JPWO2015141541A1 - Photoelectric conversion positive electrode, positive electrode forming slurry, and production method thereof - Google Patents

Abstract

It is an object of the present invention to provide a positive electrode that is simple and suppresses cost and excellent in performance such as conversion efficiency and durability in a photoelectric conversion element. The present invention relates to a positive electrode for a photoelectric conversion element having a carbon material-based catalyst electrode layer containing a layered oxide (layered clay mineral).

Description

  The present invention relates to a positive electrode for a photoelectric conversion element, such as a counter electrode for a dye-sensitized solar cell or a positive electrode for a perovskite solar cell, containing carbon black, and a slurry for forming such a positive electrode.

  The expansion of the introduction of renewable energy, represented by solar power generation, is being promoted worldwide in order to cope with global warming and fossil resource depletion problems. Solar cells required for solar power generation are photoelectric conversion devices that convert solar energy into electrical energy, and it is not necessary to use finite fossil resources during power generation, and the generation of carbon dioxide is suppressed, which has an impact on the global environment. Very small. Various principles and constituent materials of solar cells have been devised, but currently, solar cells using silicon semiconductor materials (silicon type solar cells) are most popular. However, the production of silicon-type solar cells requires high-purity semiconductor materials, requires a large number of manufacturing processes, requires a large-scale device, consumes a lot of energy in the manufacturing process, and increases the manufacturing cost. There is a problem of being big.

  On the other hand, dye-sensitized solar cells (see [Non-Patent Document 1] and [Patent 1]), which have been studied as next-generation solar cells, have been used inexpensively since the proposal by Gretzell et al. From the advantages of being able to be manufactured by a simple process, it is expected to be put into practical use as a solar cell with a low environmental load during power generation and manufacturing.

B.O "Regan and M.Graetzel, Nature, 353, p.737-740 (1991) TN Murakami, S. Ito, Q. Wang, MK Nazeeruddin, T. Bessho, I. Cesar, P. Liska, RH Bak7, P. Comte, P. Pechy, M. Graetzel, J Electrochem. Soc., 153 (12 ), (2006) A2255. Ramasamy, W. J. Lee, D. Y. Lee, J. S. Song., APPLI. PHYS. LET., 90 (2007) 173103. Abstracts of the 80th Annual Meeting of the Electrochemical Society 3B19 J. Burschka, M. Gra ̈ tzel and et.al., J. Am. Chem. Soc., 133, 18042 (2011) M. Lee, J. Teuscher, T. Miyasaka, T. Murakami, H. Snaith, Science, 338, 643 (2012) N. Jeon, S. Seok and et.al., Nature, 517, 466 (2015) A. Mei, M. Gr ä tzel, H. Han and et.al. Science 345, 295 (2014)

Japanese Patent No. 2664194 JP 2012-59599 A JP 2005-116302 A JP 2010-251310 A JP 2012-169095 JP 2013-140701 JP 2012-59599 A

  For example, as shown in [Patent Document 1] and [Patent Document 2], a conventional general dye-sensitized solar cell mainly includes a transparent substrate such as glass, a transparent conductive layer (negative electrode current collector). And a porous semiconductor electrode layer (negative electrode) holding a photosensitizing dye, an electrolyte layer, a counter electrode (positive electrode), a counter substrate, a sealing material, and the like.

  The transparent conductive layer provided on the transparent substrate is made of ITO (Indium Tin Oxide) or FTO (fluorine-doped tin oxide) and functions as a negative electrode current collector. The semiconductor electrode layer as the negative electrode is often a porous layer in which fine particles of a metal oxide semiconductor such as titanium oxide are sintered, and is provided in contact with the transparent conductive layer. The photosensitizing dye is adsorbed on the surface of the metal oxide constituting the porous semiconductor electrode layer in contact with the transparent conductive layer. As the electrolyte layer, an electrolytic solution containing a redox species (redox pair) is used. The counter electrode is composed of a platinum layer or the like and is provided on the counter substrate.

  The dye-sensitized solar cell is configured such that light enters from the transparent substrate (negative electrode current collector) side. A part of the incident light is absorbed by the photosensitizing dye, and a part of the electrons excited by this light absorption is taken out to the semiconductor electrode layer. On the other hand, the photosensitizing dye that has lost electrons is reduced by the reducing species (reducing agent) in the electrolyte layer. Oxidized species (oxidant) generated in the electrolyte layer by this reaction receives electrons from the counter electrode and returns to the reduced species. As a result, the dye-sensitized solar cell operates as a photovoltaic cell having the transparent conductive layer and the semiconductor electrode layer as the negative electrode and the counter electrode as the positive electrode.

  The dye-sensitized solar cell does not require a large-scale apparatus such as a vacuum processing step for manufacturing, and has an advantage that it can be manufactured with high productivity by using an inexpensive oxide semiconductor such as titanium oxide by a coating process. . In addition, there are various photosensitizing dyes that can absorb light in each wavelength region in a wide wavelength region centered on the visible light region, so the wavelength of light to be absorbed can be selected by changing the type of dye used, or multiple By combining these dyes, there is an advantage that high conversion efficiency can be achieved with a low amount of light using light in a wide wavelength region. In addition, by using a lightweight and flexible base material such as plastic, there is a possibility that it can be manufactured with high productivity and low cost by a roll-to-roll process. For this reason, it has attracted much attention in recent years as a new generation solar cell.

  Conventionally, platinum is mainly used as a counter electrode (positive electrode) of a dye-sensitized solar cell because it has excellent catalytic action and corrosion resistance. The formation of the platinum layer includes a sputtering method and a wet method in which platinum is released by thermally decomposing chloroplatinic acid after applying a chloroplatinic acid solution. The platinum layer is excellent in catalytic activity, corrosion resistance, and conductivity, but there are also problems such as platinum is scarce in resources and expensive, and high vacuum process or high temperature process is required for production. . Therefore, a configuration using carbon black as the electrode material of the counter electrode has been reported.

  Since the active point of carbon black is located at the crystal edge and has more crystal edges than carbon nanotubes and graphite, the ability to donate electrons to the oxidized species generated in the electrolyte (reduction ability) ) Is considered to be as good as platinum. Murakami et al.'S study refined a carbon paste using an aqueous solvent and used it as a counter electrode, which is close to the Pt counter electrode. It is said that the performance was realized [Non-Patent Document 2], and Ewawamoothi Ramasamy et al. Refined the carbon paste using the viscose method, and it was also said that the performance close to the Pt counter electrode was achieved ( 3]).

