JP2012021197A - Device for producing gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for producing gas at high gas-generation efficiency.SOLUTION: The device for producing gas includes: a light receiving surface and back surface thereof; a photoelectric conversion unit where a potential difference occurs between the light receiving surface and the back surface by receiving; a first electrode for electrolysis, which is provided at the back surface side of the photoelectric conversion unit, and electrically connected with the back surface of the photoelectric conversion unit; a second electrode for electrolysis, which is provided at the back surface side of the photoelectric conversion part, and electrically connected with the rear surface of the photoelectric conversion unit; and a thermoelectric conversion unit disposed between the rear surface of the photoelectric conversion unit and the first electrode for electrolysis or the second electrode for electrolysis. The device is characterized in that the first electrode for electrolysis and the second electrode for electrolysis are so provided as to be immersed in an electrolyte, and then to electrolyze the electrolyte by using the electromotive force generated as a result of the photoelectric conversion unit receiving light, thus producing a first gas and a second gas; and the thermoelectric conversion unit absorbs heat from the photoelectric conversion unit, and releases the heat to the first electrode for electrolysis and the second electrode for electrolysis.

Description

  The present invention relates to a gas production apparatus.

In recent years, solar cells that do not generate CO ₂ with power generation are becoming widespread due to concerns about global warming. However, power generation using solar cells has a problem that the power generation amount varies depending on the time zone, and the power generation amount varies depending on the season. In order to solve this problem, a power generation system has been conceived in which electric power generated by a solar cell is stored as hydrogen generated by electrolysis of water, and fuel cell power generation using this hydrogen as a fuel eliminates fluctuations in power generation. Yes. For this reason, various techniques combining solar cells and electrolytic cells have been proposed.
For example, in Patent Document 1, a thin-film solar cell and an electrocatalyst layer are formed in parallel on a transparent electrode film formed on a substrate, and the electrolyte is electrolyzed by irradiating the thin-film solar cell with light. An enabling hydrogen production apparatus is disclosed.
In Patent Document 2, an electrolysis chamber in which a p-type semiconductor layer, an n-type semiconductor layer, and an electrode plate are formed in this order on a conductor layer; and an n-type semiconductor layer and a p-type semiconductor on the conductor layer. A hydrogen production apparatus including a layer and an electrolyte in which electrode plates are formed in this order is disclosed.

JP 2003-288955 A JP 2004-197167 A

However, in a conventional apparatus combining a solar cell and an electrolytic cell, the gas generation efficiency is low because the temperature in the apparatus is substantially the same. That is, the lower the temperature in the solar cell, the higher the photoelectric conversion efficiency, and the higher the temperature in the electrolytic cell, the higher the electrolysis efficiency of the electrolytic solution. For this reason, when the temperature in the apparatus is lowered, the photoelectric conversion efficiency of the solar cell is increased, but the electrolysis efficiency of the electrolytic solution is decreased. Moreover, when the temperature in the apparatus is increased, the efficiency of electrolysis of the electrolytic solution is increased, but the photoelectric conversion efficiency of the solar cell is decreased.
This invention is made | formed in view of such a situation, and provides the gas manufacturing apparatus with high gas generation efficiency.

  The present invention has a light receiving surface and its back surface, and is provided on the back surface side of the photoelectric conversion portion, a photoelectric conversion portion that generates a potential difference between the light receiving surface and the back surface by receiving light, and A first electrolysis electrode electrically connected to the back surface of the photoelectric conversion unit, and a second electrolysis electrode provided on the back surface side of the photoelectric conversion unit and electrically connected to the light receiving surface of the photoelectric conversion unit And a thermoelectric conversion portion provided between the back surface of the photoelectric conversion portion and the first electrolysis electrode or the second electrolysis electrode, and the first electrolysis electrode and the second electrolysis electrode are formed in the electrolytic solution. The thermoelectric conversion part is provided so as to be capable of being immersed and to be able to electrolyze the electrolytic solution by an electromotive force generated by receiving light from the photoelectric conversion part to generate a first gas and a second gas, respectively. Absorbs heat from the photoelectric conversion part, and the first electrolysis electrode Others provide a gas production apparatus, characterized in that the heat radiation to the second electrolysis electrode.

According to the present invention, the second electrolysis electrode electrically connected to the light receiving surface of the photoelectric conversion unit and the first electrolysis electrode electrically connected to the back surface of the photoelectric conversion unit can be immersed in the electrolytic solution. Therefore, by making light incident on the photoelectric conversion unit, the electrolytic solution can be electrolyzed at the first electrolysis electrode and the second electrolysis electrode to generate the first gas and the second gas, respectively.
According to the present invention, since the first electrolysis electrode and the second electrolysis electrode are provided on the back surface of the photoelectric conversion unit, light can be incident on the light receiving surface of the photoelectric conversion unit without passing through the electrolyte solution. It is possible to prevent absorption of incident light and scattering of incident light. As a result, the amount of light incident on the photoelectric conversion unit can be increased, and the light utilization efficiency can be increased.

According to the present invention, since the first electrolysis electrode and the second electrolysis electrode are provided on the back surface of the photoelectric conversion unit, the light incident on the light receiving surface is reflected by the first electrolysis electrode, the second electrolysis electrode, and Are not absorbed or scattered by the first gas and the second gas respectively generated from the gas. As a result, the amount of light incident on the photoelectric conversion unit can be increased, and the light utilization efficiency can be increased.
According to the present invention, the thermoelectric conversion unit is provided between the back surface of the photoelectric conversion unit and the first electrolysis electrode or the second electrolysis electrode and has a heat absorption surface and a heat dissipation surface. The heat absorption surface can cool the photoelectric conversion part, and the heat dissipation surface of the thermoelectric conversion part can heat the first electrolysis electrode or the second electrolysis electrode. As a result, the temperature of the photoelectric conversion unit can be lowered, and the photoelectric conversion efficiency of the photoelectric conversion unit can be increased. Moreover, the temperature of the electrode for 1st electrolysis or the electrode for 2nd electrolysis can be made high, the speed | rate of the electrolytic reaction of electrolyte solution can be made quick, and the generation amount of 1st gas and 2nd gas can be increased. Can do.

It is a schematic plan view which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus in dotted line AA of FIG. It is a schematic back view which shows the structure of the gas manufacturing apparatus of one Embodiment of this invention. It is a schematic sectional drawing of the gas manufacturing apparatus of one Embodiment of this invention.

  The gas manufacturing apparatus of the present invention has a light receiving surface and a back surface thereof, and is provided on a back surface side of the photoelectric conversion portion, and a photoelectric conversion portion that generates a potential difference between the light receiving surface and the back surface by receiving light. And a first electrolysis electrode electrically connected to the back surface of the photoelectric conversion portion, a first electrode provided on the back surface side of the photoelectric conversion portion, and electrically connected to the light receiving surface of the photoelectric conversion portion. Two electrolysis electrodes, and a thermoelectric conversion portion provided between the back surface of the photoelectric conversion portion and the first electrolysis electrode or the second electrolysis electrode, and the first electrolysis electrode and the second electrolysis electrode are , Provided so as to be immersed in the electrolytic solution, and provided so that the electrolytic solution can be electrolyzed by an electromotive force generated by the photoelectric conversion unit receiving light to generate the first gas and the second gas, respectively. The thermoelectric converter absorbs heat from the photoelectric converter. 1, characterized in that the heat radiation to the electrolysis electrode or the second electrolysis electrode.

  The thermoelectric conversion part is a part that absorbs heat on the heat absorption surface when current flows and emits heat on the heat dissipation surface, or a part that generates electromotive force due to a temperature difference between the heat absorption surface and the heat dissipation surface.

The gas manufacturing apparatus of the present invention further includes a first electrode provided on the light receiving surface of the photoelectric conversion unit, and a second electrode provided on the back surface of the photoelectric conversion unit, It is preferable that the second electrode is electrically connected to the second electrolysis electrode, and the second electrode is electrically connected to the first electrolysis electrode.
According to such a configuration, the light receiving surface of the photoelectric conversion unit and the second electrolysis electrode can be electrically connected, and the back surface of the photoelectric conversion unit and the first electrolysis electrode are electrically connected. Can do. Thereby, the electromotive force generated in the photoelectric conversion unit can be efficiently output to the first electrolysis electrode and the second electrolysis electrode.
In the gas manufacturing apparatus of the present invention, the first insulating layer provided between the second electrode and the thermoelectric conversion unit, and the thermoelectric conversion unit provided between the first electrolysis electrode or the second electrolysis electrode. It is preferable to further include the second insulating layer formed.
According to such a configuration, it is possible to prevent leakage current from flowing.

