JP2015082351A - Method for manufacturing electrode substrate for solar battery, apparatus for manufacturing electrode substrate for solar battery, and electrode substrate for solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrode substrate for a solar battery, for improving generation efficiency, an apparatus for manufacturing an electrode substrate for a solar battery, and an electrode substrate for a solar battery.SOLUTION: An electrode substrate 3 for a solar battery includes a transparent substrate 11, a transparent conductive film (indium tin oxide layer) 12 disposed on the transparent substrate 11, an indium oxide layer 13 disposed on the indium tin oxide layer, and a porous metal oxide layer 14 disposed on the indium oxide layer 13. Oxidation of the indium tin oxide layer is suppressed by the indium oxide layer 13, which suppresses increase in the resistance of the indium tin oxide layer. A crystal lattice of the indium oxide layer 13 is approximately the same as a crystal lattice of the indium tin oxide layer, which prevents warpage or the like of the transparent substrate 11 caused by mismatch of crystal lattices between the indium tin oxide layer and the indium oxide layer 13.

Description

  The present invention relates to a method for manufacturing an electrode substrate for a solar cell, an apparatus for manufacturing an electrode substrate for a solar cell, and an electrode substrate for a solar cell.

  In recent years, attention has been focused on dye-sensitized solar cells that can produce solar cells at low cost and low energy. In an electrode substrate (photoelectrode) of a dye-sensitized solar cell, a transparent conductive film is provided between a transparent substrate and a porous metal oxide layer, for example, as described in Patent Document 1 below. Electrons generated in the porous metal oxide layer on which is supported are collected.

JP 2006-318770 A

  The electrode substrate of the dye-sensitized solar cell as described above has a porous structure in which a metal oxide layer dispersed in an organic solvent is formed on a transparent conductive film and is heated to the atmosphere at a predetermined temperature (eg, 350 ° C. or higher). It is produced by firing a porous metal oxide layer. Here, as the transparent conductive film, it is conceivable to use indium tin oxide (hereinafter referred to as “ITO”) in order to reduce its resistance value. However, when ITO is used for the transparent conductive film, the ITO is oxidized during atmospheric heating, and the resistance value of the transparent conductive film increases. As a result, the power generation efficiency of the dye-sensitized solar cell may be reduced.

  Then, this invention makes it a subject to provide the manufacturing method of the electrode substrate for solar cells which aims at the improvement of power generation efficiency, the manufacturing apparatus of the electrode substrate for solar cells, and the electrode substrate for solar cells.

  A method for manufacturing an electrode substrate for a solar cell according to the present invention includes a first step of forming an indium tin oxide layer on a transparent substrate, a second step of forming an indium layer on the indium tin oxide layer, and an indium layer. Forming a metal oxide layer on the substrate, forming a transparent substrate, an indium tin oxide layer, an indium having an indium layer and a metal oxide layer, and subjecting the intermediate to a heat treatment to form a metal oxide layer And forming a porous metal oxide layer as a porous metal oxide layer.

  In this method of manufacturing an electrode substrate for a solar cell, an indium layer is formed on an indium tin oxide layer that functions as a transparent conductive film, and a metal oxide layer is formed on the indium layer. Thereby, when heat-processing an intermediate body, while an indium layer is oxidized with the oxygen in a metal oxide layer and air | atmosphere, the oxidation of an indium tin oxide layer will be suppressed. Thus, by suppressing the oxidation of the indium tin oxide layer, an increase in the resistance value of the indium tin oxide layer can be suppressed, and the power generation efficiency can be improved. In addition, since the indium tin oxide layer contains indium oxide as a main component, the crystal lattice of the oxidized indium layer is almost the same as the crystal lattice of the indium tin oxide layer. Thereby, it is possible to prevent the transparent substrate from being warped due to mismatch of crystal lattices between the indium tin oxide layer and the oxidized indium layer. Therefore, warpage of the electrode substrate can be prevented.

  The indium layer is preferably thinner than the indium tin oxide layer. By reducing the thickness of the indium layer, the translucency of the indium layer can be improved, and the power generation efficiency of the solar cell can be further improved.

  The transparent substrate is preferably a glass substrate. By using a glass substrate which is a transparent substrate with high heat resistance, the temperature of the heat treatment can be increased. As a result, the bondability between the metal oxides is improved during the heat treatment, and the power generation efficiency can be further improved.

