JP2002270861A - Light function film and light function element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light function film that is also sensitive to a short- wavelength light source, has high durability, has a wide selection range in components, and is environment-friendly, so as to manufacture the film at a low cost and improve density and miniaturization, and to provide a light function element using the light function film. SOLUTION: The light function film generates a light carrier by applying light to the film, and utilizes the change in current/voltage to be induced by the light carrier outside the film. Or, the light function film utilizes the change in an electric field due to charges remaining in the film after the light carrier has traveled outside the film, where a photoelectric discharge fine particle 12 made of an inorganic material is included in a metal oxide 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical functional film and an optical functional element using the same, and more specifically, to a photoelectric conversion element such as a solar cell or a sensor, an electrophotographic photosensitive member, an optical recording medium, an optical recording medium. In the field of optical functional devices that generate light carriers by irradiating light into the film, such as a printing original plate, and use the change in current and voltage caused by the light carriers, or remain in the film after the movement of the light carriers The present invention relates to all fields of optical functional devices utilizing electric field changes due to electric charges.

[0002]

2. Description of the Related Art First, trends and needs of the above-mentioned optical functional films and optical functional devices using them in main fields will be described.

The market for photoelectric conversion elements such as solar cells and sensors is expected to increase further in the future, but reduction of manufacturing costs is a major issue in order to cope with the trend of energy saving. Currently used solar cells and sensors have a structure based on a single crystal wafer such as Si or GaAs, a hydrogenated amorphous Si film or a CuInSe ₂ film. Since these are manufactured by using the Czochralski method, the Bridgman method, the CVD method, the PVD method, etc., there is a limit in reducing the manufacturing cost of the device. Therefore, it has been energetically researched and developed to produce a photoelectric conversion film by a simple method such as a coating method and a spray method.

The electrophotographic photoreceptor is one of the application fields of the present invention because it is the same as the above-mentioned photoelectric conversion element in that photocarriers are generated by light irradiation. The trend of electrophotographic photoreceptors was that amorphous Se system, CdS particle resin dispersion system and ZnO particle resin dispersion system were commercialized at first, and then hydrogenated amorphous Si system was commercialized. Some of these are still used in some products, but now,
Most electrophotographic products such as copiers and printers use a photoreceptor using an organic semiconductor because it can be manufactured by a simple method such as a dip coating method and a spray method.

In the image-related field, in recent years, higher image quality and higher definition have been demanded, and the diameter of a writing light beam has been reduced even in electrophotographic application products. Due to the basic principle of optics, it is necessary to shorten the wavelength of the writing light source in order to reduce the diameter. At present, laser diodes having an oscillation wavelength of around 400 nm are commercially available.
For G, 532 nm can be used. In this wavelength region, there is a concern that photodeterioration of not only the dye but also the binder resin may occur in a photoreceptor made of an organic compound which is currently widely used.

[0006]

As described above, in the field of the above-mentioned optical functional element, an element which is durable to irradiation of visible light, in particular, short-wavelength light whose use will increase in the future, and which can be manufactured at low cost. Is desired. Further, there has been a demand for an element using an environmentally friendly non-polluting material. In order to respond to such needs, it is desirable to be able to manufacture by a simple method such as dip coating method and spray method, and to form a film mainly composed of an inorganic substance which can be expected to be durable even when irradiated with short wavelength light. .

[0007] Many metal oxide materials are stable in the air, rich in resources, and non-polluting materials. In addition, by adopting a sol-gel method or the like as a forming method, a dip coating method, a spray method, or the like is adopted. It is possible to use a film forming technique such as that described above, and to reduce the manufacturing cost. Therefore, it is expected that a metal oxide material is used as a main material of the optical functional film.

However, Cu ₂ O, Pb which has photosensitivity to visible light
Metal oxide materials such as O, Ag ₂ O, and CdO are problems in terms of stability, pollution-free properties, and abundance of resources, and cannot enjoy the advantages of the above-described metal oxides. Therefore, large ZnO band gap have been proposed a method to impart in the visible region of light sensitivity sensitized and TiO ₂ in an organic dye or a metal complex, it has been a number considered.

As a conventional example of a photoelectric conversion device having a structure for sensitizing such a metal oxide, a dye-sensitized photoelectric conversion device has been proposed by Graetzl et al. ("Registered Patent 2
664194 ") has a structure in which a metal oxide semiconductor thin film such as TiO ₂ or ZnO having a large surface area is provided between two conductive glass electrodes, and a ruthenium complex or phthalocyanine or the like is provided on the surface of the metal oxide semiconductor thin film. It has a structure in which a sensitizing dye is adsorbed, and an oxidation-reduction electrolyte solution containing iodine as a main component is interposed therebetween.