In the gas manufacturing apparatus of the present invention, a first conductive portion that electrically connects the first electrode and the second electrolysis electrode, and a second conductive portion that electrically connects the second electrode and the first electrolysis electrode And further comprising
It is preferable that the first conductive part is provided in a contact hole that penetrates the photoelectric conversion part and the thermoelectric conversion part, and the second conductive part is provided in a contact hole that penetrates the thermoelectric conversion part.
According to such a configuration, the first electrode and the second electrolysis electrode can be efficiently electrically connected, and the second electrode and the first electrolysis electrode can be efficiently electrically connected.
In the gas manufacturing apparatus of the present invention, the thermoelectric conversion unit includes a p-type semiconductor unit, an n-type semiconductor unit, a first thermoelectric conversion electrode, and a second thermoelectric conversion electrode, and the p-type semiconductor unit and the n-type semiconductor. The part is preferably sandwiched between the first thermoelectric conversion electrode and the second thermoelectric conversion electrode.
According to such a configuration, current can flow through the p-type semiconductor portion and the n-type semiconductor portion, and the thermoelectric conversion portion can have a heat absorption surface and a heat dissipation surface.

In the gas manufacturing apparatus of the present invention, it is preferable that the p-type semiconductor unit and the n-type semiconductor unit are provided such that a current flows due to an electromotive force generated when the photoelectric conversion unit receives light.
According to such a configuration, it is not necessary to supply power to the thermoelectric conversion unit from the outside.
In the gas manufacturing apparatus of the present invention, it is preferable that the gas manufacturing apparatus further includes a current control unit that controls a current flowing through the p-type semiconductor unit and the n-type semiconductor unit.
According to such a configuration, the current flowing through the thermoelectric conversion unit can be controlled, and the heat absorption amount of the heat absorption surface and the heat dissipation amount of the heat dissipation surface can be controlled. Thereby, the power consumption by the thermoelectric conversion part can be suppressed. Moreover, the temperature of a photoelectric conversion part, the electrode for 1st electrolysis, or the electrode for 2nd electrolysis can be controlled.

In the gas manufacturing apparatus of the present invention, it is preferable that there are a plurality of thermoelectric conversion units.
According to such a configuration, the gas production apparatus absorbs heat from the photoelectric conversion unit and dissipates heat to the electrolysis electrode, and the thermoelectric conversion unit in which an electromotive force is generated due to a temperature difference between the photoelectric conversion unit and the electrolysis electrode. Can be provided. Thus, an electromotive force can be generated using a temperature difference between the photoelectric conversion unit and the electrode for electrolysis, and the electromotive force can be used for the decomposition reaction of the electrolytic solution.
In the gas production apparatus of the present invention, it is preferable that the gas production apparatus further includes a translucent substrate, and the photoelectric conversion unit is provided on the translucent substrate such that the light receiving surface is on the translucent substrate side.
According to such a structure, a photoelectric conversion part can be formed on a translucent substrate.

In the gas manufacturing apparatus of the present invention, it is preferable to further include an electrolytic solution chamber capable of storing an electrolytic solution in which the first electrolytic electrode or the second electrolytic electrode is immersed.
According to such a configuration, the first electrolysis electrode and the second electrolysis electrode can be immersed in the electrolytic solution, and the first gas and the second gas can be generated, respectively.
In the gas manufacturing apparatus of the present invention, it is preferable that a back substrate is further provided on the back surface side of the photoelectric conversion unit, and the electrolyte chamber is provided between the back surface of the photoelectric conversion unit and the back substrate.
According to such a configuration, it is possible to form an electrolytic solution chamber capable of storing an electrolytic solution in which the first electrolytic electrode and the second electrolytic electrode are immersed.

In the gas manufacturing apparatus of the present invention, a partition partitioning the electrolyte chamber capable of storing the electrolyte solution immersed in the first electrolysis electrode and the electrolyte chamber capable of storing the electrolyte solution immersed in the second electrolysis electrode is further provided. It is preferable to provide.
According to such a configuration, the first gas and the second gas generated respectively at the first electrolysis electrode and the second electrolysis electrode can be separated, and the first gas and the second gas can be recovered more efficiently. can do.
In the gas production apparatus of the present invention, the partition preferably includes an ion exchanger.
According to such a configuration, the ion concentration between the electrolyte introduced into the electrolyte chamber above the first electrolysis electrode and the electrolyte introduced into the electrolyte chamber above the second electrolysis electrode is increased. The imbalance can be eliminated, and the first gas and the second gas can be generated stably.

In the gas production apparatus of the present invention, it is preferable that the photoelectric conversion unit has a photoelectric conversion layer including a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer.
According to such a configuration, the photoelectric conversion unit can have a pin structure, and photoelectric conversion can be performed efficiently. Moreover, the electromotive force generated in the photoelectric conversion unit can be increased, and the electrolytic solution can be electrolyzed more efficiently.
In the gas production apparatus of the present invention, one of the first electrolysis electrode and the second electrolysis electrode is a hydrogen generation unit that generates H ₂ from the electrolytic solution, and the other generates O ₂ from the electrolytic solution. It is an oxygen generation part, and it is preferable that the hydrogen generation part and the oxygen generation part include a catalyst for a reaction for generating H ₂ from the electrolytic solution and a catalyst for a reaction for generating O ₂ from the electrolytic solution, respectively.
According to such a configuration, hydrogen as fuel for the fuel cell can be produced by the gas production apparatus of the present invention. Moreover, the rate at which the electrolysis reaction of the electrolytic solution proceeds can be increased by including each catalyst.
In the gas production apparatus of the present invention, it is preferable that at least one of the hydrogen generation unit and the oxygen generation unit is formed of a porous conductor carrying a catalyst.
According to such a configuration, the surface area of at least one of the hydrogen generation part and the oxygen generation part can be increased, and oxygen or hydrogen can be generated more efficiently. In addition, by using a porous conductor, a change in potential due to a current flowing between the photoelectric conversion unit and the catalyst can be suppressed, and hydrogen or oxygen can be generated more efficiently.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configurations shown in the drawings and the following description are merely examples, and the scope of the present invention is not limited to those shown in the drawings and the following description.

Configuration of Gas Production Apparatus FIG. 1 is a schematic plan view showing the structure of a gas production apparatus according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the gas production apparatus taken along the dotted line AA in FIG. FIG. 3 is a schematic back view showing the structure of the gas production apparatus according to one embodiment of the present invention. In FIG. 3, the back substrate 14 is omitted. FIG. 4 is a schematic cross-sectional view of the gas production apparatus according to one embodiment of the present invention, and corresponds to the schematic cross-sectional view of the gas production apparatus taken along the dotted line BB in FIG.

  The gas manufacturing apparatus 23 of the present embodiment has a light receiving surface and a back surface thereof, and a photoelectric conversion unit 2 that generates a potential difference between the light receiving surface and the back surface by receiving light, and a back surface of the photoelectric conversion unit 2 The first electrolysis electrode 8 provided on the back side and electrically connected to the back surface of the photoelectric conversion unit 2, provided on the back side of the photoelectric conversion unit 2, and electrically connected to the light receiving surface of the photoelectric conversion unit 2 A second electrolysis electrode 7 connected to the thermoelectric conversion portion 30 provided between the back surface of the photoelectric conversion portion 2 and the first electrolysis electrode 8 or the second electrolysis electrode 7. The electrode 8 and the second electrode 7 for electrolysis are provided so as to be immersed in the electrolytic solution, and the electrolytic solution is electrolyzed by the electromotive force generated by the photoelectric conversion unit 2 receiving light to respectively convert the first gas and the second gas. It is provided so that it can be generated, and the thermoelectric conversion unit 30 is a photoelectric conversion unit. Characterized by radiating the first electrolysis electrode 8 or the second electrolysis electrode 7 absorbs heat from.

  Further, the gas production apparatus 23 of the present embodiment includes the translucent substrate 1, the back substrate 14, the first conductive unit 10, the second conductive unit 21, the insulating unit 11, the partition wall 13, the first electrode 4, and the second electrode 5. May be provided. Hereinafter, each component of the gas manufacturing apparatus 23 of this invention is demonstrated.

1. Translucent board | substrate The translucent board | substrate 1 will not be specifically limited if it is a board | substrate which has translucency. As a material of the translucent substrate 1, for example, a transparent rigid material such as soda glass, quartz glass, Pyrex (registered trademark), synthetic quartz plate, or a transparent resin plate or a film material is preferably used. In view of chemical and physical stability, it is preferable to use a glass substrate.
On the surface of the translucent substrate 1 on the photoelectric conversion unit 2 side, a fine uneven structure can be formed so that incident light is effectively irregularly reflected on the surface of the photoelectric conversion unit 2. This fine concavo-convex structure can be formed by a known method such as reactive ion etching (RIE) treatment or blast treatment.

2. 1st electrode The 1st electrode 4 can be provided on the translucent board | substrate 1, and can be provided so that the light-receiving surface of the photoelectric conversion part 2 may be contacted. Moreover, the 1st electrode 4 may have translucency. By providing the first electrode 4, the current flowing between the light receiving surface of the photoelectric conversion unit 2 and the second electrolysis electrode 7 can be increased.
The first electrode 4 may be made of a transparent conductive film such as ITO or SnO _2, or may be made of a metal finger electrode such as Ag or Au.