In [Patent Document 2], a carbon-containing conductive layer having a resistivity of 0.001 to 0.1 Ω · cm is provided on one surface of the counter electrode substrate, and the specific surface area is 500 to 3000 m ² / g on the surface. A dye-sensitized solar cell having a counter electrode provided with a carbon-containing catalyst layer is proposed.
[Patent Document 3] includes, as carbon materials, acicular carbon, ketjen black, acetylene black, fullerene, carbon nanotubes (including carbon nanohorns), etc., which are further improved by polymerization or introduction of functional groups. The possibility of manifesting an effect is suggested, and the specific surface area is desirably large in order to improve the charge transfer rate on the counter electrode, generally at least 100 m ² / g or more, preferably 300 m ² / g. The surface area of the counter electrode produced using this carbon is 100 times or more the projected area, and the particle size of the carbon is generally 100 nm or less. However, the particle size is larger for the purpose of improving the formability of the counter electrode. It is possible to mix large carbon, but considering the case where the thickness of the counter electrode is 20 to 30 μm at maximum, 1 to several at maximum Is about m, it is described that.

  In [Patent Document 4], a technique for producing a screen paste that is particularly commonly used by dispersing carbon black particles in an organic solvent, more specifically, carbon powder and a metal semiconductor are used. Screen printing of a dye-sensitized solar cell counter electrode, characterized in that a carbon paste is obtained by adding a solvent and a low boiling point solvent to obtain a dispersion, and distilling the dispersion to remove the low boiling point solvent Carbon paste preparation methods have been proposed.

More recently, a “perovskite solar cell” ([Non-patent document 6]) developed from a solid-state dye-sensitized solar cell ([Non-patent document 5]) has attracted attention because of its high conversion efficiency ([[ Non-patent document 7]).
For example, a general perovskite solar cell as shown in [Non-patent document 6] or [Non-patent document 7] is mainly composed of a transparent substrate such as glass, a transparent conductive layer (negative electrode current collector), and photosensitization. Porous semiconductor electrode layer (negative electrode) holding a perovskite compound crystal, hole transport material (spiro-MeoTAD (2,2 ', 7,7'-tetrakis (N, Np-dimethoxy-phenylamino) -9,9'-spirobi-fl uorene)) and a gold electrode (positive electrode) are constructed according to the procedure shown in FIG. 1 to produce a perovskite solar cell.

In this perovskite solar cell, the use of a carbon electrode has been proposed. For example, in [Non-Patent Document 8], in a cell manufactured by the procedure shown in FIG. 2, a hole transport material (spiro-MeoTAD) Is replaced with a carbon material (graphite), and a gold electrode (positive electrode) is not used. It has been reported that cell durability can be improved by replacing the organic component spiro-MeoTAD with a carbon material.
According to [Non-Patent Document 8], this type of perovskite solar cell requires a graphite electrode film having a film thickness of 10 μm or more as a carbon electrode, and screen printing is proposed as a coating method. .
In the figure, 1 is a glass substrate, 2 is an FTO transparent conductive film, 3 is a TiO ₂ buffer layer, 4 is a TiO ₂ porous film, 5 is a perovskite compound, 6 is a hole transport material, 7 is a gold electrode, 8 Indicates an insulating layer, and 9 indicates a carbon electrode film.

As described above, in the counter electrode (positive electrode) of the dye-sensitized solar cell, carbon black has been studied as a material to replace platinum, and in order to increase the charge transfer rate of the carbon black electrode as in [Patent Document 3]. It has been proposed to increase the specific surface area of carbon black particles (decrease the particle diameter).
In addition, carbon black is oxidized at a high temperature (400 ° C or higher) during coating to reduce conductivity, and in extreme cases, it may be burned out. It is conceivable to select so-called “conductive carbon” having high properties. In fact, [Patent Document 3] uses conductive carbon.

  However, the performance required for the positive electrode of the dye-sensitized solar cell is not only conductive but also “reduction of redox species”, and as described in [Patent Document 4], conductive carbon has low reducing ability. Therefore, when conductive carbon is used, it is necessary to increase the number of particles, that is, to increase the carbon electrode film thickness. As the electrode film thickness increases, there is a high possibility that the adhesion to the counter electrode substrate will be impaired, and a concomitant use of a polymer is conceivable as a solution ([Patent Document 3]). However, the inclusion of a polymer, which is usually an insulator, causes a detrimental effect that the conductivity is impaired this time. For this reason, for example, as in [Patent Document 3], a structure in which an adhesion layer is formed in advance has been proposed. However, the structure and the manufacturing process are complicated, and the dye sensitization is characterized by low cost and low environmental load. In a solar cell, a counter electrode composition that is more complicated and costly is not preferable.

  In addition, in the case of perovskite solar cells using carbon electrodes, as in the case of dye-sensitized solar cells, process cost issues, adhesion between the carbon electrode film and the substrate to improve cell durability, and robustness Is considered an important requirement.

  An object of the present invention is to provide a positive electrode for a solar cell that has a simple process, a low manufacturing cost, and excellent performances such as conversion efficiency and durability. The positive electrode refers to a site where an oxidation reaction is performed, and is generally called a counter electrode in the case of a dye-sensitized solar cell, but is included in the concept of the positive electrode. It includes both what are called “counter electrodes” and others. What is called a counter electrode or a cathode also corresponds to the “positive electrode” in the present invention. In the case of the perovskite type, 9 in FIG. The carbon electrode film shown by corresponds also to a positive electrode.

Means to be Solved by the Invention

The inventor of the present invention has a composition and a positive electrode that can obtain a carbon black porous electrode having a low charge transfer resistance even when a general carbon black having a small structure and a large specific surface area is used as a conductive carbon. Inventing the molding process, studying the types and blending amounts of materials to further improve the adhesion to the positive electrode substrate without impairing their performance, and improving these performances by including specific materials The present invention has been found. That is, the present invention
(1) A positive electrode for a photoelectric conversion element having a carbon material-based catalyst electrode layer containing a layered oxide,
(2) The positive electrode for a photoelectric conversion element according to the above (1), wherein the weight ratio of the content of the layered oxide and the carbon material is 30: 0.05 to 3:16,

(3) The positive electrode for a photoelectric conversion element according to the above (1) or (2), wherein the film thickness is 10 μm or less and the organic polymer component content is 20% or less,
(4) A slurry for forming a positive electrode for a photoelectric conversion element, comprising a layered oxide,
(5) Layered oxide as at least component (a), carbon black as component (b), conductive material other than carbon black as component (c), components other than components (b) and (c) as component (d) A slurry for forming a positive electrode for a photoelectric conversion element comprising an inorganic fine particle material and a solvent as the component (e),
(6) The slurry for forming a positive electrode for a photoelectric conversion element according to the above (4) or (5), comprising 0.05 to 16% by weight of a layered oxide,
(7) (a) Component content is 0.05 to 16% by weight, (b) Component content is 2 to 50% by weight, (c) Component content is 0.025 to 14% by weight, (d) The positive electrode forming slurry for a photoelectric conversion element according to the above (5), wherein the content is 0.5 to 40% by weight,
(8) A method for producing a positive electrode for a photoelectric conversion element, wherein the slurry according to any one of (4) to (7) above is applied onto a substrate, solidified and / or dried.
Exist.

