JP5250835B2 - Dye-sensitized solar cell - Google Patents

Description

  The present invention relates to a dye-sensitized solar cell.

  Dye-sensitized solar cells are simple in structure and can be manufactured in the printing process, so significant cost reductions are expected in both materials and processes. Next-generation solar cells follow silicon, GaAs, and CIS systems. It is attracting attention as a battery.

  In this dye-sensitized solar cell, the dye molecules adsorbed on the semiconductor surface absorb the sunlight, and so-called spectral enhancement is caused by electron injection from the dye LUMO (lowest orbital) to the semiconductor CB (conduction band). Do a feeling.

  Since the dye molecule is bonded to the semiconductor surface via an adsorbing group, it is generally considered to be a monomolecular layer. That is, in order to convert light incident on the solar cell into electrons with high efficiency, a technique for improving the light absorption ability of the dye is required.

  On the other hand, a major breakthrough was achieved by forming titanium oxide ultrafine particles as a porous film containing appropriate pores.

  By adsorbing a single molecule of a dye molecule on the particle surface in this porous film, the specific surface area of the light absorption / electron injection site can be increased to several thousand times, and the sunlight incident on the solar cell is efficiently used. Can be converted to electrons well.

  Electrons injected from the dye diffuse efficiently in the titanium oxide porous film and reach the transparent electrode. On the other hand, a dye that has lost electrons receives electrons from iodine ions in the electrolyte. Furthermore, the iodine ions that have passed the electrons receive the electrons on the counter electrode Pt substrate. The dye-sensitized solar cell drives an external circuit through this series of light absorption / oxidation reduction processes.

  However, at present, the transparent electrode has a resistance of the order of several ohms. Therefore, when the cell size of the dye-sensitized solar cell is increased, the fill factor is reduced due to Joule heat loss, and the photoelectric conversion efficiency is significantly reduced. This is a big bottleneck in achieving cost reduction by increasing the size of the cell.

  On the other hand, a configuration in which a bus bar made of a low-resistance metal member, a current collecting grid, or the like is formed on a transparent conductive substrate to compensate for the resistance of the transparent conductive film is known.

  As a method for forming a current collecting grid, for example, a method of applying a silver particle paste on a substrate by screen printing and baking to form a current collecting grid is the most common technique, but as a technique for forming a slightly more elaborate grid, A technique for forming a current collecting grid by forming a silver thin wire layer by photographic method using silver halide and forming a metal plating layer having conductivity has been introduced (for example, see Patent Documents 1 and 2).

  Furthermore, in order to achieve cost reduction in the production process, a so-called roll-to-roll method using a flexible substrate (also referred to as a flexible substrate) is required.

  However, in order to obtain a highly efficient dye-sensitized solar cell, a high-temperature sintering process at 400 ° C. or higher is indispensable when forming a semiconductor porous film, and a flexible transparent resin that can withstand temperatures up to that temperature. There was no substrate, and a high-efficiency dye-sensitized solar cell could not be obtained by a low-temperature process.

  In contrast, the electrode substrate coated with the semiconductor porous membrane layer is made of a flexible metal foil, and the opposite cathode electrode side is made of a transparent resin substrate. And the proposal which solves such a subject is made | formed (for example, refer patent document 3, nonpatent literature 1).

  However, even in this configuration, when the area is increased, the conversion efficiency is remarkably lowered as in the above-described problem.

  In addition, a technique for achieving a flexible and large-area cell by fixing a metal mesh coated with Pt on the cathode electrode has been introduced (see, for example, Patent Document 4).

  However, the type of cell irradiated with light from the cathode electrode still has a problem that the conversion efficiency is still lower than that of the cell irradiated from the semiconductor porous membrane layer side.

  Moreover, as a factor of low conversion efficiency, the area through which light is transmitted, that is, the so-called aperture ratio is reduced by using a metal mesh, and the transmittance is remarkably lowered, so that the performance is easily lowered.

On the other hand, when a coarse mesh is used to increase the aperture ratio, a trade-off occurs that the surface specific resistance increases and the Joule heat loss increases, and thus the above-mentioned problems cannot be solved. In addition, there is a demand for a dye-sensitized solar cell that is flexible (flexible) and that improves the conversion efficiency of a large area cell.
JP 2005-332705 A JP 2007-95567 A JP-A-11-288745 JP 2006-286534 A Chem. Commun. , 2006, 4004-4006

  The present invention is to provide a dye-sensitized solar cell with good photoelectric conversion characteristics. Another object of the present invention is to provide a dye-sensitized solar cell having a large area cell and high conversion efficiency while being flexible.

1. A cathode electrode comprising an anode electrode having a semiconductor porous layer in which at least a sensitizing dye is adsorbed on a substrate containing at least a conductor, and a translucent conductive substrate facing the semiconductor porous layer side of the anode electrode In the dye-sensitized solar cell having a configuration in which an electrolyte layer is sealed between the two electrodes, the anode electrode and the cathode electrode,
The translucent conductive substrate has a current collector having a line width of 5 μm to 20 μm and an aperture ratio of 84% to 98% on at least a transparent substrate, and the surface of the current collector is a first surface A dye-sensitized solar cell, which is covered with a conductive coating layer.

  2. The current collector has a two-layer structure in which a conductive metal is electroplated on a silver thin wire, and a line width ratio between the current collector and the silver thin wire is 1.2 to 2.0 (line width ratio = current collector). (2) (line width / silver thin line width). 2. The dye-sensitized solar cell as described in 1 above.

3. Dye-sensitized solar cell according to the 1 or 2, wherein the cross-sectional area of the collector wire is 30μm ² ~200μm ^2.

  4). 4. The dye-sensitized solar cell according to any one of 1 to 3, wherein the conductive coating layer is made of a metal oxide.

  5. 4. The dye-sensitized solar cell according to any one of 1 to 3, wherein the conductive coating layer is made of a conductive polymer.

  6). The surface of the current collecting wire is covered with a first conductive coating layer, and the opening of the translucent conductive substrate is covered with a second conductive coating layer. The dye-sensitized solar cell of any one of -5.

  7). 7. The dye-sensitized solar cell as described in 6 above, wherein the first conductive coating layer is made of a material having redox catalytic ability.

  8). 8. The dye-sensitized solar cell as described in 6 or 7 above, wherein the second conductive coating layer is made of a metal oxide.

  9. 8. The dye-sensitized solar cell according to any one of 1 to 7, wherein the second conductive coating layer is made of a conductive polymer.

  10. 10. The dye-sensitized solar cell according to any one of 1 to 9, wherein each of the transparent substrates is made of a flexible substrate.

  According to the present invention, a dye-sensitized solar that uses a light-transmitting and low-resistance light-transmitting conductive substrate as a cathode electrode, irradiates light from the cathode electrode side, and generates power, so that the efficiency does not decrease even when the area is increased. Batteries could be provided.

  In the dye-sensitized solar cell of this invention, it is providing the dye-sensitized solar cell with a favorable photoelectric conversion characteristic by the structure prescribed | regulated in any one of Claims 1-10. Moreover, it was possible to provide a dye-sensitized solar cell having a large area cell and high conversion efficiency while being flexible.

  Hereinafter, details of each component according to the present invention will be described.

  As a result of various studies on the above problems, the present inventors have solved the above-mentioned problem by optimally designing a transparent conductive substrate used for a cathode electrode as a counter electrode of the anode electrode as described in claim 1. It came to. The specific configuration will be described below.

  First, the dye-sensitized solar cell of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing the basic structure of the dye-sensitized solar cell of the present invention.

  As shown in FIG. 1, the dye-sensitized solar cell of the present invention includes an anode electrode having a semiconductor porous layer 3 in which a sensitizing dye molecule 2 is adsorbed on a substrate 1 containing a conductor, and the anode electrode. A cathode electrode composed of a light-transmitting conductive substrate (sometimes referred to as “cathode electrode”) 4 and a charge transfer layer (sometimes referred to as “electrolyte layer”) 5 between them are sealed with a sealing material 6. It consists of the structure sealed by.

  The translucent conductive substrate 4 of the dye-sensitized solar cell of the present invention has a line width of at least 5 μm to 20 μm on the transparent base material 41 and an aperture ratio of 84% to 98%. A current collector 42 is provided, and the surface of the current collector 42 is further covered with a conductive coating layer 43.

  In FIG. 1, the current collector 42 shows an embodiment in which a conductive metal plating layer 42 b is provided on a thin metal wire 42 b.

  In the configuration of the dye-sensitized solar cell of the present invention, it is preferable that light is incident from the cathode electrode side to generate electric power. In FIG. 1, + represents a positive electrode, and-represents a negative electrode.

  When constituting the dye-sensitized solar cell of the present invention, the semiconductor porous membrane layer 3, the charge transfer layer 5 and the cathode electrode 4 are housed in a case with a sealing agent 6 and sealed. Alternatively, it is preferable to seal them entirely with resin.

  When the dye-sensitized solar cell of the present invention is irradiated with sunlight or an electromagnetic wave equivalent to sunlight, the sensitizing dye 2 adsorbed on the semiconductor porous membrane layer 3 is excited by absorbing the irradiated sunlight or electromagnetic wave. To do.

  The electrons generated by the excitation move to the semiconductor porous film layer 3 and then pass through the external circuit via the base material 1 containing a conductor. Then, the redox species in the charge transfer layer 5 is reduced from the translucent conductive layer substrate 4, specifically, the current collecting line 42 through the conductive coating layer 43.

  The sensitizing dye 2 that has moved electrons to the semiconductor porous membrane layer 3 is an oxidant, but is reduced by supplying electrons from the cathode electrode 4 via the redox electrolyte in the charge transfer layer 5. Then, the redox electrolyte in the charge transfer layer 5 is oxidized and returned to the state where it can be reduced again by the electrons supplied from the cathode electrode 4. Thus, by flowing electrons, an external circuit can be driven, and the dye-sensitized solar cell of the present invention can be configured.

<< Translucent conductive substrate (also called cathode electrode) >>
A translucent conductive substrate (also referred to as a cathode electrode) according to the present invention will be described.

<Collector>
The translucent conductive substrate according to the present invention has a current collector (hereinafter referred to as “current collector grid”) having a line width of 5 μm to 20 μm and an aperture ratio of 84% to 98% on a transparent base material. And at least the surface of the current collector is covered with a first conductive coating layer.

  In order to obtain a high aperture ratio, the current collector according to the present invention is characterized by a line width of 5 μm to 20 μm, preferably 6 μm to 15 μm, and most preferably about 7 μm to 13 μm.

  Further, the current collector according to the present invention has an opening ratio of 84% to 98%, preferably 85% to 96%, and most preferably 87% to 95%.

Here, the “aperture ratio” means the ratio of the area obtained by subtracting the area where the current collector is tightened to the entire area irradiated with the light of the translucent conductive substrate,
[(Aperture ratio) = {(Overall area) − (Area where the current collector is tightened)} / (Overall area) × 100] (%).

  The line width and the aperture ratio are calculated by analyzing an image taken with a microscope and obtaining the area of each part. Although the aperture ratio can be obtained from the line width of the thin wire, etc., there is actually a slight difference between the aperture ratio obtained from the line width of the metal thin wire and the aperture ratio obtained by image analysis.

  This is due to the fact that the edges of the current collector are roughened due to plating treatment, etc., and that a clean corner is not formed at the intersection of the wires, resulting in a tanned shape. In most cases, this is obtained by image analysis. The aperture ratio value is small.

  The current collector according to the present invention has a configuration (also referred to as a conductive metal plating layer) in which a conductive metal is plated by electrolytic plating or electroless plating on the surface (including the surroundings) of a fine metal wire (for example, a silver fine wire). More preferably, it is preferable to have a configuration (also referred to as a conductive metal plating layer) in which a conductive metal is plated by electrolytic plating after forming a pattern made of fine metal wires (for example, silver fine wires).

  With this configuration, the metal wires (for example, silver wires) on which fine and accurate patterns can be easily formed are plated with a highly conductive metal to reduce the resistance of the current collector and increase the aperture ratio (high light transmittance). ).

  As the fine metal wire according to the present invention, a fine silver wire is particularly preferably used from the viewpoint of performing accurate patterning on the translucent conductive substrate.

  Moreover, in this invention, it is preferable that the line | wire width ratio of a collector wire and a metal fine wire (for example, silver fine wire) is the range of 1.2-2.0.

Here, the line width ratio represents the line width ratio observed from the direction perpendicular to the substrate of the current collector after plating with respect to the silver thin wire before plating,
[(Line width ratio) = (Line width of current collector) / (Line width of silver thin wire)].

  When the line width ratio (also referred to as the line width ratio) is 1.2 or more, a sufficiently low resistance film can be obtained because the plated metal is sufficiently formed, and the effect of the present invention is particularly high and preferable.

  Moreover, when the line width ratio is 2 or less, the original metal fine wire (for example, silver fine wire) pattern is maintained, and the intersections of the lines can form clean corners and maintain a high aperture ratio, which is preferable. Among these, the aspect in which the line width ratio is 1.3 to 1.7, and further 1.3 to 1.6 is particularly preferable because of the high effects described above.

Collecting wire according to the present invention preferably has a cross-sectional area is 30μm ² ~200μm ^2. A thickness of 30 μm ² or more is preferable because sufficient conductivity can be obtained and the surface specific resistance can be reduced. Moreover, if it is 200 micrometers ² or less, since the disorder of the line | wire by plating is small and it is easy to maintain a high aperture ratio, it is a preferable aspect. Further preferred cross-sectional area is 35μm ² ~150μm ^2, and most preferably 40μm ² ~100μm ^2.

  In the present invention, a conductive metal pattern can be formed by drawing a fine line pattern of a lattice shape or an antenna shape by exposure in order to provide a low resistance and a high aperture ratio, and then performing a development process or the like. preferable.

  As the conductive metal pattern, a mesh shape, an antenna shape, a lattice shape, or the like is preferable, and an aspect in which the mesh pattern is orthogonal is more preferable. Further, since the intersections between the thin metal wires are likely to be thickened in the steps from exposure to development and plating, the aperture ratio is lowered, so that it is preferable that the number of hands joined at the intersections between the sides is small.

  For example, in a quadrilateral mesh, four lines intersect, but a hexagonal shape is joined to each other at a side so that a pattern in which three lines intersect is more preferable.

  The method for forming a pattern composed of a fine metal wire (for example, a silver fine wire) is not particularly limited as long as it is a means that can achieve a preferred embodiment of the present invention, and examples thereof include a printing method, a silver salt method, an etching method, and the like. However, a printing method and a silver salt method are particularly preferable as a method for producing an elaborate pattern.

  When forming a metal thin wire (for example, silver thin wire) by a printing method, the metal thin wire (for example, silver thin wire) is adjusted by adjusting the type, amount, size, shape, etc. of the metal component contained in the printing ink. ) Part shape and conductivity can be adjusted.

  In the present invention, when metal fine wires (for example, silver fine wires) are printed, printing methods such as screen printing, gravure printing, offset printing, and ink jet printing can be used. Among these, gravure printing and inkjet printing can be particularly preferably used from the viewpoint of easily forming a fine pattern continuously.

  In addition, among the fine metal wires according to the present invention, when a silver fine wire that is particularly preferably used is formed by a silver salt method, a silver halide coated on a photosensitive material containing a silver halide emulsion, and It can be adjusted by adjusting the type and amount of the binder to be held, or by appropriately controlling the composition of the development processing solution used and the development processing conditions in the development processing step following pattern exposure.

  Although there is no particular limitation on the method for producing the translucent conductive substrate according to the present invention, it is easy to form a pattern, and as a particularly useful method capable of producing a large amount of translucent conductive substrate at low cost. A so-called silver salt method in which a photosensitive material having a layer composed of a photosensitive silver halide and a binder is exposed to light and then subjected to development processing will be described in detail.

(Formation of current collector by silver salt method)
A method for forming a current collector (hereinafter also referred to as “current collector grid”) according to the present invention by a silver salt method will be described in detail.

  As a preferred embodiment of the present invention, a silver halide emulsion-containing layer containing a photosensitive silver halide and a binder, which will be described later, is provided on the support. Agents, activators and the like.

In the present invention, the content of photosensitive silver halide is preferably embodiments less than 0.05 g / ^{m 2} or more 3 g / ^{m 2} in terms of silver, particularly preferably in terms of silver 0.15 g / ^{m 2} or more 1.5g / M ^{2 or} less, more preferably 0.3 g / m ² or more and less than 1.0 g / m ² .