  Moreover, it is preferable that heat processing are performed at 400 degreeC or more. By raising the temperature at which the intermediate containing the metal oxide layer is heated, the bondability between the metal oxides can be improved, and the power generation efficiency can be further improved.

  Further, the sheet resistance of the indium tin oxide layer after the fourth step may be 10Ω / □ or less.

  Moreover, the manufacturing apparatus of the electrode substrate for solar cells which concerns on this invention WHEREIN: The 1st film-forming part which forms an indium tin oxide layer on a transparent substrate, and the 2nd film-forming which forms an indium layer on an indium tin oxide layer Forming a metal oxide layer on the indium layer, forming a transparent substrate, an indium tin oxide layer, an indium having an indium layer and a metal oxide layer, and a heat treatment on the intermediate And a heating unit to be performed.

  In this solar cell electrode substrate manufacturing apparatus, a second film forming unit that forms an indium layer on an indium tin oxide layer that functions as a transparent conductive film, and a third film forming unit that forms a metal oxide layer on the indium layer. A film portion. When the atmosphere is heated by the heating unit, the indium layer is oxidized by oxygen in the metal oxide layer and in the atmosphere, while oxidation of the indium tin oxide layer is suppressed. For this reason, an increase in the resistance value of the indium tin oxide layer is suppressed, and the power generation efficiency can be improved. In addition, since the indium tin oxide layer contains indium oxide as a main component, the crystal lattice of the oxidized indium layer is almost the same as the crystal lattice of the indium tin oxide layer. Thereby, it is possible to prevent the transparent substrate from being warped due to mismatch of crystal lattices between the indium tin oxide layer and the oxidized indium layer. Therefore, warpage of the electrode substrate can be prevented.

  The electrode substrate of the solar cell according to the present invention is provided on a transparent substrate, an indium tin oxide layer provided on the transparent substrate, an indium oxide layer provided on the indium tin oxide layer, and an indium oxide layer. And a porous metal oxide layer formed.

  In the electrode substrate of this solar cell, an indium oxide layer is provided between an indium tin oxide layer that functions as a transparent conductive film and a porous metal oxide layer. By this indium oxide layer, oxygen can be suppressed from being supplied to the indium tin oxide layer from the porous metal oxide layer and the atmosphere, and an increase in the resistance value of the indium tin oxide layer can be suppressed. Thereby, the power generation efficiency can be improved. In addition, since the indium tin oxide layer contains indium oxide as a main component, the crystal lattice of the indium oxide layer is almost the same as the crystal lattice of the indium tin oxide layer. Thereby, it is possible to prevent the transparent substrate from warping due to the mismatch of the crystal lattice between the indium tin oxide layer and the indium oxide layer. Therefore, warpage of the electrode substrate can be prevented.

  The thickness of the indium oxide layer is preferably thinner than the thickness of the indium tin oxide layer. By reducing the thickness of the indium oxide layer, the translucency of the indium oxide layer can be improved, and the power generation efficiency can be further improved.

  The transparent substrate is preferably a glass substrate. By using a glass substrate which is a transparent substrate with high heat resistance, the temperature of heat treatment can be increased. As a result, the bondability between the metal oxides is improved during the heat treatment, and the power generation efficiency can be further improved.

  Further, the sheet resistance of the indium tin oxide layer may be 10Ω / □ or less.

  According to the present invention, it is possible to improve power generation efficiency and prevent warping of the electrode substrate.

It is a schematic structure of a dye-sensitized solar cell provided with the electrode substrate for solar cells which concerns on one Embodiment of this invention. It is a graph which shows the volume resistivity of ITO conductive glass and FTO conductive glass. It is a block diagram of a structure of the manufacturing apparatus for manufacturing the electrode substrate of FIG. It is sectional drawing of the ion plating apparatus using RPD method. It is sectional drawing which shows an example of the method of manufacturing the electrode substrate of FIG.

  Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic structure of a dye-sensitized solar cell including an electrode substrate for a solar cell according to an embodiment of the present invention. As shown in FIG. 1, the dye-sensitized solar cell 1 is a solar cell that converts light energy into electrical energy by using an adsorbed dye 15, for a solar cell that constitutes a positive electrode 2 and a negative electrode. The electrode 4 is sandwiched between the electrode substrate 3 (hereinafter also simply referred to as “electrode substrate 3”). The positive electrode 2 and the electrode substrate 3 are electrically connected to each other via an external circuit 5. As the positive electrode 2 and the electrolyte 4, known positive electrodes and electrolytes can be used, respectively. The electrode substrate 3 is a photoelectrode that generates electrons when irradiated with light L, and includes a transparent substrate 11, a transparent conductive film 12, an indium oxide layer 13, a porous metal oxide layer 14, and a dye 15. .