A case where the first electrode 4 is a transparent conductive film will be described below.
The transparent conductive film is used to facilitate contact between the light receiving surface of the photoelectric conversion unit 2 and the second electrolysis electrode 7.
What is generally used as a transparent electrode can be used. Specifically, In—Zn—O (IZO), In—Sn—O (ITO), ZnO—Al, Zn—Sn—O, SnO _{2 and the} like can be given. The transparent conductive film preferably has a sunlight transmittance of 85% or more, particularly 90% or more, and particularly 92% or more. This is because the photoelectric conversion unit 2 can absorb light efficiently.
As a method for producing the transparent conductive film, a known method can be used, and examples thereof include sputtering, vacuum deposition, sol-gel method, cluster beam deposition method, and PLD (Pulse Laser Deposition) method.

3. Photoelectric Conversion Unit The photoelectric conversion unit 2 is provided on the translucent substrate 1 and generates a potential difference between the light receiving surface and the back surface by receiving light. The photoelectric conversion unit 2 is, for example, a photoelectric conversion unit using a silicon-based semiconductor, a photoelectric conversion unit using a compound semiconductor, a photoelectric conversion unit using a dye sensitizer, or a photoelectric conversion unit using an organic thin film.
The photoelectric conversion unit 2 can be cooled by the heat absorption surface of the thermoelectric conversion unit 30. Thereby, the temperature rise of the thermoelectric conversion unit 30 can be suppressed, and the photoelectric conversion efficiency can be increased.

The photoelectric conversion unit 2 needs to generate an electromotive force necessary for generating the first gas and the second gas in the first electrolysis electrode 8 and the second electrolysis electrode 7 by receiving light.
When the first gas and the second gas are hydrogen and oxygen, the photoelectric conversion unit 2 decomposes water contained in the electrolytic solution in the first electrolysis electrode 8 and the second electrolysis electrode 7 to generate hydrogen and oxygen. Therefore, it is necessary to generate an electromotive force necessary for this. The potential difference between the first electrolysis electrode 8 and the second electrolysis electrode 7 needs to be larger than the theoretical voltage (1.23 V) for water decomposition, and for this purpose, a sufficiently large potential difference needs to be generated in the photoelectric conversion unit 2. There is. Therefore, it is preferable that the photoelectric conversion unit 2 connects two or more junctions in series such as a pn junction to generate an electromotive force.

  Examples of the material that performs photoelectric conversion include silicon-based semiconductors, compound semiconductors, and materials based on organic materials, and any photoelectric conversion material can be used. In order to increase the electromotive force, these photoelectric conversion materials can be stacked. In the case of stacking, it is possible to form a multi-junction structure with the same material, but stacking multiple photoelectric conversion layers with different optical band gaps and complementing the low sensitivity wavelength region of each photoelectric conversion layer mutually By doing so, incident light can be efficiently absorbed over a wide wavelength region.

Moreover, it is possible to interpose a conductor such as a transparent conductive film between the layers in order to improve the serial connection characteristics between the photoelectric conversion layers and to match the photocurrent generated in the photoelectric conversion unit 2. Thereby, it becomes possible to suppress deterioration of the photoelectric conversion unit 2.
An example of the photoelectric conversion unit 2 will be specifically described below. The photoelectric conversion unit 2 may be a combination of these.

3-1. Photoelectric conversion part using a silicon-based semiconductor Examples of the photoelectric conversion part 2 using a silicon-based semiconductor include a single crystal type, a polycrystalline type, an amorphous type, a spherical silicon type, and combinations thereof. Any of them can have a pn junction in which a p-type semiconductor and an n-type semiconductor are joined. Further, a pin junction in which an i-type semiconductor is provided between a p-type semiconductor and an n-type semiconductor may be provided. Further, it may have a plurality of pn junctions, a plurality of pin junctions, or a pn junction and a pin junction.
The silicon-based semiconductor is a semiconductor containing silicon, such as silicon, silicon carbide, or silicon germanium. In addition, silicon or the like in which n-type impurities or p-type impurities are added is included, and crystalline, amorphous, or microcrystalline silicon is also included.
The photoelectric conversion unit 2 using a silicon-based semiconductor may be a thin film or a thick photoelectric conversion layer formed on the substrate 1, and a pn junction or a pin junction is formed on a wafer such as a silicon wafer. A thin film photoelectric conversion layer may be formed on a wafer on which a pn junction or a pin junction is formed.

An example of forming the photoelectric conversion unit 2 using a silicon-based semiconductor is shown below.
A first conductivity type semiconductor layer is formed on the first electrode 4 laminated on the translucent substrate 1 by a method such as a plasma CVD method. As the first conductive type semiconductor layer, a p + type or n + type amorphous Si thin film doped with a conductivity type determining impurity atom concentration of about 1 × 10 ^{18 to} 5 × 10 ²¹ / cm ³ , a polycrystalline or A microcrystalline Si thin film is used. The material of the first conductivity type semiconductor layer is not limited to Si, and it is also possible to use a compound such as SiC, SiGe, or Si _x O _1-x .

On the first conductivity type semiconductor layer thus formed, a polycrystalline or microcrystalline crystalline Si thin film is formed as a crystalline Si photoactive layer by a method such as plasma CVD. The conductivity type is the first conductivity type having a lower doping concentration than the first conductivity type semiconductor, or the i conductivity type. The material for the crystalline Si-based photoactive layer is not limited to Si, and it is also possible to use a compound such as SiC, SiGe, or Si _x O _1-x .

Next, in order to form a semiconductor junction on the crystalline Si-based photoactive layer, a second conductivity type semiconductor layer having a conductivity type opposite to the first conductivity type semiconductor layer is formed by a method such as plasma CVD. As the second conductivity type semiconductor layer, an n + type or p + type amorphous Si thin film doped with about 1 × 10 ^{18 to} 5 × 10 ²¹ / cm ^{3 of} conductivity type determining impurity atoms, or a polycrystalline or microscopic A crystalline Si thin film is used. The material of the second conductivity type semiconductor layer is not limited to Si, and it is also possible to use a compound such as SiC, SiGe, or Si _x O _1-x . In order to further improve the bonding characteristics, it is possible to insert a substantially i-type non-single-crystal Si-based thin film between the crystalline Si-based photoactive layer and the second conductive type semiconductor layer. In this manner, one photoelectric conversion layer closest to the light receiving surface can be stacked.

  Subsequently, a second photoelectric conversion layer is formed. The second photoelectric conversion layer is composed of a first conductivity type semiconductor layer, a crystalline Si-based photoactive layer, and a second conductivity type semiconductor layer, each layer corresponding to the first photoelectric conversion layer. The first conductive type semiconductor layer, the crystalline Si-based photoactive layer, and the second conductive type semiconductor layer are formed. When a potential sufficient for water splitting cannot be obtained with a two-layer tandem, it is preferable to take a three-layer structure or more. However, the volume crystallization fraction of the crystalline Si photoactive layer of the second photoelectric conversion layer is preferably higher than that of the first crystalline Si photoactive layer. Similarly, when three or more layers are laminated, it is preferable to increase the volume crystallization fraction as compared with the lower layer. This increases the absorption in the long wavelength region, shifts the spectral sensitivity to the long wavelength side, and can improve the sensitivity in a wide wavelength region even when the photoactive layer is configured using the same Si material. It is because it becomes. That is, by using a tandem structure with Si having different crystallization rates, the spectral sensitivity is widened, and light can be used with high efficiency. At this time, if the low crystallization rate material is not on the light receiving surface side, high efficiency cannot be achieved. Further, when the crystallization rate is lowered to 40% or less, the amorphous component increases and deterioration occurs.

3-2. Photoelectric Conversion Part Using Compound Semiconductor The photoelectric conversion part 2 using a compound semiconductor is, for example, CdTe / CdS composed of GaP, GaAs, InP, InAs, and II-VI group elements composed of III-V group elements. And CIGS (Copper Indium Gallium DiSelenide) composed of I-III-VI group and the like, and a pn junction formed.

An example of a manufacturing method of the photoelectric conversion unit 2 using a compound semiconductor is shown below. In this manufacturing method, all film-forming processes are performed using a metal organic chemical vapor deposition (MOCVD) apparatus. It is done continuously. As a group III element material, for example, an organic metal such as trimethylgallium, trimethylaluminum, or trimethylindium is supplied to the growth apparatus using hydrogen as a carrier gas. For example, a gas such as arsine (AsH ₃ ), phosphine (PH ₃ ), and stibine (SbH ₃ ) is used as the material of the group V element. As a dopant of p-type impurities or n-type impurities, for example, diethyl zinc for p-type conversion, monosilane (SiH ₄ ), disilane (Si ₂ H ₆ ), hydrogen selenide (H ₂ Se) for n-type conversion. Etc. are used. These source gases can be thermally decomposed by supplying them onto a substrate heated to, for example, 700 ° C., and a desired compound semiconductor material film can be epitaxially grown. The composition of these growth layers can be controlled by the gas composition to be introduced, and the film thickness can be controlled by the gas introduction time. When multi-junction laminating these photoelectric conversion parts, it is possible to form a growth layer with excellent crystallinity by adjusting the lattice constant between layers as much as possible, and to improve the photoelectric conversion efficiency. Become.

