p-diethylamino-phenyl)-
85% by weight with 4,4-diethyl-1,3-butadiene
The above is a fullerene having 60 carbon atoms and a polycarbonate (trade name: K-1300w, manufactured by Teijin Kasei) dissolved in 1,2-trichloroethane at a weight ratio of 2: 1: 2,
The dispersed liquid was applied by dip coating and dried to form a charge transport layer having a film thickness of 20 μm.

When the sensitivities of the thus prepared photoconductors were measured in the same manner as in Example 1, all of them had a high sensitivity of about 0.5 (μJ ^-1 · cm ² ). afterwards,
This photoconductor was assembled in the same electrophotographic apparatus as in Example 1, and charging, exposure and development, and transfer were repeated, and 1 sheet was formed at a speed of 65 sheets per minute.
When 0,000 images were output, the obtained image showed almost no change compared with the initial image.

When the potential of the image area and the potential of the non-image area at the time of development were measured, the results shown in FIG. 6 were obtained. As is clear from FIG. 6, the electrophotographic photosensitive members of Examples 4 to 6 are
It can be seen that the potential of the image area is low and the potential of the non-image area is high, and that it has excellent charge holding ability. This is because fullerene does not form a charge transfer complex and thus has low dark conductivity.

Comparative Examples 2 and 3 The average thickness of the charge generation layer is 0.001 μm (Comparative Example 2),
An electrophotographic photoreceptor was prepared in the same manner as in Example 4 except that the thickness was 2 μm (Comparative Example 3), and the sensitivity was evaluated. As a result, the electrophotographic photosensitive member of Comparative Example 2 could not be measured, and the electrophotographic photosensitive member of Comparative Example 3 was 1.2 (μJ ⁻¹ · c
m ² ) and low sensitivity.

The potential of the image area and the potential of the non-image area during development were measured. The results are also shown in FIG. As is apparent from FIG. 6, the electrophotographic photosensitive member of Comparative Example 2 has a high electric potential in the image area, while the electrophotographic photosensitive member of Comparative Example 3 has a low electric potential in the non-image area and cannot output an image. .

Example 7 A photosensitive member was formed by forming a film on a round aluminum rod having a diameter of 15 mm as follows.

First, on the surface of a round bar, 1-phenyl-1,
2,3-Trihydroquinoline 6-carboxyalhydrido-1,1-diphenylhydrazone and polycarbonate (trade name: K-1300w, manufactured by Teijin Chemicals) at a weight ratio of 1: 2 1,2-trichloroethane. The solution dissolved and dispersed in was applied by dip coating and dried to form a charge transport layer having a film thickness of 20 μm.

When the sensitivities of the thus prepared photoconductors were measured in the same manner as in Example 1, all of them had a high sensitivity of about 0.5 (μJ ^-1 cm ² ). afterwards,
This photoconductor was assembled in the same electrophotographic apparatus as in Example 1, and charging, exposure and development, and transfer were repeated, and 1 time was performed at a speed of 20 sheets per minute.
When 0,000 images were output, the obtained image showed almost no change compared with the initial image.

Next, a liquid in which 85% by weight or more of a higher fullerene having a carbon number of 70 or more was dispersed and mixed with an organic solvent was spray-coated on the charge transport layer to form a charge generation layer. A thermosetting silicone resin was applied on the charge generation layer to a thickness of 0.5 μm to form a protective layer.

When the sensitivity of the thus prepared photosensitive member was measured, it was as high as about 0.25 (μJ ^-1 · cm ² ). Thereafter, this photoreceptor was assembled in the same electrophotographic apparatus as in Example 1, and charging, exposure and development, and transfer were repeated, and 100,000 images were output at a speed of 40 sheets per minute. The obtained image was Compared to the initial image, there was almost no change.

Example 8 An electrophotographic photosensitive member was prepared in the same manner as in Example 7, except that 90% by weight or more of the fullerenes in the charge generation layer were C ₆₀ , and the electrophotographic photosensitive member was assembled and charged. When exposure, development and transfer were repeated, an image could be output at a speed of 3 sheets per minute.

Examples 9 to 13 An aluminum coating film was formed on each surface of five cylinders having a diameter of 10 mm so that the surface resistance was 500 Ω / □. A photoconductive layer was formed on this film as follows to prepare a photoconductor.