If the content of the photosensitive silver halide is 0.05 g / m ² or more, the resistance can be lowered by the current collecting grid, which is preferable. This is presumed that a sufficient amount of developed silver nuclei serving as a catalyst for physical development or metal plating treatment described later is supplied, so that an effective conductive grid pattern can be easily formed.

In addition, if the photosensitive silver halide content is 3 g / m ² or less, the amount of the binder is optimized with respect to the amount of silver halide, so that sufficient coating strength can be obtained, and fine edges and fine lines can be obtained. It becomes easy to form.

In the present invention, the amount of the binder of the photosensitive material is 10 mg / m ^{2 to} 0.3 g / m ² , more preferably 50 mg / m ^{2 to} 0.2 g / m ² , from the viewpoint of achieving both conductivity and film properties. This is a particularly preferred embodiment. If the amount of the binder is 10 mg / m ² or more, the amount of the binder is optimized with respect to the amount of silver halide, so that a sufficient coating strength can be obtained, and fine edges and fine lines can be easily formed.

If the binder amount is 0.3 g / m ² or less, the distance between the photosensitive silver halide grains is sufficiently small, so that a developed silver network is easily formed, and an effective conductive grid pattern is easily formed. In addition, the progress of plating in the case of performing plating treatment on the pattern portion formed of metallic silver generated by development is a preferable mode.

(Silver halide grains)
The composition of the silver halide grains used in the present invention has an arbitrary halogen composition such as silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide and silver chloroiodide. However, silver chlorobromide grains are preferably used in order to harden the gradation and improve the exposure stability. Inclusion of bromine improves the storage stability of the silver halide grains. However, if the bromine content is too high, the developability tends to deteriorate, and the silver halide coating amount is less than 1.5 g / m ^2. In some cases, the bromine content is 2 to 30 mol%, more preferably 5 to 20 mol%, since it is particularly easy to soften.

  In order to reduce the surface specific resistance after the silver halide grains are developed into metal silver grains, the contact area between the developed silver grains needs to be as large as possible. For that purpose, in order to increase the surface area ratio, the smaller the silver halide grain size, the better.However, too small grains tend to aggregate and form large agglomerates. Exists.

  The average grain size of the silver halide grains used in the present invention is preferably 0.01 μm to 0.5 μm, more preferably 0.03 μm to 0.3 μm, in terms of a sphere equivalent diameter. In addition, the sphere equivalent diameter of silver halide grains represents the diameter of grains having a spherical shape and the same volume.

  The average grain size of silver halide grains is the temperature at the time of preparation of silver halide grains, pAg, pH, addition rate of silver ion solution and halogen solution, grain size control agent (for example, 1-phenyl-5-mercaptotetrazole, 2-mercaptobenzimidazole, benztriazole, tetrazaindene compounds, nucleic acid derivatives, thioether compounds, etc.) can be appropriately combined and controlled.

In the present invention, an embodiment in which the value obtained by dividing the coating silver amount (g / m ² ) by the particle size (μm) is 6 or more and 25 or less is preferable. When a large amount of photosensitive silver halide having a relatively small particle size is used, this value tends to be larger than 25. In this case, the silver halide grains are likely to slip off from the coating at the edge when the film is cut. Tend to be.

  In addition, when a small amount of photosensitive silver halide having a relatively large particle size is used, this value tends to be smaller than 6, and in this case, the number of photosensitive silver halide grains in a unit area is reduced, so that the conductivity is reduced. This is because it tends to decrease.

  The shape of the silver halide grains used in the present invention is not particularly limited. For example, a spherical shape, a cubic shape, a plate shape (hexagonal plate shape, triangle plate shape, tetragonal plate shape, etc.), octahedron shape, and tetrahedron shape. Various shapes such as shapes can be used. In order to increase the sensitivity, tabular grains having an aspect ratio of 2 or more, 4 or more, and further 8 to 16 can be preferably used.

  The particle size distribution is not particularly limited, but a narrow distribution is preferable from the viewpoint of enhancing the transparency while sharply reproducing the outline of the pattern during pattern formation by exposure and maintaining high conductivity.

  The particle size distribution of the silver halide grains used in the light-sensitive material according to the present invention is preferably monodispersed silver halide grains having a coefficient of variation of 0.22 or less, more preferably 0.15 or less. Here, the coefficient of variation is a coefficient representing the breadth of the particle size distribution, and is defined by the following equation. Coefficient of variation = S / R (wherein S represents the standard deviation of the particle size distribution and R represents the average particle size).

  The silver halide grains used in the present invention may further contain other elements. For example, in a photographic emulsion, it is also useful to dope metal ions used to obtain a high-contrast emulsion. In particular, Group 8-10 metal ions such as iron ion, rhodium ion, ruthenium ion and iridium ion are preferably used because the difference between the exposed portion and the unexposed portion tends to be clearly generated during the formation of the metallic silver pattern.

  These metal ions can be added to the silver halide emulsion in the form of a salt or a complex salt. Transition metal ions represented by rhodium ions and iridium ions can also be compounds having various ligands. Examples of such a ligand include cyanide ions, halogen ions, thiocyanate ions, nitrosyl ions, water, hydroxide ions, and the like. Specific examples of the compound include potassium bromide rhodate and potassium iridate.

In the present invention, the content of the metal ion compound contained in the silver halide is preferably 10 ⁻¹⁰ to 10 ⁻² mol / mol Ag per mol of silver halide, and 10 ⁻⁹ to 10 ^−3. More preferably, it is mol / mol Ag.

  In order for silver halide grains to contain the above metal ions, each of the metal compounds is subjected to physical ripening before formation of silver halide grains, during formation of silver halide grains, after formation of silver halide grains, etc. What is necessary is just to add in the arbitrary places in a process. Moreover, in addition, the solution of a heavy metal compound can be continuously performed over the whole particle formation process or a part.

  In the present invention, chemical sensitization performed on a photographic emulsion can be performed to further improve sensitivity. Chemical sensitization uses, for example, noble metal sensitization such as gold, palladium, platinum sensitization, chalcogen sensitization such as sulfur sensitization with inorganic sulfur or organic sulfur compounds, and reduction sensitization such as tin chloride and hydrazine. be able to.

  The silver halide grains are preferably subjected to spectral sensitization. Preferred spectral sensitizing dyes include cyanine, carbocyanine, dicarbocyanine, complex cyanine, hemicyanine, styryl dye, merocyanine, complex merocyanine, holopolar dye, and the like. Can be used alone or in combination.

  Particularly useful dyes are cyanine dyes, merocyanine dyes, and complex merocyanine dyes. Any of nuclei usually used for cyanine dyes can be used as these basic heterocyclic nuclei. That is, a pyrroline nucleus, an oxazoline nucleus, a thiazoline nucleus, a pyrrole nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, an imidazole nucleus, a tetrazole nucleus, a pyridine nucleus, and a nucleus in which an alicyclic hydrocarbon ring is fused to these nuclei, and these A nucleus fused with an aromatic hydrocarbon ring, i.e., indolenine nucleus, benzindolenin nucleus, indole nucleus, benzoxazole nucleus, naphthoxazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, benzoselenazole nucleus, benzimidazole nucleus, Such as quinoline nuclei. These nuclei may be substituted on carbon atoms.

  The merocyanine dye or the complex merocyanine dye includes a pyrazoline-5-one nucleus, a thiohydantoin nucleus, a 2-thiooxazolidine-2,4-dione nucleus, a thiazolidine-2,4-dione nucleus, and a rhodanine nucleus as a nucleus having a ketomethylene structure. , 5-membered to 6-membered heterocyclic nuclei such as thiobarbituric acid nuclei can be applied.

  These sensitizing dyes may be used alone or in combination. A combination of sensitizing dyes is often used for the purpose of supersensitization.

  In order to incorporate these sensitizing dyes in a silver halide emulsion, they may be dispersed directly in the emulsion, or water, methanol, propanol, methyl cellosolve, 2,2,3,3-tetrafluoro A solvent such as propanol may be added to the emulsion alone or in a mixed solvent.

  Further, as described in JP-B Nos. 44-23389, 44-27555, and 57-22089, an aqueous solution prepared by coexisting an acid or a base, U.S. Pat. No. 3,822, , 135, 4,006, 025, etc., and an emulsion or a colloidal dispersion prepared by coexisting a surfactant such as sodium dodecylbenzenesulfonate. You may add to.

  Further, after dissolving in a substantially immiscible solvent such as phenoxyethanol, water or a hydrophilic colloid dispersion may be added to the emulsion. As described in JP-A-53-102733 and JP-A-58-105141, it may be directly dispersed in a hydrophilic colloid and the dispersion may be added to the emulsion.

(Binder)
In the silver halide emulsion-containing layer according to the present invention, silver halide grains are uniformly dispersed, and the silver halide grains are supported on a support to ensure adhesion between the silver halide emulsion-containing layer and the support. A binder is used for the purpose. The binder that can be used in the present invention is not particularly limited, and both water-insoluble polymers and water-soluble polymers can be used, but from the viewpoint of improving developability, it is preferable to use water-soluble polymers.

  In the light-sensitive material according to the present invention, it is advantageous to use gelatin as a binder. If necessary, gelatin derivatives, graft polymers of gelatin and other polymers, proteins other than gelatin, sugar derivatives, cellulose derivatives, A hydrophilic colloid such as a synthetic hydrophilic polymer such as a single or copolymer can also be used.

(High contrast agent)
In the present invention, it is preferable that the photosensitive material has a high contrast in order to draw a silver fine line pattern with clear edges. As the method, a method of increasing the silver chloride content to narrow the particle size distribution, or a hydrazine compound It is preferable to use a tetrazolium compound as a high contrast agent. The hydrazine compound is a compound having a —NHNH— group, and a typical one is represented by the following general formula (1).

General formula (1) T-NHNHCO-V, T-NHNHCOCO-V
In the formula, each T represents an optionally substituted aryl group or heterocyclic group. The aryl group represented by T includes a benzene ring or a naphthalene ring, and this ring may have a substituent. As a preferable substituent, a linear or branched alkyl group (preferably having a carbon number of 1 to 20). Methyl group, ethyl group, isopropyl group, n-dodecyl group, etc.), alkoxy group (preferably C2-C21 methoxy group, ethoxy group, etc.), aliphatic acylamino group (preferably C2-C21 alkyl) Group, acetylamino group, heptylamino group, etc.), aromatic acylamino group and the like. In addition to these, for example, the substituted or unsubstituted aromatic ring as described above is -CONH-, -O- , —SO ₂ NH—, —NHCONH—, —CH ₂ CH═N— and the like are also included.

  V is a hydrogen atom, an optionally substituted alkyl group (methyl group, ethyl group, butyl, trifluoromethyl group, etc.), aryl group (phenyl group, naphthyl group), heterocyclic group (pyridyl group, piperidyl group, pyrrolidyl group) , Furanyl group, thiophene group, pyrrole group, etc.).

  The above hydrazine compound can be synthesized with reference to the description in US Pat. No. 4,269,929. The hydrazine compound can be contained in the silver halide grain-containing layer, in the hydrophilic colloid layer adjacent to the silver halide grain-containing layer, or in another hydrophilic colloid layer.

  Particularly preferred hydrazine compounds are listed below.

(H-1): 1-trifluoromethylcarbonyl-2-{[4- (3-n-butylureido) phenyl]} hydrazine (H-2): 1-trifluoromethylcarbonyl-2- {4- [ 2- (2,4-di-t-pentylphenoxy) butyramide] phenyl} hydrazine (H-3): 1- (2,2,6,6-tetramethylpiperidyl-4-amino-oxalyl) -2- { 4- [2- (2,4-di-t-pentylphenoxy) butyramide] phenyl} hydrazine (H-4): 1- (2,2,6,6-tetramethylpiperidyl-4-amino-oxalyl)- 2- {4- [2- (2,4-di-t-pentylphenoxy) butyramide] phenylsulfonamide} hydrazine (H-5): 1- (2,2,6,6-tetramethylpiperidyl-4- Amino- Oxalyl) -2- {4- [3- (4-chlorophenyl-4-phenyl-3-thia) butanamide] benzenesulfonamide} hydrazine (H-6): 1- (2,2,6,6-tetramethyl Piperidyl-4-amino-oxalyl) -2- (4- (3-thia-6,9,12,15-tetraoxatricosanamide) benzenesulfonamido) phenylhydrazine (H-7): 1- (1- Methylenecarbonylpyridinium) -2- (4- (3-thia-6,9,12,15-tetraoxatricosanamide) benzenesulfonamido) phenylhydrazine chloride.

  When hydrazine is used as the thickening agent, an amine compound or a pyridine compound can be preferably used in order to enhance the reducing action of hydrazine. As the amine compound that promotes the reducing action of the hydrazine compound, it is particularly preferable that the molecule has at least one piperidine ring or pyrrolidine ring, at least one thioether bond, and at least two ether bonds.

  In addition to the above-described amine compounds, pyridinium compounds and phosphonium compounds can also be preferably used as compounds that promote the reduction action of hydrazine. Since onium compounds are positively charged, they are considered to promote high contrast by adsorbing to negatively charged silver halide grains and accelerating electron injection from the developing agent during development. ing.

  As preferred pyridinium compounds, reference can be made to bispyridinium compounds described in JP-A-5-53231 and JP-A-6-242534. Particularly preferred pyridinium compounds are those in which a bispyridinium body is formed by linking at the 1-position or 4-position of pyridinium. The salt is preferably a chlorine ion or a bromine ion as a halogen anion, and other examples include a boron tetrafluoride ion and a perchlorate ion, and a chlorine ion or a boron tetrafluoride ion is preferable.

Hydrazine compounds, amine compounds, pyridinium compounds and tetrazolium compound, silver halide is preferred to moles per 1 × ^{10 -6} mol to 5 × ^{10 -2} mol containing, in particular 1 × ^{10 -4} mol to 2 × 10 ^{- Two} moles are preferred. It is easy to adjust the addition amount of these compounds to increase the degree of contrast γ to 6 or more.

  These compounds are used by being added to a layer containing halogenated particles or another hydrophilic colloid layer. If it is water-soluble, add it to an aqueous solution, and if it is water-insoluble, add it to a silver halide grain solution or hydrophilic colloid solution as a water-miscible organic solvent solution such as alcohols, esters, and ketones. That's fine. Moreover, when it does not melt | dissolve in these organic solvents, it can add by making into a microparticle with a magnitude | size of 0.01 micrometer-10 micrometers with a ball mill, a sand mill, a jet mill.

  As the fine particle dispersion method, a technique of solid dispersion of a dye as a photographic additive can be preferably applied. For example, a desired particle size can be obtained by using a dispersing machine such as a ball mill, a planetary rotating ball mill, a vibrating ball mill, or a jet mill. When a surfactant is used during dispersion, stability after dispersion can be improved.

<Transparent substrate>
The transparent substrate according to the present invention means that the light transmittance is 50% or more, preferably 80% or more, and particularly preferably 95% or more. As a material, it is possible to use a glass plate, a ceramic polishing plate such as titanium oxide or alumina, and various known plastic sheets.

  Specific examples of the plastic sheet include triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), syndiotactic polyester (SPS), and polycarbonate (PC). Polyarylate (PA), polyetherimide (PEI), polysulfone (PSF), polyethersulfone (PES), cyclic polyolefin, phenoxy resin, brominated phenoxy and the like.

  The softening point of the base material is determined by the temperature of the baking treatment of the semiconductor porous film layer described later, but when using a plastic sheet, it is preferable to fire the semiconductor by plasma irradiation, and it is exposed to high temperature, so it becomes softer It is preferable to use a plastic sheet having a high point, and the softening point is preferably 100 ° C. or higher, more preferably 150 ° C. or higher.

  The softening point can be evaluated by measuring the Vicat softening point defined in JIS-K7206.

  In order to improve the adhesion between the base material and the silver halide emulsion layer, the transparent base material according to the present invention has a mode in which an undercoat layer is previously applied prior to the application of the silver halide emulsion layer. preferable.

  As the binder preferably used for the undercoat layer, for example, gelatin, gelatin derivatives, gelatin and other polymer graft polymers, various latexes, water-soluble polymers, and the like can be preferably used.

  Examples of water-soluble polymers include vinyl alcohol polymers such as polyvinyl alcohol, water-soluble polyesters, etc., and latexes include acrylic-styrene polymer latex, styrene-diolefin polymer latex, and vinylidene chloride. Polymer latex or polyurethane polymer latex can be used, and among them, latex obtained by polymerizing an ethylenically unsaturated monomer is preferable from the viewpoint of easily improving the adhesion improving function.