  In addition to the portion where the pn junction is formed, for example, a known window layer on the light receiving surface side or a known electric field layer on the non-light receiving surface side may be provided to improve carrier collection efficiency. Further, a buffer layer for preventing diffusion of impurities may be provided.

3-3. Photoelectric conversion part using a dye sensitizer The photoelectric conversion part using a dye sensitizer is mainly composed of, for example, a porous semiconductor, a dye sensitizer, an electrolyte, a solvent, and the like.
As a material constituting the porous semiconductor, for example, one or more kinds of known semiconductors such as titanium oxide, tungsten oxide, zinc oxide, barium titanate, strontium titanate, cadmium sulfide can be selected. As a method for forming a porous semiconductor on a substrate, a paste containing semiconductor particles is applied by a screen printing method, an ink jet method and the like, dried or baked, a method of forming a film by a CVD method using a raw material gas, etc. , PVD method, vapor deposition method, sputtering method, sol-gel method, method using electrochemical oxidation-reduction reaction, and the like.

  As the dye sensitizer adsorbed on the porous semiconductor, various dyes having absorption in the visible light region and the infrared light region can be used. Here, in order to firmly adsorb the dye to the porous semiconductor, the carboxylic acid group, carboxylic anhydride group, alkoxy group, sulfonic acid group, hydroxyl group, hydroxylalkyl group, ester group, mercapto group, phosphonyl in the dye molecule It is preferable that a group or the like is present. These functional groups provide an electrical bond that facilitates electron transfer between the excited state dye and the conduction band of the porous semiconductor.

  Examples of dyes containing these functional groups include ruthenium bipyridine dyes, quinone dyes, quinone imine dyes, azo dyes, quinacridone dyes, squarylium dyes, cyanine dyes, merocyanine dyes, and triphenylmethane dyes. Xanthene dyes, porphyrin dyes, phthalocyanine dyes, berylene dyes, indigo dyes, naphthalocyanine dyes, and the like.

  Examples of the method for adsorbing the dye to the porous semiconductor include a method in which the porous semiconductor is immersed in a solution in which the dye is dissolved (dye adsorption solution). The solvent used in the dye adsorption solution is not particularly limited as long as it dissolves the dye, and specifically, alcohols such as ethanol and methanol, ketones such as acetone, ethers such as diethyl ether and tetrahydrofuran. Nitrogen compounds such as acetonitrile, aliphatic hydrocarbons such as hexane, aromatic hydrocarbons such as benzene, esters such as ethyl acetate, water, and the like.

The electrolyte is composed of a redox pair and a solid medium such as a liquid or polymer gel holding the redox pair.
In general, iron- and cobalt-based metals and halogen substances such as chlorine, bromine, and iodine are preferably used as the redox pair, and metal iodides such as lithium iodide, sodium iodide, and potassium iodide and iodine are used. The combination of is preferably used. Furthermore, imidazole salts such as dimethylpropylimidazole iodide can also be mixed.

  As the solvent, carbonate compounds such as propylene carbonate, nitrile compounds such as acetonitrile, alcohols such as ethanol and methanol, water, aprotic polar substances, and the like are used. Of these, carbonate compounds and nitrile compounds are preferred. Used.

3-4. Photoelectric conversion part using organic thin film A photoelectric conversion part using an organic thin film comprises an electron hole transport layer composed of an organic semiconductor material having electron donating properties and electron accepting properties, or an electron transport layer having electron accepting properties. It may be a laminate of a hole transport layer having an electron donating property.
The electron-donating organic semiconductor material is not particularly limited as long as it has a function as an electron donor, but it is preferable that a film can be formed by a coating method, and among them, an electron-donating conductive polymer is preferably used. The

  Here, the conductive polymer refers to a p-conjugated polymer, which is composed of a p-conjugated system in which double bonds or triple bonds containing carbon-carbon or heteroatoms are alternately linked to single bonds, and exhibits semiconducting properties. Point.

  Examples of the electron-donating conductive polymer material include polyphenylene, polyphenylene vinylene, polythiophene, polycarbazole, polyvinyl carbazole, polysilane, polyacetylene, polypyrrole, polyaniline, polyfluorene, polyvinyl pyrene, polyvinyl anthracene, and derivatives, Examples thereof include a polymer, a phthalocyanine-containing polymer, a carbazole-containing polymer, and an organometallic polymer. Among these, thiophene-fluorene copolymer, polyalkylthiophene, phenyleneethynylene-phenylene vinylene copolymer, fluorene-phenylene vinylene copolymer, thiophene-phenylene vinylene copolymer, and the like are preferably used.

The electron-accepting organic semiconductor material is not particularly limited as long as it has a function as an electron acceptor. However, it is preferable that a film can be formed by a coating method, and among them, an electron-donating conductive polymer is preferably used. The
Examples of the electron-accepting conductive polymer include polyphenylene vinylene, polyfluorene, and derivatives and copolymers thereof, or carbon nanotubes, fullerene and derivatives thereof, CN group or CF ₃ group-containing polymers, and -CF thereof. Examples thereof include _3- substituted polymers.

In addition, an electron-accepting organic semiconductor material doped with an electron-donating compound, an electron-donating organic semiconductor material doped with an electron-accepting compound, or the like can be used. Examples of the electron-accepting conductive polymer material doped with the electron-donating compound include the above-described electron-accepting conductive polymer material. As the electron-donating compound to be doped, for example, a Lewis base such as an alkali metal such as Li, K, Ca, or Cs or an alkaline earth metal can be used. The Lewis base acts as an electron donor. Examples of the electron-donating conductive polymer material doped with the electron-accepting compound include the above-described electron-donating conductive polymer material. As the electron-accepting compound to be doped, for example, a Lewis acid such as FeCl ₃ , AlCl ₃ , AlBr ₃ , AsF ₆ or a halogen compound can be used. In addition, Lewis acid acts as an electron acceptor.

  In the photoelectric conversion unit 2 shown above, it is assumed that sunlight is received and photoelectric conversion is primarily performed. However, it is emitted from a fluorescent lamp, an incandescent lamp, an LED, or a specific heat source depending on the application. It is also possible to perform photoelectric conversion by irradiating artificial light such as light.

4). Second Electrode The second electrode 5 can be provided on the back surface of the photoelectric conversion unit 2. By providing the second electrode 5, the potential of the back surface of the photoelectric conversion unit 2 and the potential of the first electrolysis electrode 8 can be made substantially the same. Moreover, the electric current which flows between the back surface of the photoelectric conversion part 2 and the electrode 8 for 1st electrolysis can be enlarged. Thereby, the first gas or the second gas can be generated more efficiently by the electromotive force generated in the photoelectric conversion unit 2.
Although it will not specifically limit if the 2nd electrode 5 has electroconductivity, For example, it is a metal thin film, for example, is thin films, such as Al, Ag, Au. These can be formed by, for example, sputtering. Further, for example, a transparent conductive film such as In—Zn—O (IZO), In—Sn—O (ITO), ZnO—Al, Zn—Sn—O, and SnO ₂ is used.

5. Thermoelectric Conversion Unit The thermoelectric conversion unit 30 is provided between the back surface of the photoelectric conversion unit 2 and the first electrolysis electrode 8 or the second electrolysis electrode 7. Moreover, the thermoelectric conversion part 30 can have an endothermic surface and a heat radiating surface. This endothermic surface can be the photoelectric conversion portion side surface of the thermoelectric conversion portion, and the heat dissipation surface can be the first electrolysis electrode 8 side or the second electrolysis electrode 7 side of the thermoelectric conversion portion 30. . Thus, the thermoelectric conversion unit 30 can absorb heat from the photoelectric conversion unit 2 and dissipate heat to the first electrolysis electrode 8 or the second electrolysis electrode 7. The photoelectric conversion efficiency of the photoelectric conversion unit 2 can be increased by cooling the photoelectric conversion unit 2 and lowering the temperature. Further, by heating the first electrolysis electrode 8 or the second electrolysis electrode 7 and increasing the temperature, the rate of the electrolytic reaction of the electrolytic solution in the first electrolysis electrode 8 and the second electrolysis electrode 7 is increased. The generation efficiency of the first gas and the second gas can be increased.

  The thermoelectric conversion unit 30 may include p-type semiconductor units 6a and 6b, n-type semiconductor units 3a and 3b, a first thermoelectric conversion electrode 26, and a second thermoelectric conversion electrode 27. The p-type semiconductor portions 6a and 6b and the n-type semiconductor portions 3a and 3b may be sandwiched between the first thermoelectric conversion electrode 26 and the second thermoelectric conversion electrode 27. As a result, current can flow through the p-type semiconductor portions 6a and 6b and the n-type semiconductor portions 3a and 3b, and the thermoelectric conversion portion 30 is provided on the first thermoelectric conversion electrode 26 side and the second thermoelectric conversion electrode 27 side. And may have an endothermic surface and a heat dissipating surface. The heat absorption surface and the heat dissipation surface can be exchanged depending on the direction of current flow. Further, the p-type semiconductor units 6a and 6b and the n-type semiconductor units 3a and 3b may be alternately connected in series via the first thermoelectric conversion electrode 26 and the second thermoelectric conversion electrode 27.