Here, the photosensitivity to visible light is imparted by adding a sensitizing dye. In addition, by increasing the surface area of the metal oxide semiconductor thin film, a large amount of the sensitizing dye is adsorbed on the surface of the metal oxide semiconductor thin film, thereby increasing the light use efficiency. It is reported that the durability is 10 months or more. However, since the sensitizing dye is deteriorated, it is desired to further improve the durability for practical use.

Here, a conventional example of a photoelectric conversion element using a metal oxide will be described. In the color sensor disclosed in JP-A-10-160574, in order to reduce the manufacturing cost, a photoelectric conversion function is provided by using an optoelectronic material layer in which ultrafine particles are dispersed in a homogeneous medium of an organic or inorganic substance. Have. Here, the medium of the inorganic substance is Sn
Metal oxides such as O ₂ , TiO ₂ , InO ₂ , ITO, and Al ₂ O ₃ are used, and ultrafine particles dispersed in a medium include:
A group IV semiconductor, a group III-V compound semiconductor, a group II-VI compound semiconductor and the like are used. With this configuration, an optoelectronic material having sensitivity even in a wavelength region where the metal oxide does not generate carriers is realized.

In this prior art, the types of ultrafine particles disclosed are limited to group IV semiconductors, group III-V compound semiconductors and group II-VI compound semiconductors. There is a limit in controlling the photoelectric characteristics such as generation efficiency. Also, those materials are easily oxidized on the surface,
An oxide layer formed by oxidation serves as a barrier when injecting and releasing carriers, and thus has a problem that the photoelectric conversion function is reduced.

As an example of a configuration for sensitizing a metal oxide in the field of electrophotographic photoreceptors, there is a ZnO particle resin dispersion system which has been studied from an early development stage as described above (edited by the Electrophotographic Society of Japan). Basics and Applications of Electrophotographic Technology ”, published by Corona). This is a method in which a sensitizing dye such as rose bengal is adsorbed on the surface of ZnO fine particles, and a film dispersed in a binder resin is formed on a conductive support. Did not. One of the causes of the low durability is deterioration of the sensitizing dye and the resin binder.

An object of the present invention is to solve the above-mentioned problems in the prior art, to be able to manufacture at low cost, to achieve high density,
In order to respond to high definition, it is possible to provide sensitivity to short wavelength light source, high durability, wide range of choice of constituent materials, and provide environmentally friendly optical functional film,
And an optical functional element using the optical functional film.

[0015]

Means for Solving the Problems In order to achieve the above object, the present invention employs the following configuration.

According to the first aspect of the present invention, there is provided an optical functional film which irradiates a film with light to generate photocarriers and uses a change in current and voltage caused by the photocarriers outside the film.
Alternatively, in an optical functional film utilizing a change in an electric field due to electric charges remaining in the film after the movement of the photocarriers, the optical functional film is made of an inorganic material having a photoelectron emitting function in a metal oxide. The photoemission fine particles are dispersed, and the ionization energy of the photoemission fine particles is larger than the electron affinity of the metal oxide, and the photoemission fine particles have an empty level at which electrons are excited upon light irradiation. It is characterized in that the energy from the level of the photoelectron emitting fine particles to the vacuum level is smaller than the electron affinity of the metal oxide.

Each of the optical functional elements according to the present invention, which will be described later, is generated when the above-mentioned optical functional film is irradiated with light.
Either the change in current and voltage caused by the photocarriers is used outside the film, or the change in the electric field due to the charge remaining in the film after the movement of the photocarriers is used outside the film.

FIG. 1 shows the structure of an optical functional film according to the present invention. As shown in FIG. 1, the basic configuration of the optical functional film according to the present invention is a configuration in which photoelectron emission fine particles 12 made of an inorganic material are included in a metal oxide 10. Here, metal oxide 1
0 does not limit the type. Further, the photoelectron emitting fine particles 12
The type is not limited, and any material of a semiconductor material, an insulator material, and a metalloid material can be selected, and it is not necessary to show photoconductivity by itself. In addition, the form in which the photoelectron emitting fine particles 12 are contained in the metal oxide 10 is preferably a state in which the respective photoelectron emitting fine particles 12 are dispersed in the metal oxide 10, but the photoelectron emitting fine particles 12 are bound to each other. You can also take a state that is.