  The transparent substrate 11 has a property of transmitting light (particularly visible light). For example, a glass substrate or a resin substrate is used as the transparent substrate 11. As the glass substrate, for example, glass such as soda lime glass, borosilicate glass, and silica glass is used. As a resin material used for the resin substrate, for example, a resin material such as an acrylic resin, a polyamide resin, a polyimide resin, or a polyester resin is used. Here, a glass substrate is preferably used from the viewpoint of strength and heat resistance. The thickness of the transparent substrate 11 is 0.1 mm to 12 mm, preferably 1.1 mm to 2 mm. In order to suppress diffusion of the glass component, for example, a silicon oxide film or the like may be formed on the surface of the transparent substrate 11.

  The transparent conductive film 12 is a film having a property of transmitting light (particularly visible light) and conductivity, and is provided on the transparent substrate 11. As the transparent conductive film 12, a conductive film made of ITO (hereinafter also referred to as an indium tin oxide layer) is used. The film thickness of the transparent conductive film 12 is 50 nm to 300 nm, preferably 100 nm to 200 nm, and more preferably 120 nm to 150 nm. The sheet resistance of the transparent conductive film 12 is 10Ω / □ or less, preferably 7Ω / □ or less.

  In general, the material of the transparent conductive film 12 may be fluorine-doped tin oxide (hereinafter referred to as “FTO”) in addition to ITO. ITO is used from the viewpoint of conductivity. Here, each characteristic of ITO and FTO will be described in comparison.

  FIG. 2 shows the volume when an ITO film (ITO conductive glass) and an FTO film (FTO conductive glass) are heated in the atmosphere (heated in an atmospheric atmosphere) for 1 hour at each temperature. It is a graph which shows a resistivity. Graph 21 shows the volume resistivity of ITO conductive glass, and graph 22 shows the volume resistivity of FTO conductive glass. As shown in FIG. 2, it can be seen that the volume resistivity of the ITO conductive glass is significantly lower than the volume resistivity of the FTO conductive glass from room temperature to around 350 ° C.

  Moreover, when atmospheric heating is performed at 400 ° C. or higher, the volume resistivity of the ITO conductive glass rapidly increases. This is because the sheet resistance of the ITO conductive glass is increased by oxidizing the ITO and filling the oxygen vacancies among the doped tin and oxygen vacancies that are the carrier generation source of the ITO. However, it can be seen that the volume resistivity of the ITO conductive glass is still lower than the volume resistivity of the FTO conductive glass even if it rapidly increases. Therefore, even when atmospheric heating is performed, it can be seen that ITO conductive glass is superior to FTO conductive glass from the viewpoint of electrical conductivity. Moreover, even if it heats to air | atmosphere at high temperature, if an ITO conductive glass does not oxidize, it turns out that the ITO conductive glass is more advantageous than an FTO conductive glass from a viewpoint of electrical conductivity.

  Returning to FIG. 1, the indium oxide layer 13 is made of indium oxide and provided on the transparent conductive film 12. The indium oxide layer 13 functions as a buffer layer that prevents oxygen and the like from being supplied to the transparent conductive film 12 during atmospheric heating or the like (details will be described later). Here, since ITO contains indium oxide as a main component, the crystal lattice of the indium oxide layer 13 and the crystal lattice of the transparent conductive film 12 are substantially the same. For this reason, by using the indium oxide layer 13, it is possible to suppress the occurrence of warping of the electrode substrate 3 due to the crystal lattice mismatch between the transparent conductive film 12 and the indium oxide layer 13. The film thickness of the indium oxide layer 13 is 1 nm to 50 nm, preferably 3 nm to 30 nm, more preferably 5 nm to 20 nm, which is at least smaller than the thickness of the transparent conductive film 12 from the viewpoints of electrical conductivity and translucency. The indium oxide layer 13 may contain unoxidized indium.