On the coating film on each of the above cylinders, 85% by weight or more of fullerene having 70 or more carbon atoms was vapor-deposited to form a photoconductor as a charge generation layer. The thickness of this charge generation layer is 0.005 μm (Example 9) and 0.015 μm.
(Example 10), 0.15 μm (Example 11), 0.8
μm (Example 12) and 1.2 μm (Example 13).

A charge transport layer similar to that of Example 4 was formed on the charge generation layer thus formed. The sensitivities of the thus prepared photoconductors were measured in the same manner as in Example 1 and found to be approximately 1.0 (μJ ^-1 · cm).
² ) (Example 9), 0.4 (μJ ^-1 · cm ² ) (Example 10), 0.2 (μJ ^-1 · cm ² ) (Example 11),
0.43 (μJ ⁻¹ · cm ² ) (Example 12), 0.9
The sensitivity was as high as (μJ ⁻¹ · cm ² ) (Example 13).
Of these, Examples 10, 1 in which the thickness of the charge generation layer was in the range of 0.01 μm or more and less than 1.0 μm
The electrophotographic photoreceptors 1 and 12 showed particularly high sensitivity.

Example 14 A photoconductor similar to that shown in FIG. 5 was produced. In this embodiment,
100μm thick polyester film (240mm ×
(200 mm), a gold coating having a film thickness of 2000 angstroms was formed on both sides of the electrode layer having a surface resistance of 500 Ω / □. 240m by fusing the long sides of this film
A cylinder of m × 60 mmφ was formed. The photoconductor of the present invention was formed on the outer surface of this cylinder by the following method.

This cylinder was installed in a vacuum device, and a C ₇₀
The fullerene having a content of 99.5% or more was set as a raw material in a Knudsen cell. Then, the degree of vacuum is set to 5 × 10.
^-4 Pa, the cell was heated to 270 ° C and left for 2 hours. At this time, a mask was set on the upper part of the cell so that the low temperature deposits from the cell did not reach the cylinder. The substrate temperature was kept at 40 ° C.

Next, the cell was heated at a heating rate of 5 ° C./min to 500 ° C. While the temperature of the cell reached 500 ° C., 50% or more of the fullerene in the cell became a gas, the fullerene adhered to the cylinder, and a fullerene thin film was formed. At this time, the cylinder was left at room temperature, but the temperature increased several degrees due to the vaporized fullerene and radiation from the cell. At this time, the cylinder is moved to 30 [r. p. m], so that the thin film of fullerene is uniformly deposited on the cylinder.

In this way, a thin film of fullerene to be the charge generation layer was deposited to a thickness of 2000 (A). FIG. 7 shows the result of obtaining the two-body distribution function g (R) of the obtained fullerene thin film. A first peak is shown near R = 12 (A), and 0.7 <g (R) <1.2 in the region of R ≧ 20 (A).
It became.

The obtained fullerene thin film was subjected to X with CuKα.
Line diffraction was performed. As a result, the fullerene thin film obtained in this example did not have a peak due to C ₇₀ .

Further, the obtained fullerene was charged with 10 V, 5
When dark conductivity was measured when a voltage of 0 V was applied,
1.43 × 10 ^-14 Ω ^-1 m ^-1 , 4.64 × 10 ^-15 Ω ^-1
A sufficient resistance of m ^-1 was obtained.

Then, on the fullerene thin film, NN-cyphenyl-NN-bis (3-methylphenyl 9- (1,1-biphenyl) -4,4-diamine as a charge transport molecule was added to the polycarbonate resin in a weight ratio of 1: 2. 1, 1, 1
-Dissolved in trichloroethane and made into a uniform solution, it was applied so that the film thickness after drying would be 20 μm to form a charge transport layer.

The photoconductor thus prepared was incorporated into a back exposure type electrophotographic printer. After charging the surface of the photoconductor to 500 V, irradiation light for data writing (55
When the data was written at 0 nm), the charge amount half-exposure amount was 0.5 [μJ ⁻¹ · cm ² ].