The size of the photoelectron emitting fine particles 12 is desirably 100 nm or less. If it is more than these values, it is difficult to obtain light sensitivity. This is considered to be because the diameter of the fine particles is equal to or greater than the distance from which the optical carrier can escape. Even if the distance from which the optical carrier can escape is short, and the photoconductivity has not been found in the past, it is possible to extract the optical carrier by forming fine particles and combining with a metal oxide.

Further, the energy potential relationship of the material in the present invention needs to be as follows (see FIG. 2). χo <Ep <Eo EpV ≤ χo Ep; ionization energy of photoelectron emission fine particles EpV; energy from sky level to vacuum level of photoelectron emission fine particles (= Ephν) Eo; ionization energy of metal oxide (= metal oxide Affinity of metal oxide + band gap energy of metal oxide) χo; electron affinity of metal oxide hν; incident light energy

In the optical functional film according to the present invention, the metal oxide often has a large band gap and a large resistivity. In such a case, the electrical environment of the junction is considered to be close to non-equilibrium. Therefore, in the present invention, when selecting a material, the relationship of the energy potential before the junction is used. When each material satisfies these relationships, the charge generated by the photoelectron emitting fine particles can be taken out as a photocarrier into the metal oxide. The photoelectron appearance energy, electron affinity, and sky level of each material are obtained by using a UPS or by using a combination of the UPS and optical absorption and reflection measurement.

Further, the invention according to claim 2 is characterized in that the metal acid
Is a type of Ti, Zn, Sr, In, W, V, Al, Fe, Sn
Or a metal oxide containing multiple types of metal elements.
It is a sign. To give an example of this metal oxide,
TiO_Two, ZnO, SrTiO_Three, In_TwoO_Three, WO_Three, V_TwoO_Five, Al _TwoO_Three, Fe
_TwoO_Three, SnO_Two And the like. These metal oxides
Large electron affinity and large band gap,
It is easy to meet the conditions shown in claim 1 and the pollution-free material
In some respects, it is suitable as the metal oxide of the present invention.

These metal oxides are formed into a film by applying a solution obtained by dissolving a metal alkoxide or acetylacetonate in an organic solvent or an acidic aqueous solution of a metal ion by a dip method or a spray method and firing the film. In addition to the above method, it can be manufactured by a sputtering method, an EB evaporation method, a laser ablation method, a CVD method, or the like.

Further, the invention according to claim 3 is characterized in that the photoelectron emission fine particles contain carbon as a main component. The invention according to claim 4 is characterized in that the photoelectron emission fine particles include graphite. The invention according to claim 5 is characterized in that the photoelectron emission fine particles include carbon nanotubes (CNT).

Further, the invention according to claim 6 is characterized in that the photoelectron emission fine particles contain fullerene. Allotropes of carbon include diamond, amorphous carbon,
Examples include graphite, CNT, and fullerene. These are pollution-free materials and can be obtained in fine particles. Further, at least at 500 ° C. or less, it does not oxidize in the air,
A natural oxide film serving as a barrier for photoelectron emission cannot be formed on the surface of the fine particles.

Graphite has a structure in which six-membered rings of carbon having sp2 orbitals are stacked in a plane, and exhibits the properties of a metalloid. CNTs and fullerenes are separated from soot produced by carbon arc discharge or from soot aggregated in the gas phase by heating and evaporating graphite in an inert gas.

CNT has carbon 6 having an orbit close to sp2.
In this structure, the member ring has a cylindrical surface and at least one end is closed. There is a structure in which there is a single tube, and a structure in which a plurality of tubes have the same axis and are stacked in multiple layers. Some tubes exhibit semiconducting and semimetallic properties, which are mixed. Fullerene is composed of a 6-membered ring and a 5-membered ring of carbon close to sp2, and has a soccer ball-like structure. There are types such as C60, C70, C76, and C84, and has light sensitivity from visible light to ultraviolet light (Seiro Kanamori et al., Iwanami Lecture Modern Physics 7 "Solid", published by Iwanami Shoten).

Graphite fine particles, CNTs and fullerenes are dissolved or suspended in the coating solution shown in the above-mentioned method for preparing a metal oxide, and coated and fired to prepare the optical functional film. Alternatively, graphite fine particles, CNT and fullerene are stirred and mixed with a metal oxide by a ball mill or the like, and then baked to produce a sputtering target or an EB vapor deposition raw material. Is prepared.

Diamond, CNT, graphite, and fullerene, like diamond and amorphous carbon, do not oxidize at least at 500 ° C. or less, and cannot form a natural oxide film on the surface of the fine particles as a barrier to photoelectron emission. For the same reason, it is possible to select conditions under which the carbon allotrope particles are not oxidized even when dissolved or suspended in the coating solution shown in the above-described method for producing a metal oxide and baked. Thus, the above-mentioned optical functional film can be easily produced because the target for the EB and the EB vapor deposition raw material can be easily produced.