The porous metal oxide layer 14 is made of a metal oxide semiconductor and is provided on the indium oxide layer 13. Examples of metal oxide semiconductors include oxides such as titanium, zirconium, hafnium, strontium, tantalum, chromium, molybdenum, and tungsten, or composite oxides containing the above metals, such as perovskite oxides such as SrTiO ₃ and CaTiO _3. Is used. In this embodiment, titanium oxide having a light absorption peak in the ultraviolet region is used as the metal oxide semiconductor. Such metal oxide semiconductors are preferably in the form of particles and bonded to each other in terms of porosity. The particle size of the metal oxide semiconductor is 10 nm to 500 nm, preferably 5 nm to 350 nm, and more preferably 5 nm to 200 nm.

  The dye 15 has a property (photosensitization action) excited by the light L, and is adsorbed on the porous metal oxide layer 14. As the dye 15, a dye generally used in a dye-sensitized solar cell (for example, a ruthenium complex, a cyan dye, a coumarin dye, or a cyanine dye) can be used. In order to achieve high conversion efficiency, it is desirable to use a dye whose absorption spectrum of the dye overlaps the sunlight spectrum in a wide wavelength range and has high light resistance.

  FIG. 3 is a block diagram of a configuration of a manufacturing apparatus for manufacturing the electrode substrate 3 described above. As shown in FIG. 3, the electrode substrate manufacturing apparatus 100 (hereinafter also simply referred to as “manufacturing apparatus 100”) includes a first film forming apparatus (first film forming unit) 200 and a second film forming apparatus (second forming apparatus). (Film part) 300, 3rd film-forming apparatus (3rd film-forming part) 400, and heating apparatus (heating part) 500 are provided at least. In addition, the apparatus with which the manufacturing apparatus 100 is provided is not limited to each film-forming apparatus 200,300,400 and the heating apparatus 500, You may further provide other apparatuses (for example, washing | cleaning apparatus etc.).

  The first film forming apparatus 200 is an apparatus for forming the transparent conductive film 12 on the transparent substrate 11. The second film forming apparatus 300 is an apparatus for forming the indium layer 16 on the transparent conductive film 12. The third film forming apparatus 400 is an apparatus for forming the metal oxide layer 17 on the indium layer 16. Examples of the first film forming apparatus 200 and the second film forming apparatus 300 include a vacuum vapor deposition apparatus, a sputtering apparatus, a CVD apparatus, and an ion plating apparatus.

  Examples of the third film forming apparatus 400 include various coating apparatuses and ink jet printers. The first film forming apparatus 200 and the second film forming apparatus 300 may be the same film forming apparatus or different film forming apparatuses. The heating device 500 is a device that heats the film formation target and the film formed by the film formation apparatus, and various furnaces such as an electric furnace (for example, a muffle furnace) are used.

  FIG. 4 is a cross-sectional view of an ion plating apparatus using an RPD method (reactive plasma deposition method) as an example of the first film forming apparatus 200. The RPD method is a method in which an electric current is passed through the evaporation material by, for example, plasma beam irradiation to directly heat and evaporate the evaporation material. An ion plating apparatus using the RPD method is formed by diffusing a film forming material (evaporated material) evaporated by the RPD method into a vacuum container and attaching the film forming material to the surface of the film forming target. It is an apparatus for performing a film.

  As shown in FIG. 4, the first film formation apparatus 200 is configured such that the film formation target 211 is in an upright or inclined state so that the plate thickness direction of the film formation target 211 is horizontal. This is a so-called vertical film forming apparatus in which the object 211 is arranged and transported in the vacuum chamber 210. The first film forming apparatus 200 includes a hearth mechanism 202, a transport mechanism 203, a wheel hearth 206, a plasma source 207, a pressure adjustment device 208, and a vacuum chamber 210.

  The vacuum chamber 210 is irradiated from a transfer chamber 210 a for transferring a film formation target 211 on which a film of the film formation material Ma is formed, a film formation chamber 210 b for diffusing the film formation material Ma, and a plasma source 207. A plasma port 210c for receiving the plasma beam P in the vacuum chamber 210; The vacuum chamber 210 is made of a conductive material and connected to the ground potential.

  The transport mechanism 203 transports the film formation target holding member 216 that holds the film formation target 211 in the transport direction A while facing the film formation material Ma. The plasma source 207 is connected to the film forming chamber 210b through a plasma port 210c provided on the side wall of the film forming chamber 210b. The plasma source 207 generates a plasma beam P in the vacuum chamber 210. The plasma beam P generated in the plasma source 207 is emitted from the plasma port 210c with its direction controlled into the film formation chamber 210b.

