JP2006302618A - Dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized solar cell equipped with a low-cost catalyst electrode excellent in collecting efficiency with sufficient durability. <P>SOLUTION: The dye-sensitized solar cell 101 comprises: a translucent substrate 1 (a glass substrate or the like); a semiconductor electrode 2 (made of porous titania or the like) with sensitizing dye fitted on its one side; a ceramic substrate 3 (made of alumina or the like) arranged in opposition to one side of the translucent substrate 1; a collecting electrode 4 set in opposition to the semiconductor electrode 2 on the surface and containing tungsten, a catalyst electrode 5 fitted on the surface; and electrolyte solution 6 (containing electrolyte of I<SB>2</SB>, LiI, imidazolium iodide or the like) contained in at least a part each of the semiconductor electrode 2 and the catalyst electrode 5 and filled between them. The catalyst electrode 5 is provided with a porous resin layer 51 and activated carbon 52 retained by the porous resin layer 51. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dye-sensitized solar cell that directly converts light energy into electric energy. More specifically, the present invention relates to a dye-sensitized solar cell having a catalyst electrode that is excellent in current collection efficiency and inexpensive and has sufficient durability.

  At present, in solar power generation, solar cells using single crystal silicon, polycrystalline silicon, amorphous silicon, and HIT (Heterojunction with Intrinsic Thin-layer) combined with these have been put into practical use and have become the main technology. Although these solar cells have an excellent photoelectric conversion efficiency of nearly 20%, this silicon solar cell has a high energy cost for material production, and has many problems in terms of environmental impact, etc. There are also limitations.

  On the other hand, a dye-sensitized solar cell proposed by Gratzel et al. Has attracted attention as an inexpensive solar cell (see, for example, Patent Document 1 and Non-Patent Document 1). This solar cell has a structure in which an electrolytic solution is interposed between a titania porous electrode carrying a sensitizing dye and a catalyst electrode, and although the conversion efficiency is lower than that of current silicon solar cells, Cost reduction is possible in terms of manufacturing method and the like.

  In this dye-sensitized solar cell, a catalyst electrode made of platinum that is excellent in catalytic action and has sufficient corrosion resistance against an electrolytic solution is often used. However, platinum is extremely expensive, which hinders cost reduction of the dye-sensitized solar cell. Thus, it has been proposed to use activated carbon having sufficient catalytic action and cheaper than platinum for the catalyst electrode. (For example, refer to Patent Document 2).

Japanese Patent Laid-Open No. 1-220380 Nature (Vol. 353, pp. 737-740, 1991) JP 2003-297446 A

When activated carbon is used, a catalyst electrode cannot be formed by itself, for example, a method of binding activated carbon to a substrate with a binder, a method of bonding a composite sheet having activated carbon bound to a substrate, and the like. Proposed. However, these methods have a problem that the conductivity of the formed catalyst electrode is low, and the current collection efficiency in the catalyst electrode cannot be sufficiently increased.
The present invention has been made in view of the above situation, and an object of the present invention is to provide a dye-sensitized solar cell having a catalyst electrode that is excellent in current collection efficiency and inexpensive and has sufficient durability. And

The present invention is as follows.
1. Translucent substrate 1, semiconductor electrode 2 provided on one surface side of translucent substrate 1 and having a sensitizing dye, and ceramic substrate disposed to face the one surface side of translucent substrate 1 3, a collector electrode 4 provided on the surface of the ceramic substrate 3 so as to face the semiconductor electrode 2 and containing tungsten, a catalyst electrode 5 provided on the surface of the collector electrode 4, and the semiconductor An electrolyte solution 6 contained in at least a part of each of the electrode 2 and the catalyst electrode 5 and filled between the semiconductor electrode 2 and the catalyst electrode 5, the catalyst electrode 5 being porous A dye-sensitized solar cell comprising: a resin layer 51; and activated carbon 52 held by the porous resin layer 51.
2. The catalyst electrode 5 is formed by bonding a porous resin sheet holding activated carbon 52 to the surface of the current collecting electrode 4. 2. A dye-sensitized solar cell according to 1.
3. The catalyst electrode 5 is formed by applying a slurry containing activated carbon 52 and a resin to the surface of the collecting electrode 4 and drying the slurry. 2. A dye-sensitized solar cell according to 1.
4). 1. The porous resin layer 51 is made of a fluororesin. To 3. The dye-sensitized solar cell of any one of these.
5. 1. The porous resin layer 51 further containing carbon black. To 4. The dye-sensitized solar cell of any one of these.
6). Between the one surface side of the translucent substrate 1 and the ceramic substrate 3 or the collector electrode 4 is sealed with resin or glass around the semiconductor electrode 2. To 5. The dye-sensitized solar cell of any one of these.

The dye-sensitized solar cell of the present invention has an excellent current collection efficiency and is provided with an inexpensive catalyst electrode, and has sufficient durability because one substrate is a ceramic substrate.
Further, when the catalyst electrode 5 is formed by bonding a porous resin sheet holding the activated carbon 52 to the surface of the current collecting electrode 4, and the catalyst electrode 5 is a slurry containing the activated carbon 52 and the resin as the current collecting electrode. When it is applied to the surface of 4 and dried, an inexpensive catalyst electrode can be easily formed.
Furthermore, when the porous resin layer 51 is made of a fluororesin, a highly durable dye-sensitized solar cell can be obtained.
Moreover, when carbon black is further contained in the porous resin layer 51, the conductivity of the catalyst electrode is improved, and a dye-sensitized solar cell including a catalyst electrode having more excellent current collection efficiency can be obtained. .
Further, when the space between the one surface side of the translucent substrate 1 and the ceramic substrate 3 or the collecting electrode 4 is sealed with resin or glass around the semiconductor electrode 2, the electrolytic solution 6 is placed in this sealed space. Thus, a dye-sensitized solar cell having sufficient durability can be obtained.