Japanese Patent Application Laid-Open No. 5-289381 discloses a conventional example of an electrophotographic photosensitive member intended to cope with a shorter wavelength of a writing light source by including fullerenes in a charge generation layer. . The charge generation layer manufactured by the method disclosed herein has a single structure composed of carbon clusters containing fullerenes or a structure in which fullerenes are dispersed in a resin, which is different from the structure of the present invention. In the case of the former structure, since only the allotrope of carbon is used,
There is a limit in controlling the charge generation characteristics. In the case of the latter structure, since the resin is used as a binder, it is expected that light deterioration is likely to occur.

Further, the invention according to claim 7 is characterized in that the photoelectron emission fine particles are metal oxides. The invention according to claim 8 is characterized in that the metal oxide photoelectron emission fine particles are made of one or more of Cu ₂ O, Ag ₂ O, and Fe ₂ O ₃ . Incidentally, the Cu ₂ O (bandgap ～2.2EV) is because it is unstable, since Fe ₂ O ₃ (bandgap ～2.3EV) is low photoconductivity not increased purity, Ag ₂ O (bandgap ~ 1.5e
Since V) has a high material cost, it has not heretofore been practically used alone as an optical functional film as described above.

If the size of the photoemission fine particles is small,
Since the photocarriers can be extracted to the metal oxide layer before recombining, the photoelectron emission fine particles can be used even if the crystal quality and purity are inferior to those of a single case. Further, since the photoelectron emission fine particles are dispersed in the metal oxide serving as the base material, they need only be used in a small amount. Even if an expensive material is used, the problem of material cost is reduced.

When the photoelectron emission fine particles are a metal oxide, the third electrical potential due to the formation of the natural oxide is eliminated from the beginning at the interface with the metal oxide, so that the electrical environment is simplified. In addition, the reliability of the device can be improved. In this case, since the photoelectron emission fine particles are the same metal oxide as the metal oxide as the base material, even when the solution is applied and fired to produce the optical functional film, the metal oxide is fired. In the case where a sputtering target or an EB vapor deposition raw material is produced by using the above method, and the optical functional film is produced using the sputtering target or the EB vapor deposition method, a mixing step can be taken from the beginning, and the dispersibility of the photoelectron emission fine particles is also good. Become.

According to a ninth aspect of the present invention, there is provided an optical sensor using the optical functional film according to any one of the first to eighth aspects. The configuration of the sensor according to the present invention is not limited, and includes all configurations in which photocarriers generated by light irradiation cause a change in resistance and a change in electromotive force in the device. For example, a photoconductive sensor configured to provide a pair of electrodes in contact with the optical functional film, a pn junction, a pi junction,
a photovoltaic sensor having a configuration in which a stack including the optical functional film having an n-junction is sandwiched between a pair of electrodes, and a photovoltaic sensor having a Schottky junction having a configuration in which the optical functional film is sandwiched between a pair of electrodes. There are cases.

The following is an example of a pn junction. The optical functional film often has n-type conductivity and is used as an n-type layer. Semiconductor materials that can be the p-type layer include metal oxides such as CuAlO ₂ , SrCu ₂ O ₂ , NiO, FeO, Cu ₂ O, and Bi ₂ O ₃ . In addition, a p-type group IV semiconductor, a group III-V compound semiconductor,
II-VI compound semiconductors can also be used.

FIG. 3 shows the basic structure of the photoconductive photosensor according to the present invention. Incidentally, in FIG.
Denotes a transparent conductive film, 16 denotes an optical function film, and 22 denotes a conductive substrate.

According to a tenth aspect of the present invention, there is provided a solar cell using the optical functional film according to any one of the first to eighth aspects. FIG. 4 shows a basic configuration of a pn junction photovoltaic photosensor and a solar cell according to the present invention. In FIG. 4, reference numeral 14 denotes a transparent conductive film, 18 denotes an n-layer (optical functional film), 20 denotes a p-layer, and 22 denotes a conductive substrate.

The configuration of the solar cell of the present invention is not limited, and includes all configurations in which photocarriers generated by light irradiation generate electromotive force in the device. For example, the pn junction, the pin junction, and the Schottky junction photovoltaic type described in the configuration example of the optical sensor are exemplified. Further, similar examples are given in the section of the conventional example, and the transparent conductive film 24 formed on the transparent substrate is provided.
And the optical functional film 16 formed on the surface of the conductive substrate 22.
There is also a configuration of a wet solar cell having a configuration in which an electrolyte solution 26 is enclosed between them (see FIG. 5). In addition, 28 is a pacer.