  The p-type semiconductor portions 6a and 6b and the n-type semiconductor portions 3a and 3b are not particularly limited. For example, a bismuth (Bi) -tellurium (Te) -based n-type p-type semiconductor pair can be used, and Bi-Te. Antimony (Sb), selenium (Se) or the like may be added to the component.

The current that flows through the thermoelectric conversion unit 30 may be a current that flows due to an electromotive force generated when the photoelectric conversion unit 2 receives light, or may be a current that flows due to power supplied from outside the apparatus.
By configuring the thermoelectric conversion unit 30 so that a current flows due to the electromotive force of the photoelectric conversion unit 2, thermoelectric conversion can be performed without supplying electric power to the thermoelectric conversion unit from the outside of the apparatus. The method of providing the thermoelectric conversion unit 30 so that the current flows by the electromotive force generated by the photoelectric conversion unit 2 receiving light is not particularly limited. For example, the second thermoelectric conversion electrode 27 is used as the second electrode as shown in FIG. 5 and the second electrolysis electrode 7 are electrically connected to each other.

  Further, a current control unit that controls the current flowing through the p-type semiconductor units 6a and 6b and the n-type semiconductor units 3a and 3b can be provided. The current control unit is not particularly limited. For example, the current control unit is formed using a material whose electrical resistance is easily changed by temperature in the conductive unit 24 that electrically connects the thermoelectric conversion electrodes 26 and 27 and the second electrode 5. Thus, the flowing current can be controlled. Further, a current control unit may be provided outside the sealing material 16, and the current flowing through the p-type semiconductor units 6a and 6b and the n-type semiconductor units 3a and 3b may be controlled by the current control unit. In this case, the current control unit can be provided so as to control the current flowing through the wiring that electrically connects the thermoelectric conversion unit 30 and the external power source. Alternatively, the current control unit can be provided so as to control the current flowing through the wiring that electrically connects the thermoelectric conversion unit and the photoelectric conversion unit 2.

  Moreover, the thermoelectric conversion part 30 may be plural. For example, thermoelectric conversion units 30a and 30b can be provided as shown in FIG. Further, the two adjacent thermoelectric conversion units 30 may have the heat absorption surface and the heat dissipation surface opposite to each other. Thereby, this one thermoelectric conversion part 30a can cool the photoelectric conversion part 2, and can heat the electrode for electrolysis, and the other thermoelectric conversion part 30b is between the photoelectric conversion part 2 and the electrode for electrolysis. An electromotive force can be generated by utilizing the temperature difference. This electromotive force can be used for the electrolytic reaction of the electrolytic solution in the first electrolysis electrode 8 and the second electrolysis electrode 7, and the generation amounts of the first gas and the second gas can be increased.

6). Insulating part The insulating part 11 is between the back surface of the photoelectric conversion part 2 and the thermoelectric conversion part 30, between the thermoelectric conversion part 30, the first electrolysis electrode 8 and the second electrolysis electrode 7, between the first conductive part 10 and It can be provided between the photoelectric conversion unit 2 and the thermoelectric conversion unit 30, between the second conductive unit 21 and the thermoelectric conversion unit 30, and between the p-type semiconductor units 6a and 6b and the n-type semiconductor units 3a and 3b. . Moreover, when providing the several thermoelectric conversion part 30, it can also provide between the two adjacent thermoelectric conversion parts 30. FIG.
By providing the insulating portion 11, the leakage current can be further reduced.

The insulating part 11 can be used regardless of an organic material or an inorganic material. For example, polyamide, polyimide, polyarylene, aromatic vinyl compound, fluorine polymer, acrylic polymer, vinylamide polymer, etc. Examples of organic polymers and inorganic materials include metal oxides such as Al ₂ O ₃ , SiO ₂ such as porous silica films, fluorine-added silicon oxide films (FSG), SiOC, HSQ (Hydrogen Silsesquioxane) films, SiN _x , It is possible to use a method of forming a film by dissolving silanol (Si (OH) ₄ ) in a solvent such as alcohol and applying and heating.

  As a method for forming the insulating portion 11, a film containing a paste containing an insulating material is applied by a screen printing method, an ink jet method, a spin coating method, etc., dried or baked, or a CVD method using a source gas is used. And a method using a PVD method, a vapor deposition method, a sputtering method, a sol-gel method, and the like.

7). First Conductive Part, Second Conductive Part The first conductive part 10 can be provided so as to contact the first electrode 4 and the second electrolysis electrode 7 respectively. By providing the first conductive portion 10, the first electrode 4 and the second electrolysis electrode 7 in contact with the light receiving surface of the photoelectric conversion portion 2 can be easily electrically connected. Moreover, the 2nd electroconductive part 21 can be provided so that it may contact with the 2nd electrode 5 and the electrode 8 for 1st electrolysis, respectively.
Since the first conductive unit 10 contacts the first electrode 4 in contact with the light receiving surface of the photoelectric conversion unit 2 and the second electrolysis electrode 7 provided on the back surface of the photoelectric conversion unit 2, the light reception of the photoelectric conversion unit 2 is performed. If the cross-sectional area of the first conductive portion parallel to the surface is too large, the area of the light receiving surface of the photoelectric conversion portion 2 is reduced. In addition, if the cross-sectional area of the first conductive unit 10 parallel to the light receiving surface of the photoelectric conversion unit 2 is too small, a difference occurs between the potential of the light receiving surface of the photoelectric conversion unit 2 and the potential of the second electrolysis electrode 7. In some cases, a potential difference for decomposing the electrolytic solution cannot be obtained, and the generation efficiency of the first gas or the second gas may be reduced. Therefore, the cross-sectional area of the first conductive part parallel to the light receiving surface of the photoelectric conversion part 2 needs to be within a certain range. For example, the cross-sectional area of the first conductive part parallel to the light-receiving surface of the photoelectric conversion unit 2 (when there are a plurality of first conductive parts, the total cross-sectional area) is 100% of the area of the light-receiving surface of the photoelectric conversion unit 2 In this case, it can be 0.1% or more and 10% or less, preferably 0.5% or more and 8% or less, and more preferably 1% or more and 6% or less.

The first conductive unit 10 may be provided in a contact hole that penetrates the photoelectric conversion unit 2. Thereby, the reduction in the area of the light receiving surface of the photoelectric conversion unit 2 due to the provision of the first conductive unit 10 can be further reduced. Moreover, by this, the electric current path between the light-receiving surface of the photoelectric conversion part 2 and the 2nd electrode 7 for electrolysis can be shortened, and 1st gas or 2nd gas can be generated more efficiently. . In addition, this makes it possible to easily adjust the cross-sectional area of the first conductive unit 10 parallel to the light receiving surface of the photoelectric conversion unit 2.
Moreover, the contact hole provided with the 1st electroconductive part 10 may have one or more, and may have a circular cross section. The cross-sectional area of the contact hole parallel to the light-receiving surface of the photoelectric conversion unit 2 (the sum of the cross-sectional areas when there are a plurality of contact holes) is 0 when the area of the light-receiving surface of the photoelectric conversion unit 2 is 100%. .1% or more and 10% or less, preferably 0.5% or more and 8% or less, more preferably 1% or more and 6% or less.
Further, the second conductive portion 21 may be provided in a contact hole that penetrates the thermoelectric conversion portion 30.

  The material of the 1st electroconductive part 10 and the 2nd electroconductive part 21 will not be restrict | limited especially if it has electroconductivity. A paste containing conductive particles, for example, a carbon paste, an Ag paste or the like applied by screen printing, an inkjet method, etc., dried or baked, a method of forming a film by a CVD method using a raw material gas, a PVD method, Examples thereof include a vapor deposition method, a sputtering method, a sol-gel method, and a method using an electrochemical redox reaction.

8). First Electrolysis Electrode The first electrolysis electrode 8 is provided on the back side of the photoelectric conversion unit 2. Thus, the first electrolysis electrode 8 does not block light incident on the photoelectric conversion unit 2.
Further, the first electrolysis electrode 8 is electrically connected to the back surface of the photoelectric conversion unit 2. As a result, the potential of the back surface of the photoelectric conversion unit 2 and the potential of the first electrolysis electrode 8 can be made substantially the same. Further, the first electrolysis electrode 8 can be immersed in the electrolytic solution stored in the electrolytic solution chamber 15. As a result, the electrolysis reaction can proceed on the surface of the first electrolysis electrode 8. Therefore, the first electrolysis electrode 8 can generate the first gas from the electrolytic solution by the electromotive force of the photoelectric conversion unit 2.