Hereinafter, the present invention will be described in detail.
The dye-sensitized solar cell of the present invention is provided on a translucent substrate 1, a semiconductor electrode 2 provided on one surface side of the translucent substrate 1 and having a sensitizing dye, and on the one surface side of the translucent substrate 1. The ceramic substrate 3 disposed oppositely, the collector electrode 4 provided on the surface of the ceramic substrate 3 so as to face the semiconductor electrode 2 and containing tungsten, and the catalyst electrode provided on the surface of the collector electrode 4 5 and an electrolyte 6 contained in at least a part of each of the semiconductor electrode 2 and the catalyst electrode 5 and filled between the semiconductor electrode 2 and the catalyst electrode 5, the catalyst electrode 5 being porous The resin layer 51 and the activated carbon 52 held by the porous resin layer 51 are included.

Examples of the “translucent substrate 1” include substrates made of glass, resin sheets, and the like. This resin sheet is not particularly limited, and examples thereof include resin sheets prepared using polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyphenylene sulfide, polycarbonate, polysulfone, and polyethyleneidene norbornene. The thickness of the translucent substrate 1 varies depending on the material and is not particularly limited. However, the visible light transmittance represented by the translucency described below is 60 to 99%, particularly 85 to 99%. It is preferable.
In addition, this translucency means that the transmittance | permeability of visible light with a wavelength of 400-900 nm is 10% or more. The visible light transmittance is preferably 60% or more, particularly preferably 85% or more.
Translucency (%) = (amount of light transmitted through the translucent substrate / amount of light incident on the translucent substrate) × 100

  The “semiconductor electrode 2” includes a porous electrode substrate and a sensitizing dye attached to the porous electrode substrate. The porous electrode substrate can be formed of a metal oxide, a metal sulfide or the like. Examples of the metal oxide include titania, tin oxide, zinc oxide, niobium oxide such as niobium pentoxide, tantalum oxide, and zirconia. Furthermore, double oxides such as strontium titanate, calcium titanate, and barium titanate can also be used. Examples of the metal sulfide include zinc sulfide, lead sulfide, bismuth sulfide and the like. The method for producing the porous electrode substrate is not particularly limited. For example, a translucent conductive layer, which will be described later, is usually provided on one surface of the translucent substrate 1 with a paste containing fine particles such as metal oxide and metal sulfide. It can be produced by applying to the surface of 8 and firing. The method for applying the paste is not particularly limited, and examples thereof include a screen printing method, a doctor blade method, a squeegee method, and a spin coating method. The porous electrode substrate produced in this way is formed in the form of an aggregate made up of fine particles.

  The porous electrode substrate is coated with a colloidal solution in which fine particles such as metal oxide and metal sulfide and a small amount of organic polymer are dispersed on the surface of the translucent conductive layer 8 and the like, then dried, Alternatively, the organic polymer can be decomposed and removed by heating and then baked. This colloidal solution can also be applied by various methods such as a screen printing method, a doctor blade method, a squeegee method, and a spin coating method. The porous electrode substrate produced by this method is also formed in the form of an aggregate made up of fine particles.

  Although the firing conditions are not particularly limited, the firing temperature can be 400 to 600 ° C., particularly 450 to 550 ° C., and the firing time can be 10 to 300 minutes, particularly 20 to 40 minutes. The firing atmosphere can be an oxidizing atmosphere such as an air atmosphere or an inert atmosphere such as a rare gas atmosphere such as argon and a nitrogen gas atmosphere.

  The porous electrode substrate can be subjected to titanium chloride treatment. The conversion efficiency can be improved by this titanium chloride treatment. For this treatment, titanium tetrachloride is usually used, but titanium trichloride can also be used. The titanium chloride treatment method is not particularly limited, and (1) a treatment method comprising a step of bringing a porous electrode substrate and a titanium chloride aqueous solution into contact with each other and then firing, and (2) titanium chloride particles on the porous electrode substrate. Examples of the treatment method include a step of exposing to a dry gas (air, nitrogen gas, etc.) at a high temperature (for example, 400 to 600 ° C.) and then baking.

  The “sensitizing dye” has an effect of improving the efficiency of photoelectric conversion. As this sensitizing dye, a complex dye and an organic dye can be used. Examples of complex dyes include metal complex dyes, and examples of organic dyes include polymethine dyes and merocyanine dyes. Examples of the metal complex dye include a ruthenium complex dye and an osmium complex dye, and a ruthenium complex dye is particularly preferable. Moreover, in order to expand the wavelength range in which photoelectric conversion is performed and improve the conversion efficiency, two or more sensitizing dyes having different wavelength ranges in which photoelectric conversion is performed can be used in combination. In this case, it is preferable to set the type of sensitizing dye to be used in combination and the amount ratio thereof depending on the wavelength range and intensity distribution of the irradiated light. Furthermore, the sensitizing dye preferably has a functional group for bonding to the semiconductor electrode. Examples of this functional group include a carboxyl group, a sulfonic acid group, and a cyano group.