An eleventh aspect of the present invention is an electrophotographic photosensitive member using the optical functional film according to any one of the first to eighth aspects. As shown in FIG. 6, the electrophotographic photosensitive member according to the present invention is made of aluminum, SUS,
(Stainless steel) or other conductive substrate 22 on the photosensitive member layer including the optical functional film 16, or all of the optical functional film 16
Provided with a photoreceptor layer made of

This electrophotographic photoreceptor is currently widely used in copiers,
It has the same electrical characteristics as the electrophotographic photoreceptor used in printers. In the image forming process, the entire surface of the photoreceptor is positively or negatively charged by a corona charging method or a roller charging method, and then a desired region is irradiated with light to perform an exposure process.
At this time, one of the positive and negative carriers generated in the photoreceptor layer moves to the substrate electrode, and the other carrier reaches the surface of the electrophotographic photoreceptor layer to eliminate the charged charge.

Thereafter, the charged toner is transported to the surface of the photoreceptor, and a developing process of attaching the charged toner in accordance with the charge amount on the surface of the electrophotographic photoreceptor to the surface of the electrophotographic photoreceptor is performed. Next, a transfer process of attaching the toner to the paper is performed to form an image.

According to a twelfth aspect of the present invention, there is provided an optically-written electrostatic recording medium using the optical functional film according to any one of the first to eighth aspects. recent years,
Optical write / read recording media such as CD-RWs and DVD-RAMs have been increasingly demanded in recent years as writable large-capacity, high-density recording media. At the time of writing, these elements irradiate the medium with the light beam of the laser diode to raise the temperature, thereby changing the state of the medium such as phase change. At the time of reading, the difference in the reflectance of the medium is detected.

On the other hand, a large-capacity, high-recording-density recording method that can be written on a principle different from these has also been proposed. For example, Japanese Patent No. 2667222 discloses an electrostatic recording method in which a high density can be expected because an information unit is an electrostatic charge.

According to this method, the other surface of the photoconductor composed of the photoconductive layer having the electrode film provided on one surface is brought into close contact with or in contact with the other surface of the charge holding medium having the electrode film provided on one surface. Then, image exposure is performed on the photoreceptor while a voltage is applied between the two electrodes, and the charge generated inside the photoreceptor is injected into the charge holding medium or charged by the discharge generated between the photoreceptor surface and the charge holding medium surface. Then, information is recorded by introducing charges into the charge holding medium. Reading is performed by causing a detection electrode to face a charge holding medium and detecting a potential generated by charges induced on the detection electrode.

Here, as an example of the charge holding medium, an example in which the insulating resin contains fine particles having photoconductivity or conductivity is mentioned. Even in the writing electrostatic recording, it is considered that the wavelength of the writing light source will be shortened in the future due to the high density. Further, the electrostatic recording medium disclosed in Japanese Patent No. 2667222 has a structure in which an organic compound is mainly used, and therefore, there is a concern about light deterioration.

In the electrostatic recording medium of the present invention, only one kind of charge among holes and electrons generated in the optical functional film by the light irradiation moves out of the film, and the other kind of charge is stored in the film. , Information is recorded. To increase the charge retention, the resistivity of the electrostatic recording medium is 1 × 10 ¹² Ω
m or more.

Hereinafter, an example of a method of writing / reading / erasing will be described. As shown in FIG. 7, writing is performed on one surface of the transparent substrate 30 by using a transparent conductive film 14 such as ITO or SnO ₂ or a thin Au film.
Transparent electrode plate 32 provided with a transparent metal film such as Ag, Pd, etc.
Is brought into contact with or close to the surface of the electrostatic recording medium 34. Next, while applying a voltage 36 between the transparent electrode plate 32 and the conductive substrate 22 of the electrostatic recording medium 34, the writing light 38 is incident from the surface of the transparent electrode plate 32 where the conductive film is not provided.

At this time, light is absorbed by the photoelectron emitting fine particles in the electrostatic recording medium 34, and a hole-electron pair is generated. Of these, only one type of charge moves through the film by the action of the applied electric field, and is discharged to the conductive substrate 22 or the transparent electrode plate 32, and another type of charge remains in the film and is recorded.

Reading is performed by, similarly to the above-mentioned conventional example, making the detection electrode face the charge holding medium and detecting the potential generated by the charge induced on the detection electrode. Erasing is performed on the transparent electrode plate 3.
2 is brought into contact with or close to the surface of the electrostatic recording medium 34, and an AC voltage is applied between the transparent electrode plate 32 and the conductive substrate 22 of the electrostatic recording medium 34.