  Ethylenically unsaturated monomers include acrylic esters, methacrylic esters, vinyl esters, acrylamides, methacrylamides, styrenes, divinylbenzene, acrylonitrile, methacrylonitrile, N-vinyl pyrrolidone, N-vinyl oxazolidone , Vinylidene chloride, phenyl vinyl ketone and the like. These monomers may be used alone or in combination of two or more.

  Further, at least one of the ethylenically unsaturated monomers is preferably a monomer having an epoxy group or a monomer having an active methylene group, more preferably a monomer having an epoxy group and a monomer having an active methylene group are used in combination. It is. Examples of the monomer having an epoxy group include glycidyl methacrylate and glycidyl acrylate. Examples of the ethylenically unsaturated monomer having an active methylene group include 2-acetoacetoxyethyl methacrylate, 2-acetoacetoxyethyl acrylate, 2- Acetoacetamidoethyl methacrylate and the like can be used.

  As the water-soluble polymer used in the polymerization, most of water-soluble natural polymers and water-soluble synthetic polymers having a water-soluble anionic group, cationic group or nonionic group in the molecular structure can be used. As a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a tertiary amine or an ammonium salt as a cationic group, and a nonionic group as a hydroxyl group, an amide group, a methoxy group, an alkylene oxide group Are preferably groups such as an oxyethylene group and a pyrrolidone group as a heteroatom ring.

  Among water-soluble synthetic polymers, anionic or nonionic ones are preferable, and anionic polymers are particularly preferable. More preferred are polymers having a sulfonate, and a polystyrene sulfonic acid copolymer, a sulfonated product of isoprene-styrene copolymer, and a copolyester having 5-sulfoisophthalic acid as a copolymerization component are more preferable. Two or more water-soluble polymers may be used in combination.

  The latex used for the undercoat layer can be produced by an emulsion polymerization method. For example, water is used as a dispersion medium, and the monomer is 10% by mass to 50% by mass with respect to water and 0.05% by mass to 5% with respect to the monomer. It is produced by polymerizing with stirring at about 30 ° C. to 100 ° C., preferably 60 ° C. to 90 ° C. for 3 hours to 8 hours, using a mass% polymerization initiator and 0.1% by mass to 20% by mass of a dispersant. be able to. Conditions such as the amount of monomer, amount of polymerization initiator, reaction temperature, and reaction time can be widely changed.

Examples of the polymerization initiator include water-soluble peroxides (for example, potassium persulfate, ammonium persulfate, etc.), water-soluble azo compounds (for example, 2,2′-azobis (2-aminodipropane) hydrochloride, etc.) or these A redox polymerization initiator combined with a reducing agent such as Fe ²⁺ salt or sodium bisulfite can be used.

  The average particle diameter of the latex may be various, such as about 0.02 μm to 0.8 μm, but the range of 0.05 μm to 2.0 μm is preferable.

Moreover, the aspect which adds a metal oxide to an undercoat layer, adjusts a refractive index, and also serves as a reflectance fall function is especially preferable. As an example of the metal oxide, ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₂ , V ₂ O ₅ , or a composite oxide thereof is preferable. In particular, SnO ₂ (tin oxide) is preferable from the viewpoint of miscibility with the binder, conductivity, and transparency.

As an example including a different element, Sb, Nb, a halogen element, or the like can be added to SnO ₂ . The amount of these different elements added is preferably in the range of 0.01 mol% to 25 mol%, but is particularly preferably in the range of 0.1 mol% to 15 mol%.

In the present invention, an embodiment using a colloidal tin oxide sol is particularly preferable from the viewpoint of improving transparency. In the present invention, for particles having a diameter of 10 ⁻⁷ to 10 ⁻⁵ cm, since the dispersion state is stable, this size is referred to as a colloid dimension, and an embodiment in which particles of a colloid dimension are used as colloid particles. preferable.

  Tin oxide is preferably in the form of an amorphous sol or crystalline particles. In the case of water-based coating, an amorphous sol is preferable, and in the case of solvent-based coating, the form of crystalline particles is preferable. In particular, from the viewpoint of workability, the form of an amorphous sol with an aqueous coating is preferable from the viewpoint of workability.

Regarding the method for producing an amorphous SnO ₂ sol that can be preferably used in the present invention, a method in which SnO ₂ fine particles are dispersed in a suitable solvent, or a decomposition reaction of a Sn compound that is soluble in the solvent in the solvent. Any method such as a manufacturing method may be used. A method for producing from a decomposition reaction of a Sn compound soluble in a solvent in the solvent will be described below.

Sol-soluble Sn compounds include compounds containing oxo anions such as K ₂ SnO ₃ .3H ₂ O, water-soluble halides such as SnCl ₄ , R ′ ₂ SnR ₂ , R ₃ SnX, R ₂ It has the structure of SnX _2, for _{example, (CH 3) 3 SnCl ·} ( _{pyridine), (C 4 H 9)} 2 Sn (O 2 CC 2 H 5) 2 , such as an organometallic _{compound, Sn (SO 4) 2 ·} 2H Oxo salts such as ₂ O can be mentioned.

After dissolving Sn compounds soluble in these solvents in the solvent, SnO ₂ sols are produced by intermediate methods such as physical methods such as heating and pressurization, chemical methods such as oxidation, reduction, and hydrolysis. For example, a method of producing a SnO ₂ sol.

  When coating these undercoat layers in the form of glass or plastic sheet, it is preferable to hydrophilize the substrate itself. The method for the hydrophilic treatment is not particularly limited, but it is preferable to perform, for example, a corona discharge treatment.

(exposure)
In the photosensitive material according to the present invention, the photosensitive material is exposed to form a conductive metal pattern by development, physical development, and plating described later. Examples of the light source used for exposure include light such as visible light and ultraviolet light, radiation such as electron beam and X-ray, and ultraviolet light or near infrared light is preferably used. Further, a light source having a wavelength distribution may be used for exposure, or a light source having a narrow wavelength distribution may be used.

  Various light emitters that emit light in the spectral region are used as necessary for visible light. For example, one or more of a red light emitter, a green light emitter, and a blue light emitter are mixed and used. The spectral region is not limited to the above red, green, and blue, and phosphors that emit light in the yellow, orange, purple, or infrared region are also used. An ultraviolet lamp is also preferable, and g-line of a mercury lamp, i-line of a mercury lamp, etc. are also used.

In the present invention, exposure can be performed using various laser beams. For example, scanning using monochromatic high-density light such as a gas laser, light emitting diode, semiconductor laser, semiconductor laser, or a second harmonic light source (SHG) that combines a nonlinear laser and a solid state laser using a semiconductor laser as an excitation light source An exposure method can be preferably used, and a KrF excimer laser, an ArF excimer laser, an F ₂ laser, or the like can also be used.

  In order to make the system compact and quick, exposure is preferably performed using a semiconductor laser, a semiconductor laser, or a second harmonic generation light source (SHG) that combines a solid-state laser and a nonlinear optical crystal.

  In order to design a device that is particularly compact, quick, long-life, and highly stable, exposure is preferably performed using a semiconductor laser.

  Specifically, an ultraviolet semiconductor, a blue semiconductor laser, a green semiconductor laser, a red semiconductor laser, a near infrared laser, or the like is preferably used as the laser light source.

  The method of exposing the silver halide emulsion-containing layer to an image may be performed by surface exposure using a photomask or by scanning exposure using a laser beam. At this time, either condensing exposure using a lens or reflection exposure using a reflecting mirror may be used, and exposure methods such as surface contact exposure, near field exposure, reduced projection exposure, and reflection projection exposure can be used. The output of the laser used for the exposure varies depending on the sensitivity of the silver halide grains, the exposure speed, and the optical system of the apparatus, but an aspect of about several tens of μW to 5 W is preferable.

(Development processing)
In the present invention, after the photosensitive material is exposed, development processing is performed. The development process is preferably a so-called black-and-white development process that does not contain a color developing agent.

  As the developing solution, in addition to hydroquinones such as hydroquinone, sodium hydroquinonesulfonate and chlorohydroquinone as developing agents, 1-phenyl-3-pyrazolidone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1- Combined use with pyrazolidones such as phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, 1-phenyl-4-methyl-3-pyrazolidone and superadditive developing agents such as N-methylparaaminophenol sulfate. Can do.

  Further, it is preferable to use a reductone compound such as ascorbic acid or isoascorbic acid together with the superadditive developing agent without using hydroquinone.

  In the development processing solution, sodium sulfite salt or potassium sulfite salt as a preservative, sodium carbonate salt or potassium carbonate salt as a buffering agent, diethanolamine, triethanolamine, diethylaminopropanediol or the like as a development accelerator can be appropriately used.

  The development processing solution used in the development processing can contain an image quality improving agent for the purpose of improving the image quality. Examples of the image quality improver include nitrogen-containing heterocyclic compounds such as 1-phenyl-5-mercaptotetrazole and 5-methylbenzotriazole.

  In the present invention, it is preferable that the development processing performed after exposure includes pre-fixing physical development. The term “physical development before fixing” as used herein refers to a process of reinforcing developed silver by supplying silver ions from outside the silver halide grains having a latent image by exposure before performing a fixing process described later.

  As a specific method for supplying silver ions from the developing solution, for example, silver nitrate is dissolved in the developing solution in advance and silver ions are dissolved, or thiosulfuric acid is added in the developing solution. Examples include a method in which a silver halide solvent such as sodium or ammonium thiocyanate is dissolved, the unexposed silver halide is dissolved during development, and the development of silver halide grains having a latent image is supplemented. It is done.

  In the present invention, it is preferable to use a formulation in which a silver halide solvent is dissolved in advance in a developing solution because a decrease in the transmittance of the film due to the occurrence of fogging in an unexposed portion can be suppressed.

  In the development processing in the present invention, after the development of the exposed silver halide grains, fixing processing is performed for the purpose of removing and stabilizing the unexposed silver halide grains. For the fixing treatment in the present invention, a fixer formulation used for a photographic film or photographic paper using silver halide grains can be used.

  The fixing solution used in the fixing process can use sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, or the like as a fixing agent. Aluminum sulfate, chromium sulfate, or the like can be used as a hardener for fixing. As the preservative for the fixing agent, sodium sulfite, potassium sulfite, ascorbic acid, erythorbic acid and the like described in the developing solution can be used, and citric acid, oxalic acid, and the like can be used.

  The washing water used in the present invention includes N-methyl-isothiazol-3-one, N-methyl-isothiazol-5-chloro-3-one, and N-methyl-isothiazole-4,5 as antifungal agents. -Dichloro-3-one, 2-nitro-2-bromo-3-hydroxypropanol, 2-methyl-4-chlorophenol, hydrogen peroxide and the like can be used.

(Physical development processing)
In the present invention, in order to efficiently perform the electrolytic plating process described later, it is preferable to promote the contact between the developed silvers by physical development process to increase the conductivity. The physical development process refers to a process for improving conductivity by supplying a silver source not contained in the photosensitive material in advance during the development process or after the process. Physical development can be performed by immersing a photosensitive material containing a silver halide emulsion having a latent image in a processing solution containing silver ions or silver complex ions and a reducing agent.

  In the present invention, physical development is defined not only when the development start point of physical development is the latent image nucleus but also when developed silver is the physical development start point, and this can be preferably used.

  When performing physical development in the present invention, it is preferable to use the pH of the physical developer in the range of 2 to 6 because the effects of the present invention can be stably extracted. In addition, it is a preferable aspect of the present invention that the physical developer has a buffering capacity, and thus the effects of the present invention can be stably extracted.

  The physical development processing can be performed during development, at any timing after development, before fixing, and after fixing processing, but is preferably performed after the fixing processing from the viewpoint of maintaining high transparency.

(Conductive metal plating treatment (also simply called plating treatment))
In the current collector according to the present invention, it is preferable to form a conductive metal pattern by a plating process. For this plating process, various conventionally known plating methods can be used. Electroplating can be performed alone or in combination.

  Among them, it is possible to preferably use electrolytic plating that has high plating efficiency and is less likely to cause a decrease in transmittance due to plating adhesion to unnecessary portions.

  As a metal that can be used for electrolytic plating, for example, copper, nickel, cobalt, tin, silver, gold, platinum, and other various alloys can be used, but the plating process is relatively easy and has high conductivity. From the viewpoint that it is easy to obtain, it is particularly preferable to use electrolytic copper plating.

  The plating treatment can be performed during development, at any timing after development, before fixing, and after fixing processing, but is preferably performed after the fixing processing from the viewpoint of maintaining high transparency.

  In the present invention, an embodiment in which the initial current density in electrolytic plating is 1.2 to 3.0 times the average current density is preferable. The current density here refers to the magnitude of the current per unit area of the electrode in electrolytic plating, and the initial current density is the average value of the current density in the time corresponding to the first 10% of the time required for the entire process of electrolytic plating. The average current density refers to the average value of the current density in the entire electrolytic plating process.

  When the initial current density is 1.2 times or more of the average current density, the in-plane plating uniformity tends to be particularly improved, and when the initial current density is 3.0 times or less of the average current density, The adhesion of the plated metal tends to be particularly improved.

  In the present invention, an embodiment in which the amount of metal applied by physical development or metal plating is 10 to 100 times in terms of mass with respect to developed silver obtained by exposing and developing the photosensitive material is preferable.

  This value can be determined by quantifying the metal contained in the photosensitive material by, for example, fluorescent X-ray analysis before and after physical development or metal plating.

  In the present invention, the description of physical development or metal plating means performing at least one of physical development or plating treatment, and means that both physical development and metal plating may be included. In the invention, it is preferable to perform both physical development and metal plating.

(Oxidation treatment)
In the present invention, it is preferable to carry out an oxidation treatment after the development treatment, physical development or plating treatment. By the oxidation treatment, unnecessary metal components can be ionized and dissolved and removed, and the transmittance can be further increased.

  As a treatment liquid used for the oxidation treatment, for example, a treatment method using an aqueous solution containing Fe (III) ions, or hydrogen peroxide, persulfate, perborate, perphosphate, percarbonate, perhalogen A treatment liquid containing a conventionally known oxidant such as a method of treatment using an aqueous solution containing a peroxide such as an acid salt, a hypohalite, a halogenate, or an organic peroxide can be used.

  The oxidation process is preferably performed after the development process and before the plating process because the transmittance can be improved efficiently in a short time, and particularly preferably after the physical development. is there.

<< Conductive coating layer (first conductive coating layer, second conductive coating layer) >>
The conductive coating layers (first conductive coating layer and second conductive coating layer) according to the present invention will be described.

  The present invention is characterized in that at least the surface of the current collector is covered with the first conductive coating layer. Examples of the conductive material used for the conductive coating layer include inorganic conductive materials made of various known metals and metal oxides, polymer conductive materials, inorganic-organic composite conductive materials, carbon materials, Alternatively, any material such as a conductive material in which these are arbitrarily mixed can be used.

  The conductive coating layer according to the present invention has not only the function of supplying electrons from the current collector to the charge transport layer, but also the effect of a protective layer that prevents corrosion of the current collector grid due to iodine redox contained in the charge transport layer. It is preferable.

Specific examples of the inorganic conductive material include metals such as platinum, gold, silver, copper, zinc, titanium, aluminum, rhodium, and indium, conductive carbon, tin-doped indium oxide (ITO), and tin oxide (SnO ₂ ). , Fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), zinc oxide (ZnO ₂ ), and niobium-doped titanium oxide (Nb—TiO ₂ ).

  Among these inorganic conductive materials, because of the structure of the dye-sensitized solar cell, iodine is used for the electrolyte layer, so that it is coated with platinum, titanium, aluminum, carbons, and metal oxides from the viewpoint of corrosion resistance. Is preferred.

  Specific examples of the polymer-based conductive material include conductive polymers and polyacetylene obtained by polymerizing thiophene, pyrrole, furan, aniline, etc., which may or may not be variously substituted. From the viewpoint of high properties, polythiophene is preferable, and polyethylenedioxythiophene (PEDOT / PSS) is particularly preferable.

  The first conductive coating layer according to the present invention is characterized by covering the surface of the current collector according to the present invention. Preferably, the surface of the current collector and the entire opening of the translucent conductive substrate are covered. A structure coated with a conductive coating layer is preferable in terms of both low resistance and high aperture ratio.

  As a preferred embodiment of the present invention, the surface of the current collector is covered with the first conductive coating layer, and the opening of the translucent conductive substrate is covered with the second conductive coating layer. More preferably.