  The method for attaching the sensitizing dye to the porous electrode substrate is not particularly limited. For example, the porous electrode substrate is immersed in a solution in which the sensitizing dye is dissolved in an organic solvent to impregnate the solution, and then the organic solvent is used. It can be made to adhere by removing. Alternatively, this solution can be applied to a porous electrode substrate and impregnated, and then adhered by removing the organic solvent. Examples of the coating method include a wire bar method, a slide hopper method, an extrusion method, a curtain coating method, a spin coating method, and a spray coating method. Further, this solution can be applied by various printing methods such as offset printing, gravure printing, and screen printing.

  The adhesion amount of the sensitizing dye is not particularly limited, but is preferably 0.01 to 1 mmol, particularly preferably 0.5 to 1 mmol with respect to 1 g of the porous electrode substrate. When the adhesion amount is 0.01 to 1 mmol, photoelectric conversion in the semiconductor electrode is efficiently performed. In addition, if the sensitizing dye that has not adhered to the porous electrode substrate is liberated around the electrode, the conversion efficiency may decrease. For this reason, it is preferable to remove the excess sensitizing dye by washing the semiconductor electrode after the treatment for attaching the sensitizing dye. This removal can be performed by washing with an organic solvent such as acetonitrile and an alcohol solvent using a washing tank. Furthermore, in order to attach many sensitizing dyes, it is preferable to heat the porous electrode substrate and perform treatments such as dipping and coating. In this case, in order to avoid water adsorbing on the surface of the porous electrode substrate, it is preferable to perform the treatment promptly at 40 to 80 ° C. without heating to room temperature after heating.

  The thickness of the semiconductor electrode 2 is not particularly limited, but may be 0.1 to 100 μm, preferably 1 to 30 μm, and particularly preferably 2 to 25 μm. When the thickness of the semiconductor electrode 2 is 0.1 to 100 μm, photoelectric conversion is sufficiently performed and power generation efficiency is improved. Furthermore, the semiconductor electrode 2 is preferably heat-treated in order to improve its strength and adhesion to the translucent conductive layer 8 and the like. The temperature and time of the heat treatment are not particularly limited, but the heat treatment temperature is preferably 40 to 700 ° C., particularly 100 to 500 ° C., and the heat treatment time is preferably 10 minutes to 10 hours, particularly preferably 20 minutes to 5 hours.

  By providing the “ceramic substrate 3”, the durability of the dye-sensitized solar cell can be improved. As the ceramic for producing the ceramic substrate 3, various ceramics such as oxide ceramics, nitride ceramics, carbide ceramics can be used. Examples of the oxide ceramic include alumina, mullite, zirconia and the like. Examples of the nitride ceramic include silicon nitride, sialon, titanium nitride, and aluminum nitride. Further, examples of the carbide-based ceramic include silicon carbide, titanium carbide, and aluminum carbide.

  As the ceramic, alumina, silicon nitride, zirconia and the like are preferable, and alumina is particularly preferable. Alumina has high corrosion resistance, high strength, and excellent electrical insulation. By using this alumina substrate, a dye-sensitized solar cell having superior durability can be obtained. In the case of a ceramic substrate containing alumina, when the total amount of ceramic contained in this substrate is 100% by mass, alumina is 80% by mass or more, particularly 90% by mass or more, and further 95% by mass or more (100% by mass). It may be.

  The ceramic substrate 3 is preferably densified. For example, in the case of alumina, the relative density is preferably 90% or more, particularly 93% or more, and more preferably 95% or more. If the ceramic substrate has a high density and a high strength as described above, a highly durable dye-sensitized solar cell can be obtained. The thickness of the ceramic substrate 3 is not particularly limited, but can be 100 μm to 5 mm, particularly 500 μm to 5 mm, more preferably 1 to 5 mm, and preferably 300 μm to 3 mm. When the thickness of the ceramic substrate is 100 μm to 5 mm, particularly 300 μm to 3 mm, a dye-sensitized solar cell having sufficient strength as a support layer and excellent durability can be obtained.

  The method for producing the ceramic substrate 3 is not particularly limited. The ceramic substrate 3 is usually prepared by preparing a slurry containing ceramic powder, a sintering aid, a binder, a solvent, a plasticizer, and the like, and using this slurry, a green sheet is formed by a doctor blade method or the like. The fired sheet can be produced by holding and firing at a predetermined temperature for a required time according to each ceramic.

  The “collecting electrode 4” is provided in order to improve the current collecting efficiency because the catalyst electrode 5 in the present invention has lower conductivity than the catalyst electrode made of platinum. Although the planar shape of the current collecting electrode 4 is not particularly limited, the current collecting electrode 4 can be arranged in a planar shape or linearly so as to divide the catalyst electrode 5 into predetermined regions. In order to obtain a current collecting electrode 4 having sufficiently low resistance and capable of further improving the current collecting efficiency, it has a planar shape similar to that of the catalyst electrode 5 and is 50% or more, particularly 65% with respect to the catalyst electrode 5. % Or more, and more preferably 80% or more (the same area, that is, 100% with respect to the catalyst electrode 5). More preferably, the catalyst electrode 5 is arranged in a similar shape.

  Furthermore, when arrange | positioning so that it may divide | segment into a predetermined area | region, the shape can be made into a grid | lattice form, a mesh shape, a comb-tooth shape, radial form etc., for example. In addition, when arrange | positioning so that it may divide | segment into a predetermined area | region, not only when it is divided | segmented by the completely continuous current collection electrode 4, but also when there is a discontinuous part in the current collection electrode 4 partly means. Furthermore, the thickness of the current collecting electrode 4 is not particularly limited, and is preferably set in consideration of its electric resistance and cost. The current collecting electrode 4 is formed by a physical vapor deposition method such as a magnetron sputtering method and an electron beam vapor deposition method, a screen printing method using a paste, or the like, using a mask on which a predetermined pattern is formed. Can do.