  The first electrolysis electrode 8 can be heated by the heat dissipation surface of the thermoelectric conversion unit 30. As a result, the temperature of the first electrolysis electrode 8 can be increased, and the electrolysis reaction of the electrolytic solution on the surface of the first electrolysis electrode 8 can be activated. As a result, the first gas can be generated efficiently.

Further, the first electrolysis electrode 8 can be provided so as not to contact the second electrolysis electrode 7. As a result, it is possible to prevent leakage current from flowing between the first electrolysis electrode 8 and the second electrolysis electrode 7.
Further, the first electrolysis electrode 8 may be a hydrogen generating part that generates H ₂ from the electrolytic solution or an oxygen generating part that generates O ₂ from the electrolytic solution. As a result, the first gas can be hydrogen or oxygen, and the gas producing apparatus of the present embodiment can decompose water contained in the electrolyte and produce hydrogen that serves as a fuel for the fuel cell.

9. Second Electrolysis Electrode The second electrolysis electrode 7 is provided on the back side of the photoelectric conversion unit 2. Thus, the second electrolysis electrode 7 does not block light incident on the photoelectric conversion unit 2.
The second electrolysis electrode 7 is electrically connected to the light receiving surface of the photoelectric conversion unit 2. Thereby, the potential of the light receiving surface of the photoelectric conversion unit 2 and the potential of the second electrolysis electrode 7 can be made substantially the same. The second electrolysis electrode 7 can be immersed in an electrolytic solution stored in the electrolytic solution chamber 15. As a result, the electrolysis reaction can proceed on the surface of the second electrolysis electrode 7. From these things, the 2nd electrode 7 for electrolysis can generate 2nd gas from electrolyte solution with the electromotive force of the photoelectric conversion part 2. FIG.

  The second electrolysis electrode 7 can be heated by the heat dissipation surface of the thermoelectric conversion unit 30. As a result, the temperature of the second electrolysis electrode 7 can be increased, and the electrolytic reaction of the electrolytic solution on the surface of the second electrolysis electrode 7 can be activated. As a result, the second gas can be generated efficiently.

The second electrolysis electrode 7 can be provided so as not to contact the first electrolysis electrode 8. As a result, it is possible to prevent leakage current from flowing between the first electrolysis electrode 8 and the second electrolysis electrode 7.
Further, the second electrolysis electrode 7 may be a hydrogen generating part that generates H ₂ from the electrolytic solution or an oxygen generating part that generates O ₂ from the electrolytic solution. Thus, the second gas can be hydrogen or oxygen, and the gas producing apparatus of the present embodiment can decompose water contained in the electrolyte and produce hydrogen that serves as a fuel for the fuel cell.

10. Hydrogen generating part The hydrogen generating part is a part that generates H ₂ from the electrolytic solution, and can be either the first electrolysis electrode 8 or the second electrolysis electrode 7. Further, the hydrogen generation unit may include a catalyst for a reaction in which H ₂ is generated from the electrolytic solution. Thereby, the reaction rate of the reaction in which H ₂ is generated from the electrolytic solution can be increased. The hydrogen generation part may consist only of a catalyst for the reaction in which H ₂ is generated from the electrolytic solution, or this catalyst may be supported on a support. Further, the hydrogen generation unit may have a catalyst surface area larger than the area of the light receiving surface of the photoelectric conversion unit 2. Thereby, the reaction in which H ₂ is generated from the electrolytic solution can be set to a faster reaction rate. The hydrogen generation part may be a porous conductor carrying a catalyst. This can increase the catalyst surface area. In addition, a change in potential due to a current flowing between the light receiving surface or the back surface of the photoelectric conversion unit 2 and the catalyst included in the hydrogen generation unit can be suppressed. Moreover, when this hydrogen generating part is the first electrolysis electrode 8, even if the second electrode 5 is omitted, a change in potential due to current flowing between the back surface of the photoelectric conversion part 2 and the catalyst is suppressed. Can do. Furthermore, the hydrogen generation unit may include at least one of Pt, Ir, Ru, Pd, Rh, Au, Fe, Ni, and Se as a hydrogen generation catalyst.

The catalyst for the reaction of generating H ₂ from the electrolyte (hydrogen generation catalyst) is a catalyst that promotes the conversion of two protons and two electrons into one molecule of hydrogen, is chemically stable, and generates hydrogen overvoltage. Can be used. For example, platinum group metals such as Pt, Ir, Ru, Pd, Rh, and Au, which have catalytic activity for hydrogen, and alloys or compounds thereof, Fe, Ni, and Se that constitute the active center of hydrogenase that is a hydrogen-producing enzyme. An alloy or a compound, a combination thereof, or the like can be preferably used. Among them, a nanostructure containing Pt and Pt has a small hydrogen generation overvoltage and can be suitably used. Materials such as CdS, CdSe, ZnS, and ZrO ₂ whose hydrogen generation reaction is confirmed by light irradiation can also be used.

  Although it is possible to directly support the hydrogen generating catalyst on the back surface of the photoelectric conversion unit 2, the catalyst can be supported on a conductor in order to increase the reaction area and improve the gas generation rate. Examples of the conductor carrying the catalyst include metal materials, carbonaceous materials, and conductive inorganic materials.

  As the metal material, a material having electronic conductivity and resistance to corrosion in an acidic atmosphere is preferable. Specifically, noble metals such as Au, Pt, Pd, metals such as Ti, Ta, W, Nb, Ni, Al, Cr, Ag, Cu, Zn, Su, Si, and nitrides and carbides of these metals, Examples of the alloy include stainless steel, Cu—Cr, Ni—Cr, and Ti—Pt. It is more preferable that the metal material contains at least one element selected from the group consisting of Pt, Ti, Au, Ag, Cu, Ni, and W from the viewpoint that there are few other chemical side reactions. These metal materials have a relatively small electric resistance, and can suppress a decrease in voltage even when a current is extracted in the surface direction. Further, when using a metal material having poor corrosion resistance in an acidic atmosphere such as Cu, Ag, Zn, etc., noble metals and metals having corrosion resistance such as Au, Pt, Pd, carbon, graphite, glassy carbon, A metal surface having poor corrosion resistance may be coated with a conductive polymer, a conductive nitride, a conductive carbide, a conductive oxide, or the like.

  As the carbonaceous material, a chemically stable and conductive material is preferable. Examples thereof include carbon powders and carbon fibers such as acetylene black, vulcan, ketjen black, furnace black, VGCF, carbon nanotube, carbon nanohorn, and fullerene.

Examples of the inorganic material having conductivity include In—Zn—O (IZO), In—Sn—O (ITO), ZnO—Al, Zn—Sn—O, SnO ₂ , and antimony oxide-doped tin oxide. .

  In addition, examples of the conductive polymer include polyacetylene, polythiophene, polyaniline, polypyrrole, polyparaphenylene, polyparaphenylene vinylene, and the like, and examples of the conductive nitride include carbon nitride, silicon nitride, gallium nitride, indium nitride, and nitride. Germanium, titanium nitride, zirconium nitride, thallium nitride, etc. are listed, and conductive carbides include tantalum carbide, silicon carbide, zirconium carbide, titanium carbide, molybdenum carbide, niobium carbide, iron carbide, nickel carbide, hafnium carbide, tungsten carbide. , Vanadium carbide, chromium carbide, and the like. Examples of the conductive oxide include tin oxide, indium tin oxide (ITO), and antimony oxide-doped tin oxide.

  The structure of the conductor supporting the hydrogen generation catalyst includes a plate shape, a foil shape, a rod shape, a mesh shape, a lath plate shape, a porous plate shape, a porous rod shape, a woven fabric shape, a nonwoven fabric shape, a fiber shape, and a felt shape. It can be used suitably. Further, a grooved conductor in which the surface of the felt-like electrode is pressure-bonded in a groove shape is preferable because the electric resistance and the flow resistance of the electrode liquid can be reduced.

11. Oxygen generating portion The oxygen generating portion is a portion that generates O ₂ from the electrolytic solution, and is one of the first electrolysis electrode 8 and the second electrolysis electrode 7. Further, the oxygen generation unit may include a catalyst for a reaction in which O ₂ is generated from the electrolytic solution. Thereby, the reaction rate of the reaction in which O ₂ is generated from the electrolytic solution can be increased. Further, the oxygen generation part may consist only of a catalyst for the reaction that generates O ₂ from the electrolytic solution, or the catalyst may be supported on a carrier. Further, the oxygen generation unit may have a catalyst surface area larger than the area of the light receiving surface of the photoelectric conversion unit 2. Thereby, the reaction in which O ₂ is generated from the electrolytic solution can be set to a faster reaction rate. The oxygen generation part may be a porous conductor carrying a catalyst. This can increase the catalyst surface area. In addition, a change in potential due to a current flowing between the light receiving surface or the back surface of the photoelectric conversion unit 2 and the catalyst included in the oxygen generation unit can be suppressed. Moreover, when this oxygen generating part is the first electrolysis electrode 8, even if the second electrode 5 is omitted, a change in potential due to current flowing between the back surface of the photoelectric conversion part 2 and the catalyst is suppressed. Can do. Furthermore, the oxygen generation unit may include at least one of Mn, Ca, Zn, Co, and Ir as an oxygen generation catalyst.