  Here, the first conductive coating layer may have any composition as described above, but is preferably made of a material having catalytic ability to promote the redox reduction reaction of the charge transfer layer.

  Specific examples include platinum, rhodium metal, ruthenium metal, ruthenium oxide, carbons, conductive polymers, polythiophene, polypyrrole, polyaniline, PEDOT / PSS, and the like.

  The first conductive coating layer according to the present invention may be light transmissive or non-light transmissive.

  In addition, the second conductive coating layer is mainly composed of a structure covering the opening, and may have any composition as described above as long as it has light transmissivity, but as a composition that can achieve both light transmissivity and low resistance. It is preferable to use metal oxides, polymer-based conductive materials, and the like.

  The conductive coating layer having a high light transmittance (also referred to as a high light transmittance) preferably has a transmittance of 50% or more, preferably 80% or more when the opening is covered, 95 % Or more is particularly preferable.

  The light transmittance can be measured by a transmittance measuring means well known to those skilled in the art.

  As a method for forming the above-described conductive coating layer, a known appropriate method according to the conductive material can be used. For example, when forming a conductive layer made of a metal oxide such as ITO, a sputtering method is used. And thin film forming methods such as CVD, SPD (spray pyrolysis deposition) and vapor deposition. Further, when forming a conductive layer made of a polymer-based conductive material, it is preferably formed by various known coating methods.

  In the present invention, the material for forming the first conductive coating layer and the second conductive coating layer may be the same material or different materials, but at least the second conductive coating layer is formed of the present conductive coating layer. From the viewpoint of sufficiently functioning the power generation function of the dye-sensitized solar cell of the invention, it is essential to be light transmissive.

  The thickness of the conductive layer is preferably about 0.01 μm to 5 μm, and more preferably about 0.05 μm to 2.0 μm.

  By carrying out the present invention, the resistance of the translucent conductive substrate is reduced, and more specifically, the surface resistance value can be lowered. The surface resistance value of the translucent conductive substrate according to the present invention is preferably 10Ω / □ or less, more preferably 1Ω / □ or less, and particularly preferably 0.5Ω / □ or less. .

  The surface resistivity can be measured based on, for example, JIS K6911, ASTM D257, etc., and can be easily measured using a commercially available surface resistivity meter.

<< Substrate containing conductor >>
As the base material including the conductor according to the present invention, an inorganic conductive material made of various known metals or metal oxides, an inorganic-organic composite conductive material, a carbon-based material, or an arbitrary mixture thereof. Anything such as a conductive material can be used.

  Among these, in the semiconductor porous film forming process described later, it is preferable to use an inorganic conductive heat-resistant substrate as a composition that can substantially withstand a high firing temperature.

Specific examples of the inorganic conductive material include metals such as platinum, gold, silver, copper, zinc, titanium, aluminum, rhodium, and indium, conductive carbon, tin-doped indium oxide (ITO), and tin oxide (SnO ₂ ). , Fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), zinc oxide (ZnO ₂ ), and niobium-doped titanium oxide (Nb—TiO ₂ ).

  Among these inorganic conductive materials, platinum, titanium, aluminum, rhodium, indium, conductive carbon, and the like are preferable from the viewpoints of high conductivity and corrosion resistance to the electrolyte.

  When producing a flexible dye-sensitized solar cell, the conductive heat-resistant substrate described above is preferably in the form of a film that can be wound on a roll. In order to improve the strength and durability of the dye-sensitized solar cell on the surface opposite to the semiconductor porous film layer side by forming a semiconductor porous film on the conductive heat-resistant substrate film by high-temperature baking More preferably, a film-like support made of resin is laminated.

  In a dye-sensitized solar cell, a specific metal oxide or the like is further formed on the conductive heat-resistant substrate in order to suppress a decrease in open voltage due to a short circuit between the conductive heat-resistant substrate and the electrolyte. It is preferable to form a thin layer of about several nm to several tens of nm.

  Specifically, titanium oxide, zinc oxide, tin oxide, indium oxide, niobium oxide, tungsten oxide, zirconium oxide, strontium titanate, barium titanate, calcium titanate, etc. can be raised, and these are used alone or in combination. The film is preferably formed using a vacuum deposition method, a sputtering method, a CVD method, a dip coating method, or the like.

<Semiconductor porous membrane layer>
The porous body forming the semiconductor porous film layer according to the present invention is preferably composed of ceramic semiconductor fine particles represented by metal oxide. The composition of the semiconductor fine particles is not particularly limited as long as the band gap between the valence band (VB) and the conduction band (CB) is about 3 eV, but a metal oxide is preferable in view of easy formation of the nanoporous film.

  Typical metal oxides include, for example, titanium oxide, zinc oxide, tin oxide, indium oxide, niobium oxide, tungsten oxide, zirconium oxide, strontium titanate, barium titanate, and calcium titanate. Titanium oxide, zinc oxide, tin oxide, niobium oxide, and strontium titanate are preferable in view of the energy level of the conduction band and the adsorptivity of the dye. Titanium oxide and zinc oxide are preferable, and titanium oxide is most preferable.

  In the present invention, for the purpose of improving the performance of the dye-sensitized solar cell, the semiconductor fine particles may be mixed. Furthermore, the surface of the semiconductor A may be coated with the semiconductor B or the core-shell fine particles. Composite fine particles may be used.

  In order to obtain the effects of the present invention, the metal oxide semiconductor is preferably doped with a metal element. As the metal element species, monovalent to pentavalent metal ion dopants can be selected. For example, Li, Be, B, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe , Co, Ni, Cu, Zn, Ga, Ge, Rb, Sr, Y, Zr, Nb, Mo, Cd, In, Ir, Sn, Sb, Cs, Ba, La, Hf, Ta, W, Tl, Pb Bi, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, etc. can be raised. The doping amount of the metal ion dopant is preferably 0.01 mol% to 10 mol%, more preferably 0.1 mol% to 5.0 mol%, more preferably 0.1 mol% with respect to the number of metal atoms of the metal oxide semiconductor. -1.0 mol% is most preferred.

  In order to obtain a sufficient effect, a doping amount of 0.01% or more is preferable, and a doping amount that is solid-solved in the semiconductor fine particles is preferably 10 mol% or less.

  The method for producing the semiconductor fine particles according to the present invention can be performed using a generally known technique. Fine particle forming methods are roughly classified into a vapor phase method and a liquid phase method. The gas phase method is a method of forming crystals from a gaseous raw material, which is preferable from the viewpoint of mass production of low-cost, high-purity particles that facilitate the construction of a continuous process.

  On the other hand, the liquid phase method is a method in which one kind of raw material or two or more kinds are mixed in a solution and particles are formed by utilizing the solubility change of the raw material and the product. The single jet method, double jet method, sol -Gel method is used, and it is widely used as a method for synthesizing high-quality fine particles with uniform particle shapes that are not suitable for extreme mass production.

  Moreover, although it is a kind of liquid phase method, a melt method in which a raw material is melted and particles are formed by utilizing a change in solubility at the time of cooling, a method of forming in a flux salt melted at a high temperature in the same manner as the melt method, etc. Is mentioned.

  The semiconductor fine particles used in the light absorption layer of the present invention may be formed by any of the above methods as long as the particle size can be controlled, but the semiconductor composition can be easily controlled and the particle size can be controlled. The sol-gel method is preferably used for the reason that uniform high quality fine particles can be synthesized. The particle formation method using the sol-gel method hydrolyzes an organometallic compound using an acid or the like as a catalyst, and nucleates to grow particles in a liquid phase by a continuous condensation reaction to obtain desired metal oxide fine particles. It is a technique to obtain.

  An organometallic compound is a compound in which a metal and an organic substance are covalently bonded, coordinated or ionically bonded, and examples thereof include metal alkoxides, metal acylates, metal chelates, organometallic salts, and halogen metal compounds. In view of reactivity and stability, metal alkoxides are preferably used.

  The organometallic compound useful in the present invention is preferably a compound represented by the following general formula, but is not limited thereto.

(General formula)
M (R ₁ ) _x (R ₂ ) _y (R ₃ ) _z
In the above general formula, M is a metal (for example, Li, Be, B, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga , Ge, Rb, Sr, Y, Zr, Nb, Mo, Cd, In, Ir, Sn, Sb, Cs, Ba, La, Hf, Ta, W, Tl, Pb, Bi, Ce, Pr, Nd, Pm , Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, etc.), R ₁ is an alkyl group, R ₂ is an alkoxy group, R ₃ is a β-diketone coordination group, β-ketocarboxylate A group selected from a coordinating group, a β-ketocarboxylic acid coordinating group and a ketooxy group (ketooxy coordinating group), where the valence of the metal M is m, x + y + z = m, and x = 0 to m, Or x = 0 to m−1, y = 0 to m, z = 0 to m, and all are 0. The other is a positive integer.

Examples of the alkyl group represented by R ₁ include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the alkoxy group represented by R ₂ include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a 3,3,3-trifluoropropoxy group.

Further, a hydrogen atom in the alkyl group may be substituted with a fluorine atom. The group selected from the β-diketone coordination group, β-ketocarboxylic acid ester coordination group, β-ketocarboxylic acid coordination group and ketooxy group (ketooxy coordination group) represented by R ₃ is β-diketone coordination group. Examples of the group include 2,4-pentanedione (also referred to as acetylacetone or acetoacetone), 1,1,1,5,5,5-hexamethyl-2,4-pentanedione, 2,2,6,6-tetra Methyl-3,5-heptanedione, 1,1,1-trifluoro-2,4-pentanedione, and the like. Examples of β-ketocarboxylic acid ester coordination groups include, for example, acetoacetic acid methyl ester, acetoacetic acid And ethyl ester, propyl acetoacetate, ethyl trimethylacetoacetate, methyl trifluoroacetoacetate and the like, β-ketocarboxylic acid Examples of the coordinating group include acetoacetic acid and trimethylacetoacetic acid, and examples of the ketooxy coordinating group include, for example, an acetooxy group (or acetoxy group), propionyloxy group, butyryloxy group, acryloyloxy group, methacryloyl group. An oxy group etc. can be mentioned.

  The number of carbon atoms in these groups is preferably 18 or less including the above-mentioned organometallic compounds. Further, as illustrated, it may be linear or branched, or a hydrogen atom substituted with a fluorine atom.

In the present invention, from the viewpoint of handling, an organometallic compound with a low risk of explosion is preferable, and an organometallic compound having at least one oxygen in the molecule is preferable. Organometallic compound containing at least one alkoxy group as such R2, or R ₃ of the beta-diketone coordinating group, beta-ketocarboxylic acid ester coordinating group, beta-keto carboxylic Sanhai position group and Ketookishi group A metal compound having at least one group selected from (ketoxy coordination group) is preferred.

  Specific organometallic compounds are shown below.

  Examples of organic titanium compounds include organic titanium compounds, titanium hydrogen compounds, and titanium halides. Examples of organic titanium compounds include triethoxy titanium, trimethoxy titanium, triisopropoxy titanium, tributoxy titanium, tetraethoxy titanium, Tetraisopropoxy titanium, methyldimethoxy titanium, ethyl triethoxy titanium, methyl triisopropoxy titanium, triethyl titanium, triisopropyl titanium, tributyl titanium, tetraethyl titanium, tetraisopropyl titanium, tetrabutyl titanium, tetradimethylamino titanium, dimethyl titanium di ( 2,4-pentanedionate), ethyltitanium tri (2,4-pentanedionate), titanium tris (2,4-pentanedionate), titanium tris (acetomethylaceta) G), triacetoxy titanium, dipropoxypropionyloxy titanium, etc., dibutylyloxy titanium, titanium hydrogen compound as monotitanium hydrogen compound, dititanium hydrogen compound, etc., and halogenated titanium as trichlorotitanium, tetrachlorotitanium, etc. Any of these can be preferably used in the present invention. Two or more of these may be mixed and used at the same time.

  Examples of tin compounds include organic tin compounds, tin hydrogen compounds, and tin halides. Examples of organic tin compounds include tetraethyltin, tetramethyltin, di-n-butyltin diacetate, tetrabutyltin, and tetraoctyltin. , Tetraethoxytin, methyltriethoxytin, diethyldiethoxytin, triisopropylethoxytin, diethyltin, dimethyltin, diisopropyltin, dibutyltin, diethoxytin, dimethoxytin, diisopropoxytin, dibutoxytin, tin dibutyrate, tin Examples of diacetacetonate, ethyltin acetoacetonate, ethoxytin acetoacetonate, dimethyltin diacetoacetonate, tin hydrogen compounds, etc., and tin halides include tin dichloride and tin tetrachloride.

  Examples of the organosilicon compound include tetraethylsilane, tetramethylsilane, tetraisopropylsilane, tetrabutylsilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diethylsilanedi (2 , 4-pentanedionate), methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, etc., as silicon hydrogen compounds, tetrahydrogen silane, hexahydrogen disilane, etc., as halogenated silicon compounds, tetrachlorosilane , Methyltrichlorosilane, diethyldichlorosilane and the like, and any of them can be preferably used in the present invention.

  Examples of organic zirconium compounds include zirconium ethoxide, zirconium isopropoxide, zirconium n-propoxide, zirconium n-butoxide, zirconium t-butoxide, zirconium 2-ethylhexyl oxide, zirconium 2-methyl-2-butoxide, tetrakis (trimethyl). Siloxy) zirconium, zirconium di-n-butoxide (bis-2,4-pentanedionate), zirconium diisopropoxide bis (2,2,6,6-tetramethyl-3,5-heptanedionate, zirconium dimethacrylate Dibutoxide, zirconium hexafluoropentanedionate, zirconium methacryloxyethyl acetoacetate tri-n-propoxide, zirconium 2,4-pe Tanjioneto, zirconium 2,2,6,6-tetramethyl-3,5-heptanedionate, zirconium trifluoro pentanedionate, and the like.

  Examples of the aluminum alkoxide include aluminum (III) n-butoxide, aluminum (III) s-butoxide, aluminum (III) t-butoxide, aluminum (III) ethoxide, aluminum (III) isopropoxide, aluminum (III ) S-butoxide bis (ethyl acetoacetate), aluminum (III) di-s-butoxide ethyl acetoacetate, aluminum (III) diisopropoxide ethyl acetoacetate, aluminum (III) ethoxyethoxy ethoxide, aluminum hexafluoropenta Dionate, aluminum (III) 3-hydroxy-2-methyl-4-pyronate, aluminum (III) 9-octadecenyl acetoacetate diisopropoxide, aluminum (III) 2,4-pe Tanjioneto, aluminum (III) phenoxide, and aluminum (III) 2,2,6,6-tetramethyl-3,5-heptanedionate.

  Other organometallic compounds include, for example, niobium isopropoxide, antimony ethoxide, arsenic triethoxide, barium 2,2,6,6-tetramethylheptanedionate, beryllium acetylacetonate, bismuth hexafluoropentanedionate. , Dimethylcadmium, calcium 2,2,6,6-tetramethylheptanedionate, chromium trifluoropentanedionate, cobalt acetylacetonate, copper hexafluoropentanedionate, magnesium hexafluoropentanedionate-dimethyl ether complex, gallium ethoxy , Tetraethoxygermane, tetramethoxygermane, hafnium t-butoxide, hafnium ethoxide, indium acetylacetonate, indium 2,6-dimethyl Minoheptanedionate, ferrocene, lanthanum isopropoxide, lead acetate, tetraethyllead, neodymium acetylacetonate, platinum hexafluoropentanedionate, trimethylcyclopentadienylplatinum, rhodium dicarbonylacetylacetonate, strontium 2,2,6 , 6-tetramethylheptanedionate, tantalum methoxide, tantalum trifluoroethoxide, tellurium ethoxide, tungsten ethoxide, vanadium triisopropoxide oxide, magnesium hexafluoroacetylacetonate, zinc acetylacetonate, diethylzinc, etc. Is mentioned.

  Next, the solvent used for the sol-gel reaction will be described. The solvent uniformly mixes each component in the sol solution, and at the same time prepares the solid content of the composition of the present invention, so that it can be applied to various coating methods to improve the dispersion stability and storage stability of the composition. Is. These solvents are not particularly limited as long as they can fulfill the above purpose. Preferable examples of these solvents include water and organic solvents that are highly miscible with water.

  Examples of organic solvents include tetrahydrofuran, dimethoxyethane, formic acid, acetic acid, methyl acetate, alcohols (methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, tert-butyl alcohol), ethylene glycol, diethylene glycol, triethylene glycol , Ethylene glycol monobutyl ether, acetone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide and the like.