  The collecting electrode 4 contains tungsten. Since the current collecting electrode 4 is in contact with the electrolytic solution 6 contained in the catalyst electrode 5, corrosion resistance to the electrolytic solution 6 is required. However, tungsten is excellent in corrosion resistance and is inexpensive. preferable. The current collecting electrode 4 may be made of pure tungsten (this pure tungsten means that tungsten having a purity of 99.98% or more is used as it is and no other metal is mixed). It may consist of a mixture with other metals. Among these, the collector electrode 4 made of pure tungsten is particularly preferable because it is more excellent in corrosion resistance to the electrolytic solution.

  When tungsten and other metals are used in combination, the content of tungsten is 95% by mass or more, particularly 98% by mass or more, and further 99.9% by mass, when the total of tungsten and other metals is 100% by mass. % Or more is preferable. When the content of tungsten is 95% by mass or more, a current collecting electrode having high current collecting efficiency and excellent corrosion resistance against an electrolytic solution can be obtained.

  The “catalyst electrode 5” provided on the surface of the current collecting electrode 4 provided to face the semiconductor electrode 2 includes a porous resin layer 51 and activated carbon 52 held on the porous resin layer 51. The retained state means a state in which the activated carbon 52 is fixed to the wall surface of the communication hole of the porous resin layer 51. In addition to the activated carbon 52 thus fixed to the wall surface of the communication hole, the porous resin layer 51 is retained. May contain activated carbon.

  The resin constituting the “porous resin layer 51” is not particularly limited, and may be a thermoplastic resin or a thermosetting resin. As the thermoplastic resin, various synthetic resins such as fluororesin, polyester, and polyamide can be used. Examples of the fluororesin include tetrafluoroethylene, fluorinated ethylene polypropylene copolymer, and polyvinylidene fluoride. Examples of the polyester include polyethylene terephthalate and polyethylene naphthalate. Examples of the polyamide include polyamide 6, polyamide 66, polyamide 12, and the like. Moreover, as a thermosetting resin, an epoxy resin, a phenol resin, unsaturated polyester resin, a polyimide, a polyurethane, etc. can be used. Of these resins, fluororesins that are highly durable resins are preferred.

The porous resin layer 51 has a communication hole, and the activated carbon 52 is held on the wall surface of the communication hole. Therefore, it is preferable that the average pore diameter and porosity of the communication holes of the porous resin layer 51 are appropriately set so that a predetermined amount of activated carbon is retained in consideration of the average particle diameter of the activated carbon 52 and the like. The average pore diameter and porosity of the communication holes are not particularly limited, but the average pore diameter may be 0.001 to 10 μm, particularly 0.01 to 1 μm, and the porosity may be 1 to 99%, particularly 10 to 90%. . If the average pore diameter of the communication holes is 0.01 to 1 μm and the porosity is 10 to 90%, a necessary amount of activated carbon can be retained, and the activated carbon 52 is dropped from the porous resin layer 51. Can be suppressed, which is preferable.
The average pore diameter of the communication holes can be calculated by, for example, observing a cross section of the porous resin layer 51 with an electron microscope and dividing the accumulated pore diameter by the number of holes. Moreover, the porosity of the porous resin layer 51 can be measured by, for example, the BET method.

  The thickness of the porous resin layer 51 is not particularly limited, and may be 1 to 200 μm, particularly 10 to 100 μm, and further 10 to 50 μm. If this thickness is 10-50 micrometers, since the resistance of the catalyst electrode 5 becomes low, it is preferable.

  The “activated carbon 52” is not particularly limited, and various activated carbons can be used. As this activated carbon 52, for example, normal activation treatment using zinc chloride, phosphoric acid or the like on woody materials such as coconut shells and sawdust, and organic substances containing many carbons such as lignite, peat, resin and petroleum pitch Can be used, followed by dry distillation. As this activated carbon, the high-purity thing manufactured using resin as a raw material is preferable. Although this raw material resin is not specifically limited, Thermosetting resins, such as a phenol resin with which manufacture of activated carbon is easy, are preferable.

The holding amount of the activated carbon 52 fixed and held on the wall surface of the communication hole of the porous resin layer 51 is not particularly limited, but when the porous resin layer 51 is 100 parts by mass, 1 to 99 parts by mass, particularly It can be 10-90 mass parts. If the amount of the activated carbon 52 held is 10 to 90 parts by mass, the catalyst electrode 5 having sufficient catalytic action can be obtained, and a dye-sensitized solar cell with high conversion efficiency can be obtained.
In addition, the activated carbon 52 may be contained in the porous resin layer 51 in addition to being held as described above. Thereby, the electroconductivity of the porous resin layer 51 improves.