The half-exposure amount of 0.5 [μJ ^-1 · cm ² ] remained even after repeated use of this photoreceptor. Comparative Example 4 A fullerene thin film was formed in the same manner as in Example 14 except that the temperature of the cylinder during vapor deposition was changed to 120 ° C., and then a photoreceptor was prepared. Further, when X-ray diffraction was performed in the same manner as in Example 14, the angle 2θ between the incident X-ray and the diffraction line was 2θ = 1.
A peak peculiar to C ₇₀ was observed near 0.

The two-body distribution function of this fullerene thin film is shown in FIG.
Shown in In the range of 30 <R <45 (A), g (R) is 0.
It can be seen that it is 7 or less. Furthermore, when a voltage of 10 V and 50 V was applied to this fullerene thin film and the dark conductivity was measured, it was 2.13 × 10 ^-12 Ω ^-1 m ^-1 , 1.55 × 10
^{It was -14} Ω ^-1 m ^-1 , and a sufficient resistance could not be obtained.

Further, the obtained photoconductor was incorporated in a back exposure type electrophotographic printer as in Example 14, the surface of the photoconductor was charged to 500 V, and data was written with irradiation light for data writing (550 nm). The half-exposure amount of charge was 150 [μJ ⁻¹ · cm ² ], and Example 1
The sensitivity was very low as compared with the photoconductor obtained in No. 4.
Further, after the light irradiation, the resistance in the dark became small, and even if it was charged again, the charge amount could not be 50 V or more and could not be used repeatedly.

Example 15 A photoconductive layer was formed on the outer surface of an aluminum rod-shaped support having a diameter of 5 mm by the following method. That is, the support was assembled in a vacuum apparatus, fullerene having a C ₇₈ content of 80% or more was set as a raw material in a Knudsen cell, and a fullerene thin film was vapor-deposited to a thickness of 1000 Å as in Example 14. did. At that time, the temperature of the support is 50
° C or lower.

Then, NN-diphenyl-NN-bis (3-methylphenyl 9) was used as a charge transport molecule on the deposited film.
-(1,1-Biphenyl) -4,4-diamine was dissolved in 1,1,2-trichloroethane in a polycarbonate resin in a weight ratio of 1: 1 to form a uniform solution, and the film thickness after drying was 20 μm. To form a charge transport layer.

At this time, the two-body distribution function g (R) of the produced photoconductor is 0.7 <g in the region of R ≧ 20 (A) or more.
(R) <1.2. Further, when the photoconductor was subjected to X-ray diffraction in the same manner as in Example 14, no peak attributable to C ₇₈ was observed in the X-ray diffraction pattern.

The thus prepared photoconductor was incorporated into a back exposure type electrophotographic printer. This is one in which a light source is incorporated inside the photosensitive drum. When data was written with irradiation light for data writing (550 nm), the half-exposure amount of charge was 0.6 [μJ ⁻¹ · cm ² ] and the sensitivity was very high.

Comparative Example 5 A photoconductor was prepared in the same manner as in Example 15 except that the temperature of the cylinder during vapor deposition was changed to 200 ° C., and was compared with the photoconductor obtained in Example 15.

At this time, the two-body distribution function g (R) of the produced photoconductor is shown in FIG. A first peak is shown near R = 12 (A), and g (R) is 0.7 in the range of 30 <R <45.
It was below.

Further, when X-ray diffraction was performed in the same manner as in Example 14, a peak peculiar to C ₇₈ was observed. The thus prepared photoconductor was incorporated into a back exposure type electrophotographic printer in the same manner as in Example 14, and data was written with irradiation light for data writing (550 nm). μJ ⁻¹ · cm ² ], which was extremely low in sensitivity as compared with the photoconductor obtained in Example 15. Further, after the light irradiation, the resistance in the dark became small, and it could not be used repeatedly.

Comparative Example 6 Exactly the same as Example 15 except that C ₇₀ and carbazole were co-evaporated on the same support as in Example 15 to form a charge transfer complex containing 1000 Å of fullerene. A photoconductor was created.

With this photosensitive member, the surface of the photosensitive member could not be charged, and the half-exposure amount could not be measured. Example 16 100 μm thick polyester film (240 mm ×
Gold coatings were formed on both sides of the surface (200 mm) so that the surface resistance was 500Ω. Fuse the long side of this film,
A 240 mm × 60 mm φ cylinder was formed. The photoconductive imaging member of the present invention was formed on the outer surface of this cylinder by the following method. That is, a fullerene having a C ₇₀ content of 80% or more, NN-diphenyl-NN-bis (3-methylphenyl 9 (1,1-biphenyl) -4,4-diamine, and a polycarbonate resin are used in a weight ratio of 1: 1: 3. So 1,1,2-
It was dispersed in trichloroethane by ball milling for 100 hours, and a uniform liquid was applied to the outside so that the film thickness after drying was 20 μm.