  During the sol-gel reaction, the metal alkoxide is hydrolyzed and polycondensed in water and an organic solvent. At this time, it is preferable to use a catalyst in order to promote the reaction.

  As a catalyst for hydrolysis, an acid is generally used. As the acid, an inorganic acid or an organic acid is used. Inorganic acids include hydrochloric acid, hydrogen bromide, hydrogen iodide, sulfuric acid, sulfurous acid, nitric acid, phosphoric acid, and organic acid compounds include carboxylic acids (formic acid, acetic acid, propionic acid, butyric acid, succinic acid, trifluoroacetic acid, perfluoro Octanoic acid, benzoic acid, phthalic acid, etc.), sulfonic acids (methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid), p-toluenesulfonic acid, pentafluorobenzenesulfonic acid, etc.), phosphoric acid / phosphonic acid (phosphoric acid dimethyl ester) , Phenylphosphonic acid, etc.), Lewis acids (boron trifluoride etherate, scandium triflate, alkyl titanic acid, aluminate, etc.), heteropolyacids (phosphomolybdic acid, phosphotungstic acid, etc.), and the like.

  The semiconductor porous membrane layer of the present invention preferably has a structure in which a light absorption layer and a light reflection layer are laminated in order from the light transmissive substrate side, and the light reflection layer has an aspect ratio (hereinafter sometimes abbreviated as AR). Is more preferably 3 or more shape anisotropic fine particles.

  Examples of the shape anisotropic fine particles include particles having shape anisotropy such as flat plate shape, flake shape, plate shape, needle shape, columnar shape, fiber shape, rugby ball shape, spindle shape, etc. , Flake-like and plate-like, and the plate-like shape is most preferred from the light reflectivity.

  A preferred aspect ratio is 3 or more and 200 or less, and more preferably 10 or more and 100 or less. The light absorption layer of the present invention preferably has an average particle diameter of 5 nm to 100 nm that does not substantially scatter sunlight, more preferably 8 nm to 80 nm, and most preferably 10 nm to 30 nm from the specific surface area and void size.

  The reflective layer preferably has an average particle diameter of 100 nm to 10 μm for reflecting sunlight, more preferably about 200 nm to 3 μm, and most preferably about 250 nm to 2 μm from the viewpoint of reflection efficiency and conversion efficiency.

  Here, the average particle diameter is calculated by calculating the equivalent circle diameter when the projected area of particles observed with a transmission electron microscope (for example, JEM-2010F type manufactured by JEOL Ltd.) is converted into a perfect circle, and the number of observed particles is 500. The average equivalent circle diameter is shown above.

  The aspect ratio indicates a value obtained by dividing the average particle diameter by an average thickness of 500 or more particles observed from the lateral direction.

  Here, the fact that sunlight is not substantially scattered means that visible light (mainly 400 nm to 780 nm light) contained in sunlight, ultraviolet light called UVA (315 nm to 400 nm light), near infrared light to far light. It means that spectral light including infrared rays (light of 780 nm or more) is not scattered. This wavelength region can be classified by Mie scattering, and the scattering characteristics are affected by the wavelength of light, particle diameter, and particle refractive index.

  In the case of inorganic fine particles, it is generally said that scattering occurs when a particle size comparable to the wavelength is present. Experimentally, it can be confirmed by simulating the average radiant energy of sunlight observed in the temperate region and evaluating the haze value of the semiconductor porous film with spectrum light called air mass 1.5 (AM1.5). .

  Regarding the semiconductor porous membrane layer according to the present invention, from the viewpoint of improving the conversion efficiency, the thickness of the light absorption layer is preferably 5 μm to 20 μm, more preferably 8 μm to 18 μm, and particularly preferably 11 μm to 15 μm. It is.

  The light reflecting layer can be designed with a thickness of about 0.5 μm to 10 μm, preferably 1 μm to 5 μm, and more preferably 1 μm to 3 μm. If the thickness of the light reflecting layer is too thin, sufficient light reflectivity cannot be obtained. On the other hand, if the thickness is too thick, the thickness of the semiconductor porous membrane layer itself is increased and the diffusion of the electrolyte is inhibited. There is a possibility that the recombination chance between the electrons injected into the dye and the dye hole is increased and the Voc is lowered.

  Further, the film thickness of the semiconductor porous film layer including the light absorption layer and the light reflection layer is preferably 10 μm to 20 μm, more preferably 13 μm to 17 μm, and particularly preferably 14 μm to 16 μm.

  Next, a method for producing a semiconductor porous film according to the present invention will be described.

As a method for producing the semiconductor porous film, it is possible to apply a known method,
(1) A method of forming a semiconductor layer by applying a suspension containing semiconductor fine particles on a conductive substrate, drying and firing,
(2) Electrophoretic electrodeposition method in which a conductive substrate is immersed in a colloidal solution, and semiconductor fine particles are adhered to the conductive substrate by electrophoresis.
(3) A method in which a foaming agent is mixed and applied to a colloidal solution or dispersion and then sintered to make it porous.
(4) After the polymer microbeads are mixed and applied, a method of removing the polymer microbeads by heat treatment or chemical treatment to form voids and making it porous can be applied.

  Among the above-described production methods, a known method can be applied particularly as a coating method, and examples include a screen printing method, an ink jet method, a roll coating method, a doctor blade method, a spin coating method, and a spray coating method. Can do.

  In particular, in the case of the above method (1), the particle diameter of the semiconductor fine particles in the suspension is preferably finer and is preferably present as primary particles.

  The suspension containing the semiconductor fine particles can be prepared by dispersing the semiconductor fine particles in a solvent.

  The solvent is not particularly limited as long as it can disperse the semiconductor fine particles, and includes water, an organic solvent, and a mixed solution of water and an organic solvent.

  As the organic solvent, alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone, acetone and acetyl acetone, hydrocarbons such as hexane and cyclohexane, and the like are used. In the suspension, a surfactant, a viscosity modifier (polyhydric alcohol such as polyethylene glycol), a dispersant and the like can be added as necessary. The concentration range of the semiconductor fine particles in the solvent is preferably 0.1% by mass to 70% by mass, and more preferably 0.1% by mass to 30% by mass.

  The above paste is preferably sufficiently primary particles using a known disperser. Examples of the disperser that can be used in the present invention include an ultrasonic disperser, a bead mill disperser, and a roll mill disperser, and can be appropriately selected depending on the dispersion step and the viscosity of the paste.

  The suspension containing the semiconductor fine particles obtained as described above is applied on a conductive substrate, dried, etc., and then baked in air or in an inert gas. A metal oxide semiconductor layer is formed.

  The semiconductor porous film layer obtained by applying and drying a suspension on a conductive substrate is composed of an aggregate of semiconductor fine particles, and the particle size of the fine particles is the primary particle size of the semiconductor fine particles used. It depends. The semiconductor porous membrane layer formed on the conductive substrate is a mechanically fragile film having a weak bonding force with the conductive substrate and a bonding force between the fine particles. It is preferable to increase the mechanical strength by baking treatment to obtain a fired product film that is strongly fixed to the substrate.

  By carrying out the firing process at the same time, so-called necking due to fusion adhesion is formed between the particles, and the effect of improving the electron conductivity in the semiconductor porous film is obtained.

  In the present invention, the fired product film may have any structure, but preferably has a porous structure (also referred to as a porous layer having voids).

  Here, the porosity of the semiconductor porous membrane layer is preferably 10% by volume or less, more preferably 8% by volume or less, and particularly preferably 0.01% by volume to 5% by volume.

  The porosity of the semiconductor porous film layer means a porosity that is penetrating in the thickness direction of the dielectric, and can be measured using a commercially available device such as a mercury porosimeter (for example, Shimadzu Polarizer 9220 type). I can do it.

  The firing temperature is about 300 ° C. to 1000 ° C. However, in the case of titanium oxide, care must be taken because the crystal phase obtained varies depending on the firing temperature.

  When titanium oxide is used in the present invention, it is generally preferable to use an anatase crystal formed at a temperature of 600 ° C. or lower in order to form a photocatalytically inactive rutile crystal at a firing temperature of 900 ° C. or higher.

  The semiconductor porous membrane layer of the present invention is, for example, titanium tetrachloride for the purpose of increasing the surface area of the semiconductor fine particles after the baking treatment, and for increasing the electron conductivity between the semiconductor fine particles and the substrate electrode, or between the semiconductor fine particles. Chemical plating using an aqueous solution or electrochemical plating using a titanium trichloride aqueous solution may be performed.

<Dye>
In the present invention, the dye 3 adsorbed on the surface of the semiconductor porous membrane layer 2 described above has absorption in various visible light regions and / or infrared light regions, and is the lowest higher than the conduction band of the metal oxide semiconductor. A dye having an empty level is preferable, and various known dyes can be used. For example, azo dyes, quinone dyes, quinone imine dyes, quinacridone dyes, squarylium dyes, cyanine dyes, cyanidin dyes, merocyanine dyes, triphenylmethane dyes, xanthene dyes, porphyrin dyes, perylene dyes Examples thereof include dyes, indigo dyes, phthalocyanine dyes, naphthalocyanine dyes, rhodamine dyes, and rhodanine dyes. Metal complex dyes are also preferably used. In this case, Cu, Ni, Fe, Co, V, Sn, Si, Ti, Ge, Cr, Zn, Ru, Mg, Al, Pb, Mn, In, Mo Y, Zr, Nb, Sb, La, W, Pt, Ta, Ir, Pd, Os, Ga, Tb, Eu, Rb, Bi, Se, As, Sc, Ag, Cd, Hf, Re, Au, Ac Various metals such as Tc, Te, and Rh can be used.

  Of the above, polymethine dyes such as cyanine dyes, merocyanine dyes, and squarylium dyes are one of preferred embodiments. Specifically, JP-A-11-35836, JP-A-11-67285, JP-A-11- No. 86916, JP-A-11-97725, JP-A-11-158395, JP-A-11-163378, JP-A-11-214730, JP-A-11-214731, JP-A-11-238905 Examples thereof include dyes described in JP-A-2004-207224, JP-A-2004-319202, EP-A 892411, and U.S. Pat.

  Furthermore, a metal complex dye is also one preferred embodiment, and a metal phthalocyanine dye, a metal porphyrin dye or a ruthenium complex dye is preferable, and a ruthenium complex dye is particularly preferable. Examples of the ruthenium complex dye include U.S. Pat. Nos. 4,927,721, 4,684,537, 5,084,365, 5,350,644, 5,463,057, 5,525,440, and JP-A-7-249790. No. 10 / 504,512, WO 98/50393 pamphlet, JP 2000-26487, JP 2001-2223037, JP 2001-226607, JP 3430254. And the like, and complex dyes described in each specification.

  These dyes preferably have a large extinction coefficient and are stable against repeated redox. The dye is preferably chemically adsorbed on the metal oxide semiconductor, and has a functional group such as a carboxy group, a sulfonic acid group (sulfo group), a phosphoric acid group, an amide group, an amino group, a carbonyl group, or a phosphine group. It is preferable to have.

  In the present invention, it is particularly preferable to use a rhodanine dye as the dye adsorbed on the surface of the metal oxide. Any structure can be used as long as it is a rhodanine dye, but it is particularly preferable to use at least one dye represented by the following general formula (1) or general formula (2). .

In General Formula (1) or General Formula (2), X _{11 to} X ₁₄ and X _{21 to} X ₂₆ each independently represent an oxygen atom, a sulfur atom, or a selenium atom, and X ₁₁ , X ₁₂ , X ₁₄ , and X ₂₁ , X ₂₂ , X ₂₄ and X ₂₆ are each a sulfur atom or a selenium atom, more preferably a sulfur atom. X ₁₃ , X ₂₃ and X ₂₅ are preferably oxygen atoms.

In General formula (1) or General formula (2), R <_12> , R <_13> and R <_22> , R < ₂₃ > represents a hydrogen atom or a substituent each independently.

In General Formula (1) or General Formula (2), R ₁₄ represents a carboxy group (—COOH group) or a phosphono group (—PO ₃ H ₂ group), R ₂₄ and R ₂₆ represent a hydrogen atom, a carboxy group ( —COOH group) or a phosphono group (—PO ₃ H ₂ group), and at least one represents a carboxy group (—COOH group) or a phosphono group (—PO ₃ H ₂ group).

In General Formula (1) or General Formula (2), L ₁₁ , L ₂₁ , and L ₂₂ each independently represent a divalent linking group. Examples of the divalent linking group include a methylene group (—CH ₂ —), an ethylene group (—CH ₂ CH ₂ —), a trimethylene group (—CH ₂ CH ₂ CH ₂ —), and the like. A methylene group and an ethylene group.

In the general formula (1) or (2), R ₁₅ and R ₂₅ each represents an alkyl group, preferably a linear or branched alkyl group having 1 to 8 carbon atoms, and a straight chain having 2 to 4 carbon atoms. Chain and branched alkyl groups (for example, ethyl group, i-propyl group, n-butyl group and the like) are more preferable.

Moreover, the alkyl group represented by each of R ₁₅ and R ₂₅ may further have a substituent described later.

In general formula (1) or general formula (2), examples of substituents such as R ₁₂ , R ₁₃ , R ₂₂ and R ₂₃ include alkyl groups (for example, methyl group, ethyl group, i-propyl group, t- Butyl group, n-dodecyl group and 1-hexylnonyl group), cycloalkyl group (eg cyclopropyl group, cyclohexyl group, bicyclo [2.2.1] heptyl group and adamantyl group) and alkenyl group (eg 2- Propylene group, oleyl group, etc.), aryl group (for example, phenyl group, ortho-tolyl group, ortho-anisyl group, 1-naphthyl group, 9-anthranyl group, etc.), heterocyclic group (for example, 2-tetrahydrofuryl group, 2- Thiophenyl group, 4-imidazolyl group, 2-pyridyl group, etc.), halogen atom (eg fluorine atom, chlorine atom, bromine atom etc.), cyano group, nitro group B, hydroxy group, mercapto group, carboxy group, carbonyl group (for example, alkylcarbonyl group such as acetyl group, trifluoroacetyl group, pivaloyl group, benzoyl group, pentafluorobenzoyl group, 3,5-di-t-butyl- Arylcarbonyl groups such as 4-hydroxybenzoyl group), oxycarbonyl groups (eg alkoxycarbonyl groups such as methoxycarbonyl group, cyclohexyloxycarbonyl group, n-dodecyloxycarbonyl group, phenoxycarbonyl group, 2,4-di-t -Aryloxycarbonyl groups such as amylphenoxycarbonyl group, 1-naphthyloxycarbonyl group and heterocyclic oxycarbonyl groups such as 2-pyridyloxycarbonyl group, 1-phenylpyrazolyl-5-oxycarbonyl group), carbamoyl group For example, dimethylcarbamoyl group, alkylcarbamoyl group such as 4- (2,4-di-t-amylphenoxy) butylaminocarbonyl group, arylcarbamoyl group such as phenylcarbamoyl group, 1-naphthylcarbamoyl group), alkoxy group (for example, methoxy Group, 2-ethoxyethoxy group, etc.), aryloxy group (eg, phenoxy group, 2,4-di-t-amylphenoxy group, 4- (4-hydroxyphenylsulfonyl) phenoxy group, etc.), heterocyclic oxy group (eg, 4-pyridyloxy group, 2-hexahydropyranyloxy group, etc.), carbonyloxy group (for example, alkylcarbonyloxy group such as acetyloxy group, trifluoroacetyloxy group, pivaloyloxy group, benzoyloxy group, pentafluorobenzoyloxy group) Aryl such as Xyl groups, etc.), urethane groups (eg, alkylurethane groups such as N, N-dimethylurethane groups, arylurethane groups such as N-phenylurethane groups, N- (p-cyanophenyl) urethane groups), sulfoxyl groups, sulfonyloxy A group (for example, an alkylsulfonyloxy group such as a methanesulfonyloxy group, a trifluoromethanesulfonyloxy group, an n-dodecanesulfonyloxy group, an arylsulfonyloxy group such as a benzenesulfonyloxy group, a p-toluenesulfonyloxy group), an amino group (for example, Dimethylamino group, cyclohexylamino group, alkylamino group such as n-dodecylamino group, anilino group, arylamino group such as pt-octylanilino group, etc.), sulfonylamino group (for example, methanesulfonylamino group, heptafluoro) Propans Alkylsulfonylamino groups such as sulfonylamino groups, n-hexadecylsulfonylamino groups, p-toluenesulfonylamino groups, arylsulfonylamino groups such as pentafluorobenzenesulfonylamino), sulfamoylamino groups (for example, N, N-dimethylsulfone) Alkylsulfamoylamino groups such as famoylamino group, arylsulfamoylamino groups such as N-phenylsulfamoylamino group), acylamino groups (eg alkylcarbonylamino groups such as acetylamino group, myristoylamino group, benzoyl) Arylcarbonylamino groups such as amino groups), ureido groups (for example, alkylureido groups such as N, N-dimethylaminoureido groups, N-phenylureido groups, arylureido groups such as N- (p-cyanophenyl) ureido groups), A sulfonyl group (for example, an alkylsulfonyl group such as a methanesulfonyl group and a trifluoromethanesulfonyl group and an arylsulfonyl group such as a p-toluenesulfonyl group), a sulfamoyl group (for example, a dimethylsulfamoyl group, 4- (2,4-di-t -Arylphenoxy) alkylsulfamoyl group such as butylaminosulfonyl group, arylsulfamoyl group such as phenylsulfamoyl group), alkylthio group (eg methylthio group, t-octylthio group etc.), arylthio group (eg phenylthio group) And a heterocyclic thio group (for example, 1-phenyltetrazol-5-thio group, 5-methyl-1,3,4-oxadiazole-2-thio group, etc.). These substituents may be further substituted with the substituents shown above.

In General Formula (1) or General Formula (2), R ₁₂ , R ₁₃ , R ₂₂ , and R ₂₃ may be bonded to each other to form a ring structure, and the formed ring structure is an aliphatic ring. Any of aromatic rings may be used, and it may be a hydrocarbon ring or a heterocyclic ring. The ring formed by bonding may be substituted with the substituent shown above, or may be further condensed with another ring structure. In general formula (1) or general formula (2), It may be further condensed with the represented compound itself.

In the general formula (1) or general formula (2), examples of the substituents for R ₁₂ , R ₁₃ , R ₂₂ , and R ₂₃ include those described above. Preferred are a hydrogen atom, a halogen atom, and a substituent. Or it is an unsubstituted alkyl group, an aryl group, a heterocyclic group, and an alkoxycarbonyl group, More preferably, they are a hydrogen atom and a substituted or unsubstituted alkyl group.

In General Formula (1) or General Formula (2), R ₁₁ and R ₂₁ each represent a substituent, and can be the same substituents as R ₁₂ , R ₁₃ , and R ₂₂ and R ₂₃ described above. However, at least one or more is preferably an electron-withdrawing substituent, in which case n represents an integer of 1 to 4. In the case of an electron-withdrawing substituent, the Hammett's substituent constant σp is preferably 0.1 or more and 0.8 or less, and the sum of the σp values of the substituents is preferably 0.1. It is preferably 2 or more and 2.0 or less, and most preferably 0.25 or more and 1.5 or less.

  Here, as the value of Hammett's substituent constant σp, Hansch, C .; It is preferable to use the values described in the report of Leo et al. (For example, J. Med. Chem. 16, 1207 (1973); ibid. 20, 304 (1977)).

  For example, a substituent or atom having a value of σp of 0.10 or more includes a chlorine atom, a bromine atom, an iodine atom, a carboxyl group, a cyano group, a nitro group, a halogen-substituted alkyl group (for example, trichloromethyl, trifluoromethyl, chloro Methyl, trifluoromethylthiomethyl, trifluoromethanesulfonylmethyl, perfluorobutyl), aliphatic / aromatic or heterocyclic acyl groups (eg formyl, acetyl, benzoyl), aliphatic / aromatic or heterocyclic sulfonyl groups (eg trifluoromethane) Sulfonyl, methanesulfonyl, benzenesulfonyl), carbamoyl groups (eg carbamoyl, methylcarbamoyl, phenylcarbamoyl, 2-chloro-phenylcarbamoyl), alkoxycarbonyl groups (eg methoxycarbonyl, ethoxycarbo) Diphenylmethylcarbonyl), substituted aromatic groups (eg pentachlorophenyl, pentafluorophenyl, 2,4-dimethanesulfonylphenyl, 2-trifluoromethylphenyl), heterocyclic residues (eg 2-benzoxazolyl, 2-benzthiazolyl, 1-phenyl-2-benzimidazolyl, 1-tetrazolyl), azo group (eg phenylazo), ditrifluoromethylamino group, trifluoromethoxy group, alkylsulfonyloxy group (eg methanesulfonyloxy), acyloxy group ( For example, acetyloxy, benzoyloxy), arylsulfonyloxy group (for example, benzenesulfonyloxy), phosphoryl group (for example, dimethoxyphosphonyl, diphenylphosphoryl), sulfamoyl group (for example, N-ethylsulfamoy) N, N-dipropylsulfamoyl, N- (2-dodecyloxyethyl) sulfamoyl, N-ethyl-N-dodecylsulfamoyl, N, N-diethylsulfamoyl) and the like.

  Examples of the substituent having a value of σp of 0.35 or more include a cyano group, a nitro group, a carboxyl group, a fluorine-substituted alkyl group (for example, trifluoromethyl, perfluorobutyl), an aliphatic / aromatic or heterocyclic acyl group (for example, Acetyl, benzoyl, formyl), aliphatic / aromatic or heterocyclic sulfonyl groups (eg trifluoromethanesulfonyl, methanesulfonyl, benzenesulfonyl), carbamoyl groups (eg carbamoyl, methylcarbamoyl, phenylcarbamoyl, 2-chloro-phenylcarbamoyl), Alkoxycarbonyl group (for example, methoxycarbonyl, ethoxycarbonyl, diphenylmethylcarbonyl), fluorine or sulfonyl group-substituted aromatic group (for example, pentafluorophenyl, 2,4-dimethanesulfonylphenyl), heterocyclic residue ( Example, if 1-tetrazolyl), an azo group (e.g. phenylazo), an alkylsulfonyloxy group (e.g. methanesulfonyloxy), a phosphoryl group (e.g., dimethoxyphosphoryl, diphenylphosphoryl), a sulfamoyl group, and the like.

  Examples of the substituent having a value of σp of 0.60 or more include cyano group, nitro group, aliphatic / aromatic or heterocyclic sulfonyl group (for example, trifluoromethanesulfonyl, difluoromethanesulfonyl, methanesulfonyl, benzenesulfonyl) and the like. .

R ₁₁ and R ₂₁ are preferably a halogen atom, a halogen-substituted alkyl group (such as a trifluoromethyl group), an alkoxycarbonyl group, a carbamoyl group, or a cyano group.

  The compound of the general formula (1) or the general formula (2) includes ions and salts derived from the compound in addition to the compound itself represented by the general formula.

  For example, when it has a sulfonic acid group in the molecular structure, it includes, in addition to the compound, an anion generated by dissociation of the sulfonic acid group, and a salt formed by the anion and a counter cation.

  Such a salt may be a salt formed with a metal ion such as sodium salt, potassium salt, magnesium salt or calcium salt, or an organic base such as pyridine, piperidine, triethylamine, aniline or diazabicycloundecene. It may be a formed salt. Similarly, in the case of a compound having a basic group in the molecule, a cation produced by protonation of the compound, and hydrochloride, sulfate, acetate, methylsulfonate, p-toluenesulfonate, etc. Also included are salts formed with acids.

  Specific examples of the compound represented by the general formula (1) or the general formula (2) in the present invention are shown below, but the present invention is not limited thereto.

  Examples of the compound represented by the above general formula (1) or (2) include, for example, “Myanine, Soybean and Relayed Compounds” (1964, published by InterScience Publishers) by F.M. ), U.S. Pat. Nos. 2,454,629, 2,493,748, JP-A-6-301136, 2003-203684 and the like. Can be synthesized.

  These compounds (also referred to as dyes) preferably have a large extinction coefficient and are stable against repeated redox. The above compound is preferably chemically adsorbed on the metal oxide semiconductor, and includes a carboxy group, a sulfonic acid group (sulfo group), a phosphoric acid group, an amide group, an amino group (including a substituted amino group), an alkoxy group. It preferably has a functional group such as a carbonyl group, an aryloxycarbonyl group, or a phosphono group.

  In the present invention, the method for adsorbing the dye to the semiconductor porous membrane layer is not particularly limited, and a known method can be used. For example, a method of dissolving a dye in an organic solvent to prepare a dye solution and immersing the semiconductor layer on the transparent conductive film in the obtained dye solution, or a method of applying the obtained dye solution to the surface of the semiconductor layer, etc. Can be mentioned.

  In the former, a deep method, a roller method, an air knife method or the like can be applied, and in the latter, a wire bar method, an application method, a spin method, a spray method, an offset printing method, a screen printing method, or the like can be applied.

  Prior to the dye adsorption, the surface of the semiconductor layer may be subjected to a treatment such as a decompression treatment or a heat treatment in advance to activate the surface and remove moisture in the film.

  From the viewpoint of preferably obtaining a sensitizing effect on the semiconductor layer, the time for immersing the semiconductor film in the dye solution is preferably 3 hours to 48 hours, and more preferably 4 hours to 24 hours.

  In addition, the dye solution may be heated to a temperature at which it does not boil as long as the dye does not decompose. The preferred temperature range is 10 ° C. to 50 ° C., particularly preferably 15 ° C. to 35 ° C., but this is not the case when the solvent boils in the temperature range as described above.

  Moreover, when making it adsorb | suck in the upper limit which boils, it is preferable to perform an adsorption | suction process on the conditions which a solvent does not deplete using a reflux apparatus etc.

  In addition, the dye solution in which the semiconductor film is immersed can be irradiated with ultrasonic waves. A commercially available apparatus can be used for the ultrasonic irradiation, and the irradiation time is preferably 30 minutes to 4 hours, more preferably 1 hour to 3 hours.

  The solvent used for the dye solution may be any solvent that dissolves the dye, and a conventionally known solvent can be used. In addition, the solvent is preferably a solvent purified in accordance with a conventional method, or a solvent having higher purity by performing distillation and / or drying as necessary prior to use of the solvent, for example, methanol, ethanol , Butanol, one or more hydrophobic solvents, aprotic solvents, hydrophobic and aprotic solvents or mixtures thereof.

  Here, examples of the hydrophobic solvent include halogenated aliphatic hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride; hydrocarbons such as hexane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene; chlorobenzene, And halogenated aromatic hydrocarbons such as dichlorobenzene; esters such as ethyl acetate, butyl acetate, and ethyl benzoate;

  Examples of the aprotic solvent include ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether, diisopropyl ether and dimethoxyethane; nitrogen compounds such as acetonitrile, dimethylacetamide and hexamethylphosphoric triamide; carbon disulfide; Sulfur compounds such as dimethyl sulfoxide; phosphorus compounds such as hexamethylphosphoramide; and combinations thereof.

  Solvents preferably used include alcohol solvents such as methanol, ethanol, n-propanol, n-butanol and t-butanol, ketone solvents such as acetone and methyl ethyl ketone, diethyl ether, diisopropyl ether, tetrahydrofuran and 1,4-dioxane. Ether solvents, halogenated hydrocarbon solvents such as methylene chloride and 1,1,2-trichloroethane, and nitrogen compounds such as acetonitrile, particularly preferably methanol, ethanol, acetone, methyl ethyl ketone, tetrahydrofuran, methylene chloride and acetonitrile. .

The density | concentration of the pigment | dye in a pigment | dye solution can be suitably adjusted with the pigment | dye to be used, the kind of solvent, and a pigment | dye adsorption process, for example, 1 * 10 < ^-5 > mol / liter or more, Preferably it is 5 * 10 < ^-5 > -1 *. About 10 ⁻² mol / liter is mentioned.

  Note that if the amount of dye adsorbed is small, the sensitizing effect will be insufficient. Conversely, if the amount of adsorbed is large, the dye not adsorbed on the oxide semiconductor will float, which will reduce the sensitizing effect and increase the photoelectric conversion efficiency. This is not preferable because it causes a decrease.

  From the above, it is preferable to quickly remove the unadsorbed dye by washing. As the cleaning solvent, a solvent having relatively low solubility of the dye and easy to dry is preferable. Moreover, it is preferable to perform washing in a heated state.

  In addition, after removing excess dye by washing, the surface of the oxide semiconductor fine particles may be treated with an organic basic compound to promote removal of unreacted dye in order to make the adsorption state of the dye more stable. Good.

  Examples of the organic basic compound include derivatives such as pyridine and quinoline. When these compounds are liquid, they may be used as they are, but when they are solid, they may be dissolved in a solvent, preferably the same solvent as the dye solution.

  When two or more compounds (dyes) represented by the above general formula (1) or (2) are used, the ratio of the dyes to be mixed is not particularly limited and is selected and optimized from the respective dyes. It is preferable to use about 10% mol or more per dye from mixing in equimolar amounts.

  As a specific method when two or more kinds of dyes are used in combination, the dyes may be adsorbed on the semiconductor layer sequentially or may be mixed and dissolved. Moreover, the structure which laminates | stacks the semiconductor which adsorb | sucked the pigment | dye previously at a post process may be sufficient.

  When the dye is adsorbed to the oxide semiconductor layer using a solution in which the dye to be used in combination is mixed and dissolved, the total concentration of the dye in the solution may be the same as when only one kind is supported.

  As a solvent in the case of using a mixture of dyes, the above-mentioned solvents can be used. Even when a solution is prepared for each dye to be used in combination and adsorbed to the semiconductor layer, the solvent described above can be used as the solvent, and the solvent for each dye to be used may be the same or different.

  When preparing a separate solution for each dye and immersing in each solution in order, the surface layer of the semiconductor layer on which the first dye is immersed and adsorbed is lightly washed with a good solvent for the dye. Multilayer adsorption can be achieved by immersion adsorption of the two dyes.

  Or it can also be set as multilayer adsorption | suction by immersing in the 1st pigment | dye liquid only in the upper layer of a semiconductor porous membrane layer with sufficient precision, and immersing the whole in a 2nd pigment | dye liquid.

  When the dye is supported on the thin film of oxide semiconductor fine particles, it is effective to support the dye in the presence of the inclusion compound in order to prevent the association between the dyes. Examples of inclusion compounds include steroidal compounds such as cholic acid, crown ether, cyclodextrin, calixarene, polyethylene oxide, and the like. Deoxycholic acid, dehydrodeoxycholic acid, chenodeoxycholic acid, methyl cholate are preferable. Examples include esters, cholic acids such as sodium cholate, polyethylene oxide, and the like.

  Further, after the dye is supported, the surface of the semiconductor layer may be treated with an amine compound such as 4-t-butylpyridine. As a treatment method, for example, a method in which a substrate provided with a semiconductor fine particle thin film carrying a pigment in an amine ethanol solution is immersed.

《Charge transfer layer》
The charge transfer layer is a layer containing a charge transport material having a function of replenishing electrons to the oxidant of the dye. Examples of typical charge transport materials that can be used in the present invention include a solvent in which a redox counter ion is dissolved, an electrolyte solution such as a room temperature molten salt containing the redox counter ion, and a solution of the redox counter ion. Examples thereof include a gel-like quasi-solidified electrolyte impregnated with a matrix, a low-molecular gelling agent, and the like, and a polymer solid electrolyte. In addition to charge transport materials that involve ions, electron transport materials and hole transport materials can also be used as materials whose carrier transport in solids is involved in electrical conduction, and these can be used in combination. Is possible.

  When using an electrolytic solution for the charge transfer layer, the redox counter ion contained is not particularly limited as long as it can be used in a generally known solar cell.

Specifically, those containing an oxidation-reduction counter ion such as I ⁻ / I ³⁻ series, Br ²⁻ / Br ³⁻ series, ferrocyanate / ferricyanate, ferrocene / ferricinium ion, cobalt Metal redox systems such as metal complexes such as complexes, organic redox systems such as alkyl thiol-alkyl disulfides, viologen dyes, hydroquinone / quinone, sulfur compounds such as sodium polysulfide, alkyl thiols / alkyl disulfides, etc. .

More specifically as iodine, iodine and LiI, NaI, KI, CsI, a combination of a metal iodide such as CaI _2, tetraalkylammonium iodide, pyridinium iodide, quaternary ammonium compounds such as imidazolium iodide And combinations with iodine salts of quaternary imidazolium compounds.

As More specifically bromine, bromine and LiBr, NaBr, KBr, CsBr, combination of metal bromide such as CaBr _2, tetraalkylammonium bromide, a combination of a bromine salt of a quaternary ammonium compound such as pyridinium bromide Can be mentioned.

