JPH0468750B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Field of Application of the Invention The present invention relates to a photovoltaic device with a function of storing and re-discharging energy generated by light irradiation. (B) Summary of the Invention The present invention combines a solar cell and a redox solution to directly irradiate incident light onto a semiconductor that generates photovoltaic force through light irradiation, that is, a solar cell, thereby using energy from light irradiation. Photovoltaic power generation that dramatically increases the efficiency of the redox reaction method and re-reacts the reaction products produced thereby, making it possible to stably extract energy from light irradiation regardless of the intensity of the irradiated light. It is a device. (C) Prior Art Conventional photoelectric conversion devices, particularly solar cells, can generate photovoltaic force by irradiation with light. However, this solar cell produces output only when it is irradiated with sunlight and is proportional to the intensity of the irradiation, so the output fluctuates greatly depending on whether it is sunny or cloudy. When installed on the roof of a general household, there are drawbacks such as no photovoltaic power being generated when illuminating at night, which is a major problem for practical use in civilian use. A method of using a secondary electric ground to compensate for these problems is known. However, secondary batteries have drawbacks such as being expensive and requiring separate installation locations. On the other hand, redox reactions are known. This typically involves irradiating light onto an oxide semiconductor such as TiO ₂ in water, and using the electrons and holes generated on this surface to cause redox (oxidation).
- A general term for reduction reactions or solutions that carry out such reactions). In such conventional redox reactions, it has been considered an essential condition that the semiconductor electrode in contact with the redox solution be irradiated with light. In particular, the semiconductor used in this reaction, typically an oxide semiconductor such as titanium oxide, is irradiated with light to create an interface level between the semiconductor and the redox solution, and this level bends the energy band of the semiconductor surface upward. This is based on the idea of using a depletion layer region formed near the surface. Figure 1 shows a conventional example (JP-A-54-4582 or Appl.
Phys. Lett Vol. 29 No. 6, 15 (1976) p380-340). Glass container 2 containing redox solution 3 and water
An anode 55 and a cathode 54 are provided, and the surface of the anode is made of a semiconductor coated with titanium oxide. Further, light, particularly sunlight 10, is added, and in titanium oxide, which is an N-type semiconductor, electrons and holes are generated by the sunlight. One of the holes gathers on the surface and reacts with oxygen ions in the water, and oxidizing gas is generated on the anode electrode side and released to the outside from the outlet 44. On the other hand, when the switch is turned on, the electrons generated in the semiconductor 55 are neutralized by hydrogen ions at the cathode electrode 54 via the load 53 to generate hydrogen gas, which is emitted to the outside from the outlet 43. In this way, a redox reaction occurs. (d) Problems with the conventional technology In the redox reaction shown in Figure 1, reaction products between the semiconductor and the solution are gradually formed as the reaction between the semiconductor itself and the redox solution progresses on the surface of the semiconductor, resulting in the formation of interface states. As the density changes, it becomes difficult for the reaction products to conduct current, which means that the interface states tend to deteriorate, so even if the actual reaction is carried out by light irradiation, the reaction will essentially stop within 1 hour to 1 day. It was so hot that I ended up doing it. Further, in the conventional redox reaction, as shown in FIG. 1, the irradiated light 10 passes through the container 2 and proceeds in the solution as 10', and then is irradiated onto the cathode or anode electrode 55. Therefore, about 30 to 40% of the irradiated light 10 is reflected 60 at the container surface and the interface with the container solution, and about 60 to 70% of the light 1
0' progresses in solution. If this solution is translucent, for example water, it will easily absorb short wavelength light of 100 to 300 mm, and as a result, only 5 to 10% of the total irradiation light will be irradiated with the short wavelength light necessary for the electrode. . Furthermore, on the surface of this electrode, 20 ~
Since 40% is reflected20, the part of the irradiated light that actually contributes to the reaction is from 300nm to 1100nm.
up to visible, infrared light, and _TiO2 electrode 55
(Eg = 3.2 eV, that is, converting wavelengths below 388 nm into electricity) As a result, only 10 to 20% of the total irradiation light is effective at 300 to 350 nm. For this reason, it has a major drawback in that only 0.5 to 1% of the total incident light, such as sunlight, is effectively utilized.
In addition, if the redox solution is a colored liquid, all the light will be absorbed in this solution.