The catalyst for the reaction of generating O ₂ from the electrolyte (oxygen generating catalyst) is a catalyst that promotes the conversion of two water molecules into one molecule of oxygen, four protons, and four electrons, and is chemically stable. In addition, a material having a small oxygen generation overvoltage can be used. For example, oxides or compounds containing Mn, Ca, Zn, Co, which are active centers of Photosystem II, which is an enzyme that catalyzes the reaction of generating oxygen from water using light, and platinum such as Pt, RuO ₂ , IrO ₂ It is possible to use compounds containing group metals, oxides or compounds containing transition metals such as Ti, Zr, Nb, Ta, W, Ce, Fe, Ni, and combinations of the above materials. Among these, iridium oxide, manganese oxide, cobalt oxide, and cobalt phosphate can be suitably used because they have low overvoltage and high oxygen generation efficiency.

  Although it is possible to directly support the oxygen generating catalyst on the back surface of the photoelectric conversion unit 2, the catalyst can be supported on a conductor in order to increase the reaction area and improve the gas generation rate. Examples of the conductor carrying the catalyst include metal materials, carbonaceous materials, and conductive inorganic materials. These explanations apply as long as there is no contradiction in the explanation of the hydrogen generation catalyst described in “10. Hydrogen generation section”.

  When the catalytic activity of the hydrogen generating catalyst and the oxygen generating catalyst alone is small, a promoter can be used. Examples thereof include oxides or compounds of Ni, Cr, Rh, Mo, Co, and Se.

  The method for supporting the hydrogen generating catalyst and the oxygen generating catalyst can be applied directly to a conductor or semiconductor, PVD methods such as vacuum deposition, sputtering, and ion plating, dry coating methods such as CVD, The method can be appropriately changed depending on the material such as an analysis method. A conductive material can be appropriately supported between the photoelectric conversion unit and the catalyst. Also, when the catalytic activity for hydrogen generation and oxygen generation is not sufficient, the reaction surface area is increased by supporting it on porous materials such as metals and carbon, fibrous materials, nanoparticles, etc., and the hydrogen and oxygen generation rates are improved. It is possible to make it.

12 Electrolytic Solution Chamber The electrolytic solution chamber 15 can be provided so as to be able to store an electrolytic solution in which the first electrolysis electrode 8 and the second electrolysis electrode 7 are immersed. Thus, the first electrolysis electrode 8 and the second electrolysis electrode 7 can be immersed in the electrolytic solution, and the electrolytic reaction of the electrolytic solution is performed on the surfaces of the first electrolysis electrode 8 and the second electrolysis electrode 7. Can be advanced. The electrolyte chamber 15 can be, for example, a space formed between the first electrolysis electrode 8 and the second electrolysis electrode 7 and the back substrate 14.
The electrolyte chamber 15 can be a flow path for collecting the first gas generated from the first electrolysis electrode 8 and the second gas generated from the second electrolysis electrode 7.

13. Back Substrate The back substrate 14 can be provided on the first electrolysis electrode 8 and the second electrolysis electrode 7 so as to face the translucent substrate 1. The back substrate 14 can be provided such that a space is provided between the first electrolysis electrode 8 and the second electrolysis electrode 7 and the back substrate 14. This space can be used as the electrolytic solution chamber 15.
Further, the back substrate 14 can accommodate the photoelectric conversion unit 2, the thermoelectric conversion unit 30, the first electrolysis electrode 8, and the second electrolysis electrode 7, and is a part of the outer box that can form the electrolytic solution chamber 15. There may be.

  Moreover, since the back substrate 14 constitutes the electrolytic solution chamber 15 for storing the electrolytic solution and confining the generated first gas and second gas, a substance with high confidentiality is required. The back substrate 14 is not particularly limited, whether it is transparent or opaque. Examples of the back substrate include a transparent rigid material such as quartz glass, Pyrex (registered trademark), and a synthetic quartz plate, or a transparent resin plate and a transparent resin film. Among them, it is preferable to use a glass material because it is a gas that is not chemically permeable and is chemically and physically stable.

  When an outer box is used for the back substrate 14, the outer box is made of, for example, a steel material such as stainless steel or a synthetic resin such as a ceramic such as zirconia or alumina, a phenol resin, a melamine resin (MF), or a glass fiber reinforced polyamide resin. Is preferred.

14 Partition Wall The partition wall 13 can be provided so as to partition the space between the first electrolysis electrode 8 and the back substrate 14 and the space between the second electrolysis electrode 7 and the back substrate 14. As a result, the first gas and the second gas generated by the first electrolysis electrode 8 and the second electrolysis electrode 7 can be prevented from mixing, and the first gas and the second gas can be separated. It can be recovered.
The partition wall 13 may include an ion exchanger. As a result, the ion concentration that is unbalanced by the electrolytic solution in the space between the first electrolysis electrode 8 and the back substrate 14 and the electrolytic solution in the space between the second electrolysis electrode 7 and the back substrate 14 is reduced. Can be kept constant. In other words, the ion concentration imbalance caused by the electrolysis reaction in the first electrolysis electrode 8 and the second electrolysis electrode 7 can be eliminated by the movement of ions through the partition walls 9. When hydrogen and oxygen are generated by the electrolysis reaction of H ₂ O in the first electrolysis electrode 8 and the second electrolysis electrode 7, the partition wall 13 contains an ion exchanger, thereby eliminating the proton concentration imbalance. can do.

When the electrolytic solution is electrolyzed to generate hydrogen and oxygen, the ratio of the hydrogen generation amount and the oxygen generation amount from the electrolytic solution is a molar ratio of 2: 1, and the first electrolysis electrode 8 and the second electrolysis are used. The amount of gas generated varies depending on the electrode 7. For this reason, it is preferable that the partition wall 13 is made of a material that allows water to pass through in order to keep the water content in the apparatus constant.
For the partition wall 13, for example, an inorganic film such as porous glass, porous zirconia, or porous alumina or an ion exchanger can be used. As the ion exchanger, any ion exchanger known in the art can be used, and a proton conductive membrane, a cation exchange membrane, an anion exchange membrane, or the like can be used.

  The material of the proton conductive film is not particularly limited as long as it is a material having proton conductivity and electrical insulation, and a polymer film, an inorganic film, or a composite film can be used.

  Examples of the polymer membrane include Nafion (registered trademark) manufactured by DuPont, Aciplex (registered trademark) manufactured by Asahi Kasei Co., and Flemion (registered trademark) manufactured by Asahi Glass Co., Ltd., which are perfluorosulfonic acid electrolyte membranes. Examples thereof include membranes and hydrocarbon electrolyte membranes such as polystyrene sulfonic acid and sulfonated polyether ether ketone.

  Examples of the inorganic film include films made of phosphate glass, cesium hydrogen sulfate, polytungstophosphoric acid, ammonium polyphosphate, and the like. Examples of the composite membrane include a membrane made of a sulfonated polyimide polymer, a composite of an inorganic material such as tungstic acid and an organic material such as polyimide, and specifically, Gore Select membrane (registered trademark) or pores manufactured by Gore. Examples thereof include a filling electrolyte membrane. Furthermore, when used in a high temperature environment (for example, 100 ° C. or higher), sulfonated polyimide, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), sulfonated polybenzimidazole, phosphonated polybenzimidazole, sulfuric acid. Examples include cesium hydrogen and ammonium polyphosphate.

  The cation exchange membrane may be any solid polymer electrolyte that can move cations. Specifically, fluorine ion exchange membranes such as perfluorocarbon sulfonic acid membranes and perfluorocarbon carboxylic acid membranes, polybenzimidazole membranes impregnated with phosphoric acid, polystyrene sulfonic acid membranes, sulfonated styrene / vinylbenzene copolymers Examples include membranes.

When the anion transport number of the supporting electrolyte solution is high, it is preferable to use an anion exchange membrane. As the anion exchange membrane, a solid polymer electrolyte capable of transferring anions can be used. Specifically, a polyorthophenylenediamine film, a fluorine-based ion exchange film having an ammonium salt derivative group, a vinylbenzene polymer film having an ammonium salt derivative group, a film obtained by aminating a chloromethylstyrene / vinylbenzene copolymer, etc. Can be mentioned.
When hydrogen generation and oxygen generation are selectively performed by a hydrogen generation catalyst and an oxygen generation catalyst, respectively, and ion movement accompanying this occurs, it is not always necessary to arrange a member such as a special membrane for ion exchange. . For the purpose of only physically isolating the gas, it is possible to use an ultraviolet curable resin or a thermosetting resin described in a sealant described later.