  As a solvent, it is an electrochemically inert compound that has low viscosity and improved ion mobility, or has a high dielectric constant and improved effective carrier concentration, and can exhibit excellent ionic conductivity. Is desirable. Specifically, carbonate compounds such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, ether compounds such as dioxane, diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl Ethers, chain ethers such as polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, alcohols such as methanol, ethanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, Ethylene glycol, diethylene glycol, Polyhydric alcohols such as reethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerin, nitrile compounds such as acetonitrile, glutarodinitrile, propionitrile, methoxypropionitrile, methoxyacetonitrile, benzonitrile, tetrahydrofuran, dimethylsulfur Aprotic polar substances such as foxide and sulfolane can be used.

  A preferable electrolyte concentration is 0.1 M / L or more and 15 M / L or less, and more preferably 0.2 M / L or more and 10 M / L or less. Moreover, the preferable addition density | concentration of an iodine when using an iodine type is 0.01 M / L or more and 0.5 M / L or less.

  The molten salt electrolyte is preferable from the viewpoint of achieving both photoelectric conversion efficiency and durability. Examples of the molten salt electrolyte include WO95 / 18456 pamphlet, JP-A-8-259543, JP-A-2001-357896, Electrochemistry, Vol.65, No.11, p.923 (1997) and the like. And electrolytes containing known iodine salts such as pyridinium salts, imidazolium salts, and triazolium salts described in (1). These molten salt electrolytes are preferably in a molten state at room temperature, and it is preferable not to use a solvent.

  Gelled by techniques such as oligomers and polymers containing electrolytes or electrolyte solutions, addition of polymers, addition of low-molecular gelling agents and oil gelling agents, polymerization including polyfunctional monomers, polymer crosslinking reaction, etc. (Pseudo-solidification) can also be used.

  In the case of gelation by addition of a polymer, polyacrylonitrile and polyvinylidene fluoride can be preferably used.

  In the case of gelation by adding an oil gelling agent, a preferred compound is a compound having an amide structure in the molecular structure. When the electrolyte is gelled by a polymer crosslinking reaction, it is desirable to use a polymer containing a crosslinkable reactive group and a crosslinking agent in combination.

  In this case, a preferable crosslinkable reactive group is a nitrogen-containing heterocyclic ring (for example, a pyridine ring, an imidazole ring, a thiazole ring, an oxazole ring, a triazole ring, a morpholine ring, a piperidine ring, a piperazine ring), and a preferable crosslinking agent. Is a bifunctional or higher functional reagent (for example, alkyl halide, halogenated aralkyl, sulfonate ester, acid anhydride, acid chloride, isocyanate, etc.) capable of electrophilic reaction with a nitrogen atom.

  The concentration of the electrolyte is usually 0.01% by mass to 99% by mass, and preferably about 0.1% by mass to 90% by mass.

Further, as the gel electrolyte, an electrolyte composition containing an electrolyte and metal oxide particles and / or conductive particles can also be used. As the metal oxide particles, TiO ₂ , SnO ₂ , WO ₃ , ZnO, ITO, BaTiO ₃ , Nb ₂ O ₅ , In ₂ O ₃ , ZrO ₂ , Ta ₂ O ₅ , La ₂ O ₃ , SrTiO ₃ , Y Examples thereof include one or a mixture of two or more selected from the group consisting of ₂ O ₃ , Ho ₂ O ₃ , Bi ₂ O ₃ , CeO ₂ , and Al ₂ O ₃ . These may be doped impurities or complex oxides. Examples of the conductive particles include those made of a substance mainly composed of carbon.

  Next, the polymer electrolyte is a solid substance capable of dissolving the redox species or binding with at least one substance constituting the redox species, for example, polyethylene oxide, polypropylene oxide, polyethylene succinate, Polymer functional groups such as poly-β-propiolactone, polyethyleneimine, polyalkylene sulfide, or cross-linked products thereof, polyphosphazene, polysiloxane, polyvinyl alcohol, polyacrylic acid, polyalkylene oxide, Examples include those obtained by adding a polyether segment or oligoalkylene oxide structure as a side chain or a copolymer thereof. Among them, those having an oligoalkylene oxide structure as a side chain or a polyether segment as a side chain. Those with is preferable.

  In order to contain the redox species in the solid, for example, a method of polymerizing in the coexistence of a monomer that becomes a polymer compound and a redox species, a solid such as a polymer compound is dissolved in a solvent as necessary. Then, the above-mentioned method of adding the redox species can be used. The content of the redox species can be appropriately selected according to the required ion conduction performance.

  In the present invention, instead of an ion conductive electrolyte such as a molten salt, a solid hole transport material which is organic or inorganic or a combination of both can be used.

  Organic hole transport materials include aromatic amines and triphenylene derivatives, polyacetylene and its derivatives, poly (p-phenylene) and its derivatives, poly (p-phenylene vinylene) and its derivatives, polythienylene vinylene and its Conductive polymers such as derivatives, polythiophene and derivatives thereof, polyaniline and derivatives thereof, polytoluidine and derivatives thereof can be preferably used.

In order to control the dopant level, a compound containing a cation radical such as tris (4-bromophenyl) aminium hexachloroantimonate is added to the hole transport material, or the potential of the oxide semiconductor surface is controlled. In order to perform (space charge layer compensation), a salt such as Li [(CF ₃ SO ₂ ) ₂ N] may be added.

  A p-type inorganic compound semiconductor can be used as the inorganic hole transport material. The p-type inorganic compound semiconductor for this purpose preferably has a band gap of 2 eV or more, and more preferably 2.5 eV or more.

  Also, the ionization potential of the p-type inorganic compound semiconductor needs to be smaller than the ionization potential of the dye-adsorbing electrode from the condition that the holes of the dye can be reduced. Although the preferable range of the ionization potential of the p-type inorganic compound semiconductor varies depending on the dye used, it is generally preferably 4.5 eV or more and 5.5 eV or less, and more preferably 4.7 eV or more and 5.3 eV or less. .

  A preferred p-type inorganic compound semiconductor is a compound semiconductor containing monovalent copper, preferably CuI and CuSCN, and most preferably CuI.

A preferable hole mobility of the charge transfer layer containing the p-type inorganic compound semiconductor is 10 ⁻⁴ cm ² / V · sec or more and 10 ⁴ cm ² / V · sec or less, and more preferably 10 ⁻³ cm ² / V · sec. It is not less than sec and not more than 10 ³ cm ² / V · sec. The preferable conductivity of the charge transport layer is 10 ⁻⁸ S / cm or more and 10 ² S / cm or less, and more preferably 10 ⁻⁶ S / cm or more and 10 S / cm or less.

  In the present invention, the method for forming the charge transfer layer 4 between the semiconductor electrode and the cathode electrode 5 is not particularly limited. For example, the semiconductor electrode and the cathode electrode are disposed opposite to each other, and then both electrodes are disposed. A method of forming the charge transfer layer 4 by filling the above-described electrolyte solution and various electrolytes in between, and forming the charge transfer layer 4 by dropping or coating the electrolyte or various electrolytes on the semiconductor electrode or the cathode electrode, and then charge A method of superimposing the other electrode on the moving layer 4, a method of forming a hole for electrolyte injection in the electrode of the cell sealed except for the charge moving layer, and forming the charge moving layer 4 by injecting the electrolyte therefrom Can be used.

  In addition, in order to prevent electrolyte from leaking between the semiconductor electrode and the cathode electrode, the gap between the semiconductor electrode and the cathode electrode is sealed with a film or resin as necessary, or the semiconductor electrode and the charge transfer It is also preferable to store the layer 4 and the cathode electrode 5 in an appropriate case.

  In the case of the former forming method, as a method for filling the charge transfer layer, a normal pressure process using capillary action by dipping or the like, or a vacuum process in which the gas phase in the gap is replaced with a liquid phase at a pressure lower than normal pressure can be used. .

  In the latter forming method, microgravure coating, dip coating, screen coating, spin coating or the like can be used as a coating method. In the wet charge transfer layer, the counter electrode is provided in an undried state and measures for preventing liquid leakage at the edge portion are taken.

  In the case of a gel electrolyte, there is a method in which it is applied in a wet manner and solidified by a method such as polymerization. In this case, the counter electrode can be applied after drying and fixing.

  In the case of a solid electrolyte or a solid hole transport material, a charge transfer layer can be formed by a dry film formation process such as a vacuum deposition method or a CVD method, and then a cathode electrode can be applied. Specifically, it can be introduced into the electrode by techniques such as vacuum deposition, casting, coating, spin coating, dipping, electropolymerization, and photoelectropolymerization. It is formed by evaporating the solvent by heating to an arbitrary temperature.

The thickness of the charge transfer layer is preferably 10 μm or less, more preferably 5 μm or less, and further preferably 1 μm or less. The conductivity of the charge transfer layer is preferably 1 × 10 ⁻¹⁰ S / cm or more, and more preferably 1 × 10 ⁻⁵ S / cm or more.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these.

  In addition, although the display of "part" or "%" is used in an Example, unless there is particular notice, it represents "mass part" or "mass%".

  The structural formulas of the compounds used in the examples are shown below.

Example 1
<< Production of translucent conductive base material >>
[Undercoat layer formation]
A glass substrate having a thickness of 2 mm is subjected to a corona discharge treatment of 12 W · min / m ² , and the undercoating liquid B-1 is applied so as to have a dry film thickness of 0.1 μm, and then 12 W · min / m ^2. The undercoat coating solution B-2 was applied to a dry film thickness of 0.06 μm.

  Then, heat processing for 1.5 minutes was implemented at 120 degreeC, and the glass substrate (Base1) after subtraction was obtained.

<Undercoating liquid B-1>
Copolymer latex liquid of 20 parts by mass of styrene, 40 parts by mass of glycidyl methacrylate and 40 parts by mass of butyl acrylate (solid content: 30%) 50 g
SnO ₂ sol (A) 440 g
Compound (UL-1) 0.2g
Finish with water 1000ml
<Undercoating liquid B-2>
10g gelatin
Compound (UL-1) 0.2g
Compound (UL-2) 0.2g
Silica particles (average particle size 3μm) 0.1g
Hardener (UL-3) 1g
Finish with water 1000ml
(Preparation of SnO ₂ sol (A))
65 g of SnCl ₄ .5H ₂ O was dissolved in 2000 ml of distilled water to make a homogeneous solution, which was then boiled to obtain a precipitate. The produced precipitate is taken out by decantation and washed with distilled water many times.

  Silver nitrate is added dropwise to distilled water in which the precipitate has been washed, and after confirming that there is no reaction of chlorine ions, distilled water is added to the washed precipitate to make a total volume of 2000 ml. To this, 40 ml of 30% aqueous ammonia was added and heated to obtain a uniform sol.

Further, while adding ammonia water, the solution was concentrated by heating until the solid content concentration of SnO ₂ reached 8.3% by mass to obtain SnO ₂ sol (A).

[Preparation of silver halide fine grain emulsion EMP-1]
In the reaction vessel, the following solution-A was kept at 34 ° C., and the pH was adjusted to 2 using nitric acid (concentration 6%) while stirring at high speed using the mixing and stirring apparatus described in JP-A-62-2160128. .95.

  Subsequently, the following Solution-B and Solution-C were added at a constant flow rate over 8 minutes and 6 seconds using the double jet method. After completion of the addition, the pH was adjusted to 5.90 using sodium carbonate (concentration 5%), and then the following Solution-D and Solution-E were added.

(Solution-A)
Alkali-treated inert gelatin (average molecular weight 100,000) 18.7g
Sodium chloride 0.31g
Following (Solution-I) 1.59ml
1246 ml of pure water.

(Solution-B)
169.9g of silver nitrate
Nitric acid (concentration 6%) 5.89ml
Finish to 317.1 ml with pure water.

(Solution-C)
Alkali-treated inert gelatin (average molecular weight 100,000) 5.66 g
Sodium chloride 58.8g
13.3 g of potassium bromide
(Solution-I) 0.85 ml
(Solution-II) 2.72 ml
Finish to 317.1 ml with pure water.

(Solution-D)
2-Methyl-4hydroxy-1,3,3a, 7-tetraazaindene 0.56 g
112.1 ml of pure water.

(Solution-E)
Alkali-treated inert gelatin (average molecular weight 100,000) 3.96 g
Following (Solution-I) 0.40ml
128.5 ml of pure water.

(Solution-I)
Surfactant: 10% by mass methanol solution of polyisopropylene polyethylene oxydisuccinate sodium salt (Solution-II)
10% by weight aqueous solution of a rhodium hexachloride complex.

  After completion of the above operation, desalting and washing with water using a flocculation method at 40 ° C. according to a conventional method, adding Solution-F and an antibacterial agent, dispersing well at 60 ° C., and adjusting the pH at 40 ° C. By adjusting to 5.90, a silver chlorobromide cubic grain emulsion (EMP-1) finally containing 10 mol% of silver bromide and having an average grain size of 0.09 μm and a coefficient of variation of 10% was obtained.

(Solution-F)
Alkali-treated inert gelatin (average molecular weight 100,000) 16.5g
Pure water 139.8 ml.

(Preparation of photosensitive material 101)
After applying the above-mentioned silver halide fine grain emulsion EMP-1 on the glass substrate (Base 1) prepared above so that the amount of applied silver is 0.8 g / m ^{2 in} terms of silver. The photosensitive material 101 was prepared by drying.

  In the preparation of the photosensitive material 101, a hardening agent (tetrakis (vinylsulfonylmethyl) methane) was added at a ratio of 50 mg per 1 g of gelatin. Further, a surfactant (disulfosulfonic acid di (2-ethylhexyl) · sodium) was added as a coating aid to adjust the surface tension.

  The amount of gelatin was adjusted so that the volume ratio of silver to gelatin was 0.5. The volume ratio of silver and gelatin as used herein refers to a value obtained by dividing the volume of silver halide fine particles applied by the volume of gelatin applied.

<< Production of Translucent Conductive Substrate S101 >>
The photosensitive material 101 produced above was exposed using an ultraviolet lamp through a lattice-like photomask having a line width (also referred to as a silver thin line width) of 8 μm and a line-to-line spacing of 250 μm. .

  Next, after developing for 30 seconds at 35 ° C. using the following developer (DEV-1), fixing processing is performed for 60 seconds at 35 ° C. using the following fixing solution (FIX-1). Washing with water was performed. Further, physical development was performed at 30 ° C. for 5 minutes using the following physical developer (PD-1), followed by washing with water.

  Thereafter, the photosensitive material 101 was cut into a size of 300 mm × 300 mm, immersed in a plating solution (EPL-1), and subjected to electrolytic copper plating at 25 ° C.

  The electrolytic copper plating was performed by adjusting the applied current and the processing time until the line width of the current collector became 13.5 μm, washed with water and dried to obtain a plated current collector board.

  Using a tin-doped indium oxide (ITO) material as a target, a high-frequency magnetron sputtering device is used to form a conductive coating layer on the surface of the current collector (current collector grid) and the opening so that the film thickness is 150 nm (here The conductive coating layer provided on the surface of the current collector becomes the first conductive coating layer.) Further, similarly, Pt is formed so that the film thickness is 2 nm using a platinum plate as a target, A translucent conductive substrate S101 was produced.

(DEV-1: Developer)
500 ml of pure water
Metol 2g
80 g of anhydrous sodium sulfite
Hydroquinone 4g
4g borax
Sodium thiosulfate 10g
Potassium bromide 0.5g
Add water to bring the total volume to 1L.

(FIX-1: Fixer)
750 ml of pure water
Sodium thiosulfate 250g
Anhydrous sodium sulfite 15g
Glacial acetic acid 15ml
Potash alum 15g
Add water to bring the total volume to 1L.

(PD-1: Physical developer)
800ml of pure water
Citric acid 31g
Hydroquinone 7.8g
Disodium hydrogen phosphate 1.1g
Ammonia water (28%) 2.2ml
Silver nitrate 1.5g
Add water to bring the total volume to 1L.

(EPL-1: Electrolytic plating solution)
Copper sulfate (pentahydrate) 200g
50g of sulfuric acid
Sodium chloride 0.1g
Add water to bring the total volume to 1L.

<< Production of Translucent Conductive Substrate S102 >>
In the production of the light-transmitting conductive substrate S101, the light-transmitting property is the same except that the photosensitive material 101 is exposed using a lattice-shaped photomask having a line width of 8 μm and a distance between lines of 500 μm. A conductive substrate S102 was produced.