[0050]

Embodiments of the present invention will be described below in detail with reference to preferred embodiments shown in the drawings.

[Embodiment 1] The present embodiment relates to a photoconductive photosensor. C in alumina crucible of evaporation equipment
Add u ₂ O (Furuuchi Chemical) powder and put 20 He gas into the evaporator.
sccm, O ₂ gas was introduced at 1 sccm, and the substrate temperature was set to −5.
At 0 ° C., Cu ₂ O is evaporated in gas at a pressure of 133 Pa. Fine particles of Cu ₂ O are deposited on the substrate. This Cu ₂ O
Of fine particles and Ti (OC ₂ H ₅ ) ₄ (manufactured by Wako Pure Chemical Industries)
Is weighed so that the number of atoms becomes 1: 500, and C ₂ H ₅ OH and
Add to the H ₂ O solution and stir.

The sol-like liquid thus obtained was applied on a SUS plate by a doctor blade method, and then, in air at 500 ° C.
For 3 hours, and dispersed with 500 nm thick Cu ₂ O fine particles.
Obtain iO ₂ film. On this film, I was formed by sputtering.
By laminating the TO film, a parallel-plate type photoconductive element having a thickness of 450 nm and having a large resistance change at the time of light irradiation / darkness was obtained.

FIG. 8 is a cross-sectional view of a parallel plate type photoconductive device manufactured according to the above embodiment. As shown in FIG. 8, the parallel-plate type photoconductive element according to the present embodiment has a 500 nm thick Cu ₂ O fine particle dispersed on a SUS conductive substrate 22.
The TiO ₂ film is further provided with an ITO transparent conductive film 14 having a thickness of 450 nm formed thereon.

[Embodiment 2] This embodiment is directed to a wet type solar cell.
It is related. FIG. 9 shows the wet-type thick plate manufactured in this example.
1 shows a cross-sectional view of a positive battery. N_TwoIn an atmosphere, multi-layer carbon
Tube BU201 (made by Bucky, USA) with Zn (OC_TwoH _Five)_Two No
So that the number of C and Zn atoms is 1: 1
The liquid weighed and suspended in_TwoH_FiveOH and H_TwoO 20:
1) Make a sol-like solution while dropping the solution.

This sol-like liquid was applied on one side in an N ₂ atmosphere.
After being applied by dip coating on a borosilicate glass substrate 40 having a SnO ₂ conductive film 42,
And heat for 10 minutes. After repeating this coating-heating step six times, the coating was heated at 500 ° C. for 3 hours in the air to obtain a thickness of 3 μm.
The first electrode 46 is obtained by laminating the m CNT fine particle-dispersed ZnO optical functional film 44.

A second electrode 50 made of a borosilicate glass substrate 40 having a Pt semi-transparent film 48 on one side is arranged so that the Pt semi-transparent film 48 faces the first electrode 46. The first electrode 46 is installed parallel to the first electrode 46 at an interval of 1 mm, and the periphery of the two electrodes is sealed with resin. As the electrolyte solution 52 between the two electrodes, tetrapropylammonium iodide and iodine dissolved in an acetonitrile / ethylene carbonate solvent are introduced. The periphery of the first electrode 46 and the second electrode 50 is sealed with epoxy resin to obtain a wet solar cell.

The wet solar cell obtained in this manner was identified as AM1
Irradiation showed high photoelectric conversion efficiency. In FIG. 9, reference numeral 28 denotes the aforementioned spacer.

Embodiment 3 The present embodiment relates to an electrophotographic photosensitive member. Zn (OC ₂ H ₅ ) on an Al cylindrical substrate with an outer diameter of 40 mm
_A sol solution is prepared by dropping a (50: 1) solution of C ₂ H ₅ OH and H ₂ O into the benzene solution of Step ₂ . This sol solution was applied by dip coating in an N ₂ atmosphere on an Al cylindrical substrate provided with the above-mentioned photocharge generation layer.
Heat for a minute. After repeating this coating-heating step 10 times, the coating was heated at 500 ° C. for 3 hours in the air to have a thickness of 10 μm.
A ZnO charge transport layer was obtained.