Effect of the invention

  The positive electrode for solar cells including the counter electrode for dye-sensitized solar cells and the positive electrode for perovskite solar cells of the present invention has high performance such as conversion efficiency and durability, low cost, and good solar by a simple manufacturing process. Battery characteristics can be realized.

FIG. 1 is an explanatory view showing a method for producing a perovskite solar cell. FIG. 2 is an explanatory view showing a method for producing a perovskite solar cell. FIG. 3 is an explanatory diagram showing an example of the structure of the battery of the present invention. FIG. 4 is a schematic diagram showing an outline of the steps of the example. FIG. 5 is an explanatory diagram showing a TG-DTA chart of the counter electrode of Examples 5-1 to 5-7. FIG. 6 is an explanatory diagram plotting the calculation results of the organic polymer residual ratio of the counter electrode of Examples 5-1 to 5-7. FIG. 7 is a structural diagram showing a cross-sectional observation photograph of Example 2-1. FIG. 8 is a structural diagram showing a cross-sectional observation photograph of Comparative Example 2-1. FIG. 9 is a structural diagram showing a cross-sectional observation photograph of Example 6. FIG. 10 is a structural diagram showing a cross-sectional observation photograph of Example 7.

  The present invention relates to a positive electrode for a solar cell that forms a positive electrode provided with a layer containing carbon black on a substrate, and has excellent performance by forming a positive electrode using a slurry containing a specific component. The solar cell can be obtained.

[Slurry components]
The slurry of the present invention usually contains carbon black, a conductive material, and inorganic fine particles as solid components, and a solvent is used as a dispersion medium. In the present invention, a layered oxide is further contained. Each component will be described below.

〔Carbon black〕
The carbon black that can be used in the present invention is not particularly limited.
Although the specific surface area of carbon black is not limited, it is preferably 50 m ² / g or more and 1000 m ² / g or less, more preferably 80 m ² / g or more and 800 m ² / g or less. 15 m ² / g 0 or more and 600 m ² / g or less is most preferable. The specific surface area is a value measured according to JIS K 6217. It can be calculated and calculated from the amount of nitrogen adsorbed on the carbon surface.
The primary particle size of carbon black is preferably 3 nm or more and 100 nm or less, more preferably 5 nm or more and 70 nm or less, and most preferably 8 nm or more and 60 nm or less. The measurement of the particle diameter is an arithmetic average diameter obtained by observing the carbon black particles with an electron microscope. Specific examples of carbon black include furnace black, lamp black, channel black, acetylene black, thermal black, and ketjen black.

[Conductive material]
The conductive material may be basically any material as long as it has conductivity and can be dispersed in a liquid medium to form a slurry, and has been conventionally used in a positive electrode containing carbon black. Various types can be used. Carbon black itself also has conductivity, but it is usually preferable to include a conductive material other than carbon black in order to improve conductivity and ensure sufficient conversion efficiency of the battery. is there. Examples of powders and granular carbon materials other than carbon black include, but are not limited to, graphite, graphene, graphite, activated carbon, fullerene, single-walled or multi-walled carbon nanotubes, and the like. Various materials conventionally known for use in the positive electrode can be used as appropriate, and one or more of these materials can be used in combination.

〔solvent〕
The solvent to be used is not particularly limited. Alcohol solvents such as ethanol, isopropyl alcohol, benzyl alcohol, and terpineol Glycerin, glycol solvents such as ethylene glycol and propylene glycol, halogen solvents such as chloroform and chlorobenzene, acetonitrile, propionitrile Nitrile solvents such as acetone, methyl ethyl ketone, ketone solvents such as cyclohexanone, ester solvents such as ethyl acetate and butyl acetate, hydrocarbons such as hexane, mineral spirits, toluene, xylene, dimethylformamide, n-methylpyrrolidone, etc. Examples include amines, but are not limited thereto. Two or more solvents may be mixed and used. It may be selected from the viewpoints such as being suitable for dispersing components such as fine particles, being able to be easily removed by evaporation during baking of the coating film, and being able to form a slurry having excellent coating properties on the substrate, and also to the coating method. You may choose according to it. From these viewpoints, terpineol, n-methylpyrrolidone, and butyl carbitol acetate are particularly preferably used when applied to a glass substrate by a printing method.

[Inorganic fine particles]
In general, inorganic fine particles are included in order to have film forming properties so that the film can be maintained as an integral film after being applied to the substrate and baked. By containing inorganic fine particles, the contact (necking) between the carbon black particles is increased and the fastness of the film itself is improved.
Examples of the inorganic fine particles include metal oxides and metal semiconductors. Preferable examples of the metal oxide include titanium oxide, tin oxide, niobium oxide, zinc oxide, and tungsten oxide. It is not limited to a metal oxide, and nitrides such as titanium nitride and niobium nitride are also included.

  The particle size and shape of the inorganic fine particles are not particularly limited, but from the viewpoint of easy mixing with other components such as carbon black, the particle size is usually 200 nm or less, particularly preferably 100 nm or less.

[Organic binder resin]
The slurry of the present invention may contain an organic binder resin. The organic binder resin refers to a polymer binder, that is, an organic polymer compound that has a film forming property.
For example, ethylcellulose is contained in the slurry described in [Patent Document 3] and JP-A-2004-152747. By containing such a component, it is considered that the thixotropy of the slurry is provided and the adhesion of the film is maintained. However, when such a component is contained in the slurry or the positive electrode formed using the slurry, there are not enough pores in the counter electrode layer, and as a result, the catalyst layer that is the positive electrode and the electrolytic solution are not present. Therefore, there is a possibility that electrons are not sufficiently exchanged and the electrical conductivity of the electrode itself is also lowered. Therefore, from the viewpoint of the electric characteristics of the battery, it is desirable to reduce such components as much as possible in the coating film. As will be described later, in the present invention, by blending specific components, it is possible to greatly improve the adhesion of the film without adversely affecting the electrical characteristics, it is possible to keep the binder resin low, for example, Even if it is 5% by weight or less in the coating film or not contained at all, sufficient electrical characteristics can be obtained, and an excellent positive electrode for a photoelectric conversion element can be formed.