<< Production of Translucent Conductive Substrate S103 >>
In the production of the light-transmitting conductive substrate S101, the light-transmitting property is the same except that the photosensitive material 101 is exposed using a lattice-shaped photomask having a line width of 8 μm and a line-to-line spacing of 150 μm. A conductive substrate S103 was produced.

<< Production of Translucent Conductive Substrate S104 >>
In the production of the light-transmitting conductive substrate S101, the light-transmitting property is the same except that the photosensitive material 101 is exposed using a lattice-shaped photomask having a line width of 8 μm and a distance between the lines of 100 μm. A conductive substrate S104 was produced.

<< Production of Translucent Conductive Substrate S105 >>
In the production of the light-transmitting conductive substrate S101, the photosensitive material 101 is exposed through a grid-like photomask having a line width of 5 μm and a line-to-line spacing of 150 μm. Then, the translucent conductive substrate S105 was produced in the same manner except that the treatment time was adjusted and the treatment was performed until the line width of the current collecting line became 8.5 μm.

<< Production of Translucent Conductive Substrate S106 >>
In the production of the translucent conductive substrate S101, the photosensitive material 101 is exposed through a grid-like photomask having a line width of 12 μm and a distance between the lines of 400 μm. Then, a light-transmitting conductive substrate S106 was prepared in the same manner except that the treatment time was adjusted and the treatment was performed until the line width of the current collector became 20 μm.

<< Production of Translucent Conductive Substrate S107 >>
In the production of the light-transmitting conductive substrate S101, the photosensitive material 101 is exposed through a lattice-like photomask having a line width of 8 μm and a line-to-line spacing of 300 μm. Then, a light-transmitting conductive substrate S107 was produced in the same manner except that the treatment time was adjusted and treatment was performed until the line width of the current collector became 20 μm.

<< Production of Translucent Conductive Substrate S108 >>
In the production of the light-transmitting conductive substrate S101, the photosensitive material 101 is exposed through a grid-like photomask having a line width of 12 μm and a line-to-line spacing of 500 μm. Then, a light-transmitting conductive substrate S108 was produced in the same manner except that the treatment time was adjusted and treatment was performed until the line width of the current collector became 25 μm.

<< Production of Translucent Conductive Substrate S109 >>
In the production of the light-transmitting conductive substrate S101, the photosensitive material 101 is exposed through a grid-like photomask having a line width of 12 μm and a line-to-line spacing of 1000 μm. Then, a translucent conductive substrate S109 was produced in the same manner except that the treatment time was adjusted and the treatment was performed until the line width of the current collector became 30 μm.

<< Production of Translucent Conductive Substrate S110 >>
In the production of the translucent conductive substrate S101, a translucent conductive substrate S110 is produced in the same manner as S101 except that a tin-doped indium oxide (ITO) layer and a platinum layer are not formed on the current collecting grid and in the opening. did.

<< Production of Translucent Conductive Substrate S111 >>
Using the tin-doped indium oxide (ITO) material as a target on the 2 mm-thick glass substrate, a high-frequency magnetron sputtering apparatus is used to form a conductive coating layer so that the film thickness is 150 nm. Pt was formed on the target so that the film thickness was 2 nm, and a light-transmitting conductive substrate S111 was manufactured.

<< Production of Translucent Conductive Substrate S112 >>
In the production of the light-transmitting conductive substrate S101, a high-frequency magnetron sputtering apparatus is used to conduct the conductive film so that the film thickness becomes 150 nm, using a fluorine-doped tin oxide (FTO) material as a target instead of the tin-doped indium oxide (ITO) material. A transparent conductive substrate S112 was produced in the same manner except that a conductive coating layer was formed.

<< Production of Translucent Conductive Substrate S113 >>
In the production of the light-transmitting conductive substrate S101, the conductive coating layer formed by using a high-frequency magnetron sputtering apparatus is used instead of the conductive coating layer. C. A translucent conductive substrate S113 was produced in the same manner except that a BYTRON PH510 manufactured by Starck Co., Ltd. (an aqueous solution in which 5% of DMSO was added to BAYTRON-PH510 was used) was formed so as to have a dry film thickness of 100 nm.

  About each of obtained translucent conductive substrate S101-S113, the line width ratio before and behind plating and surface resistance were measured as follows. The measurement results are shown in Table 1.

  The translucent conductive substrates S101 to S113 are used as cathode electrodes of the dye-sensitized solar cell of the present invention.

<Measurement of line width ratio before and after plating>
In the translucent conductive substrates S101 to S113, before and after the electrolytic copper plating process, the line width of the line forming the lattice pattern was measured using a microscope MS-804 (Mortex).

<Surface resistance measurement>
In the translucent conductive substrates S101 to S113, after the electrolytic copper plating process, the surface resistance value of the translucent conductive substrate whose surface is covered with the conductive coating layer is measured with a resistivity meter (Loresta GP (MCP-T610 type)). : Measured using Dia Instruments Co., Ltd. The measurement was performed at the center of the substrate.

  For S110 (a substrate without a conductive coating layer), the surface resistance value at the center of the substrate was measured in the same manner.

<< Preparation of dye-sensitized solar cell SC-101 >>
On the titanium plate, a high-frequency magnetron sputtering apparatus was used to form a 10 nm-thick semiconductor film using a titanium oxide plate as a target material as a short-circuit prevention layer. On top of that, a titanium oxide paste for light absorption layer (Ti-Nanoxide-D / SP manufactured by SOLARONIX) was printed by a screen printer.

Here, the layer of titanium oxide paste was prepared by overprinting using a screen printing method so that the film thickness was about 12 μm. After natural drying, drying at 120 ° C. is performed for 10 minutes, the periphery of the formed semiconductor porous film is cut to 50 mm × 50 mm (effective area 25 cm ² ), and the temperature is increased to 500 ° C. over 30 minutes. And the semiconductor porous membrane layer which consists of titanium oxide was formed on the titanium plate by baking for 15 minutes at 500 degreeC constant temperature from there.

After the baking treatment, when cooled to about 100 ° C., 5.0 × 10 ⁻⁴ mol / L of ruthenium complex dye compound A (N719) for dye-sensitized solar cell, acetonitrile: t-butanol = 1: 1 ( Anode electrode A101 having a semiconductor porous membrane layer in which the dye is adsorbed and then sufficiently washed off with the acetonitrile: t-butanol solution and vacuum dried to adsorb the dye. Was made.

  In S101 of the translucent conductive substrate used as the cathode electrode, a hole for injecting an electrolyte is provided, and the S101 and A101 are made of a sheet-like spacer / sealing material having a thickness of 25 μm (SX-1170-25 manufactured by SOLARONIX) From the electrolyte injection hole provided in the translucent conductive substrate S101, in a mixed solvent of acetonitrile: ethylene carbonate having a volume ratio of 1: 4, 0.10 mol / liter of lithium iodide, 1, Charge transfer layer containing a redox electrolyte in which 2-dimethyl-3-propylimidazolium iodide 0.60 mol / liter, iodine 0.05 mol / liter, 4-t-butylpyridine 0.50 mol / liter is dissolved. The hole was closed with a hot bond, and a cover glass was attached and sealed from above using the sealant.

  An antireflection film (hard coat / antireflection type cellulose film manufactured by Konica Minolta Opto Co., Ltd.) was laminated on the light receiving surface side of the light transmitting conductive substrate S101 in the previous period to prepare a dye-sensitized solar cell sealing cell SC-101. .

<< Preparation of dye-sensitized solar cells SC-102 to SC-113 >>
In the production of the dye-sensitized solar cell SC-101, the dye-sensitized solar cell SC-101 was similarly performed except that the light-transmitting conductive substrates S102 to S113 were used instead of the light-transmitting conductive substrate S101. Each of 102 to SC-113 was prepared.

<< Evaluation of photoelectric conversion characteristics of dye-sensitized solar cells SC-102 to SC-113 >>
About the dye-sensitized solar cell produced above (also referred to as a solar cell), a solar simulator (SS-100XIL manufactured by Eihiro Seiki Co., Ltd.) was used to irradiate light with an intensity of AM1.5 filter and 100 mW / m ² . As characteristics, three each of the short-circuit current Jsc (mA / cm ² ) and the open circuit voltage value Voc (V) were evaluated by the same configuration and manufacturing method, and expressed as an average value.

  Moreover, photoelectric conversion efficiency (eta) (%) was calculated | required from Jsc, Voc, and FF (fill factor) of each pigment | dye solar cell.

  The physical characteristics (area of the semiconductor porous film, silver thin wire, line width of the collector line, line width ratio, pitch, aperture ratio, transmittance, surface resistance) of each obtained dye solar cell are shown in Table 1. Table 2 shows the photoelectric conversion characteristics of the solar cell.

From Table 1 and Table 2, compared with the comparison, the dye-sensitized solar cell (solar cell) of the present invention has a short-circuit current Jsc (mA / cm ² ), an open-circuit voltage value Voc (V), and FF (fill It can be seen that good characteristics are exhibited over all of the factor) and photoelectric conversion efficiency η (%).

Example 2
<< Production of translucent conductive base material >>
In the same manner as in Example 1, the silver halide fine grain emulsion EMP-1 prepared as described above was applied on Base 1 with an undercoat layer so that the amount of coated silver was 0.4 g / m ^{2 in} terms of silver. A photosensitive material 201 was produced in the same manner as in Example 1 except that coating was performed.

<< Production of Translucent Conductive Substrate S201 >>
The photosensitive material 201 produced as described above is exposed using an ultraviolet lamp through a lattice-like photomask having a line width (also referred to as a silver thin line width) of 12 μm and a distance between lines of 250 μm. Went.

  Next, after developing for 30 seconds at 35 ° C. using the developer (DEV-1) described in Example 1, the fixing treatment for 60 seconds at 35 ° C. is performed using the following fixing solution (FIX-1). Followed by washing with water.

  Further, using the physical developer (PD-1) described in Example 1, physical development was performed at 30 ° C. for 5 minutes, and then washing treatment was performed.

  Thereafter, the glass sample was cut into a size of 300 mm × 300 mm, immersed in a plating solution (EPL-1), and subjected to electrolytic copper plating at 25 ° C. The electrolytic copper plating was performed by adjusting the applied current and the processing time until the line width of the current collector became 13.5 μm, washed with water and dried to obtain a plated current collector board.

  Using tin-doped indium oxide (ITO) as a target, a high-frequency magnetron sputtering device is used, and a conductive coating is applied so that the film thickness is 150 nm at the top (including the surroundings) and opening of the current collector (also called current collector grid). In the same manner, Pt was formed to a thickness of 2 nm using a platinum plate as a target, and a light-transmitting conductive substrate S201 was produced.

<< Production of Translucent Conductive Substrate S202 >>
In the production of the translucent conductive substrate S201, the photosensitive material 201 is exposed through a grid-like photomask having a line width of 8 μm and an interval between lines of 250 μm. In addition, a translucent conductive substrate S202 was produced in the same manner except that the treatment time was adjusted and the treatment was performed until the line width became 12.5 μm.

About translucent conductive substrate S201 and S202 which were obtained, it is as follows before and after plating.
In the translucent conductive substrate S101 of Example 1 and the translucent conductive substrates S201 to S202 obtained above, lines of lines forming a lattice pattern before and after the electrolytic copper plating process The width was measured using a microscope MS-804 (manufactured by Moritex) and the ratio was determined and shown in Table 2.

  Moreover, the height of the current collector line subjected to electrolytic copper plating was measured using a stylus type surface shape measuring instrument DEKTAK-6M (manufactured by ULVAC), and the cross-sectional area of the current collector line was determined and shown in Table 3.

<Surface resistance measurement>
In the translucent conductive substrates S101 and S201 to S202, after the electrolytic copper plating process, the surface resistance value of the translucent conductive substrate whose surface is covered with the conductive coating layer is measured with a resistivity meter (Loresta GP (MCP-T610 Type): Measured using Dia Instruments Co., Ltd. The measurement was performed at the center of the substrate, and the results are shown in Table 3.

<< Preparation of dye-sensitized solar cells SC-201 and SC-202 >>
In the production of the dye-sensitized solar cell SC-101, the dye-sensitized solar cells SC-201 and SC-202 were similarly manufactured except that S201 and S202 were used instead of the translucent conductive substrate S101. Each was produced.

<< Evaluation of photoelectric conversion characteristics of solar cells >>
About the dye-sensitized solar cell (also referred to as solar cell) SC-201, 202 produced above, AM1.5 filter, light having an intensity of 100 mW / m ² by a solar simulator (SS-100XIL manufactured by Eihiro Seiki Co., Ltd.) Were measured, and the short circuit current Jsc (mA / cm ² ) and the open circuit voltage value Voc (V) were evaluated with the same configuration and production method, and the average value was obtained. Further, the photoelectric conversion efficiency η (%) was obtained from Jsc, Voc and FF (fill factor).

  Table 4 shows the obtained results.

  From Tables 3 and 4, the dye-sensitized solar cell SC-101 having a line width ratio of 1.69 compared to the dye-sensitized solar cell SC-201 having a line width ratio of 1.13, the line width It is clear that the dye-sensitized solar cell SC-202 having a ratio of 1.56 is further excellent in photoelectric conversion efficiency.

Example 3
《Preparation of flexible dye-sensitized solar cell》
In Example 1, a polyethylene terephthalate (PEN) substrate was used instead of the 2 mm-thick glass substrate used for the production of the translucent conductive substrate SC-101, and a titanium foil film film was used instead of the titanium plate used for the anode electrode. In addition, the titanium oxide paste for the light absorption layer was replaced with Ti-Nanoxide-D / SP made by SOLARONIX, and Ti-Nanoxide-DL made by the same was printed by a screen printer and sintered at 120 ° C. Similarly, a flexible dye-sensitized solar cell was produced.

When the obtained flexible dye-sensitized solar cell was evaluated using the evaluation method described in Example 1 and Example 2, even if the substrate and the material were changed, the book described in Example 1 and Example 2 was used. Similar to the dye-sensitized solar cell of the invention, all of the short-circuit current Jsc (mA / cm ² ), the open-circuit voltage value Voc (V), FF (fill factor), and the photoelectric conversion efficiency η (%) are all good. It is clear that the characteristic is shown.

It is a schematic sectional drawing which shows the basic structure of the dye-sensitized solar cell of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Sensitizing dye molecule 3 Semiconductor porous layer 4 Translucent conductive substrate (cathode electrode)
DESCRIPTION OF SYMBOLS 5 Charge transfer layer 6 Sealing material 41 Transparent base material 42 Current collection line 42a Conductive plating layer 42b Metal fine wire 43 Conductive coating layer

Claims (6)

A cathode electrode comprising an anode electrode having a semiconductor porous layer in which at least a sensitizing dye is adsorbed on a substrate containing at least a conductor, and a translucent conductive substrate facing the semiconductor porous layer side of the anode electrode In the dye-sensitized solar cell having a configuration in which an electrolyte layer is sealed between the two electrodes, the anode electrode and the cathode electrode,
The translucent conductive substrate has a current collector having a line width of 5 μm to 20 μm and an aperture ratio of 84% to 98% on at least a transparent substrate, and the surface of the current collector is a first surface Covered by a conductive coating layer ,
Following (1) to (4):
(1) The current collector has a two-layer configuration in which a conductive metal is electroplated on a silver thin wire, and a line width ratio between the current collector and the silver thin wire is 1.2 to 2.0 (line width ratio). = Line width of current collector / line width of silver thin line);
(2) cross-sectional area of the current wire is 30μm ² ~200μm ^2;
(3) The surface of the current collector is covered with a first conductive coating layer, and the opening of the translucent conductive substrate is covered with a second conductive coating layer; and
(4) Each of the transparent substrates is made of a flexible substrate.
A dye-sensitized solar cell that satisfies at least one of the requirements . The dye-sensitized solar cell according to claim 1, wherein the conductive coating layer is made of a metal oxide. The dye-sensitized solar cell according to claim 1, wherein the conductive coating layer is made of a conductive polymer. In the (3), said first conductive coating layer, dye-sensitized solar cell according to any one of claims 1 to 3, characterized in that a material having a redox catalytic ability. In the (3), said second conductive coating layer, dye-sensitized solar cell according to any one of claims 1 to 4, characterized in that a metal oxide. In the (3), said second conductive coating layer, dye-sensitized solar cell according to any one of claims 1 to 4, characterized in that it consists of a conductive polymer.

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