Since photo-electrical conversion was impossible in the TiO ₂ film, it was impossible to carry out a redox reaction at all. That is, it also has the disadvantage that colored solutions cannot be used. Furthermore, as is clear from FIG. 1, when a semiconductor is conventionally used for a redox reaction, it has not been possible to directly extract the electrical energy generated by light irradiation from the semiconductor. Furthermore, in the case of FIG. 1, it was impossible to control and extract the necessary amount of electrical energy from this semiconductor and store the unnecessary electrical energy as a by-product for effective use. (e) Purpose of the present invention The present invention aims at generating electrical energy by integrating a photoelectric conversion device that generates photovoltaic force by exciting electrons and holes through light irradiation with redox (reduction-oxidation reaction solution). The object of the present invention is to provide a photovoltaic power generation device that flattens (uniforms) the output of the photovoltaic device, stores and releases the stored electrical energy, and so on. The present invention not only enables effective redox reactions, but also enables three types of reactions: photo-electrical conversion and photo-redox (storage and discharge) reactions. For this reason, when sunlight is shining, electrical energy is extracted using solar cells (photoelectric conversion devices), and the surplus that cannot be used is used to efficiently extract oxygen and hydrogen through a redox reaction, or the excess electricity is Two methods of storing energy in the redox solution are provided. Furthermore, it is an object of the present invention to provide an all-time, all-weather type photovoltaic power generation device that is capable of re-reacting stored reaction products and extracting electrical energy again at night. (f) Structure of the invention The present invention provides a first electrode, a semiconductor, a second electrode,
A photovoltaic device having a third electrode, a fourth electrode, and a redox solution, wherein the semiconductor is provided on the light irradiation surface side of the first electrode in contact with the first electrode, and the semiconductor is provided on the light irradiation surface side of the first electrode, and the semiconductor The third electrode is provided on the light irradiation side of the semiconductor in contact with the semiconductor, and the third electrode is provided on the light irradiation side of the first electrode on the opposite side of the semiconductor.
The fourth electrode is provided on the opposite side of the light irradiation surface of the third electrode, and the redox solution is filled between the third electrode and the fourth electrode. The first electrode is made of a conductive substrate, and the semiconductor is made of a non-single crystal semiconductor to which an element for neutralizing recombination centers is added.
A photovoltaic generation semiconductor having at least one PIN junction, the third electrode being a redox electrode made of a different material from the first electrode,
The photovoltaic device is characterized in that the fourth electrode has a polarity opposite to that of the third electrode. The present invention also provides a photovoltaic device having a first electrode, a semiconductor, a second electrode, a third electrode, a fourth electrode, and a redox solution, wherein the semiconductor is located on the light irradiation surface of the first electrode. The second electrode is provided in contact with the semiconductor on the light irradiation side of the semiconductor, and the third electrode is provided in contact with the semiconductor on the light irradiation side of the semiconductor.
The electrode is provided in contact with the first electrode on a surface opposite to the light irradiation surface of the first electrode, and the fourth electrode is provided on the opposite side to the light irradiation surface of the third electrode, The redox solution is filled between the third electrode and the fourth electrode, the first electrode is made of a conductive substrate, and the semiconductor is doped with an element for neutralizing recombination centers. The third electrode is a redox electrode made of the same material as the first electrode, and the fourth electrode is a redox electrode made of the same material as the first electrode. The photovoltaic device is characterized in that the electrode has a polarity opposite to that of the third electrode. The present invention separates the semiconductor electrode layer where the redox reaction takes place and the semiconductor surface where the light irradiation takes place,
The first feature is that they are provided on opposite surfaces. This is because redox reactions do not originally require light irradiation on the reaction surface of the redox reaction itself, but the electrons or holes generated by light irradiation and the potential (monopolar characteristic) at the electrode surface of the third electrode for redox. is important, and the semiconductors that make up the PIN junction are intrinsic semiconductors (I which do not actively add impurities).
formation of an internal electric field in the semiconductor that promotes the generation of electrons and holes and the movement of the holes and electrons generated in the upper and lower P and N layers to the respective first and third electrodes; This is based on the idea that it is important to make all the basic functions of the redox reaction by light irradiation independent, and to improve its controllability and efficiency. Therefore, the surface to be irradiated with light is directly irradiated with sunlight without going through the liquid. The structure of the present invention is characterized in that a solar cell (photoelectric conversion device) is provided, and a redox system having a power storage effect is provided integrally on the back surface of the solar cell. In addition, the present invention uses a plasma vapor phase method to
A photovoltaic power generating semiconductor is used, in which a non-single-crystalline semiconductor with an amorphous or semi-amorphous structure doped with hydrogen or halogen elements, which is produced at a low temperature of One or more NIP joints are used in a tandem structure (PINPIN joint or
The third electrode surface in contact with the redox has a cathode or anode according to the polarity of the N- or P-type semiconductor in contact with the conductive substrate, and the reaction is determined only by the electrochemical potential. It was made so that it could be done.