  In order to reduce the organic binder in the coating film in this way, it can also be achieved by reducing the content in the slurry, but from the viewpoint of maintaining the thixotropic property of the slurry, that is, the ease of handling of the slurry. Is also a suitable option to reduce by burning out in the firing process.

  As the organic binder resin, resin cellulose such as ethyl cellulose, carboxymethyl cellulose, methyl cellulose, and hydroxyethyl cellulose is preferable, but the material constituting the polymer binder is not limited to this, and various thermoplastic resins, thermosetting Resin and mixtures thereof can also be used. Examples of the thermoplastic resin include polyalkylene glycol such as polyethylene glycol, polyethylene, polypropylene, polystyrene, polyvinylidene fluoride, methacrylic resin, polyetherimide, polyetheretherketone, polytetrafluoroethylene, and the like. Examples of the thermosetting resin include phenol resin, urea resin, melamine resin, urethane resin, and silicone resin. Moreover, a mixture thereof or the like may be used, or an amorphous or crystalline resin may be used.

  Such an organic binder is preferably used in the form of a solution for uniform mixing with other components. An organic binder resin powder and a high boiling point solvent or a low boiling point solvent are mixed, stirred and dissolved to obtain an organic binder resin solution. The solvent is not particularly limited as long as it can dissolve the resin to be used, and can be appropriately selected from the solvents described above, but by using the same solvent as that used when dispersing a solid component such as carbon black as described later, Shocks when mixed with these other ingredients can be avoided.

(Layered oxide)
The present invention is characterized in that a slurry or a positive electrode formed using the slurry contains a layered oxide. The present inventors have found that the addition of a layered oxide unexpectedly increases the adhesion of the film and significantly increases the fastness of the film, and have reached the present invention.

For example, Patent Document 5 and Non-Patent Document 4 propose proposals that a layered oxide is added to an electrolyte of a dye-sensitized solar cell, which is inexpensive, has a low environmental load, and improves the photoelectric conversion efficiency. In addition, it has been made conventionally.
However, what has been proposed in these conventional techniques is limited to the knowledge that the photoelectric conversion efficiency is improved by adding to the electrolytic solution, and suggests the effect of the positive electrode as found by the present inventors. There is nothing.

A layered oxide, also called a layered clay mineral, is an aggregate of minerals having a layered crystal structure, and its composition is mainly composed of oxides made of Al-O, Mg-O, Si-O, etc. . Originally natural viscosity minerals, there are also chemically synthesized products.
Examples of layered oxides include montmorillonite, which is the main component of the mineral bentonite, mica, beidellite, saponite, hectorite, stevensite, magadiite, islamite, kanemite, illite, sericite, etc. Is mentioned. Natural products, synthetic products, and mixtures thereof can also be used. Conventionally, layered oxides have been widely used such as adsorbents, catalysts, fillers, electrode materials, rheology control agents, etc., but can be selected from those used for these applications. Examples of commercially available products include “Lucentite” (trade name), which is a synthetic smectite manufactured by Corp Chemical Co., Ltd., and “Clast-SN20” (registered trademark), which is a lithium-type bentonite developed by Kunimine Kogyo Co., Ltd. These can be selected. In particular, “Lucentite” can exhibit excellent performance when used in the present invention.

[Method for preparing slurry]
Each of the above components can be dispersed or dissolved in a slurry to obtain the slurry of the present invention. Furthermore, such a slurry of the present invention can be applied on a substrate by a known method and solidified to obtain a positive electrode.

  As a method for preparing the slurry, a conventionally known method can be appropriately selected. Preferably, each solid component is dispersed in a solvent in advance, and each obtained dispersion is mixed with a solution of another component. Thus, the particles of the electrode film become uniform and the film thickness dependence of the counter electrode is advantageously reduced. That is, each dispersion of carbon black dispersion, conductive agent dispersion, and inorganic fine particle dispersion is prepared in advance and mixed with a layered oxide solution and an organic binder resin solution to obtain a slurry. However, it is not limited to this method, and carbon black and other fine particles can be simultaneously dispersed or dissolved.

  When dispersing the fine particle component, various dispersants can be used. For example, various known polymer dispersants such as acrylic copolymers, butyral resins, vinyl acetate copolymers, hydroxyl group-containing carboxylic esters, salts of high molecular weight polycarboxylic acids, alkyl polyamines, polyhydric alcohol esters, etc. Although a dispersing agent can be mentioned, it is not restricted to this.

[Preparation of carbon black dispersion]
It is desirable to disperse carbon black by adding a high boiling point solvent and a low boiling point solvent. Carbon black and a dispersant are added to these solvents and dispersed. A high boiling point solvent means a solvent that does not evaporate at room temperature and does not dry unless it is heated to high temperature or reduced pressure, and a low boiling point solvent refers to other solvents. It is desirable to use these solvents in combination. Solvents are necessary for the formation and maintenance of the slurry. However, if the solvent is not a high boiling point solvent, the state of the slurry changes due to volatilization before and after screen printing, and uniform printing is possible. difficult. On the other hand, it is difficult to disperse carbon black sufficiently uniformly only with a high boiling point solvent. Therefore, for example, as described in [Patent Document 3] described above, carbon black is once dispersed using a combination of a low-boiling solvent and a high-boiling solvent, and after mixing with other components, the low-boiling solvent is distilled off. Thus, a method of obtaining a slurry is suitable.

  Examples of the high boiling point solvent include alcohol solvents such as benzyl alcohol and terpineol, glycol solvents such as glycerin, ethylene glycol and propylene glycol, and amines such as n-methylpyrrolidone, but are not limited thereto. One kind or a mixture of two or more kinds of solvents may be used. Examples of the low boiling point solvent include alcohol solvents such as ethyl alcohol and isopropyl alcohol, hydrocarbon solvents such as benzene, normal hexane, and cyclohexane, but are not limited thereto, and one or two or more of these solvents may be used. You may mix and use a solvent. The above solvent is desirably selected from the solvents that can be suitably used in the slurry described above, and terpineol, n-methylpyrrolidone, butyl carbitol acetate as the high boiling point solvent, and ethanol and isopropyl alcohol as the low boiling point solvent are particularly preferable.

Examples of the dispersion method include a media medium type dispersion machine and a collision type dispersion machine.
What is a media-media type disperser? A disperser with a structure that moves small-sized media such as glass, alumina, zirconia, steel, tungsten, etc. at high speed in a vessel and grinds the slurry passing between them with the shearing force between the media. Say. Specific examples of such a media medium type dispersing machine include a paint shaker, a ball mill, a sand mill, a pearl mill, an agitator mill, a coball mill, an ultra visco mill, an ultra visco mill, an ultra fine mill, and the like. The collision type disperser refers to a disperser having a structure in which a fluid collides with one wall surface at a high speed or a fluid collides with each other at a high speed to crush pigments and the like in the fluid. Specific examples of such a collision type disperser include a star berth, nanomizer, homogenizer, and microfluidizer.

[Preparation of dispersion of conductive material and dispersion of inorganic fine particles]
The method for dispersing the conductive material and the inorganic fine particles is not limited, and can be selected from various solvents that can be suitably used in the slurry described above. In particular, it is desirable to use the same solvent as the carbon black dispersion in order to prevent aggregation and sedimentation due to solvent shock when blended with the carbon black dispersion.

[Preparation of layered oxide solution]
Since the layered oxide is usually present as a solid powder at room temperature, it is desirable to dissolve or disperse in a solvent in advance and mix with other components in order to obtain a uniform slurry. It is not particularly limited as long as it is a liquid in which the layered oxide dissolves, but it may be selected from the solvents that can be used in the slurry described above. However, like other solid components, the solvent shock during mixing with the carbon black dispersion liquid In order to avoid this, it is desirable to select the same solvent as the carbon black dispersion.

  The carbon black dispersion, conductive material dispersion, inorganic fine particle dispersion, layered oxide solution, and organic binder resin solution obtained above are mixed to obtain a slurry. When dispersed using a low boiling point solvent, the low boiling point solvent may be removed from the mixed liquid by an evaporator or the like to obtain a slurry having properties suitable for screen printing.

The composition (weight%) of the slurry is such that the amount of carbon black is 2 to 50%, preferably 3 to 30%, more preferably 5 to 20%, and the amount of conductive material is 0.025 to 14%, preferably 0.05 to 10%, more preferably 0.1 to 6%, and the amount of inorganic fine particles is adjusted to 0.5 to 40%, preferably 1 to 30%, more preferably 2.5 to 20%.
The amount of the layered oxide is adjusted to be 0.05 to 16%, preferably 0.1 to 12%, more preferably 0.25 to 8%. The amount of the organic binder resin agent is 5 to 40%, preferably 7 to 30%, more preferably 10 to 25%. When the amount of the organic binder resin agent is 5% or less, thixotropy is not expressed in the slurry for screen printing. On the other hand, if it is 40% or more, it becomes too viscous, and the separation of the plate during screen printing becomes worse.
Further, the amount of the solvent in the slurry is adjusted to 5 to 90%, preferably 10 to 85%, more preferably 20 to 80%. The slurry of the present invention described above has good thixotropy and can be made into a slurry with good plate separation during screen printing.

[Production of positive electrode]
A porous carbon electrode can be obtained by applying the slurry prepared above to a conductive substrate and firing it in an electric furnace, and this can be used as a positive electrode for a photoelectric conversion element. As the conductive substrate in this case, various known substrate materials such as FTO-coated glass, ITO-coated glass, etc., a metal substrate, a substrate in which a metal film is formed on a transparent substrate, and the like can be used.

Examples of the slurry application method include dip coating, spray coating, wire bar coating, spin coating, roller coating, blade coating, gravure coating, offset printing, and screen printing, but are not particularly limited thereto. .
The positive electrode produced using the slurry of the present invention can be an electrode having an organic polymer content of 5% by weight or less. A uniform and smooth film can be obtained. Furthermore, as shown in the Example mentioned later, while containing an appropriate amount of organic binder resin in a slurry, especially electrical conductivity improves and a tough and robust film | membrane can be obtained. Probably, an appropriate amount of organic binder resin is contained in the slurry and applied and heated, so that the organic polymer dispersant present in the dispersion liquid such as the organic binder and carbon black is burned away in the film. It is presumed that an excellent effect that electrons can be effectively taken out can be obtained by using sufficient pores as a positive electrode for a photoelectric conversion element.

[Production of solar cells]
Using the positive electrode described above, a solar cell can be manufactured using a known technique. The configuration of the battery is not particularly limited, and for example, the configuration of the battery shown in [Patent Document 6] and [Patent Document 7] can also be adopted.

(1) Configuration of Photoelectric Conversion Element FIG. 1 shows an example of the structure of a photoelectric conversion element using the positive electrode of the present invention.
The photoelectric conversion element (solar cell) 10 includes a working electrode 11, a counter electrode 12, a sealing layer 13 that connects and seals these electrodes, and a sealed space 14 that is formed by the inner wall surface of these electrodes and the sealing layer, And an electrolyte layer 15 that fills the sealed space 14.
The working electrode 11 includes a plate-like light transmissive substrate 16 made of a light transmissive member such as glass or ceramics, and a transparent electrode member 17 made of ITO (indium tin oxide), FTO (fluorine-doped tin oxide), or the like. ing. A dye-sensitized semiconductor layer 18 is fixed to one side of the transparent electrode member 17, and the sealing layer 13 is fixed so that the dye-sensitized semiconductor layer 18 is disposed in the sealed space 14.

The dye-sensitized semiconductor layer 18 has a configuration in which a sensitizing dye such as an azo dye or a ruthenium bipyridine metal complex dye is adsorbed on an oxide semiconductor such as titanium oxide (TiO ₂ ) or zinc oxide (ZnO). Then, when light such as sunlight is absorbed by the sensitizing dye, the sensitizing dye becomes excited and emits electrons, which can be injected into the oxide semiconductor.

On the other hand, the counter electrode 12 includes a counter substrate 19 made of a hard member such as glass, metal, or ceramic, and a conductive catalyst electrode layer 20 formed in a film on one surface thereof. In the present invention, a layer containing a carbon material such as carbon black is formed as the catalyst electrode layer.
The sealing layer 13 is fixed to the catalyst electrode layer 20 and is disposed so as to face the dye-sensitized semiconductor layer 18 with the sealed space 14 interposed therebetween.
The counter substrates 17 and 19 and the catalyst electrode layer 20 have a through hole 21 at a predetermined position, and the electrolyte composition can be injected from the through hole 21. In producing the electrode, first, the working electrode 11 and the counter electrode 12 are fixed with a sealing material, and then the electrolyte composition is injected and filled from the through hole 21 into the space forming the sealed space 14, and then the through hole 21 is filled. The space can be sealed with the sealing material 22, and the electrolyte layer 15 made of the electrolyte composition can be formed in the sealed space 14.

  As described above, a photoelectric conversion element such as a dye-sensitized solar cell formed using the positive electrode of the present invention does not use a platinum catalyst, and further requires no separate material such as an adhesion layer. Can be manufactured.

If the slurry of this invention is used, the positive electrode obtained will be excellent in film | membrane physical properties, such as adhesiveness, and can express high conversion efficiency. Therefore, the coating film is relatively thin and can exhibit sufficient conversion efficiency. Specifically, those having a size of 10 μm or less and 7 μm or less can be obtained, and those having a photoelectric conversion efficiency exceeding 95% of Pt can be obtained.
Since a high photoelectric conversion efficiency can be obtained even with such a thin film, the amount of the electrolytic solution impregnated in the electrode can be reduced, and the economy is excellent, and the possibility of miniaturization is increased.
The positive electrode of the present invention can be easily obtained by applying the slurry of the present invention on a substrate, heating and curing. The positive electrode of the present invention thus obtained has a carbon material-based catalyst electrode layer containing a layered oxide. Here, the carbon material-based catalyst electrode layer refers to a catalyst electrode layer containing a carbon material such as carbon black as a main component. The content of the layered oxide is not limited as long as the desired performance can be exhibited, and may be selected according to the purpose. Usually, the carbon material: layered oxidation with respect to the carbon material such as carbon black. The weight ratio is 30: 0.05 to 3:16, more preferably 20: 0.1 to 1:12, and even more preferably 20: 8 to 5: 0.25. In this range, the conversion efficiency and the coating properties are particularly excellent. Furthermore, even if the organic polymer component in the coating film is reduced as described above, the coating property is not impaired, and high conversion efficiency can be secured by reducing the organic polymer component. That is, by setting the organic polymer component to 20% or less, particularly 15% or less, the positive electrode of the present invention can obtain a sufficient coating property, and the photoelectric conversion element obtained using this has high conversion efficiency. Can be achieved.
Moreover, if a positive electrode for a perovskite solar cell is formed using the slurry of the present invention, a tough and highly efficient positive electrode can be formed even with a thin film (1 μm or less), and a perovskite solar cell with excellent performance can be obtained. . In particular, high conversion efficiency can be obtained by adjusting the film thickness. Specifically, high efficiency exceeding 4.5% can be obtained at 300 nm or less.

  As shown in the outline of the steps of the following examples in FIG. 4, slurry preparation, creation and testing of a counter electrode, and creation and testing of a battery were performed. Each item will be described below.

[Preparation of slurry]
First, the materials shown in Table-1 were blended with the compositions shown in Table-2 (Table-2 (1) and Table-2 (2)), and each dispersion and solution were prepared by the following methods.
The carbon black dispersions 1 to 8 and the conductive material dispersions 1 to 3 were dispersed for 5 hours using a paint shaker (manufactured by Asada Iron Works) and 0.5 mm diameter alumina beads. The inorganic fine particle dispersion was stirred and dispersed for 7 hours using a 0.1 mm diameter alumina bead in a paint shaker.

The layered oxide was stirred and dissolved in ethanol so as to be 15% by weight to obtain a layered oxide solution. The organic binder was dissolved by stirring in ethanol so as to be 10% by weight in terms of solid content to obtain an organic binder solution.
Next, each of these dispersions and solutions were mixed at a blending ratio shown in Table 3, and the low boiling solvent was removed with an evaporator to obtain slurries 1 to 26.

[Preparation and evaluation of counter electrode]
As the counter substrate 19, an FTO transparent conductive glass substrate made of Asahi Glass (sheet resistance: 13Ω / □ (15mm × 25mm × t1.8mm) size processed and washed by UV irradiation) was used. The slurry described in Table 3 was applied to form a 5 mm square (25 mm ² ) using a 300 mesh plate by screen printing, and dried at 120 ° C. for 3 minutes. After firing in an electric furnace (FT-101FM manufactured by Fulltec) at 450 ° C. for 30 minutes, the mixture was allowed to cool and used as the counter electrode 12.
The counter electrodes were obtained by changing the firing temperature of the slurry 10 and 14 as shown in Table 4 (Examples 5-1 to 5-7 and Comparative Examples 5-1 to 5-7).
A substrate using platinum as the counter substrate was referred to as Comparative Example 5-8.

The obtained counter electrode was subjected to film thickness measurement, adhesion evaluation, and surface resistance measurement by the following methods.
The film thickness and adhesion were measured for the slurry 8 to 11 and 13 to 16 (Examples 2-1 to 2-3, Comparative Examples 2-1 to 2-3). The surface resistance was measured for the slurry 8 to 20 (Examples 2-1 to 2-4, 3-1 to 3-3, Comparative Examples 2-1 to 2-4, 3-1 to 3-3).
A cross-sectional observation photograph was taken for the counter electrode of Example 2-1 and Comparative Example 2-1.
<Film thickness measurement>
It was measured with a compact compact surface roughness profile measuring machine “Thermcom 130A” manufactured by Tokyo Co., Ltd.

<Adhesion>
Nichibansero tape (No.405, 18mm width) is stuck on the coating surface about 30mm, and rub the tape firmly with your finger so that the coating film can be seen through. Immediately after attaching the tape, hold the edge of the tape and keep it at right angles to the surface of the coating, and peel it off instantaneously. This operation was repeated 5 times at exactly the same site, and evaluated according to the following five levels according to the degree of peeling on the coating surface.
・ 5 points that do not peel off at all ・ 4 points of peel off 1-10% of the whole film ・ 3 points of peel off 11-50% of the whole film ・ 2 points of peel off 51-80% of the whole film ・ 2 points of whole film 81 ~ Full-scale peeler 1 point

<Measurement of surface resistance of electrode film>
Using a “Loresta GP MCP-T610 type” manufactured by Mitsubishi Chemical Analytech Co., Ltd., measurement was performed by a four-terminal four-probe method and a constant current application method.
<Remaining amount of organic polymer>
The counter electrode of Examples 5-1 to 5-8 was subjected to thermal analysis using “Differential Thermal / Thermogravimetric Measuring Device: TG-DTA2020SA” manufactured by Bruker AXS, and from the obtained TG-DTA, The residual ratio (%) of the organic polymer was calculated.

<Result>
The results are shown in Tables 5-10. Examples 1-1 to 1-7 and Comparative Example 1 in which the specific surface area of carbon black was changed and compared with the presence or absence of a layered viscosity mineral were compared with those in Table 5 and the presence or absence of a layered viscosity mineral. 2-3 and Comparative Examples 2-1 to 2-3 are shown in Table-6, Examples 3-1 to 3-3 and Comparative Example 3-1 in which the types of conductive materials were changed and compared are shown in Table-7. Examples 4-1 to 4-4 and Comparative Example 3-1 which were compared by changing the kind of fine particles are shown in Table 7, Examples 5-1 to 5-7 and Comparative Example 5 which were compared by changing the firing temperature. -1 is Table-8. For comparison, the value of conversion efficiency in the case of Pt was set as 100, and the ratio (%) of each efficiency was shown.