At this time, the two-body distribution function g (R) of the produced photoconductor shows the first peak near R = 11 (A),
0.7 <g (R) <1.2 in the region of R ≧ 18 (A) or more
It became.

The photoconductor thus prepared was incorporated into a back exposure type electrophotographic printer. 500 photoconductor
After charging to V, irradiation light for data writing (550n
When the data was written in m), the half-exposure amount of charge was 0.7 [μJ ^-1 · cm ² ] and the sensitivity was very high.

Comparative Example 7 A photoconductor was prepared in the same manner as in Example 16 except that dispersion was not carried out by ball milling, and comparison was made with Example. The two-body distribution function g (R) obtained from the X-ray diffraction measurement of the photoconductor produced at this time showed a first peak near R = 11 (A).

At this time, the two-body distribution function g (R) of the produced photoconductive member, that is, the vapor deposition film of the photoconductor is R = 11 (A).
Shows the first peak in the vicinity and g in the range of 30 <R <50
There was R having (R) of 0.7 or less.

The photosensitive member thus produced was used in Example 1.
As in No. 4, when incorporated into a back exposure type electrophotographic printer and writing data with irradiation light for data writing (550 nm), the half-exposure amount of charge was 30.0 [μJ
^-1 · cm ² ], and the sensitivity was low. Further, after the light irradiation, the resistance in the dark became small, and it could not be used repeatedly.

Example 17 In this example, the present invention is applied to a photoconductive toner. Since the fullerene used in the present invention has a high carrier generation efficiency, it needs only a small amount to be mixed with the toner and can be used for toners of various colors.

That is, the fullerene used in this example is amorphous after being dissolved in toluene and then rapidly dried to vaporize the toluene. This fullerene has a composition of 80% C _{70 and} 20% C ₆₀ .

The obtained fullerene aggregate showed a boson peak in the region of neutron inelastic scattering of 5 meV or less. 100 parts by weight of polyester resin, 10 parts by weight of phthalocyanine, 3 parts by weight of polypropylene, 2 parts by weight of wax, 2 parts by weight of charge control material, and 1 part by weight of the above-mentioned non-amorphous fullerene are mixed and kneaded by a heating roller. ,
After cooling, it was coarsely crushed, further finely crushed by an ultra-high speed jet mill, and then classified by an air classifier to obtain colored fine particles (toner) having an average particle size of 7 μm.

A thin layer of this toner was formed on the drum, and 780
The image information was illuminated by a nm laser. As a result, only the toner on the irradiated portion of the laser had a reduced charge amount due to its photoconductivity and was peeled off from the drum, and a toner image was obtained. The obtained toner image was transferred to paper, and an image of good quality was obtained.

Comparative Example 8 Toner was prepared by the same procedure as in Example 17 except that crystalline fullerene obtained by evaporating a solvent from a benzene solution and having no peak observed in the region of 5 meV or less of inelastic neutron scattering was used. Was manufactured. This toner was evaluated in the same manner as in Example 17. As a result, the toner on the laser-irradiated portion was not separated from the drum.

Example 18 This example shows an example of using the present invention in combination with a charge transport material as a photorefractive hologram medium. That is, in the binder polymer at 500 ° C in advance.
To -20 ° C to obtain a density of 1.700.
10 wt% of C ₇₀ in an amorphous state of [g / cm ³ ]
The mixture was mixed, and 30 wt% of a hole transporting material, diethylaminobenzaldehydrdiphenylhydrazone, was mixed with the polymer to obtain a hologram medium. Using this hologram medium, reference light and incident light were made incident to record three-dimensional information. As a result, this hologram medium
Due to the high carrier generation efficiency, 1000 cm ³ of three-dimensional information could be written with a total energy of about 10 μJ.