Therefore, it is characterized by being completely free from the influence of the so-called interface states generated at the interface between the solution and the semiconductor. Furthermore, the redox system can also provide a planton system capable of charging and discharging that has the function of a regenerative fuel cell. (g) Details of the structure: A photovoltaic force is generated by a non-single crystal semiconductor having a PIN or NIP junction on the upper surface of a conductive substrate, such as a titanium, stainless steel or aluminum substrate, constituting the first electrode. ITO (a mixture of indium oxide and tin oxide), conductive titanium oxide, or a multilayer film of conductive titanium oxide and indium oxide, which constitutes the second electrode provided on the light-irradiated surface of this semiconductor, and other light-transmitting materials It is taken out to the outside through a second electrode constituted by a conductive film and an auxiliary electrode provided in a comb shape on the conductive film. The lower layer of the other method semiconductor is a conductive substrate (first
There is a third electrode selectively or entirely provided on the opposite side of the electrode) in contact with the redox solution,
Supply electrons or holes to this redox.
Even if the third electrode is made of the same electrode material as the first electrode, if it acts as an anode or a cathode, the first and third electrodes may be made of the same material.
In particular, when the cathode is made of stainless steel, a cathode electrode may be provided on its upper surface. Furthermore, to prevent an increase in series resistance at this third electrode, this electrode should be between 10 Å and 1 μ, especially between 50 and 300 Å.
It is important to make it extremely thin and have a resistance of 1Ω or less. Furthermore, depending on the conductivity type of the semiconductor on the conductive substrate, which is the first electrode, the third electrode, which is the redox electrode, is also adapted to have a polarity that makes it easy to transfer the electric charge generated in the semiconductor device to the redox system. It's profitable. That is, the third electrode is provided so that the portion of the semiconductor for photovoltaic generation that is in contact with the first electrode is an anode if it is a P type, and is a cathode if it is an N type. Furthermore, this redox solution may be a non-aqueous solution. In particular, when water is used in an aqueous redox solution, hydrogen is generated at the cathode electrode (the electrode that supplies electrons to the solution is called a cathode) where the semiconductor is in contact with the N layer of the redox, and hydrogen is generated at the anode electrode (the electrode that supplies holes to the solution). On the P layer side, which is the electrode that receives holes or emits electrons (for solutions, the electrode is called an anode), holes and oxygen ions react to generate oxygen gas and the like.
For this reason, an aqueous solution is not interposed between sunlight and the semiconductor and absorbs light, especially short wavelength light (100 to 300 nm), and the photoelectric conversion efficiency is high because it efficiently absorbs visible light, which has the strongest wavelength. Non-single crystal semiconductors that have an energy band width of 1.3 to 2.0 eV and constitute a PIN junction, especially amorphous semiconductors with hydrogen or halogen elements added to neutralize recombination centers, or microscopic particles of 5 to 100 Å with lattice strain. By integrating a photoelectric conversion device using a crystalline semi-almorphous semiconductor with a redox solution, it was possible to separate and generate oxygen and hydrogen from water, which is a redox solution. Also, the present invention has a significant difference compared to the conventionally known redox system using a platinum-titanium oxide semiconductor electrode system. In other words, the conventionally known titanium oxide has an energy band width of
Since it has a voltage of 3.2 eV, only ultraviolet rays with a wavelength of 387 nm or less of the irradiated light can effectively create electron-hole pairs and be separated. For this reason, sunlight etc.