  The pressure adjusting device 208 is connected to the vacuum chamber 210 and adjusts the pressure in the vacuum chamber 210. The pressure adjustment device 208 includes, for example, a decompression unit such as a turbo molecular pump or a cryopump, and a pressure measurement unit that measures the pressure in the vacuum chamber 210.

  The hearth mechanism 202 is a mechanism for holding the film forming material Ma. The hearth mechanism 202 is provided in the film forming chamber 210 b of the vacuum chamber 210. The hearth mechanism 202 has a main anode that guides the plasma beam P emitted from the plasma source 207 to the film forming material Ma. The hearth mechanism 202 is maintained at a positive potential with respect to the ground potential of the vacuum chamber 210.

  The ring hearth 206 is an auxiliary anode having a magnet for guiding the plasma beam P. The ring hearth 206 includes an annular coil 209, an annular permanent magnet part 220, and an annular container 212, and the coil 209 and the permanent magnet part 220 are accommodated in the container 212. The ring hearth 206 controls the width and thickness of the plasma beam P incident on the film forming material Ma.

  The film forming material (evaporating material) Ma is ITO. When the film forming material Ma and the hearth mechanism 202 are irradiated with the plasma beam P, the film forming material Ma is heated. As a result, the tip portion of the film forming material Ma evaporates, and the film forming material particles Mb ionized by the plasma beam P diffuse into the film forming chamber 210b. The film forming material particles Mb diffused into the film forming chamber 210b adhere to the surface of the film forming target 211 in the transfer chamber 210a.

  Next, an example of a method for manufacturing the electrode substrate 3 using the manufacturing apparatus 100 shown in FIG. 3 will be described in detail with reference to (a) to (e) of FIG.

  First, the transparent substrate 11 is carried into the manufacturing apparatus 100, and as shown in FIG. 5A, the transparent conductive film 12 made of ITO is formed on the transparent substrate 11 by the first film forming apparatus 200 (see FIG. 5A). First step). In the first step, for example, in order to suppress the surface roughness of the formed transparent conductive film 12, it is preferable to use an ion plating apparatus using the RPD method described above as the first film forming apparatus 200. The transparent conductive film 12 may be formed on the surface of the transparent substrate 11 or may be formed on a film formed on the surface of the transparent substrate 11.

  Next, as shown in FIG. 5B, the indium layer 16 made of indium is formed on the surface of the transparent conductive film 12 in the second film forming apparatus 300 (second step). At this time, the indium layer 16 is formed to be thinner than at least the thickness of the transparent conductive film 12. As described above, the second film forming apparatus 300 may be the same apparatus as the first film forming apparatus 200 or may be a different apparatus.

  Next, as shown in FIG. 5C, the metal oxide layer 17 is formed on the indium layer 16 by the third film forming apparatus 400. Thereby, the intermediate body 20 which has the transparent substrate 11, the transparent conductive film 12, the indium layer 16, and the metal oxide layer 17 is formed (3rd process). The intermediate body 20 is an intermediate product in the manufacturing process of the electrode substrate 3, and the transparent conductive film 12, the indium layer 16, and the metal oxide layer 17 are laminated on the transparent substrate 11 in this order. Here, the metal oxide layer 17 can be formed by applying a paste in which metal oxide semiconductor particles are dispersed in an organic solvent, for example, on the indium layer 16 in the third film forming apparatus 400. it can. As the organic solvent, for example, a lower alcohol or a resin material is used. Moreover, you may further contain the hardening | curing agent and the dispersing agent in the organic solvent.

  Next, in order to remove the organic solvent in the metal oxide layer 17, the heating process is performed on the intermediate 20 in the heating device 500 (fourth step). The heat treatment is performed, for example, by heating in the atmosphere at 400 ° C. or higher. According to the atmospheric heating, the organic solvent in the metal oxide layer 17 is removed and the metal oxide semiconductor particles are bonded to each other to form the porous metal oxide layer 14 ((d in FIG. 5). )). In order to improve the bonding between the metal oxide semiconductor particles, it is preferable to increase the temperature of atmospheric heating. For example, it is preferable to perform the heat treatment at 500 ° C. or higher and below the glass transition point of the transparent substrate 11 (for example, 550 ° C. to 650 ° C. or lower).