  The porous resin layer 51 can hold and / or contain various conductive substances in addition to activated carbon in order to improve the conductivity. As other conductive materials, carbon black, metal, conductive oxide, conductive polymer, and the like can be used. Examples of the metal include platinum, rhodium, copper, aluminum, nickel, and chromium. Examples of the conductive oxide include a conductive oxide used for forming the translucent conductive layer 8. Examples of the conductive polymer include polyaniline, polypyrrole, and polyacetylene. Among these, since the conductive substance fixed and held on the wall surface of the communication hole of the porous resin layer 51 comes into contact with the electrolytic solution 6, it has excellent corrosion resistance such as carbon black and platinum. It is preferable to have it. On the other hand, when contained in the porous resin layer 51, since it does not contact the electrolyte solution 6, any of the above-described conductive substances may be used. The holding amount and / or content of these conductive materials is not particularly limited depending on the type and the like, but when the porous resin layer 51 is 100 parts by mass, usually 1 to 99 parts by mass, particularly It can be 10-90 mass parts.

  As shown in FIG. 1, the catalyst electrode 5 may have a form in which a porous resin sheet holding the activated carbon 52 is bonded to the surface of the current collecting electrode 4. That is, the porous resin sheet is bonded to the surface of the collector electrode 4 to form the catalyst electrode 5. The method for producing the porous resin sheet is not particularly limited. For example, the resin composition is formed into a sheet by extrusion molding or the like, and the resin sheet is cold-drawn to obtain a porous resin sheet having a large number of voids. . Moreover, it can also produce by extruding the resin composition containing a foaming agent into a sheet, and heating and foaming this sheet. As the resin, a thermoplastic resin among the above-mentioned various resins can be used. As the thermoplastic resin, a fluororesin or the like is preferable as described above.

The method for holding the activated carbon 52 on the porous resin sheet is not particularly limited, and the porous resin sheet can be immersed in the dispersion liquid in which the activated carbon is dispersed in water or an organic solvent, and the activated carbon 52 can be impregnated and held. . Further, a dispersion liquid in which activated carbon is dispersed in water or an organic solvent such as methanol or ethanol can be impregnated by spraying the porous resin sheet with a spray gun or the like. Among these methods, the method in which the porous resin sheet is immersed in the dispersion and impregnated to retain the activated carbon is preferable because the activated carbon can be uniformly retained by the entire porous resin sheet. The dispersion medium may be water or an organic solvent, but water that is easy to handle and has no environmental problems is particularly preferable.
In addition, if activated carbon is mix | blended with the said resin composition, activated carbon can also be made to contain in a porous resin sheet.

  The method for joining the porous resin sheet to the current collecting electrode 4 is not particularly limited, and the porous resin sheet can be joined with various adhesives. As this adhesive, it is preferable to select an optimal one depending on the material of the porous resin sheet, that is, the type of resin used. As the adhesive, for example, various adhesives such as an acrylic resin adhesive, a polyurethane adhesive, and a cellulose adhesive can be used. Further, when the porous resin sheet is made of a resin that is difficult to adhere, the surface of the porous resin sheet to be joined to the current collecting electrode 4 is treated by corona discharge treatment, flame treatment, etc., thereby improving the bondability. It is preferable.

  The thickness of the porous resin sheet is the same as that of the porous resin layer 51 described above. Further, the amount of the activated carbon 52 held in the porous resin sheet is the same as in the case of the porous resin layer 51. Further, the porous resin sheet can hold and / or contain the above various conductive substances in addition to activated carbon. When these conductive substances are dispersed in the above dispersion, they can be held on the porous resin sheet, and some of them can also be contained. On the other hand, when it mix | blends with the said resin composition, it can be made to contain in a porous resin sheet, and a part can also be hold | maintained. When the porous resin sheet is 100 parts by mass, the retained amount and / or content of the conductive substance can be usually 1 to 99 parts by mass, particularly 10 to 90 parts by mass.

  As shown in FIG. 2, the catalyst electrode 5 may be configured such that a slurry containing activated carbon 52 and a resin is applied to the surface of the current collecting electrode 4 and dried. That is, a film is formed on the surface of the collecting electrode 4 by this application and drying, and this film becomes the catalyst electrode 5. The method for producing the film is not particularly limited. For example, a slurry containing activated carbon 52 and a resin is applied to the surface of the current collecting electrode 4 by various methods such as a doctor blade method, a squeegee method, and a spin coating method. , Dried to remove the solvent, and heated as necessary. The content of the activated carbon in the slurry is preferably 1 to 99% by mass, particularly 10 to 90% by mass, and more preferably 20 to 80% by mass, when the total of the activated carbon and the resin is 100% by mass. A content of activated carbon of 20 to 80% by mass is more preferable because a required amount of activated carbon can be retained in the resin layer and the catalyst electrode 5 can be made excellent in catalytic action.

  As the resin, any of a thermoplastic resin and a thermosetting resin among the above-mentioned various resins can be used. As described above, the thermoplastic resin is preferably a fluororesin, and the thermosetting resin is preferably an epoxy resin. Furthermore, as the slurry medium, water or an organic solvent such as methanol or ethanol can be used, and water that is easy to handle and has no environmental problems is particularly preferable. Moreover, in order to improve the adhesiveness and joining property of the current collection electrode 4 and a membrane | film | coat, it is preferable to mix | blend cellulose-type resins, such as carboxymethylcellulose, hydroxyethylcellulose, and hydroxybutylcellulose, with a slurry.

The thickness of the film is the same as that of the porous resin layer 51 described above. Further, the amount of the activated carbon 52 retained in the film is the same as that of the porous resin layer 51 described above. In addition to activated carbon, the film can hold and / or contain the above various conductive materials. In this embodiment, the conductive material is easy to come into contact with the electrolytic solution 6 and thus has excellent corrosion resistance. It is preferable to use a conductive material having a property. These conductive substances can be retained and / or impregnated in the film by being dispersed in the slurry. The amount and / or content of the conductive substance can be usually 1 to 99 parts by mass, particularly 10 to 90 parts by mass, when the film is 100 parts by mass.
Note that an extraction electrode can be connected to the catalyst electrode 5, and electric power can be extracted from the extraction electrode. The take-out electrode can be integrally formed at the same time when the catalyst electrode 5 is formed.