The efficiency is extremely low for continuous light centered around 500 nm. Moreover, its production requires high temperature and high energy of 600 to 800°C. On the other hand, in the present invention, Eg (energy band width) is set to 1.0 eV (electrons and holes are generated by light at a wavelength of 1240 nm or less) ~
Non-single-crystal silicon or silicon carbide that uses 2.5 eV (496 nm or less wavelength, which generates electrons and holes from light) and has Eg = 1.3 to 2.0 eV, especially in the active region that generates electrons and holes with irradiated light. Another feature is the use of silicified germanium. That is, among these silicon, especially aluminum oxide or microcrystalline silicon in the short range of 5 to 100 Å, silane,
Since SiF ₄ etc. are made at a low temperature of 200 to 300℃, Eg is 1.4
~1.9eV, so it is 3500V for light, especially sunlight.
The light absorption coefficient at short wavelengths of ~5000 Å is 10 to 30 times higher than that of single crystal silicon (Eg = 1.1 eV). In addition, the layer (intrinsic or substantially intrinsic conductivity type) in the PIN junction of the present invention has a light absorption coefficient on the short wavelength side that is 20 times larger than that of single crystal silicon, so its thickness is reduced to 0.3 to 1 μm. Typically 0.5μ
Furthermore, for a P or N layer laminated on this active semiconductor layer to stabilize it as a semiconductor electrode, Si _x C _1-x (0≦x≦1), especially x=0.2 to 0.7.
The optical energy band width of the layer is 1.8~2.8V.
The heterojunction was set to be wider than 1.3 to 2.0 eV, typically 1.6 to 1.8 eV. By adopting the above structure, the irradiated light is not absorbed by a redox solution etc. as a photoelectric conversion device, and all of the irradiated light is irradiated to the semiconductor having the PIN junction, so that, for example, 5 to 15% of the irradiated light is used as a solar cell.
By providing the third electrode as a redox electrode with optimal characteristics for performing a redox reaction, photoelectric conversion and redox reaction can be independently and accurately controlled using this electrical energy. Now I can do it. Furthermore, in the present invention, the third electrode in close contact with the redox is not limited to semiconductors, and the following materials may be used. That is, tin oxide, antimony oxide, titanium oxide, iron oxide, silicon carbide, carbon, titanium oxide to which tin oxide or antimony is added as anode materials, and silicon carbide, platinum tungsten, stainless steel, carbon, indium oxide, and indium oxide as cathode materials. titanium oxide etc. to which is added. In particular, when semiconductors are used as electrode materials, P-type semiconductors are used for the anode to make it easier to emit holes (easier to accept electrons), and phosphorus or arsenic is added for the cathode to make it easier to emit electrons. It was preferable to use an N-type semiconductor. When using metal, it is preferable to use a material with a large work function for the cathode, especially φ _M =3.5 eV or more. Regarding the photoelectric conversion device having the above-mentioned heterojunction, the patent application filed by the present inventor is U.S. Patent Publication No. 4254429 (corresponding Japanese Patent Application No. 53-83467,
83468 S53.7.8 application) U.S. Patent Publication No. 4239554 (corresponding Japanese patent application 53-86867, 86868 S53.7.17 application)
The details are explained in. Furthermore, if we create a tandem structure by stacking two or more PIN junctions, the voltage generated when one PIN junction is 0.7 to 1.0V is 1.5 V.
It is even more preferable because it can be made up to 1.8V. Examples of the present invention will be shown below with reference to the drawings. (H) Embodiment 1 FIG. 2 shows one embodiment of the present invention. In the non-single crystal semiconductor 12 having a PIN junction, a P-type semiconductor layer 14 is provided on the first electrode 30, and a layer 15 and an N-type semiconductor layer 16 are stacked thereon. 9 is provided as a counter electrode on the top. Also, the auxiliary electrode 2 of the electrode 9 facing the light irradiation 10
3 constitutes a second electrode, and the external lead terminal 8 drives the load 11 through the switch 17. On the other hand, on the opposite surface of the first electrode 30 to the surface on which the non-single crystal semiconductor is formed, a third electrode 24 for redox is provided in close contact with the third electrode 24, and an electrode 28 opposite thereto serves as its substrate. The auxiliary electrode 29 constitutes a fourth electrode. In order to mechanically protect the 12 surfaces of the photoelectric conversion semiconductor, a translucent holder (e.g. tempered glass) is used.
21 and a translucent filler 20, such as Seaflex, is provided therebetween. The periphery of this semiconductor device was auxiliary insulated at 22 with epoxy or polyimide resin to maintain redox resistance and mechanical strength. When water is used for the redox solution 3 and distributed, the ion conversion membrane 64 is not used and the water supply port 4 is used.