  Here, in the fourth step, the indium layer 16 is oxidized by oxygen in the atmosphere or oxygen in the metal oxide layer 17 to become the indium oxide layer 13. On the other hand, since the transparent conductive film 12 is not oxidized or hardly oxidized because the indium oxide layer 13 is formed, an increase in sheet resistance of the transparent conductive film 12 is suppressed. Thereby, even after atmospheric heating, the transparent conductive film 12 having a low sheet resistance can be formed.

  In addition, since ITO contains indium oxide as a main component, the crystal lattice of the indium oxide layer 13 and the crystal lattice of the transparent conductive film 12 are almost the same. For this reason, the malfunction (for example, the curvature of the transparent substrate 11, peeling in these interfaces, etc.) resulting from the mismatch of the crystal lattice of the transparent conductive film 12 and the indium oxide layer 13 can be prevented. Thereby, even if the transparent substrate 11 has a large area, problems such as warping of the transparent substrate 11 do not occur, which is preferable. In addition, when the indium layer 16 is oxidized during heating, a part of indium is bonded to the metal oxide in the metal oxide layer 17, so that the bonding strength between the layers is improved and the efficiency of electron transfer between the layers is improved. Improvements can be made.

Next, as shown in FIG. 5E, the dye 15 is adsorbed on the porous metal oxide layer 14 by bringing the dye solution into contact with the porous metal oxide layer 14. The adsorption of the dye 15 may be performed in the manufacturing apparatus 100, for example, or may be performed after the dye 15 is unloaded from the manufacturing apparatus 100. The dye solution is prepared using an alcohol-based organic solvent such as ethanol or butanol as a solvent, and the dye concentration is, for example, 3 × 10 ^{−4 to} 5 × 10 ⁻⁴ mol / l. Then, after adsorbing the dye 15 to the porous metal oxide layer 14, the solvent is removed to form the electrode substrate 3.

  As described above, in the method for manufacturing the electrode substrate 3 for a solar cell according to the present embodiment, the indium layer 16 is formed on the indium tin oxide layer functioning as the transparent conductive film 12, and the metal oxide layer 17 is formed on the indium layer 16. Form. Thereby, when the intermediate body 20 is heat-treated, the indium layer 16 is oxidized by oxygen in the metal oxide layer 17 and in the atmosphere, while the indium tin oxide layer is prevented from being oxidized. Thus, by suppressing the oxidation of the indium tin oxide layer, an increase in the resistance value of the indium tin oxide layer can be suppressed, and the power generation efficiency can be improved.

  In addition, since the indium tin oxide layer contains indium oxide as a main component, the crystal lattice of the oxidized indium layer 16 is almost the same as the crystal lattice of the indium tin oxide layer. Thereby, it is possible to prevent the transparent substrate 11 from warping due to the crystal lattice mismatch between the indium tin oxide layer and the oxidized indium layer 16. Therefore, according to the method for manufacturing the electrode substrate 3 as described above, it is possible to improve the power generation efficiency and to prevent the electrode substrate 3 from warping.

  In the present embodiment, as described above, the thickness of the indium layer 16 is made thinner than the thickness of the transparent conductive film 12. By reducing the thickness of the indium layer 16, the translucency of the indium layer 16 can be improved. In addition, by using a glass substrate with high heat resistance as the transparent substrate 11, heat treatment can be performed at 400 ° C. or higher. Therefore, the temperature at which the metal oxide layer 17 is heated can be increased, the bondability between the metal oxides can be improved, and the power generation efficiency can be further improved. Moreover, since the sheet resistance of the indium tin oxide layer which is the transparent conductive film 12 is 10 Ω / □ or less, the electrode substrate 3 is suitable for a solar cell.

  In addition, the electrode substrate 3 according to the present embodiment and the manufacturing apparatus 100 can achieve the same effect as the above-described effect of improving the power generation efficiency and preventing warpage of the electrode substrate 3.

  The present invention is not limited to the embodiment described above. For example, an auxiliary electrode may be formed on the transparent conductive film 12. Even in this case, since the sheet resistance of the transparent conductive film 12 is low, the area occupied by the auxiliary electrode on the surface of the transparent substrate 11 can be reduced and the area of the electrode substrate 3 can be increased. It becomes possible to increase the aperture ratio of the battery.