The TG-DTA chart of the counter electrode of Examples 5-1 to 5-7 is shown in FIG. 3, the calculation result of the residual ratio of the organic polymer is shown in Table 11, and the plotted result is shown in FIG.
The cross-sectional observation photographs of Example 2-1 and Comparative Example 2-1 are shown in FIGS.

  As can be seen from the results of Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3 shown in Table-6, there is a difference in adhesion depending on the presence or absence of the layered oxide. It can be seen that adhesion is good when added, and adhesion is poor when no layered oxide is added.

  As shown in FIG. 5, it was confirmed that the organic polymer component can be reduced to 2 wt% or less by forming a coating film using the slurry of the present invention and baking at a temperature of 400 ° C. or higher. It is estimated that the photoelectric conversion efficiency can be improved because the organic polymer component can be reduced.

In the image of FIG. 7, a three-dimensional network structure in which a bag-like thin film is wrapped with carbon black particles with a size of about 1 μm is seen with a layered oxide-added coating film. From this, it is considered that the carbon black dispersion 5 is adsorbed between the layers of the layered oxide, making the film dense and robust and improving the adhesion.
In the image of FIG. 8, only carbon black particles are seen, and dense three-dimensionality is not seen. From this, it is considered that the adhesion does not increase like the counter electrode of the present invention containing a layered oxide.

[Preparation of dye-sensitized solar cell working electrode]
A transparent conductive substrate (25 mm x 15 mm, 1.8 mm thick glass substrate 7 on a transparent substrate 7 having a 950 nm thick FTO layer (sheet resistance 10Ω / □) formed as a transparent conductive layer 8 A titanium oxide paste was applied on an FTO glass substrate (Asahi Glass Co., Ltd.) and baked.
The titanium oxide paste consists of one commercially available “HT / SP” (Solaronix) titanium oxide (final film thickness of about 2 μm) and “PST-18NR” (manufactured by JGC Catalysts & Chemicals) 5 porous titanium oxide. A layer (final film thickness of about 8μm), “PST-400C” (manufactured by JGC Catalysts & Chemicals Co., Ltd.), and three layers of porous titanium oxide (final film thickness of about 5μm) are sequentially applied onto the substrate by screen printing. Baked in an electric furnace (FT-101FM manufactured by Fulltech Co., Ltd.) for 30 minutes at ℃, allowed to cool (50 mM) immersed in TiCL4 aqueous solution (70 ℃ × 30 minutes), washed, dried, baked (500 ℃ × 30 minutes) And a titanium oxide film having a total thickness of 15 μm was obtained.

  Next, a sensitizing dye was supported on this titanium oxide film to form a dye-sensitized semiconductor layer 9. Specifically, a solution in which 0.3 mmol of N719 dye (ruthenium complex dye manufactured by ALDICH) was dissolved in a mixed solvent of tert-butyl alcohol and acetonitrile (volume ratio 1: 1) was prepared, and titanium oxide was added to this solution. The film was immersed at 30 ° C. for 20 hours to carry a sensitizing dye. Thereafter, the titanium oxide film was washed with acetonitrile and dried in the dark to obtain a working electrode 2 on which a dye-sensitized semiconductor layer 9 carrying a photosensitizing dye was formed.

[Production of photoelectric conversion element (dye-sensitized solar cell)]
A frame-shaped sealing layer 4 made of an ultraviolet curable resin having a width of 2.0 mm and a height of about 30 μm was formed on the transparent electrode member 8. Next, the working electrode 2 and the counter electrode 3 described above are made to face each other, and after pressure-bonding with the sealing layer interposed therebetween, the sealing layer is irradiated with ultraviolet rays and temporarily bonded. 3, a dye-sensitized solar cell having the configuration shown in FIG. A hot melt film was sandwiched between the working electrode and the counter electrode, melted by heating and pressing at 120 ° C. for 3 minutes, and after cooling, the sealing layer 4 was completely cured and fixed.
As the sealant, “HIMILAN” (trade name) manufactured by Mitsui DuPont Co., Ltd. was used as an ionomer resin.
The electrolytic solution was obtained by dissolving iodine: 0.025M, lithium iodide: 0.1M, t-butylpyridine: 0.5M, 1,2-dimethyl-3-propylimidazolium iodide: 0.6M in acetonitrile.

<Evaluation of dye-sensitized solar cell>
Pseudo sunlight (1 sun: AM1.5, 100 mW / cm ² ) was irradiated, and short circuit current density (Jsc), release voltage (Voc), fill factor (FF), and photoelectric conversion efficiency (η) were measured. (25 degreeC) A result is shown to said Table -5-9.

From Table 5, the photoelectric conversion efficiency of the dye-sensitized solar cells of Examples 1-1 to 1-4 using carbon black having a specific surface area of 200 to 560 m ² / g is particularly excellent and is equivalent to that of Comparative Example (Pt) or I was able to get a value close to that. It can be seen that the physical properties of the carbon used in the counter electrode 3, especially the specific surface area, has an effect on the conversion efficiency. For any carbon black with any specific surface area, the addition of layered oxides provides excellent fastness and adhesion. I understand that

  From the conversion efficiency values in Table 6, it can be seen that there is no difference in the conversion efficiency depending on the presence or absence of the layered oxide, and both values are close to the control (Pt). This indicates that the conversion efficiency does not adversely affect the addition of the layered oxide, and the adhesion values in Table-6 are improved by the addition of the layered oxide. It can be seen that a practical counter electrode can be obtained.

From Table-7, it is possible to suitably use a conductive material known to increase the conversion efficiency in the counter electrode of the present invention, and to obtain a value equivalent to or close to Pt by using these materials. I understand.
From the results of Example 3-1 and Comparative Example 3-1, it can be seen that even in a system using the same conductive material, the adhesion is improved by the addition of the layered oxide.
From Table 8, it can be seen that good values can be obtained with various inorganic binders, and values equivalent to or close to Pt can be obtained, which is a sufficiently practical level.
From the results of Example 4-1 and Comparative Example 4-1, it can be seen that even in the system using the same inorganic fine particles, the adhesion is improved by the addition of the layered oxide.