  The distance between the semiconductor electrode 2 and the catalyst electrode 5 and the thickness of the space filled with the electrolyte solution 6 are substantially equal, and the distance and thickness are not particularly limited, but are 200 μm or less, particularly 50 μm or less (usually 1 μm or more). It can be. If this thickness is 200 μm or less, the conversion efficiency can be sufficiently increased.

  The “electrolytic solution 6” is contained in at least a part of each of the semiconductor electrode 2 and the catalyst electrode 5 and is filled between the semiconductor electrode 2 and the catalyst electrode 5. The electrolytic solution 6 is usually contained in the entirety of each of the semiconductor electrode 2 and the catalyst electrode 5, and this is preferable because the conversion efficiency is improved.

In addition to the electrolyte, the electrolytic solution 6 usually contains a solvent and various additives. Examples of the electrolyte include (1) I ₂ and iodide, (2) Br ₂ and bromide, (3) metal complexes such as ferrocyanate-ferricyanate and ferrocene-ferricinium ion, and (4) sodium polysulfide. And electrolytes containing sulfur compounds such as alkylthiol-alkyldisulfides, (5) viologen dyes, (6) hydroquinone-quinones, and the like. As iodide in (1) is, LiI, NaI, KI, CsI, metal iodide such as CaI _2, and tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide iodine salt of quaternary ammonium compounds such as id, etc. Is mentioned. As the bromide in (2), LiBr, NaBr, KBr, CsBr, CaBr 2 , etc. of the metal bromide, and tetra-alkyl ammonium bromide, bromine salts of quaternary ammonium compounds such as pyridinium bromide and the like. Among these electrolytes, an electrolyte obtained by combining I ₂ and an iodine salt of a quaternary ammonium compound such as LiI, pyridinium iodide, and imidazolium iodide is particularly preferable. These electrolytes may use only 1 type and may use 2 or more types.

  The solvent contained in the electrolytic solution 6 is preferably a solvent having a low viscosity, a high ion mobility, and sufficient ion conductivity. Examples of such solvents include (1) carbonates such as ethylene carbonate and propylene carbonate, (2) heterocyclic compounds such as 3-methyl-2-oxazolidinone, (3) ethers such as dioxane and diethyl ether, (4 ) Chain ethers such as ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, (5) methanol, ethanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl Monoalcohols such as ether and polypropylene glycol monoalkyl ether, (6) ethylene glycol, propylene glycol, polyethylene Polyhydric alcohols such as ethylene glycol, polypropylene glycol, glycerin, (7) nitriles such as acetonitrile, butyronitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile, (8) dimethyl sulfoxide, sulfolane, etc. Examples include aprotic polar substances.

  The electrolytic solution 6 is formed by sealing between the translucent substrate 1 or the translucent conductive 8 and the ceramic substrate 3 or the collecting electrode 4 with a resin or glass around the semiconductor electrode 2 or the like. By injecting into the sealed space, each of the semiconductor electrode 2 and the catalyst electrode 5 can be contained and filled therebetween. The electrolytic solution 6 may be injected into the sealed space from the translucent substrate 1 side or from the ceramic substrate 3 side, and it is preferable to provide an injection port on the side that is easily perforated and to inject from the injection port. . In addition, although one injection port is sufficient, another hole can also be provided for air venting. Thus, by providing the hole for air venting, the electrolyte can be injected more easily.

  The injection port may be provided on either side of the translucent substrate 1 or the ceramic substrate 3. For example, when the translucent substrate 1 is a glass substrate, it is not easy to perforate. On the other hand, a ceramic substrate is easier to perforate than a glass substrate, and in particular, it can be extremely easily perforated using a punch or the like in a green sheet. Therefore, it is preferable to provide an injection port in the ceramic substrate 3. Further, the electrolytic solution 6 is provided in the joint portion 7 formed by sealing between the translucent substrate 1 or the translucent conductive 8 and the ceramic substrate 3 or the collecting electrode 4 with resin or glass. It is also possible to inject from a designated inlet.

  Examples of the resin used for sealing around the semiconductor electrode 2 include thermosetting resins such as an epoxy resin, a urethane resin, and a thermosetting polyester resin. Furthermore, this sealing can also be performed with glass. In particular, in a dye-sensitized solar cell that requires long-term durability, sealing with glass is preferable.

In the dye-sensitized solar cell of the present invention, the translucent conductive layer 8 is usually provided on one surface of the translucent substrate 1 as shown in FIGS. The translucent conductive layer 8 only needs to have translucency and conductivity. The material of the translucent conductive layer 8 is not particularly limited, and examples thereof include a thin film made of conductive oxide and a carbon thin film. Examples of the conductive oxide include indium oxide, tin-doped indium oxide, tin oxide, and fluorine-doped tin oxide (FTO). The thickness of the transparent conductive layer 8 is also different depending on the material, but are not limited to, surface resistance 100 [Omega / cm ² or less, particularly preferably 1~10Ω / cm ² become thick.
The translucent meaning and preferable visible light transmittance of the translucent conductive layer 8 are the same as those of the translucent substrate 1.

  The translucent conductive layer 8 can be formed by applying a paste containing a conductive oxide and fine particles such as carbon to one surface of the translucent substrate 1 and heating as necessary. Examples of the coating method include various methods such as a doctor blade method, a squeegee method, and a spin coating method. Furthermore, the translucent conductive layer 8 can also be formed by depositing a conductive oxide or the like on one surface of the translucent substrate 1 by sputtering, vapor deposition, or the like.

  Further, a current collecting electrode 9 on the side of the translucent substrate 1 may be provided between the translucent substrate 1 and the translucent conductive layer 8 (see FIG. 3) or on the surface of the translucent conductive layer 8. it can. The current collecting electrode 9 can be disposed so as to surround the semiconductor electrode 2 or to divide the semiconductor electrode 2 into predetermined regions. Arrangement so as to divide into the predetermined regions means not only when the current collecting electrodes 9 are completely divided but also when there are discontinuous portions in the current collecting electrodes 9. . More specifically, the planar shape of the collecting electrode 9 can be, for example, a lattice shape, a mesh shape, a comb shape, a radial shape, or the like. An extraction electrode can be connected to the current collecting electrode 9 and electric power can be extracted from the extraction electrode.

  The width and thickness of the current collecting electrode 9 are not particularly limited, and are preferably set in consideration of the electric resistance and cost. The current collecting electrode 9 can be formed of a noble metal such as platinum or gold, or a metal such as tungsten, titanium or nickel. Further, the current collecting electrode 9 is provided between the translucent substrate 1 and the translucent conductive layer 8, and is provided on the surface of the translucent conductive layer 8, and is protected by resin, glass, or the like. When this is done, the collector electrode 9 and the electrolyte 6 are not in contact. On the other hand, when the current collecting electrode 9 is provided on the surface of the translucent conductive layer 8 and is not protected by resin, glass or the like, the current collecting electrode 9 and the electrolytic solution 6 come into contact with each other. As described above, the current collecting electrode 9 may or may not be in contact with the electrolytic solution 6. In any case, it is preferable to use tungsten which is excellent in corrosion resistance and inexpensive. Further, the current collecting electrode 9 can be formed by a physical vapor deposition method such as a magnetron sputtering method and an electron beam vapor deposition method using a mask on which a predetermined pattern is formed, and a screen printing method using a paste. It can also be formed. The extraction electrode can be integrally formed at the same time when the current collecting electrode 9 is formed.

Hereinafter, the present invention will be described specifically by way of examples.
The dye-sensitized solar cell 101 shown in FIG. 1 was manufactured as follows.
Example 1
(1) Production of Semiconductor Electrode A commercially available titania paste (Solaronix) is formed on the surface of the light-transmitting conductive layer 8 of the glass substrate (translucent substrate 1, manufactured by Nippon Sheet Glass Co., Ltd.) on which the light-transmitting conductive layer 8 is formed. The product name “Ti-Nanoxide D / SP”) manufactured by the company was applied to 5 mm □ by the screen printing method. This was pre-dried at 120 ° C. for 30 minutes, and then held and fired at 500 ° C. for 30 minutes using a muffle furnace (manufactured by Motoyama, model “SK-2030D”) to produce a semiconductor electrode 2. A quality electrode substrate was formed.

  On the other hand, titanium tetrachloride was dissolved in ice-cooled water to prepare an aqueous solution having a concentration of 0.05 mol / liter. Thereafter, a glass substrate having a porous electrode substrate formed on the surface thereof was immersed in the aqueous titanium tetrachloride solution, and the aqueous solution was heated and maintained at 70 ° C. for 30 minutes to perform titanium chloride treatment. Next, the glass substrate was taken out of the aqueous solution, washed thoroughly with distilled water, and dried at room temperature for 30 minutes. Thereafter, the porous electrode substrate treated with titanium chloride was baked again by holding at 500 ° C. for 30 minutes using the muffle furnace.

Further, a ruthenium organic complex [Ru2,2bipyridil-4,4-dicarboxylate (TBA) ₂ (NCS) ₂ ] (trade name “N-719”, manufactured by Kojima Chemical Co., Ltd.) is used as a mixed solvent of acetonitrile and tert-butanol. After dissolution, an acetonitrile / tert-butanol solution having a concentration of 5 × 10 −4 mol / liter was prepared. Next, a porous electrode substrate and a glass substrate treated with titanium chloride were immersed in this ruthenium organic complex solution for 18 hours, and a ruthenium organic complex as a sensitizing dye was adhered to the porous electrode substrate to produce a semiconductor electrode 2. .

(2) Production of catalyst electrode A tungsten metallized layer (which becomes the current collecting electrode 4) having the same shape and size as the semiconductor electrode 2 is formed on one surface of an alumina substrate (ceramic substrate 3). A fluororesin sheet (manufactured by Japan Gore-Tex Co., Ltd.) on which the activated carbon was held was attached to the surface of the substrate using a conductive adhesive to produce a catalyst electrode 5.

(3) Production of dye-sensitized solar cell 0.05 mol of I ₂ , 0.1 mol of LiI, 0.6 mol of dimethylpropylimidazolium iodide and 0.5 mol of 4-tert-butylpyridine were mixed in butyronitrile. An electrolytic solution 6 was prepared. Furthermore, a spacer having an opening of 8 mm □ corresponding to the dimensions of the semiconductor electrode 2 is formed on a resin sheet (trade name “HIMILAN 1702” manufactured by Mitsui DuPont Polychemical Co., Ltd.). The substrate 1 and the ceramic substrate 3 are made to face each other via a spacer, and the electrolyte solution 6 is injected into the formed space with a syringe, and immediately after the injection, the gap is sealed with a clip, and the dye-sensitized solar Battery 101 was manufactured.

(4) Performance Evaluation The dye-sensitized solar cell produced in (3) above was irradiated with 20 mW / cm ² of light using a halogen lamp, and a standard voltammetry tool (model “HSV-100” manufactured by Hokuto Denko Co., Ltd.) Was used to measure the current-voltage curve, and the open circuit voltage (V _oc ), short circuit current density (J _SC ), fill factor (FF), and photoelectric conversion efficiency (η) were determined.
Here, the open circuit voltage (V _OC ) is a voltage value when the current value is 0 mA. The short circuit current density (J _SC ) is obtained by dividing the current value at a voltage value of 0 V by the area of the semiconductor electrode. The fill factor (FF) is also referred to as a fill factor, and is represented by (J _MAX × V _MAX ) / (J _SC × V _OC ) (J _MAX , V _MAX is the maximum power value in the current-voltage curve). Current density value and voltage value at the point. The photoelectric conversion efficiency (η) is the conversion efficiency from incident light to electrical energy, and is calculated by 100 × (V _OC × J _SC × FF) / P ₀ (P ₀ is the incident light intensity).
As a result of the performance evaluation, Voc was 0.757 V, Jsc was 3.42 mA / cm ² , FF was 0.715, and η was 9.25%.

Comparative Example 1
A dye-sensitized solar cell was manufactured in the same manner as in Example 1 except that platinum was sputtered onto the surface of the collector electrode 4 made of tungsten to form the catalyst electrode 4, and the performance was evaluated in the same manner.
As a result of the performance evaluation, Voc was 0.746 V, Jsc was 3.50 mA / cm ² , FF was 0.722, and η was 9.41%.
From this result and the result of Example 1 above, the performance of the dye-sensitized solar cell of the present invention using the porous resin sheet holding activated carbon as the catalyst electrode was determined using a catalyst electrode made of platinum. It turns out that it has the performance equivalent to the conventional one.

  It should be noted that the present invention is not limited to the description of the above-described embodiments, and can be variously modified embodiments within the scope of the present invention. For example, as the electrolytic solution, one containing an ionic liquid as a main component can be used. The ionic liquid is contained in an amount of 50% by mass or more, particularly 90% by mass or more (or 100% by mass) when the electrolytic solution is 100% by mass. As this ionic liquid, a room temperature molten salt of iodide can be used. Examples of the room temperature molten salt of iodide include various room temperature molten salts such as imidazolium salt, pyridinium salt, pyrrolidinium salt, pyrazolidium salt, isothiazolidinium salt, and isoxazolidinium salt. Of the room temperature molten salts of iodide, imidazolium salts are preferred. These room temperature molten salts may be used in combination of two or more different types.

It is a schematic diagram which shows the cross section of the dye-sensitized solar cell 101 provided with the catalyst electrode formed by joining the porous resin sheet in which activated carbon was hold | maintained of Example 1 to the current collection electrode which consists of tungsten. It is a schematic diagram which shows the cross section of the dye-sensitized solar cell 102 provided with the catalyst electrode by which the slurry containing activated carbon and resin is apply | coated to the collector electrode which consists of tungsten, and is dried. It is a schematic diagram which shows the cross section of the dye-sensitized solar cell 103 in which the translucent conductive layer was further arrange | positioned in FIG.

Explanation of symbols

  101, 102, 103; dye-sensitized solar cell, 1; translucent substrate (glass substrate), 2; semiconductor electrode, 3; ceramic substrate (alumina substrate), 4; collector electrode made of tungsten, 5; catalyst Electrode 51; Porous resin layer 52; Activated carbon 6; Electrolyte solution 7; Bonding part 8; Translucent conductive layer 9; Current collecting electrode on the side of the translucent substrate.

Claims (6)

A translucent substrate 1;
A semiconductor electrode 2 provided on one side of the translucent substrate 1 and having a sensitizing dye;
A ceramic substrate 3 disposed to face the one surface side of the translucent substrate 1;
A collector electrode 4 provided on the surface of the ceramic substrate 3 so as to face the semiconductor electrode 2 and containing tungsten;
A catalyst electrode 5 provided on the surface of the current collecting electrode 4;
An electrolyte 6 contained in at least a part of each of the semiconductor electrode 2 and the catalyst electrode 5 and filled between the semiconductor electrode 2 and the catalyst electrode 5;
The catalyst electrode 5 includes a porous resin layer 51 and activated carbon 52 held by the porous resin layer 51.   The dye-sensitized solar cell according to claim 1, wherein the catalyst electrode 5 is formed by bonding a porous resin sheet holding activated carbon 52 to the surface of the collecting electrode 4.   The dye-sensitized solar cell according to claim 1, wherein the catalyst electrode 5 is obtained by applying a slurry containing activated carbon 52 and a resin to the surface of the collector electrode 4 and drying the slurry.   The dye-sensitized solar cell according to any one of claims 1 to 3, wherein the porous resin layer 51 is made of a fluororesin.   The dye-sensitized solar cell according to any one of claims 1 to 4, wherein the porous resin layer 51 further contains carbon black.   The space between the one surface side of the translucent substrate 1 and the ceramic substrate 3 or the collector electrode 4 is sealed with resin or glass around the semiconductor electrode 2. The dye-sensitized solar cell according to any one of the above.

Images