Comparative Example 9 A hologram medium was prepared in the same manner as in Example 18 except that crystallized C ₇₀ having a density of 1.710 [g / cm ³ ] obtained from a benzene solution was used as the fullerene. Was prepared and evaluated. As a result, about 100,000 μJ of total energy was required to write the same three-dimensional information as in Example 18.

Example 19 This example shows an example in which the present invention is applied to a resist. As a sensitizer for a negative resist, a fullerene thin film obtained by a thermal evaporation method on a glass substrate in advance was peeled from the glass substrate and used in the same manner as in Example 14. The glass transition point of fullerene having C ₇₀ of 99% or more is 310
K, which showed a boson peak in the region of neutron inelastic scattering of 5 meV or less. Mixing ratio is 5wt% to resist
Met. As a result, this resist has about 6 times the sensitivity before mixing with fullerene.

Comparative Example 10 Fullerene used as a sensitizer was 99% or more of C ₇₀ , was a crystal precipitated from a benzene solution, had no glass transition point, and peaked in the region of neutron inelastic scattering of 10 meV or less. Example 19 except that no
A negative resist was prepared and evaluated in the same manner as in. As a result, the sensitivity was the same as before mixing the fullerene.

Embodiment 20 FIG. 10 is a schematic sectional view of an optical memory. In the figure, a first lower electrode 22 and a second lower electrode 2 are provided on a transparent substrate 21.
3, the photoconductor 24, and the upper electrode 25 are sequentially stacked.

The present example shows an example in which such a laminate is used for an optical memory utilizing the phase transition between an amorphous phase and a crystalline phase. First on the glass substrate which is a transparent electrode
An ITO film as a lower electrode and an Al semi-transparent electrode as a second lower electrode are formed, and C ₇₀ is 90% by thermal evaporation as a photoconductor in the same manner as in Example 14.
The above fullerene film was formed. At this time, the temperature of the glass substrate was 100 ° C. or lower. When the fullerene film was subjected to structural analysis by X-ray diffraction, the obtained two-body distribution function g
(R) was 0.8 to 1.2 in the region where the distance R was 40 angstroms or more.

An Au electrode was formed on this fullerene film by an ion sputtering method to obtain an optical memory element as shown in FIG. Using this optical memory element, information was written by an infrared laser from the ITO side while applying a bias voltage between the ITO and Au electrodes. As a result, phase transition occurred only when exposed to light, and the absorption coefficient in the region from 490 nm to 700 nm changed.

Example 21 This example shows an example in which the present invention is applied to an optical sensor in the visible range. Au was vapor-deposited on ITO, and 1,1, bis (4-
Diethylaminophenyl) -4,4'-diphenyl-
A charge transport film of 20 μm in which 30 wt% of 1,3 butadiene was molecularly dispersed was formed, and a film of fullerene of C ₆₀ 20%, C ₇₀ 75% and other 5% was provided thereon by sputtering. The neutron scattering spectrum of this film is 5 me
A boson peak was shown in a region below V.

Further, a semitransparent electrode of Al was provided on the fullerene film to form a photosensor element. This optical sensor is
It was used with a bias voltage of about 100 V applied between the 1 and Au electrodes. As a result, wavelength 400nm to 680n
Light from 10 ^-4 [μJ / cm ² ] to 10 ³ [μJ
/ Cm ² ].

Comparative Example 12 The order of forming the charge transport film and the fullerene film was changed from that of Example 21, Au was vapor-deposited on ITO, and the fullerene film was formed thereon. A sample having this ITO / Au / fullerene film configuration was annealed at a temperature of 350 ° C. for 30 hours.

From this fullerene film, no peak was observed in the region of neutron inelastic scattering of 10 meV or less. Further, a charge transport film and an Au electrode were provided on the fullerene film to form a photosensor element, and the same evaluation as in Example 21 was performed. As a result, this optical sensor element has a wavelength of 400 nm to 550 n.
Light intensity up to m from 1 [μJ / cm ² ] to 10 ² [μJ
/ Cm ² ].

Embodiment 22 This embodiment shows an example in which the present invention is used as an optical gate switch with reference to FIG.

In the figure, a drain electrode 29 and a source electrode 30 are formed on one surface of an insulating film 31, and a semiconductor layer 33 is formed so as to cover both electrodes. Further, a photoconductor layer 28 and a transparent electrode 27 are laminated on the semiconductor layer 33. A gate electrode 32 is formed on the other surface of the insulating film at a position facing the photoconductor layer.