1,42 more efficiently than oxygen gas at the anode,
Hydrogen gas was generated at the canode and released from outlets 43 and 44, respectively. In order to cause this redox reaction, the switch 19 may be turned on. In other words, the switch 17 can be used to drive the load 11 to obtain electrical energy, and the switch 19 can be used to decompose water. As a result, we obtained a conversion efficiency of 7 to 15% as a solar cell, and also succeeded in generating oxygen and hydrogen without applying an external electric field. In particular, the third electrode 24 is made extremely thin, with a thickness of 50 to 300 Å.
When iron oxide (αFe ₂ O ₃ ) is provided on the first substrate electrode and the other fourth electrode is made of platinum or graphite, a saturation current of 120 mA/cm ² can be obtained. Therefore, a short circuit current of 10 mA/cm ² can be obtained by light irradiation of AM1 (100 mW/cm ² ), which is about 10 times higher than the energy conversion efficiency of 0.2 to 0.4% obtained in the conventional example shown in Figure 1. We were able to obtain 1.5 to 3% of this. (li) Example 2 In this example, a waste water solution was used as the redox solution. For this reason, in FIG. 2, an ion exchange membrane 24 is provided, an anode 24, a cathode 2
8 to prevent the charged solutions from mixing. Propylene carbonate is used as a non-aqueous solvent for this redox.

[Formula] (hereinafter simply referred to as PPK) or acetonitrile (CH ₃ −
CN) is an anhydride, which is a typical stable non-toxic solvent with little electrode reaction. Bipyridine (bpy) or its compounds such as 4,4'(CH ₃ ) ₂ bpy (hereinafter simply referred to as bipyridine) or 1,10Phenanthroine as a redox solute.
(phen) or its compounds such as _4.7- (C ₆ H ₄ SO ₃ )phen ^2- (simply referred to as phenanphlorin) were used. In particular, the following materials using Fe, Ru, or O ₅ as solvents were used. That is, Fe (bipyridine) ₃ ²⁺ , (ClO ₄ ) ₂ ^2- (simply referred to as FBP) Fe (phenanthroline) ₃ ²⁺ , (ClO ₄ ) ₂ ^2- Ru (bipyridine) ₃ ²⁺ , (ClO ₄ ) ₂ ^{2 -} (Simply referred to as RBP) Ru (phenanthroline) ₃ ²⁺ and (ClO ₄ ) ₂ ^2- are preferred. In particular, RBP has excellent physical properties, but it is also a low-cost, non-toxic and non-polluting material.
FBP was practically preferable. By using such a material as a redox, it was possible to carry out a redox reaction, that is, FBP ²⁺ FBP ³ +e ^- anode FBP ²⁺ + e ^- FBP ¹⁺ cathode, where → charge, ← discharge. As a cathode, CBP ³⁺ +e ^- CBP ²⁺ However, CBP may also be used as a ligand solvent for chromium, as shown in the figure below, which represents piviridine for chromium. When performing this charging, the switch 19 was turned on. In addition, when discharging the accumulated energy, the switch 18 was turned on and the load 11 was used to cause the reverse reaction. Also, when used simply as the output of a photoelectric conversion device,
All you have to do is turn on the switch 17. Furthermore, since the battery is charged by light irradiation, in order to discharge the smoothed voltage at the same time, it is sufficient to turn on the switch 17 and then turn on the switch 18. By doing so, it was possible to extract optical energy at a smoothed voltage in the circuit system. In the drawing, the redox solution is further filled into ports 4 and 5, so the supply ports are 41 and 42, and the discharge ports 43 and 44.
may be provided to produce a large output. The rest of FIG. 2 is the same as in the first embodiment. By doing this, the output efficiency of charging and discharging light energy is 0.5 to 0.5, which was previously shown.