  Moreover, although the said embodiment demonstrated the case where the interface of the transparent conductive film 12 and the indium oxide layer 13 was clear, the indium oxide of the indium oxide layer 13 mixed with ITO of the transparent conductive film 12 by heat processing. In some cases, a clear interface may not be formed between the transparent conductive film 12 and the indium oxide layer 13 (hereinafter, a film in which the transparent conductive film 12 and the indium oxide layer 13 are integrated is referred to as a mixed film). In this case, the substrate can be prevented from warping due to the interface between the transparent conductive film 12 and the indium oxide layer 13.

  Even when the mixed film is formed, the transparent conductive film 12 and the indium oxide layer 13 can be discriminated by measuring an indium concentration gradient in the mixed film, for example. Specifically, since the region that was the indium oxide layer 13 before formation in the mixed film does not contain tin, the concentration of indium is higher than the region that was the transparent conductive film 12. Therefore, the indium concentration gradient in the mixed film is measured, and the region where the indium concentration greatly changes can be regarded as the interface between the transparent conductive film 12 and the indium oxide layer 13. The indium concentration gradient in the mixed film can be measured by, for example, SIMS (secondary ion mass spectrometry), XPS (X-ray photoelectron spectroscopy), or the like. Incidentally, a concentration gradient of tin may be measured instead of indium.

  DESCRIPTION OF SYMBOLS 1 ... Dye-sensitized solar cell, 2 ... Positive electrode, 3 ... Electrode substrate (electrode substrate) for solar cells, 4 ... Electrolyte, 5 ... External circuit, 11 ... Transparent substrate, 12 ... Transparent electrically conductive film (indium tin oxide layer) ), 13 ... Indium oxide layer, 14 ... Porous metal oxide layer, 15 ... Dye, 16 ... Indium layer, 17 ... Metal oxide layer, 20 ... Intermediate, 100 ... Manufacturing apparatus (manufacturing apparatus) for electrode substrate, 200: first film forming apparatus (first film forming unit), 300: second film forming apparatus (second film forming unit), 400: third film forming apparatus (third film forming unit), 500: heating device ( Heating part), L ... light.

Claims (10)

A first step of forming an indium tin oxide layer on a transparent substrate;
A second step of forming an indium layer on the indium tin oxide layer;
Forming a metal oxide layer on the indium layer and forming an intermediate having the transparent substrate, the indium tin oxide layer, the indium layer, and the metal oxide layer;
And a fourth step of forming the metal oxide layer as a porous metal oxide layer by subjecting the intermediate to a heat treatment, and a method for producing an electrode substrate for a solar cell.   The method for producing an electrode substrate for a solar cell according to claim 1, wherein the thickness of the indium layer is thinner than the thickness of the indium tin oxide layer.   The said transparent substrate is a glass substrate, The manufacturing method of the electrode substrate for solar cells of Claim 1 or 2 characterized by the above-mentioned.   The said heat processing are performed at 400 degreeC or more, The manufacturing method of the electrode substrate for solar cells as described in any one of Claims 1-3 characterized by the above-mentioned.   The sheet resistance of the said indium tin oxide layer after the said 4th process is 10 ohms / square or less, The manufacturing method of the electrode substrate for solar cells as described in any one of Claims 1-4 characterized by the above-mentioned. A first film forming unit that forms an indium tin oxide layer on a transparent substrate;
A second film forming unit for forming an indium layer on the indium tin oxide layer;
Forming a metal oxide layer on the indium layer, and forming a transparent substrate, the indium tin oxide layer, the indium layer, and an intermediate having the metal oxide layer;
An apparatus for manufacturing an electrode substrate for a solar cell, comprising: a heating unit that heat-treats the intermediate. A transparent substrate;
An indium tin oxide layer provided on the transparent substrate;
An indium oxide layer provided on the indium tin oxide layer;
An electrode substrate for a solar cell, comprising: a porous metal oxide layer provided on the indium oxide layer.   The thickness of the said indium oxide layer is thinner than the thickness of the said indium tin oxide layer, The electrode substrate for solar cells of Claim 7 characterized by the above-mentioned.   The electrode substrate for a solar cell according to claim 7 or 8, wherein the transparent substrate is a glass substrate.   The electrode substrate for a solar cell according to any one of claims 7 to 9, wherein a sheet resistance of the indium tin oxide layer is 10 Ω / □ or less.

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