A device having the structure shown in FIG. 7 was manufactured as follows. The drain electrode 19, the source electrode 20, and the gate electrode 22 are all made of aluminum, the photoconductor layer 28 is an amorphous film having a C ₆₀ of 90% or more provided by thermal evaporation, and the insulating film 21 is made of SiO _2. Compose and transparent electrode 17
Is ITO.

A voltage of 0 V was applied to the transparent electrode 17 and the source electrode 20, a voltage of -20 V was applied to the gate electrode 22, and a voltage of -5 V was applied to the drain electrode 19. When the transparent electrode was irradiated with light, a current flowed between the source and the drain. At that time, the required amount of light is 0.5 [μJ ^-1 ·
cm ² ], which was very small.

Comparative Example 13 An optical gate switch was produced in the same manner as in Example 22 except that crystalline C ₆₀ (f, C, C) was used as the fullerene film. To operate this optical gate switch, 500 [μJ ^-1 · cm ² ] at a wavelength of 500 nm.
Therefore, a large amount of light was required as compared with the optical gate switch obtained in Example 22.

Embodiment 23 This embodiment is an example in which the present invention is applied to an optical modulator.
Shown in A photoconductor layer 34 is formed on the quartz substrate 25.

The light modulation element was manufactured as follows. First,
An amorphous C ₆₀ film having a thickness of 0.05 μm was formed on quartz as a substrate by vacuum evaporation. The temperature of this film is 300K
The half-width of the peak in the region of 1140 [cm ^-1 ] to 1480 [cm ^-1 ] of the Raman scattering spectrum due to the light excitation of 488 nm was 12 [cm ^-1 ]. The neutron scattering spectrum of this film showed a boson peak in the region of 5 meV or less.

Argon ion laser (wavelength 528 nm)
Was used to measure the transmittance of the fullerene film at a light amount of 1 mJ / cm ² , the transmittance was 40%.
Next, the transmittance at a light amount of 10 J / cm ² was measured, and the transmittance was 25%. This element is a good light modulation element having the characteristic that the transmittance decreases as the amount of light increases and the output light (transmitted light) is limited.

Comparative Example 14 A crystal film of C ₆₀ was formed on quartz by vacuum vapor deposition to a thickness of 0.05 μm. 488 at 300K
1140 of the spectrum of Raman scattering by photoexcitation of nm
The full width at half maximum in the [cm ^-1 ] region was 8 [cm ^-1 ]. Further, no peak was observed in the region of inelastic neutron scattering of 10 meV or less.

Argon ion laser (wavelength 528 nm)
Was used to measure the transmittance at a light amount of 10 J ⁻¹ · cm ² , and the transmittance was 5%. Next, 1mJ ^-1
The transmission at a light amount of cm ² was 8%. In this fullerene film, there was a region in which fullerenes were polymerized. Due to the deterioration of the characteristics due to the polymerization, it is considered that the crystal film cannot be used as an optical modulator.

Example 24 This example shows an example in which the present invention is applied to a solar cell, with reference to FIG. In the figure, a light transmissive electrode 38, a photoconductor layer 37, and an upper electrode 36 are sequentially stacked on a quartz substrate 39.

Such a solar cell was manufactured as follows. First, a C ₇₀ amorphous film 27 was formed to a thickness of 0.3 μm by vacuum vapor deposition on a substrate in which a semitransparent electrode of aluminum was formed on quartz as a substrate to form a photoconductor layer. . Further, gold was vapor-deposited thereon as the upper electrode 26.
At this time, the spectrum of inelastic neutron scattering of this film is 5 m.
A boson peak was shown in the region below eV.

In this solar cell, when dark, the current flows when the aluminum electrode is negative and the gold electrode is positive, but when the aluminum electrode is positive and the gold electrode is negative, almost no current flows and the rectifying property is low. showed that. When a monochromatic light having a wavelength of 380 nm was irradiated from the side of the semitransparent electrode of aluminum, overpower was generated in which the aluminum electrode was positive and the gold electrode was negative, and it was found to be a good solar cell. The energy conversion efficiency of this solar cell was 5%.