We were able to obtain 5 to 10%, which is 5 to 10 times more than 1%. (J) Example 3 This example, whose system is shown in FIG. 3, is an example of a plant in which the redox system of Example 2 is enlarged. In the drawing, the redox solution is filled in 4 and 5 as shown in Example 2, and the light irradiation 10
The redox is added to each tank 48, 53 and circulated by pumps 46, 45, and the electrical output is sent to the external power system 51, 52 via a D-A converter and a temperature riser 49. Supplied by This system does not require light irradiation and has surplus power of 5
1, it is now possible to charge the redox systems 4 and 5. From the above, in this embodiment, the evaporation and release of electrical energy for photo-electrical conversion and the storage and release of surplus power are performed by the redox system in the same plant. This was made possible for the first time because the use of water-insoluble redox prevented the solution from deteriorating, electrode reactions, and dissolution of the electrode into the redox solution. Therefore, storage of electrical energy of 1 to 100 MWH,
This was made possible for the first time by a redox system integrated into the back side of the photoelectric conversion device. (l) Effects of the Invention As is clear from the above explanation, the present invention provides a structure for a photoelectric conversion device that can be integrated with a photoelectric conversion device and a redox reaction, and its practical effects. It has been made extremely effective in converting small kale energy for general households and even for entire towns, and is considered to be extremely important from an industrial perspective.

[Brief explanation of drawings]

FIG. 1 shows a semiconductor device for redox reaction using a conventional semiconductor device. FIG. 2 shows an outline of the semiconductor device of the present invention. FIG. 3 shows a redox power generation system using the semiconductor device shown in FIG.

Claims (1)

[Scope of Claims] 1. A photovoltaic device comprising a first electrode, a semiconductor, a second electrode, a third electrode, a fourth electrode, and a redox solution, wherein the semiconductor is a semiconductor of the first electrode. The second electrode is provided on the light irradiation side of the semiconductor in contact with the first electrode, the third electrode is provided on the light irradiation side of the semiconductor in contact with the semiconductor, and the third electrode is provided on the light irradiation side of the semiconductor in contact with the first electrode. The fourth electrode is provided in contact with the first electrode on a surface opposite to the irradiation surface, the fourth electrode is provided on the opposite side to the light irradiation surface of the third electrode, and the redox solution is in contact with the third electrode. and a fourth electrode, the first electrode is made of a conductive substrate, and the semiconductor is a PIN junction made of a non-single crystal semiconductor doped with an element for neutralizing recombination centers. The third electrode is a redox electrode made of a different material from the first electrode, and the fourth electrode is made of a material opposite to the third electrode. A photovoltaic device characterized by polarity. 2. In claim 1, the photovoltaic power generating semiconductor is characterized in that it is made of an amorphous or microcrystalline semiconductor containing silicon, germanium, or silicon carbide as a main component and having a PIN or PINPIN junction. A photovoltaic device. 3. In claim 1, the photovoltaic force is detected by the first electrode and the second electrode,
A redox reaction (charging reaction) is caused by connecting the second electrode and the fourth electrode, and a redox reaction (discharging reaction) is caused by the third electrode and the fourth electrode. A photovoltaic device. 4. In claim 1, the third electrode uses tin oxide, antimony oxide, titanium oxide, iron oxide, silicon carbide, carbon, tin oxide, or titanium oxide added with antimony as the anode material, and the cathode A photovoltaic device characterized in that silicon carbide, platinum tungsten, stainless steel, carbon, indium oxide, titanium oxide added with indium oxide, etc. are used as materials. 5 A photovoltaic device having a first electrode, a semiconductor, a second electrode, a third electrode, a fourth electrode, and a redox solution, wherein the semiconductor has the above-mentioned structure on the light irradiation surface side of the first electrode. The second electrode is provided in contact with the semiconductor on the light irradiation side of the semiconductor, and the third electrode is provided on the opposite side of the light irradiation surface of the first electrode. The fourth electrode is provided in contact with the first electrode, the fourth electrode is provided on the opposite side to the light irradiation surface of the third electrode, and the redox solution is in contact with the third electrode and the fourth electrode. The first electrode is made of a conductive substrate, and the semiconductor is an optical fiber having at least one PIN junction made of a non-single crystal semiconductor doped with an element for neutralizing recombination centers. It is a semiconductor for generating electromotive force, and the third electrode is a redox electrode made of the same material as the first electrode, and the fourth electrode has a polarity opposite to that of the third electrode. A photovoltaic device. 6 In claim 5, the first electrode and the third electrode are made of tin oxide,
Antimony oxide, titanium oxide, iron oxide, silicon carbide, carbon, tin oxide, or titanium oxide to which antimony is added is used, and silicon carbide, platinum tungsten, stainless steel, carbon,
A photovoltaic device characterized in that indium oxide, titanium oxide added with indium oxide, or the like is used.