From Table 9, in Examples 5-5, 5-6, and 5-7, in which the firing temperature of the slurry is 375 ° C. or higher, the value of the photoelectric conversion efficiency that is equal to or close to that of Pt is shown. In Examples 5-1, 5-2, and 5-3 where the firing temperature is 350 ° C. or lower, the photoelectric conversion efficiency is lower than that of Pt.
In Example 5-1, in which the baking temperature is 250 ° C. and the organic polymer remaining rate is 50.4%, the adhesion of the coating film is low. In Examples 5-2 and 5-3 fired at higher temperatures, the adhesion of the coating film is improved. This is considered to be due to the organic binder being cured at a high temperature to form a film. However, the photoelectric conversion efficiency is relatively low. This is probably because the presence of the organic polymer decreases the conductivity. In the films of Examples 5-6 and 5-7 fired at a higher temperature, the residual rate of the organic polymer is 0%, high photoelectric conversion efficiency is obtained, and a value close to platinum can be obtained. It can be said that it is a practical level. At the same time, while the organic polymer remaining rate is 0%, the coating film has excellent adhesion, and the presence of the layered oxide according to the present invention makes it possible to obtain a very good photoelectric conversion element. It turns out that it is a useful technique that can be done.

[Preparation of perovskite solar cells]
A perovskite solar cell having the basic structure shown in FIG. 2 was produced by the following procedure.
A solar cell in which an FTO layer 2 (sheet resistance 10Ω / □) with a thickness of 950 nm is formed as a transparent conductive layer on a light-transmitting substrate made of a transparent conductive base glass substrate 1 (size 25 mm × 25 mm, thickness 1.8 mm) FTO glass substrate (manufactured by Asahi Glass Co., Ltd.)) is immersed in an aqueous titanium tetrachloride solution (100-1000 mM), allowed to stand at 70 ° C. for 40 minutes, washed with pure water, and fired (500 ° C. × 30 minutes) Thus, a titanium dioxide buffer layer 3 having a thickness of 10 to 50 nm was formed.
A titanium dioxide paste was spin-coated on the titanium dioxide buffer layer 3 and baked at 500 ° C. for 30 minutes to form a titanium dioxide porous electrode 4 (negative electrode) having a thickness of 100 to 1000 nm. The titanium dioxide paste is prepared by adding an appropriate amount of ethyl cellulose solution to a dispersion (solid content 30 wt%) of commercially available fine particle titanium dioxide (“P25”). In spin coating, a corresponding film thickness was obtained at an appropriate rotation speed (500 to 5000 rpm) depending on the paste concentration. The film thickness is shown in Table-11. The titanium dioxide porous electrode 4 was immersed in an aqueous solution of titanium tetrachloride (10-100 mM), allowed to stand at 70 ° C. for 40 minutes, washed with pure water, and fired (500 ° C. × 30 minutes).

Next, 100 μL of zirconium dioxide (ZrO ₂ ) paste (20 nm ZrO ₂ particle dispersion (PGME (1-methoxy-2-propanol))) is dropped on the titanium dioxide porous electrode film 4 and spin-coated (1000 to 6000 rpm). Thereafter, the insulating layer 8 made of zirconium dioxide was obtained by drying at 120 ° C. for 30 minutes.
30 parts by weight of ethanol is added to 10 parts by weight of slurry 1 (Orion's Printex 85 (specific surface area: 200 m ² / g, primary particle size: 16 nm) dispersion) having the formulation shown in Table 3 with an ultrasonic cleaner. 100 μL of the carbon solution obtained by the dispersion treatment for a minute is dropped on the insulating layer 8, spin-coated (1000 to 5000 rpm), dried at 120 ° C. for 3 minutes, and then baked at 450 ° C. for 30 minutes to form a carbon electrode film (positive electrode) 9 was obtained. The film thickness of the insulating film 8 was 100 to 300 nm, and the film thickness of carbon was 200 to 1000 nm.
Next, 80 μL of perovskite compound precursor solution 5 (PbCl ₂ (1M), CH ₃ NH3I (0.06M), DMF) is dropped, and after spin coating (1000 to 3000 rpm), it is dried at 100 to 120 ° C. for 90 minutes. A gold deposited film was formed to obtain a perovskite solar cell.
Examples 6 and 7 were obtained by changing the film thickness of the titanium dioxide porous electrode film 4 as shown in Table-11.

<Evaluation results>
Table 11 shows the measurement results of the photoelectric conversion efficiency of the perovskite solar cells of Example 6 and Example 7. Moreover, the cross-sectional observation photograph of the electrode film obtained in Examples 6 and 7 is shown in FIG. 9 and FIG.

  As shown in Table-11, by using the positive electrode prepared from the positive electrode forming slurry of the present invention and selecting the optimum film thickness of the titanium dioxide electrode film thickness, a perovskite solar cell with good conversion efficiency of 4.65% and positive electrode adhesion It can be seen that Further, FIG. 9 and FIG. 10 show that the positive electrode of the present invention forms a good porous electrode, and the perovskite compound is filled in the titanium dioxide electrode film.

  According to the present invention, in a photoelectric conversion element, it is possible to provide a positive electrode that is simple and low in cost and excellent in performance such as conversion efficiency and durability.

1 glass substrate 2 FTO transparent conductive film 3 TiO ₂ buffer layer 4 TiO ₂ porous film 5 perovskite compound 6 hole transport material 7 gold electrode 8 insulating layer 9 carbon electrode film 10 solar cell 11 working electrode 12 counter electrode 13 sealing Layer 14 Sealed space 15 Electrolyte layer 16 Light transmissive substrate 17 Transparent electrode member
18 Dye-sensitized semiconductor layer Electrolyte layer
19 counter substrate 20 catalyst electrode layer 21 through hole 22 sealing material

Claims (8)

  A positive electrode for a photoelectric conversion element, comprising a carbon material-based catalyst electrode layer containing a layered oxide.   The positive electrode for a photoelectric conversion element according to claim 1, wherein the weight ratio of the content of the layered oxide and the carbon material is 30: 0.05 to 3:16.   The positive electrode for a photoelectric conversion element according to claim 1, wherein the film thickness is 10 μm or less and the organic polymer component content is 20% or less.   A slurry for forming a positive electrode for a photoelectric conversion element, comprising a layered oxide.   At least the layered oxide as the component (a), the carbon black as the component (b), the conductive material other than the carbon black as the component (c), and the inorganic fine particle material other than the components (b) and (c) as the component (d) A slurry for forming a positive electrode for a photoelectric conversion element, comprising a solvent as a component (e).   6. The slurry for forming a positive electrode for a photoelectric conversion element according to claim 4, wherein the layered oxide is contained in an amount of 0.05 to 16% by weight.   (a) Component content is 0.05 to 16% by weight, (b) Component content is 2 to 50% by weight, (c) Component content is 0.025 to 14% by weight, (d) Component content is The slurry for forming a positive electrode for a photoelectric conversion element according to claim 5, wherein the slurry is 0.5 to 40% by weight. A method for producing a positive electrode for a photoelectric conversion element, wherein the slurry according to any one of claims 4 to 7 is applied onto a substrate, solidified and / or dried.