Comparative Example 15 A C ₇₀ polycrystal film was formed to a thickness of 0.3 μm by vacuum evaporation on a substrate in which a semitransparent electrode of aluminum was formed on quartz, and gold was further evaporated thereon. did. In the solar cell thus obtained, a current flows when the aluminum electrode is negative and the gold electrode is positive in the dark, but almost no current flows when the aluminum electrode is positive and the gold electrode is negative, It showed rectification. Wavelength 3 from the semi-transparent electrode side of aluminum
Irradiation with monochromatic light of 80 nm generated electromotive force with the aluminum electrode being positive and the gold electrode being negative. However, the energy conversion efficiency of this solar cell was 0.08%, which was much lower than that of the solar cell obtained in Example 24.

[0161]

As described in detail above, according to the present invention,
It is possible to obtain a fullerene-containing photoconductor that can obtain high charge generation efficiency by light irradiation.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing the dependence of a two-body distribution function g (R) on a distance R.

FIG. 2 is a cross-sectional view of a photoconductor in which fullerene is molecularly dispersed in a polymer.

FIG. 3 is a diagram showing an X-ray diffraction pattern of the photoconductor of the present invention.

FIG. 4 is a diagram showing the absorption spectrum and quantum efficiency of the photoconductor of the present invention.

FIG. 5 is a schematic sectional view of a photoconductor of the present invention.

FIG. 6 is a diagram showing the relationship between the potential during development and the film thickness of the charge generation layer when the photoconductor of the present invention is used as a photoreceptor.

FIG. 7 is a diagram showing a two-body distribution function g (R) of a fullerene thin film in this example.

FIG. 8 is a diagram showing a two-body distribution function g (R) of a fullerene thin film in a comparative example.

FIG. 9 is a diagram showing a two-body distribution function g (R) of a fullerene thin film in another comparative example.

FIG. 10 is a sectional view showing an optical memory device according to another embodiment of the present invention.

FIG. 11 is a sectional view showing an optical gate switch according to another embodiment of the present invention.

FIG. 12 is a sectional view showing an optical modulator according to another embodiment of the present invention.

FIG. 13 is a sectional view showing a solar cell according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Support 2 ... Electrode layer 3 ... Photoconductor 4 ... Electrification transport layer 11 ... Electrode substrate 12 ... Polymer 13 ... Electrification generation material 14 ... Electrification transport Material 15: Photoconductor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Hosoya, 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Research and Development Center (72) Inventor Masami Sugiuchi 70, Yanagi-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Yanagimachi factory

Claims (11)

[Claims] 1. A photoconductor containing at least one of amorphous fullerene and its derivatives. 2. A two-body distribution function g obtained from structural analysis.
(R) is 0.7 when the distance is 30 angstroms or more
A photoconductor characterized by containing at least one of fullerene having a crystal structure of ˜1.3 and its derivative. 3. A photoconductor containing at least one of fullerene and its derivative in which a boson peak is observed in a region of neutron inelastic scattering of 5 meV or less at a temperature below the glass transition point. 4. A dark conductivity of 5 × 10 ¹⁴ under a voltage of 50V.
The photoconductor according to any one of claims 1 to 3, wherein: 5. The photoconductor according to claim 1, wherein 50 wt% or more of the fullerene and at least one derivative thereof are carbon clusters having a basic skeleton having 70 or more carbon atoms. 6. The photoconductor according to claim 1, wherein at least one of the fullerene and its derivative is molecularly dispersed in a matrix polymer. 7. The photoconductor according to claim 6, wherein the film thickness is 5 μm or more and 300 μm or less. 8. The photoconductor according to claim 1, wherein the photoconductor is substantially composed of a charge generation material. 9. The photoconductor according to claim 8, wherein the film thickness is 1 μm or less. 10. A photoconductor comprising a conductive support, a charge transport layer formed on the conductive support, and a charge generation layer comprising the photoconductor according to claim 1. . 11. A photoconductor containing at least one of fullerene and its derivative, wherein (1) the crystal structure of at least one of fullerene and its derivative is amorphous; (2) at least one of fullerene and its derivative. The two-body distribution function g (R) obtained from the structural analysis of
At least one in the range of 0.7 to 1.3 in the region above angstrom; and (3) boson peaks are observed in the region below 5 meV inelastic neutron scattering at a temperature below the glass transition point. A photoconductor characterized by satisfying a condition.