N_Two In an atmosphere, multilayer carbon nanotubes
BU201 (made by Bucky USA) and Ti (OC_TwoH _Five)_Four(Wako Pure Chemical Industries)
Is weighed so that the atomic ratio of C and Ti is 1: 1
Then C_TwoH _FiveOH and H_TwoAdd to the O 2 solution and stir. This sol
Liquid, N_Two Provide the ZnO charge transport layer in the atmosphere
Dip coating method on an Al cylindrical substrate
Then, it is heated at 300 ° C. for 10 minutes in the air. This application
-After repeating the heating process 6 times, at 400 ° C. in air
Heated for 3 hours, dispersed 3μm thick CNT fine particles TiO _Two film
By forming a charge generation layer composed of
Composed of TiO2 photocharge generation layer / ZnO charge transport layer
A photoreceptor was obtained.

FIG. 10 is a sectional view of an electrophotographic photosensitive member manufactured according to this embodiment. In the figure, 54 is an Al cylindrical substrate, 56 is a ZnO charge transport layer, and 58 is CNT fine particle dispersion.
3 shows a TiO2 photocharge generation layer. By using the photoreceptor thus obtained in an electrophotographic process using writing light of an LD of 410 nm, an electrophotograph of good image quality could be obtained.

Each of the above embodiments is merely an example of the present invention, and the present invention should not be limited to these embodiments, and appropriate modifications and improvements may be made within the scope of the present invention. Needless to say.

[0062]

As described above, according to the present invention, the following effects can be obtained. (1) Effects Corresponding to the Invention According to Claim 1 The basic structure of the optical functional film according to the present invention is a structure in which photoelectron emission fine particles made of an inorganic material are contained in a metal oxide. Has the following excellent features.

1) The range of selection of constituent materials is widened, and an optical functional film having more appropriate characteristics and environmental friendliness can be obtained at low cost. That is, since the photoelectron emission fine particle material has a small distance from which the photocarrier can escape, even a material that has not been found to have photoconductivity conventionally can be finely divided into particles and combined with a metal oxide. It is not necessary to show photoconductivity by itself,
Any of a semiconductor material, an insulator material, and a metalloid material can be selected.

2) Since the optical functional device according to the present invention can use a short wavelength writing light source, it can easily cope with high definition and high density. 3) Since the optical functional film according to the present invention is made of an inorganic material, light deterioration is reduced and high durability is obtained. 4) Since the optical functional film according to the present invention is made of an inorganic material, the optical functional film has high mechanical strength and easily obtains high durability. 5) Since a non-polluting material can be used, an optical functional film in consideration of the global environment can be obtained.

(2) Effects corresponding to the second aspect of the invention These metal oxides are non-polluting materials, and can be applied and fired by a dipping method or a spraying method to form a film. An optical functional film in consideration of the above can be obtained at low cost. (3) Effects Corresponding to the Inventions According to Claims 3, 4, 5, and 6 The carbon allotrope does not oxidize in the air at least at 500 ° C. or less, and a natural oxide film serving as a barrier for photoelectron emission cannot be formed on the surface of fine particles. Therefore, an optical functional film having high durability and reliability can be obtained at low cost. Since carbon allotrope is a non-polluting material, an optical functional film that considers the global environment can be obtained at low cost.

(4) Advantages Corresponding to the Seventh Invention Since the photoelectron emission fine particles are metal oxides, electrical connection with the metal oxides is simplified, and light with high durability and reliability is obtained. A functional film is obtained. Since the photoelectron emission fine particles are the same metal oxide as the metal oxide as a base material,
The step of mixing when producing the optical functional film is employed, and a low-cost and highly reliable optical functional film can be obtained. (5) Effect corresponding to the invention according to claim 8 Since Cu ₂ O, Ag ₂ O, and Fe ₂ O ₃ can be used as photoelectron emission fine particles, the range of material selection is widened.

(6) Effects Corresponding to the Inventive Aspect 9 Since the optical functional film is made of an inorganic material, an optical sensor with little light deterioration and high durability can be obtained. Since the optical functional film can be formed by a coating method and a spray method, a low-cost optical sensor can be obtained. Since it is possible to use a non-polluting material as the optical functional film, an optical sensor that considers the global environment can be obtained.

(7) Effects Corresponding to the Tenth Aspect Since the optical functional film is made of an inorganic material, a solar cell with little light deterioration and high durability can be obtained. Since the optical functional film can be formed by a coating method or a spray method, a low-cost solar cell can be obtained. Since it is possible to use a non-polluting material as the optical functional film, a solar cell in consideration of the global environment can be obtained.

(8) Effects Corresponding to the Invention of Claim 11 Since the optical function film is made of an inorganic material, light deterioration is reduced and a writing light source with a shorter wavelength can be used. Thus, an electrophotographic process capable of obtaining a high-definition image can be realized. Since the optical functional film is made of an inorganic material, the mechanical strength is increased, so that an electrophotographic photosensitive member having high durability can be obtained. Since the optical functional film can use a non-polluting material, an electrophotographic photoreceptor that considers the global environment can be obtained.