15. Sealing material The sealing material 16 is a material for adhering the translucent substrate 1 and the back substrate 14 to constitute the electrolyte chamber 15. Moreover, when a box-shaped thing is used for the back substrate 14, the sealing material 16 is a material for adhere | attaching a box-shaped thing and the translucent board | substrate 1. FIG. As the sealing material 16, for example, an ultraviolet curable adhesive, a thermosetting adhesive, or the like is preferably used, but the type thereof is not limited. The UV curable adhesive is a resin that undergoes polymerization upon irradiation with light having a wavelength of 200 to 400 nm and undergoes a curing reaction within a few seconds after light irradiation, and is divided into a radical polymerization type and a cationic polymerization type. Examples of the polymerization type resin include acrylates, unsaturated polyesters, and examples of the cationic polymerization type include epoxy, oxetane, and vinyl ether. Examples of the thermosetting polymer adhesive include organic resins such as phenol resin, epoxy resin, melamine resin, urea resin, and thermosetting polyimide. The thermosetting polymer adhesive is heated and polymerized in a state where pressure is applied at the time of thermocompression bonding, and then cooled to room temperature while being pressurized. I don't need it. In addition to the organic resin, a hybrid material having high adhesion to the glass substrate can be used. By using a hybrid material, mechanical properties such as elastic modulus and hardness are improved, and heat resistance and chemical resistance are dramatically improved. The hybrid material is composed of inorganic colloidal particles and an organic binder resin. For example, what is comprised from inorganic colloidal particles, such as a silica, and organic binder resin, such as an epoxy resin, a polyurethane acrylate resin, and a polyester acrylate resin, is mentioned.

  Here, the sealing material 16 is described, but it is not limited as long as it has a function of adhering the substrate 1 and the back substrate 14, and a member such as a screw is used from the outside using a resin or metal gasket. It is also possible to appropriately use a method of physically applying pressure to increase confidentiality.

16. Water supply port, 1st gas discharge port, and 2nd gas discharge port The water supply port 18 can be provided by making opening in a part of sealing material 16 contained in the gas manufacturing apparatus 23, for example. The water supply port 18 is installed to supply the electrolytic solution to the electrolytic solution chamber 15, and the location and shape of the water supply port 18 are not particularly limited as long as the electrolytic solution is efficiently supplied to the gas production apparatus. From the viewpoint of fluidity and ease of supply, it is preferably provided at the lower part of the gas production apparatus installed at an inclination.

  Further, the first gas outlet 20 and the second gas outlet 19 may be provided by making an opening in the sealing material 16 in the upper part of the gas manufacturing apparatus 23 when the gas manufacturing apparatus 23 is installed inclined. it can. Moreover, the 1st gas exhaust port 20 and the 2nd gas exhaust port 19 can be provided in the electrode side for 1st electrolysis and the electrode side for 2nd electrolysis, respectively, on both sides of the partition 13.

  By providing the water supply port 18, the first gas discharge port 20, and the second gas discharge port 19 in this manner, the gas production device 23 is inclined with respect to the horizontal plane with the light receiving surface of the photoelectric conversion unit 2 facing upward. It can be installed such that 18 is on the lower side and the first gas outlet 20 and the second gas outlet 19 are on the upper side. By installing in this way, electrolyte solution can be introduce | transduced in the gas manufacturing apparatus 23 from the water supply port 18, and the electrolyte chamber 15 can be satisfy | filled with electrolyte solution. In this state, the first gas and the second gas can be continuously generated by the first electrolysis electrode and the second electrolysis electrode by making light incident on the gas production apparatus 23, respectively. The generated first gas and second gas can be separated by the partition wall 13, and the first gas and the second gas rise to the upper part of the gas production device 23, and the first gas outlet 20 and the second gas exhaust It can be recovered from the outlet 19.

17. Electrolytic solution The electrolytic solution is an aqueous solution containing an electrolyte, for example, an electrolytic solution containing 0.1 M H ₂ SO ₄ , 0.1 M potassium phosphate buffer, etc. If it happens, the type of electrolyte is not limited, and the electrolyte concentration is not limited.

    1: Translucent substrate 2: Photoelectric conversion part 3a, 3b, 3c: n-type semiconductor part 4: First electrode 5: Second electrode 6a, 6b, 6c: P-type semiconductor part 7: Electrode for second electrolysis 8: 1st electrolysis electrode 10: 1st electroconductive part 11a, 11b, 11c, 11d, 11e, 11f, 11g, 11h, 11i: Insulating layer 13: Partition 14: Back substrate 15a, 15b: Electrolyte chamber 16: Sealing material 18 : Water supply port 19: 2nd gas discharge port 20: 1st gas discharge port 21: 2nd electroconductive part 23: Gas production apparatus 24, 24a, 24b, 28, 28a, 28b: Conductive part 26, 26a, 26b: 1st Thermoelectric conversion electrodes 27, 27a, 27b: second thermoelectric conversion electrodes 30, 30a, 30b: thermoelectric conversion units

Claims (16)

A photoelectric conversion unit having a light receiving surface and its back surface, and generating a potential difference between the light receiving surface and the back surface by receiving light; and
A first electrolysis electrode provided on the back side of the photoelectric conversion unit and electrically connected to the back side of the photoelectric conversion unit;
A second electrolysis electrode provided on the back side of the photoelectric conversion unit and electrically connected to the light receiving surface of the photoelectric conversion unit;
A thermoelectric conversion unit provided between the back surface of the photoelectric conversion unit and the first electrolysis electrode or the second electrolysis electrode;
The first electrolysis electrode and the second electrolysis electrode are provided so as to be immersed in the electrolytic solution, and the electrolytic solution is electrolyzed by an electromotive force generated when the photoelectric conversion unit receives light, and the first gas and the second electrolysis electrode are respectively obtained. Provided to be able to generate gas,
The thermoelectric conversion unit absorbs heat from the photoelectric conversion unit and dissipates heat to the first electrolysis electrode or the second electrolysis electrode. A first electrode provided on the light receiving surface of the photoelectric conversion unit, and a second electrode provided on the back surface of the photoelectric conversion unit,
The apparatus according to claim 1, wherein the first electrode is electrically connected to the second electrolysis electrode, and the second electrode is electrically connected to the first electrolysis electrode.   A first insulating layer provided between the second electrode and the thermoelectric conversion part; and a second insulating layer provided between the thermoelectric conversion part and the first electrolysis electrode or the second electrolysis electrode. The apparatus of claim 2 further comprising: A first conductive portion that electrically connects the first electrode and the second electrolysis electrode; and a second conductive portion that electrically connects the second electrode and the first electrolysis electrode;
The first conductive part is provided in a contact hole that penetrates the photoelectric conversion part and the thermoelectric conversion part,
The device according to claim 2, wherein the second conductive portion is provided in a contact hole that penetrates the thermoelectric conversion portion. The thermoelectric conversion part includes a p-type semiconductor part, an n-type semiconductor part, a first thermoelectric conversion electrode, and a second thermoelectric conversion electrode,
The device according to any one of claims 1 to 4, wherein the p-type semiconductor unit and the n-type semiconductor unit are sandwiched between a first thermoelectric conversion electrode and a second thermoelectric conversion electrode.   The device according to claim 5, wherein the p-type semiconductor unit and the n-type semiconductor unit are provided such that a current flows due to an electromotive force generated when the photoelectric conversion unit receives light.   The apparatus according to claim 5, further comprising a current control unit configured to control a current flowing through the p-type semiconductor unit and the n-type semiconductor unit.   The apparatus according to claim 1, wherein the thermoelectric conversion unit is plural. A translucent substrate;
The said photoelectric conversion part is an apparatus as described in any one of Claims 1-8 provided on the said translucent board | substrate so that the said light-receiving surface might become the said translucent board | substrate side.   The apparatus according to any one of claims 1 to 9, further comprising an electrolytic solution chamber capable of storing an electrolytic solution in which the first electrolytic electrode or the second electrolytic electrode is immersed. Further comprising a back substrate on the back side of the photoelectric conversion unit,
The apparatus according to claim 10, wherein the electrolyte chamber is provided between a back surface of the photoelectric conversion unit and the back substrate.   The partition which partitions off the electrolyte chamber which can store the electrolyte solution which the electrode for 1st electrolysis immerses, and the electrolyte chamber which can store the electrolyte solution which the electrode for 2nd electrolysis immerses is provided. Equipment.   The apparatus according to claim 12, wherein the partition wall includes an ion exchanger.   The device according to claim 1, wherein the photoelectric conversion unit includes a photoelectric conversion layer including a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer. Of the first electrolysis electrode and the second electrolysis electrode, one is a hydrogen generation unit that generates H ₂ from the electrolytic solution, and the other is an oxygen generation unit that generates O ₂ from the electrolytic solution,
15. The hydrogen generation unit and the oxygen generation unit each include a catalyst for a reaction in which H ₂ is generated from the electrolytic solution and a catalyst for a reaction in which O ₂ is generated from the electrolytic solution, respectively. apparatus.   The apparatus according to claim 15, wherein at least one of the hydrogen generation part and the oxygen generation part is formed of a porous conductor carrying a catalyst.

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