(9) Effect corresponding to the twelfth aspect Since the information unit is an electrostatic charge, it is possible to obtain an optical recording medium capable of high-density recording. Since the optical function film is made of an inorganic material, light deterioration is reduced, a writing light source having a shorter wavelength can be used, and an optical writing electrostatic recording medium capable of high-density recording can be obtained. Since it is possible to use a non-polluting material as the optical functional film, an electrostatic recording medium that is friendly to the global environment can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of an optical functional film according to the present invention.

FIG. 2 is a diagram illustrating the energy potential relationship of a material according to the present invention.

FIG. 3 does not show the basic configuration of the photoconductive photosensor of the invention according to claim 9;

FIG. 4 is a diagram showing a basic configuration of a pn junction photovoltaic photosensor and a solar cell according to the invention of claim 10;

FIG. 5 is a diagram showing a basic configuration of a wet solar cell as another configuration example of the invention according to claim 10;

FIG. 6 is a view showing a basic configuration of the electrophotographic photoreceptor of the invention according to claim 11;

FIG. 7 is a diagram illustrating an example of an electrostatic recording medium and an optical writing method thereof according to the present invention.

FIG. 8 is a cross-sectional view of a photoconductive photosensor manufactured according to the first embodiment.

FIG. 9 is a sectional view of a wet-type solar cell manufactured according to Example 2.

FIG. 10 is a cross-sectional view of an electrophotographic photosensitive member manufactured according to Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Metal oxide 12 Photoemission fine particle 14 Transparent conductive film 16 Optical functional film 18 n layer (optical functional film) 20 p layer 22 Conductive substrate 24 Transparent conductive film 26 Electrolyte solution 28 Spacer 30 Transparent substrate 32 Transparent electrode plate 34 Electrostatic Recording medium 38 Writing light 40 Glass substrate 42 Conductive film 44 Optical function film 46 First electrode 48 Translucent film 50 Second electrode 52 Electrolyte solution 54 Al cylindrical substrate 56 Charge transport layer 58 Charge generation layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 31/08 Q (72) Inventor Akihiro Fuse 1-3-6 Nakamagome, Ota-ku, Tokyo RICOH Company, Limited (72) Inventor Shinji Sato 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. 2H068 AA12 CA01 CA22 CA29 5F051 AA14 AA20 DA03 DA04 5F088 AA11 AB16 AB19 BA18 BB05 BB08

Claims (12)

[Claims] 1. An optical functional film that irradiates a film with light to generate optical carriers and utilizes a change in current and voltage caused by the optical carriers outside the film, or an optical functional film that moves after the optical carriers move. An optical functional film that uses a change in an electric field due to electric charges remaining outside the film, wherein the optical functional film has photoelectron emitting fine particles made of an inorganic material having a photoelectron emitting function dispersed in a metal oxide, And, the ionization energy of the photoelectron emission fine particles is larger than the electron affinity of the metal oxide, and the photoelectron emission fine particles have an empty level at which electrons are excited upon irradiation with light. An optical functional film, wherein the energy of the emitted fine particles from the level to the vacuum level is smaller than the electron affinity of the metal oxide. 2. The method according to claim 1, wherein the metal oxide is Ti, Zn, Sr, In, W,
2. The optical functional film according to claim 1, wherein the optical functional film is a metal oxide containing one or more metal elements of V, Al, Fe, and Sn. 3. The optical functional film according to claim 1, wherein the photoelectron emission fine particles contain carbon as a main component. 4. The optical functional film according to claim 3, wherein the photoelectron emission fine particles include graphite. 5. The optical functional film according to claim 3, wherein the photoelectron emission fine particles include carbon nanotubes (CNT). 6. The optical functional film according to claim 3, wherein the photoelectron emission fine particles include fullerene. 7. The optical functional film according to claim 1, wherein the photoelectron emission fine particles are a metal oxide. 8. The method according to claim 1, wherein the metal oxide photoelectron emission fine particles are Cu _2.
O, Ag ₂ O, the optical function film according to claim 7, characterized in that it consists of one or more of Fe ₂ O _3. 9. An optical sensor using the optical functional film according to claim 1. Description: 10. A solar cell using the optical functional film according to claim 1. Description: 11. An electrophotographic photosensitive member using the optical functional film according to claim 1. Description: 12. An optically written electrostatic recording medium using the optical functional film according to claim 1. Description: