JP5651887B2 - Dye-sensitized photoelectric conversion element and dye-sensitized solar cell - Google Patents

Description

  The present invention relates to a dye-sensitized photoelectric conversion element and a dye-sensitized solar cell that are lightweight and difficult to break, and relates to a dye-sensitized photoelectric conversion element and a dye-sensitized solar cell in which electric characteristics with respect to fluctuations in light intensity are constant. .

In recent years, solid pn junction photoelectric conversion elements and solar cells using the same have been actively studied as photoelectric conversion elements that convert solar energy into electric power. Solid-junction solar cells use a silicon crystal, an amorphous silicon thin film, or a multilayer thin film of a non-silicon compound semiconductor. However, these photoelectric conversion elements and solar cells using the photoelectric conversion elements have recently been reduced in cost, and are being developed in the market. However, glass is the main substrate for the substrate, has a considerable weight, has a limited installation location, and is desired to be improved.

Development of a dye-sensitized photoelectric conversion element composed of a plastic substrate is expected as a next-generation photoelectric conversion element that replaces these conventional solar cells, and the solar cell. A highly efficient photoelectric conversion method using a semiconductor film has been proposed. The dye-sensitized photoelectric conversion element is a wet photoelectric conversion element that employs a solid (semiconductor) -liquid (electrolyte) junction instead of a solid (semiconductor) -solid (semiconductor) junction in a solid junction photoelectric conversion element. . The dye-sensitized photoelectric conversion element has a high energy conversion efficiency of 11% or more at the research level, and is a promising source of electric energy.

This dye-sensitized photoelectric conversion element made of a plastic substrate generally comprises a photoelectrode layer made of dye-sensitized semiconductor particles, an electrolyte layer, and a counter electrode on a conductive support using a plastic substrate. Is made of an exterior material having a high barrier to provide durability in a poor environment. The dye-sensitized photoelectric conversion device made of this plastic substrate is required to have high efficiency when converting light energy into electric power, and competition among researchers is intensifying. On the other hand, dye-sensitized photoelectric conversion In the commercialization of devices, a low-cost manufacturing process is desired, which is a major commercialization bottleneck.

In order to increase the efficiency of the dye-sensitized photoelectric conversion element and the dye-sensitized solar cell, the photoelectrode and the counter electrode are required to have excellent conductivity. Highly conductive substrates are made of various conductive materials, but have a high cost and lack of performance stability. In addition, it has been found that the electrical output is greatly affected by fluctuations in illuminance, and the design of a circuit for collecting the generated electricity is complicated, and it has been desired to improve the completeness of the battery.

US Pat. No. 4,927,721

An object of the present invention is to provide an output improvement of a dye-sensitized photoelectric conversion element, specifically, to provide a dye-sensitized photoelectric conversion element that produces a constant output even when the illuminance fluctuation is large. Another object of the present invention is to provide a dye-sensitized photoelectric conversion element and a dye-sensitized solar cell module that are made of a plastic substrate that is lightweight and hardly damaged.

The problems of the present invention can be solved by the following aspects.

(Aspect 1) A dye-sensitized photoelectric conversion element having a photoelectrode layer made of dye-sensitized semiconductor particles, an electrolytic solution layer, a catalyst layer, and a conductive counter electrode substrate in this order on a conductive photoelectrode substrate, and In the dye-sensitized solar cell, the electrode substrate resistance of any one of the conductive photoelectrode substrate and the conductive counter electrode substrate is less than 100Ω, and the other electrode substrate resistance is 100Ω to 500Ω. A dye-sensitized photoelectric conversion element and a dye-sensitized solar cell. Providing a dye-sensitized photoelectric conversion element that produces a constant output even when the illuminance fluctuation is large, by combining the electrode substrate resistances of the conductive photoelectrode substrate and the conductive counter electrode substrate in such a range. Because it can be done.

(Aspect 1) In a dye-sensitized photoelectric conversion element having a photoelectrode layer made of dye-sensitized semiconductor particles, an electrolytic solution layer, a catalyst layer, and a conductive counter electrode substrate in this order on a conductive photoelectrode substrate. The dye sensitization is characterized in that the sheet resistance of one of the conductive photoelectrode substrate and the conductive counter electrode substrate is less than 100Ω, and the sheet resistance of the other electrode substrate is 150Ω to 500Ω. It is a sensitive photoelectric conversion element. Providing a dye-sensitized photoelectric conversion element that produces a constant output even when the illuminance fluctuation is large, by combining the electrode substrate resistances of the conductive photoelectrode substrate and the conductive counter electrode substrate in such a range. Because it can be done.

(Aspect 2) In a dye-sensitized photoelectric conversion element having a photoelectrode layer composed of dye-sensitized semiconductor particles, an electrolytic solution layer, a catalyst layer, and a conductive counter electrode substrate in this order on a conductive photoelectrode substrate. The sheet resistance of one of the conductive photoelectrode substrate and the conductive counter electrode substrate is 50Ω or less, and the sheet resistance of the other electrode substrate is 150Ω to 300Ω. It is a sensitive photoelectric conversion element. This is because, by combining the electrode substrate resistances of the conductive photoelectrode substrate and the conductive counter electrode substrate in such a range, the output stability with respect to illuminance fluctuations increases.

(Aspect 3) The ratio (P10max / P2.5max) of the power generation amount (P10max) at a light amount of 100,000 looks to the power generation amount (P2.5max) at a light amount of 25,000 lux is 1.0 to 1.5. It is a dye-sensitized photoelectric conversion element as described in aspect 1 or 2. The stability of the output with respect to the illuminance fluctuation is within a range in which the ratio (P10max / P2.5max) of the power generation amount (P10max) at the light amount of 100,000 lux to the power generation amount (P2.5max) at the light amount of 25,000 lux is applied. This is because it becomes an index.

(Aspect 4) Either one or both of the conductive photoelectrode substrate and the conductive counter electrode substrate is a plastic substrate, and the material constituting the plastic substrate is polyethylene terephthalate, polyethylene naphthalate, cycloolefin copolymer, 4. The dye-sensitized photoelectric conversion element according to any one of aspects 1 to 3, wherein the dye-sensitized photoelectric conversion element is selected from any of alicyclic polyolefins. This is because by selecting such a material, it is possible to provide a dye-sensitized photoelectric conversion element made of a plastic substrate that is lightweight and hardly damaged.

It is sectional drawing which shows the structure of one example of the dye-sensitized photoelectric conversion element of this invention. It is sectional drawing (upper stage) and top view (lower stage) which show the structure of one example of the dye-sensitized solar cell module of this invention.

  Hereinafter, the dye-sensitized photoelectric conversion element and the dye-sensitized solar cell module of the present invention will be described in detail.

1. Structure of Dye-Sensitized Photoelectric Conversion Element FIG. 1 is a cross-sectional view showing an example of the structure of the dye-sensitized photoelectric conversion element of the present invention. In the dye-sensitized photoelectric conversion element 1, an undercoat layer 13 and a porous semiconductor fine particle layer 14 carrying a sensitizing dye are laminated in this order on a conductive electrode substrate in which a transparent conductive layer 12 is laminated on a transparent substrate 11. Provided between the photoelectrode layer 15, the conductive electrode substrate in which the transparent conductive layer 12 is stacked on the transparent substrate 11, the counter electrode layer 18 in which the catalyst layer 17 is stacked, and the photoelectrode layer 15 and the counter electrode layer 18. The electrolyte layer 16, the sealing layer 19 surrounding the electrolyte layer, the current collector 20, and the terminals 21 are included. Hereinafter, the photoelectrode layer 15, the electrolytic solution layer 16, the counter electrode layer 18, and the sealing layer 19 will be described in this order.

[1] Photoelectrode layer The photoelectrode layer has a structure in which a porous semiconductor fine particle layer (hereinafter referred to as “dye-sensitized porous semiconductor fine particle layer”) carrying a sensitizing dye is formed on a conductive electrode substrate. .
(1) Conductive electrode substrate The conductive electrode substrate of this invention is a structure which has a transparent conductive layer on the transparent substrate which consists of glass or a transparent plastic substrate. As the plastic substrate material, an uncolored material having high transparency, high heat resistance, excellent chemical resistance and gas barrier properties, and low cost is preferable. Suitable materials include, for example, polyesters (eg, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), etc.), styrenes (eg, syndiotactic polystyrene (SPS), etc.), polyphenylene sulfide (PPS), polycarbonate, etc. (PC), polyarylate (PAr), polysulfone (PSF), polyestersulfone (PES), polyetherimide (PEI), transparent polyimide (PI), cycloolefin copolymer (trade name Arton, etc.) and alicyclic polyolefin (product) Name such as ZEONOR). Of these, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and alicyclic polyolefin are particularly preferable in terms of chemical stability and cost. In addition, it does not specifically limit in the structure of these plastic substrates, or its composition, If it deserves to comprise the dye-sensitized photoelectric conversion element of this invention, it can utilize.

The heat resistance of the plastic substrate preferably satisfies at least one of the physical properties of a glass transition temperature (Tg) of 100 ° C. or higher and a linear thermal expansion coefficient of 40 ppm / ° C. or lower. The Tg and linear expansion coefficient of the plastic substrate are measured by the plastic transition temperature measurement method described in JIS K 7121 and the linear expansion coefficient test method based on the thermomechanical analysis of plastic described in JIS K 7197. The Tg and linear expansion coefficient of the plastic film can be adjusted by additives. Examples of such a thermoplastic resin having excellent heat resistance include polyethylene naphthalate (PEN: 120 ° C.), polycarbonate (PC: 140 ° C.), and alicyclic polyolefin (for example, ZEONOR 1600: 160 ° C. manufactured by Nippon Zeon Co., Ltd.). , Polyarylate (PAr: 210 ° C.), polyether sulfone (PES: 220 ° C.), polysulfone (PSF: 190 ° C.), cycloolefin copolymer (COC: compound of JP 2001-150584 A, 162 ° C.), fluorene ring Modified polycarbonate (BCF-PC: compound of JP 2000-227603 A: 225 ° C.), alicyclic modified polycarbonate (IP-PC: compound of JP 2000-227603 A: 205 ° C.), acryloyl compound (JP 2002) Compound of No.-80616 300 ° C. or higher), polyimide and the like (in parentheses indicate the Tg), they are suitable as substrates in the present invention. Especially, it is preferable to use an alicyclic polyolefin for the use for which transparency is particularly required.

The material of the transparent conductive layer to be applied to the electrode substrate of the present invention includes conductive metals (eg, platinum, gold, silver, copper, aluminum, indium, titanium), conductive carbon (carbon black, carbon nanofiber, carbon Nanotubes), conductive metal oxides (eg, tin oxide, zinc oxide) or conductive composite metal oxides (eg, indium-tin oxide, indium-zinc oxide). In terms of having high optical transparency, conductive metal oxides and conductive composite metal oxides are preferred, and in terms of heat resistance and chemical stability, indium-tin composite oxide (ITO) and indium- Zinc oxide (IZO) is particularly preferred. In the material, the composition may be mixed with other materials, and the form is not limited. In addition, the method for forming the conductive layer is not limited, and a sputtering method, a vapor deposition method, a method of applying a dispersion, and the like can be selected. The light transmittance (measurement wavelength: 500 nm) of the electrode substrate provided with the transparent electrode layer on the transparent substrate is preferably 60% or more, more preferably 75% or more, most preferably 80% or more, and particularly 85. % Or more is preferable. The conductivity and transparency of the electrode substrate can be achieved by optimizing the method of forming the transparent conductive layer, for example, by optimizing the deposition time, the amount of dispersion applied, and the like.

In the present invention, a metal can be used for the conductive layer in order to achieve a low surface resistance value. High transparency can also be achieved by forming a transparent conductive layer having a metal mesh structure. It is preferable to form a transparent conductive layer having a metal mesh structure using a low-resistance metal material (eg, copper, silver, aluminum, platinum, gold, titanium, nickel, etc.). In this case, auxiliary leads for collecting current can be disposed on the conductive layer by patterning or the like. The auxiliary lead is also formed of a low-resistance metal material (eg, copper, silver, aluminum, platinum, gold, titanium, nickel, etc.) in the same manner as the conductive layer. The resistance value of the surface including the auxiliary lead is not particularly limited as long as it has the object of the present invention. Here, the auxiliary lead pattern is preferably formed on the transparent substrate by vapor deposition, sputtering, or the like, and a transparent conductive layer made of tin oxide, ITO film, IZO film or the like is further provided thereon.

The present invention is characterized in that a conductive electrode substrate having specific conductivity is used in a combination of a conductive electrode substrate constituting a photoelectrode and a counter electrode of a dye-sensitized photoelectric conversion element. Specifically, one electrode substrate resistance of the conductive photoelectrode substrate and the conductive counter electrode substrate is less than 100Ω, and the other electrode substrate resistance is 100Ω to 500Ω. Furthermore, one electrode substrate resistance is less than 100Ω, preferably 70Ω or less, more preferably 50Ω or less, still more preferably 30Ω or less, and particularly preferably 15Ω or less. The other electrode substrate resistance is 100Ω to 500Ω, preferably 100Ω to 400Ω, and more preferably 100Ω to 250Ω.

The carbon nanotube used in the present invention will be described. The carbon nanotube may be either a multi-wall carbon nanotube (multi-wall carbon nanotube; MWCT) or a single-wall carbon nanotube (single-wall carbon nanotube; SWCT). Each may be used alone or in combination. Carbon nanohorns, carbon nanocoils, and carbon nanobeads may also be used.
Carbon nanotubes are classified into metallic carbon nanotubes and semiconducting carbon nanotubes according to their conductivity, but it is preferable to adjust the mixing ratio of semiconducting properties and metallic properties according to the application. When the carbon nanotube layer is used as a conductive application, a higher ratio of metallic carbon nanotubes is preferable. When a carbon nanotube layer is used as a semiconductor application, a higher ratio of semiconductor carbon nanotubes is preferable. In the present invention, in order to improve the photoelectric conversion rate of the photoelectric conversion element, it is preferable that the ratio of semiconducting carbon nanotubes is large. The carbon nanotube of the present invention may further contain a metal or the like. Moreover, you may use the peapod nanotube in which fullerene was included. Carbon nanotubes can be synthesized by any method, for example, arc discharge method, laser ablation method, CVD method, super gloss method and the like.

The surface of the carbon nanotube used in the present invention may be modified with a functional group. The functional group is preferably a hydroxy group, a carboxy group, or an amino group. These functional groups are effective in enhancing the adhesion between the carbon nanotube layer and the easy adhesion layer by a chemical reaction with the easy adhesion layer. These functional groups can be introduced using any method (see, for example, Japanese Patent Application Laid-Open No. 2005-41835), and the amount of functional groups introduced is appropriately adjusted depending on the application. It is preferable.

The carbon nanotubes used in the present invention are preferably cross-linked from the viewpoint of giving high mechanical strength and enhancing the characteristics of the carbon nanotube layer-containing structure. As for the cross-linking of the carbon nanotube, a method of reacting with a cross-linking agent using a hydroxy group, a carboxy group, or an amino group introduced on the surface of the carbon nanotube is preferable. As the crosslinking reaction, esterification, etherification, or amidation reaction is preferably used (see, for example, JP-A-2005-41835). The crosslink density is preferably adjusted according to the application. The diameter of the carbon nanotube used in the present invention is preferably 0.3 nm or more and 100 nm or less. More preferably, they are 1 nm or more and 30 nm or less. The length of the carbon nanotube used in the present invention is preferably 0.1 μm or more and 100 μm or less.

The method for producing a carbon nanotube layer-containing structure of the present invention can be produced by applying a carbon nanotube layer on a transparent support. Regarding the coating solution containing carbon nanotubes used at this time, it is preferable to appropriately adjust physical properties such as viscosity and surface tension according to the application. Regarding the coating of coating solutions containing carbon nanotubes, reverse coaters, gravure coaters, rod coaters, air doctor coaters, spin coaters, sprays, as shown in Yuji Harasaki, “Coating Method”, published by Shinsho, October 1979 Arbitrary coating devices such as coating can be used. Although the thickness of a carbon nanotube layer is not specifically limited, 0.001-10 micrometers is preferable.

In the present invention, carbon materials other than carbon nanotubes, for example, fullerene, graphite and the like can be used instead of carbon nanotubes.

(2) Undercoat layer In this invention, an undercoat layer can be provided. When the electrolyte layer is a liquid, the undercoat layer has a structure in which the electrolyte layer is in contact with the transparent conductive layer, so an internal short circuit phenomenon called reverse electron transfer in which electrons leak from the transparent conductive layer to the electrolyte layer It has a role to prevent the photoelectric conversion efficiency from decreasing due to generation of reverse current unrelated to light irradiation and to improve the adhesion of the porous semiconductor fine particle layer to the conductive substrate. is there.

  The material for the undercoat layer is not particularly limited as long as it is a high resistance semiconductor and insulating material. For example, there are titanium oxide, niobium oxide, tungsten oxide, and the like. In addition, as a method of forming the undercoat layer, a method of directly sputtering the material on the transparent conductive layer, a solution in which the material is dissolved in a solvent, a solution in which a metal hydroxide that is a precursor of a metal oxide is dissolved, Alternatively, there is a method in which a solution containing a metal hydroxide obtained by dissolving an organometallic compound in a mixed solvent containing water is applied onto a conductive substrate composed of a substrate and a conductive layer, dried, and sintered as necessary.

  The undercoat layer of the present invention is preferably formed of an organic titanium oligomer and a hydrolysis product thereof. The organic titanium oligomer used in the present invention is a compound having a multimeric structure (—Ti—O—Ti—) in the molecule by condensing a titanium alkoxide (Ti—OR) compound or a titanium chelate compound. By oligomerizing titanium, a surface structure having a multimeric structure (—Ti—O—Ti—) in the molecule can be provided, so that the surface of the transparent conductive substrate can be densely formed without gaps. In addition, this invention is not limited to an organic titanium oligomer, The same effect will be acquired if it is an organometallic oligomer (M is a metal) which has a multimeric structure (-MOMM) in a molecule | numerator. It is done.

  When the undercoat layer is formed on a conductive substrate, a good undercoat layer can be formed even under conditions in which cracking occurs in film formation with a titanium monomer. Further, metal alkoxides conventionally used for undercoat layers are highly reactive and easily hydrolyzed, making it difficult to control the properties of the coating film surface. However, the organotitanium oligomer used in the present invention has a slow hydrolysis rate, a stable coating surface property, and a coating layer surface property of the undercoat layer when a semiconductor porous layer made of a metal oxide is overlaid. Has the advantage of being stable over a long period of time.

  The organotitanium oligomer used in the present invention is produced by a method of hydrolysis by adding water or a mixture of water and a water-soluble solvent without substantially diluting tetraalkoxytitanium with a solvent (special feature). Open 2008-156280). In addition, the organic titanium oligomer used in the present invention is a silicon compound having one or more alkoxy groups in the molecule with respect to the titanium compound oligomer in order to improve the coating film formability and coating film adhesion (adhesiveness). It may be a composite compound (Japanese Patent Laid-Open No. 2008-143990) having a structure obtained by reacting or a mixture.

  In order to form an undercoat layer on a conductive electrode substrate, it is preferable to use a sol-gel method in which an organic titanium oligomer solution is applied on a conductive substrate, dried and baked by heating to form a film. . The solvent is preferably an alcohol such as butanol, a hydrocarbon such as hexane or toluene, or a mixture thereof having a boiling point of about 100 ° C. from the viewpoint of drying speed. Examples of the coating method include a gravure coating method, a bar coating method, a printing method, a spray method, a spin coating method, a dip method, and a die coating method.

  In the method for producing a photoelectrode layer of the present invention, in order to prevent adhesion between the undercoat layer and the metal oxide porous semiconductor layer, which will be described later, in particular, peeling in the electrolytic solution, the wetting tension on the surface of the undercoat layer is 50 mN / m. Less than, the metal oxide semiconductor fine particles are overlaid. When the undercoat layer is formed from an organotitanium oligomer as in the present invention, the change in the wetting tension of the coating surface over time is slower than when formed from a metal alkoxide monomer. It becomes easy to layer the layers sequentially or continuously.

(3) Semiconductor fine particles The porous semiconductor fine particle layer of the present invention comprises a so-called mesoporous semiconductor layer in which nano-sized pores are formed in a network. As the semiconductor fine particles forming the porous semiconductor fine particle layer, metal oxides and metal chalcogenides can be used. Examples of the metal element constituting the metal oxide and the metal chalcogenide include titanium, tin, zinc, iron, tungsten, zirconium, strontium, indium, cerium, vanadium, niobium, tantalum, cadmium, zinc, lead, antimony, bismuth, Examples include cadmium and lead. This will be described below.

The semiconductor fine particles of the present invention can be produced using a known method. As the production method, for example, the sol-gel method described in “Science of Sol-Gel Method”, Agne Jofu Co., Ltd. (1998), or metal chloride is converted to an oxide by high-temperature hydrolysis in an inorganic hydrogen salt. It can be prepared by a production method, a vapor-phase spray pyrolysis method in which a metal compound is thermally decomposed at a high temperature in a gas phase to form ultrafine particles. The ultrafine particles and nanoparticles of titanium dioxide (TiO2) produced by these methods are explained in “Particle Engineering System Vol. 2 (Applied Technology)” supervised by Hiroaki Yanagida (2002). Examples of the metal oxide semiconductor material include oxides of titanium, tin, zinc, iron, tungsten, zirconium, strontium, indium, cerium, vanadium, niobium, tantalum, cadmium, lead, antimony, and bismuth. As the semiconductor material, there is an n-type inorganic semiconductor material. Specifically, TiO2, ZnO, Nb2O3, SnO2, WO3, Si, CdS, CdSe, V2O5, ZnS, ZnSe, KTaO3, FeS2, PbS, etc. are preferred, TiO2, ZnO, Nb2O3, SnO2, WO3 are more preferred, and dioxide dioxide. Titanium (TiO2) is particularly preferred.

As a method for producing titanium dioxide, there are a liquid phase method in which titanium tetrachloride and titanyl sulfate are hydrolyzed and a gas phase method in which titanium tetrachloride and oxygen or an oxygen-containing gas are mixed and burned. In the liquid phase method, anatase can be obtained as the main phase, but it becomes a sol or slurry, and drying is necessary to use it as a powder, but there is a problem that aggregation (secondary particle formation) proceeds by drying. . On the other hand, the vapor phase method is characterized by excellent dispersibility, high temperature during synthesis, and excellent crystallinity compared to the liquid phase method because no solvent is used.
By the way, there are anatase type, brookite type and rutile type in the crystal form of titanium dioxide nanoparticles. When titanium oxide is produced by a vapor phase method, titanium oxide that is stable at the lowest temperature is anatase type, and is converted into a brookite type or a rutile type as heat treatment is applied. The crystal structure can be determined by measuring a diffraction pattern by an X-ray diffraction method or detecting a crystal lattice image by observation with a transmission electron microscope. Moreover, the average particle diameter of the titanium dioxide nanoparticles can be calculated from a particle size distribution measurement by a light correlation method using a laser light scattering method or a scanning electron microscope observation method.

Crystalline titanium dioxide nanoparticles having an average primary particle size of 40 to 70 nm used in the present invention are obtained by a gas phase method, and are a mixture of rutile type crystals and anatase type crystals. % Or less. This is because when the rutile ratio exceeds 40%, the function as a photocatalyst is lowered and the photovoltaic power is lowered, so that sufficient performance as a dye-sensitized photoelectric conversion element cannot be obtained. The form of the titanium dioxide nanoparticles may be various forms such as amorphous, spherical, polyhedral, fibrous, and nanotube-like, but a polyhedral or nanotube-like form is preferable, and a polyhedral form is more preferable. From the viewpoint of dispersion stability, the solid content concentration contained in the semiconductor fine particle dispersion is 0.1 to 25 wt%, preferably 0.5 to 20 wt%, and more preferably 0.5 to 15 wt%.

On the other hand, metal oxide semiconductor nanoparticles having an average primary particle size of 10 to 30 nm used in the present invention are prepared as an aqueous solution of acidic sol in which titanium dioxide nanoparticles containing brookite crystals obtained by a liquid phase method are dispersed. Yes. This is because brookite-type titanium oxide is excellent in binding property to a dye and can provide higher photoelectric conversion efficiency than rutile or anatase-type titanium oxide. Brookite-type titanium oxide produced by a liquid phase method, particularly brookite-type titanium oxide produced by hydrolysis of titanium tetrachloride or titanium trichloride is preferred. This is because there is no problem in the state of the dispersed sol because it is used as a semiconductor nanoparticle dispersion for forming a porous semiconductor fine particle layer, the dispersion state is stable, and the coating properties are excellent. In order to enhance dispersibility, the aqueous medium is adjusted to be acidic, and the pH is 1 to 6, preferably 3 to 5. From the viewpoint of dispersion stability, the solid content concentration contained in the semiconductor fine particle dispersion is 1 to 15 wt%, preferably 2 to 12 wt%, and more preferably 2 to 10 wt%.

(4) Semiconductor fine particle dispersion The present invention relates to a photoelectrode for a dye-sensitized photoelectric conversion element in which a semiconductor fine particle dispersion is applied on a conductive electrode substrate and heat-treated to form a porous semiconductor fine particle layer. is there. In the case of using a plastic substrate in the present invention, a low temperature film forming method is adopted, so that the dispersion composition does not contain a binder material such as resin or latex added for the purpose of improving the film forming property and leveling property of the dispersion. Is preferred. The semiconductor fine particle dispersion of the present invention is a viscous milky white liquid in which semiconductor fine particles are dispersed in a solvent comprising a mixture of water and an alcohol having 5 or less carbon atoms.

The solvent used for the semiconductor fine particle dispersion of the present invention is a mixed solvent of a hydrophilic organic solvent mainly containing ethanol and water. As the hydrophilic solvent, other alcohols having 3 to 5 carbon atoms can be selected, and t-butanol, 2-butanol and the like can be added. In the semiconductor fine particle dispersion of the present invention, water is used as a dispersion solvent in addition to the alcohol. This is added for the purpose of maintaining the dispersion stability of the semiconductor fine particles and maintaining the viscosity of the dispersion at an appropriate level.

In the present invention, the dispersion may contain both semiconductor fine particles having an average primary particle diameter of 10 to 30 nm and semiconductor fine particles having an average primary particle diameter of 40 to 70 nm. By simply mixing semiconductor particles that do not overlap the average particle size range of the primary particles, the specific surface area is large and the amount of sensitizing dye supported is large. It is possible to easily produce a porous semiconductor fine particle layer having a porous structure capable of diffusing up to. Therefore, a metal oxide semiconductor nanoparticle dispersion liquid containing metal oxide semiconductor nanoparticles and a solvent as essential components as proposed in Japanese Patent Application Laid-Open No. 2002-324591 can be changed continuously or discontinuously. There is no need to spray. Moreover, the volume shrinkage distortion at the time of drying can be relieve | moderated by mixing the particle | grains from which an average particle diameter differs greatly. Furthermore, the structure of the porous semiconductor fine particle layer formed after drying is solidified by dehydration condensation of the semiconductor fine particles having an average primary particle size of 10 to 30 nm.

A paint conditioner, a homogenizer, an ultrasonic stirrer, or the like is used as a method for dispersing semiconductor fine particles having an average primary particle size of 40 to 70 nm in a solvent in the present invention, and a rotating / revolving combined mixing conditioner is preferable. Used. After dispersing semiconductor fine particles having an average primary particle size of 40 to 70 nm in a solvent, an acidic sol aqueous solution in which semiconductor fine particles having an average primary particle size of 10 to 30 nm are dispersed is added to obtain a semiconductor fine particle dispersion. Prepare. From the viewpoint of dispersion stability and coating film formability, the solid content concentration of the entire semiconductor fine particles contained in the dispersion is 5 to 30 wt%, preferably 8 to 25 wt%, and more preferably 8 to 20 wt%.

(5) Porous semiconductor fine particle layer In the porous semiconductor particle layer of the present invention, that is, the porous semiconductor particle layer constituted by the semiconductor fine particles described above, the porosity represented by the volume fraction occupied by the voids in the layer Is preferably 50% to 85%, more preferably 65% to 85%.
The porous semiconductor particle layer can include two or more types of fine particle groups. The two or more types of fine particle groups can have different particle size distributions, for example. When two or more types of fine particle groups having different particle size distributions are included, the average size of the smallest particle group is preferably 20 nm or less. For the purpose of enhancing light absorption by light scattering, it is preferable to add large particles having an average particle diameter exceeding 200 nm to the ultrafine particles at a mass ratio of 5% by mass to 30% by mass. The photoelectric conversion element of the present invention has the dye as an adsorbed molecule on the surface of the porous semiconductor particle layer because the porous semiconductor particle layer is sensitized by the dye.

(6) Sensitizing dye The sensitizing dye of the present invention will be described. As the sensitizing dye, various organic and metal complex-based sensitizing materials that have been used for the spectral sensitization of photoelectrodes using dye molecules in the field of electrochemistry are used. Also, in order to make the wavelength range of photoelectric conversion as wide as possible and increase the conversion efficiency, two or more kinds of dyes may be used in combination, and the dyes to be mixed in accordance with the wavelength range and intensity distribution of the light source The mixing ratio may be selected.

The sensitizing dye is not particularly limited as long as it is a sensitizing dye, but organic dyes (eg, cyanine dye, merocyanine dye, oxonol dye, xanthene dye, squarylium dye, polymethine dye, coumarin dye, riboflavin dye, perylene) Dyes) and metal complex dyes (eg, phthalocyanine complexes, porphyrin complexes). Examples of the metal constituting the metal complex dye include ruthenium and magnesium. In addition, synthetic dyes and natural dyes described in “Functional Materials”, June 2003, pages 5 to 18 and “Journal of Chemical Physics” (J. Chem. Phys.), B.C. An organic dye mainly composed of coumarin described in Vol. 107, page 597 (2003) can also be used. Those having an acid functional group adsorbed on the porous titanium oxide layer are preferred, specifically those having a carboxy group, a phosphate group, etc., among which those having a carboxy group are particularly preferred.

Specific examples of the sensitizing dye include, for example, xanthene dyes such as rhodamine B, rose bengal, eosin and erythrosine, cyanine dyes such as merocyanine, quinocyanine and cryptocyanine, phenosafranine, cabrio blue, thiocin and methylene blue. Examples include basic dyes, porphyrin compounds such as chlorophyll, zinc porphyrin, and magnesium porphyrin. Others include azo dyes, phthalocyanine compounds, coumarin compounds, bipyridine complex compounds, anthraquinone dyes, and polycyclic quinone dyes. Can be mentioned. Among these, the ligand (ligand) includes a pyridine ring or an imidazolium ring, and a dye of at least one metal complex selected from the group consisting of Ru, Os, Ir, Pt, Co, Fe, and Cu is High quantum yield is preferable. In particular, cis-bis (isothiocyanate) -N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) (N-719) or tris (isothiocyanate) — A dye molecule having ruthenium (II) -2,2 ′: 6 ′, 2 ″ -terpyridine-4,4 ′, 4 ″ -tricarboxylic acid (N-749) as a basic skeleton has a wide absorption wavelength range and is preferable. However, the sensitizing dye is not limited to these. Typically, one kind of sensitizing dye is used, but two or more kinds of these sensitizing dyes may be mixed and used. These are known as general-purpose names. For example, N3, N719, N749, D102, D131, D150, N205, HRS-1, MK-2, and the like can be mentioned as typical sensitizing dyes.

(7) Adsorption of sensitizing dye to porous semiconductor fine particle layer A method for adsorbing a sensitizing dye to the porous semiconductor fine particle layer in the present invention will be described. As a method for adsorbing the dye to the porous semiconductor fine particle layer, a method in which a conductive electrode substrate having a well-dried porous semiconductor fine particle layer is immersed in a sensitizing dye solution (immersion method), or a sensitizing dye solution is made porous There is a method (coating method) of applying to the fine semiconductor fine particle layer. When the immersion method is used, the temperature of the sensitizing dye solution during immersion is 0 ° C. to 80 ° C., preferably 0 ° C. to 50 ° C., particularly preferably 5 ° C. to 45 ° C. Further, the immersion time for adsorption is not particularly limited, but is preferably 0.3 minutes to 120 minutes, more preferably 0.5 minutes to 60 minutes, and further preferably 0.5 minutes to 30 minutes, Particularly preferably, it is 0.5 to 10 minutes. When the coating method is used, a coating method such as a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method, or a spray method, or a printing method such as letterpress, offset, gravure, or screen printing can be used.

The solvent used to dissolve the sensitizing dye is particularly a solvent that can dissolve the sensitizing dye and does not dissolve the porous semiconductor fine particle layer or react with the semiconductor fine particles. Not limited. In the case of consisting only of an organic solvent, it is preferable to deaerate and purify in advance in order to remove moisture and gas present in the solvent. Preferred solvents include alcohols, nitriles, halogenated hydrocarbons, ethers, amides, esters, carbonates, ketones, hydrocarbons, aromatics, nitromethane, water, and the like.
Preferred examples of the solvent used for dissolving the sensitizing dye in the present invention include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, t-butanol, pentanol, isopentanol, methoxyethanol, ethoxyethanol, propoxyethanol. , Butoxyethanol, ethylene glycol, diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether, formamide, acetamide, N, N-dimethylformamide, N-methylpyrrolidone, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, Acetonitrile, propionitrile, butyronitrile, tetrahydrofuran, 1,4-dioxane, hexa , Methylene chloride, chloroform, carbon tetrachloride, N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, dimethyl sulfoxide, propiolactone, γ-butyrolactone, benzene, toluene, xylene, anisole, etc. is there.

Among these, more preferably used solvents are methanol, ethanol, propanol, isopropanol, butanol, t-butanol, methoxyethanol, butoxyethanol, ethylene glycol, diethylene glycol, diethylene glycol monomethyl ether, N, N-dimethylformamide, N-methylpyrrolidone. , Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, acetonitrile, propionitrile, butyronitrile, tetrahydrofuran, N-methylpyrrolidone, 1,3-dimethylimidazolidinone, propiolactone, γ-butyrolactone, toluene, xylene And anisole.
Particularly preferably used solvents are methanol, ethanol, isopropanol, 1-methoxy-2-propanol, t-butanol, butoxyethanol, N, N-dimethylformamide, N-methylpyrrolidone, acetone, methyl ethyl ketone, methyl isobutyl ketone, propio Examples thereof include nitrile, butyronitrile, propiolactone, γ-butyrolactone, and toluene. These solvents may be used alone or as a mixed solvent using two or more kinds of solvents.
The concentration of the sensitizing dye in the dye solution is preferably 0.01 mM to 10 mM, more preferably 0.1 mM to 10 mM, still more preferably 0.5 mM to 8 mM, and particularly preferably 0.8 mM. ~ 6 mM. Further, the total adsorption amount of the dye is preferably 0.01 M to 100 M per unit surface area (1 m ² ) of the conductive support. The amount of the dye adsorbed on the semiconductor fine particles is preferably in the range of 0.001M to 1M per gram of semiconductor fine particles.

  In the present invention, in addition to the sensitizing dye, other combined materials (for example, cationic compounds (for example, tertiary ammonium compounds, quaternary ammonium compounds, pyridine compounds, imidazolium compounds, acid compounds (for example, carboxylic acid compounds, phosphorus compounds) Acid compounds, phosphonic acid compounds, sulfonic acid compounds, etc.) It is also preferable to use a saturated aliphatic dicarboxylic acid as a combination material, among which a saturated aliphatic dicarboxylic acid having 6 to 12 carbon atoms is preferable. Specific examples include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and dodecanedioic acid, and the concentration of the saturated aliphatic dicarboxylic acid of the present invention in the dye solution is preferably 0.00. 1 mM to 100 mM, more preferably 0.5 mM to 50 mM, particularly preferably The addition amount of the saturated aliphatic dicarboxylic acid of the present invention is preferably 1 molar equivalent to 1000 molar equivalents, more preferably 5 molar equivalents to 500 molar equivalents, relative to the molar equivalent of the dye. 10 molar equivalents to 100 molar equivalents are particularly preferred.

  In addition, after making a porous semiconductor fine particle layer adsorb | suck a sensitizing dye, in order to remove an excess sensitizing dye solution, it is preferable to wash | clean using a solvent. In this case, the above-mentioned solvents are recommended as cleaning solvents. As a cleaning method, there are a method of spraying a solvent on a dye-sensitized porous semiconductor fine particle layer and washing it away, or a method of immersing a substrate on which a dye-sensitized porous semiconductor fine particle layer is formed in a cleaning solvent tank. The substrate on which the dye-sensitized porous semiconductor fine particle layer thus obtained is formed can be further dried to obtain a photoelectrode. The drying conditions are not particularly limited, but preferably 30 ° C to 150 ° C for 0.5 minutes to 30 minutes, 40 ° C to 120 ° C for 0.5 minutes to 15 minutes, and 50 ° C to 100 ° C for 0.00 minutes. 5 to 10 minutes are preferred.

The dye-sensitized porous semiconductor particle layer is preferably substantially composed of only semiconductor fine particles and a dye. Specifically, the mass of the solid content excluding the inorganic oxide, the semiconductor fine particles and the sensitizing dye from the transparent conductive layer and the dye-sensitized porous semiconductor fine particle layer is equal to the transparent conductive layer and the dye-sensitized porous semiconductor fine particle layer. The ratio of the total mass to the total mass is preferably less than 3%, more preferably less than 1%.

[2] Electrolyte layer The electrolyte layer is a layer having a function of replenishing electrons to the oxidant of the sensitizing dye. The electrolytic solution constituting the electrolytic solution layer of the present invention is based on an electrolyte and a solvent.
(1) As an electrolyte electrolyte, a combination of iodine (I ₂ ) and metal iodide or organic iodide, bromine (Br ₂
) And metal bromide or organic bromide, ferrocyanate / ferricyanate, metal complexes such as ferrocene / ferricinium ions, sodium polysulfide, sulfur compounds such as alkylthiol / alkyl disulfide, viologen dyes, And hydroquinone / quinone. Lithium, Na, K, Mg, Ca, Cs and the like are preferable as the cation of the metal compound, and quaternary ammonium compounds such as tetraalkylammonium, pyridinium, and imidazolium are preferable as the cation of the organic compound. It is not limited to. Two or more of these may be mixed and used. Among these, electrolytes in which I ₂ and a quaternary ammonium compound such as LiI, NaI or imidazolium iodide are combined are preferable. The concentration of the electrolyte salt is preferably 0.05 to 10M, more preferably 0.2 to 3M with respect to the solvent. The concentration of I ₂ or Br ₂ is preferably 0.0005 to 1M, more preferably 0.001 to 0.5M. It is also preferable to add various additives such as 4-tert-butylpyridine and benzimidazoliums. Furthermore, an electrolytic solution containing no iodine (I ₂ ) as an electrolyte can also be preferably used.

Examples of inorganic salts used in the present invention include alkali metal halides (eg, lithium iodide, sodium iodide, potassium iodide, lithium bromide, sodium bromide, potassium bromide, lithium chloride, sodium chloride), alkaline earth Metal halides (eg, magnesium iodide, calcium iodide, magnesium bromide, calcium bromide, magnesium chloride, calcium chloride, etc.), ammonium halides (eg, ammonium iodide, ammonium bromide, ammonium chloride, etc.) It is preferable to use it. As the halogen of the halide, chlorine, bromine and iodine are preferably used, bromine and iodine are particularly preferred, and iodine is most preferred. The additive concentration of the halide is preferably 0.01 to 3.0 mol / L, more preferably 0.05 to 2.0 mol / L.

(2) Solvent Solvents of the present invention include water, alcohols, ethers, esters, carbonate esters, lactones, carboxylic acid esters, phosphate triesters, heterocyclic compounds, nitriles, and ketones. Amides, nitromethane, halogenated hydrocarbons, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, hydrocarbons, etc., but are not limited thereto. In addition, two or more of these can be mixed and used. Furthermore, it is also possible to use a room temperature ionic liquid of a tetraalkyl, pyridinium, or imidazolium quaternary ammonium salt as a solvent.

The boiling point of the solvent is preferably 200 ° C. or higher. Furthermore, an aprotic polar solvent is also preferred, glycol ether is preferred, and dialkyl glycol ether is more preferred. Specific examples of such solvents include glycols, monoalkyl glycol ethers, and dialkyl glycol ethers. Two or more of these glycol ethers may be used in combination. Specific examples of such solvents include ethylene glycol, triethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, triethylene. Examples thereof include glycol dimethyl ether and γ-butyrolactone.

(3) Other Components In the present invention, a gelling electrolyte can be obtained by dissolving a gelling agent, a polymer, a crosslinking monomer, and the like in the above electrolytic solution. In this case, the electrolytic solution component is preferably 50 to 99 wt% of the gel electrolyte, and more preferably 80 to 97 wt%.

In the present invention, inorganic compounds such as sodium thiosulfate and sodium sulfite, thiosalicylic acid, ascorbic acid, hydroquinone, phenidone, paramethylaminophenol sulfate and the like may be further added to the electrolytic solution as a reducing agent. The electrolytic solution can further contain other components. Examples of other components include benzoimidazole compounds, (iso) thiocyanate ions, and guanidinium ions. Specific examples of the benzimidazole compound include N-methylbenzimidazole, 1,2-dimethylbenzimidazole, N-butylbenzimidazole, N-benzylbenzimidazole, N- (2-ethoxyethyl) benzimidazole, and the like.

When thiocyanate ion (S ⁻ —C≡N) or isothiocyanate ion (N ⁻ = C═S) is added to the electrolytic solution, the total concentration of thiocyanate ion and isothiocyanate ion in the electrolytic solution is 0.00. 01M to 1M are preferred, 0.02M to 0.5M are more preferred, and 0.05M to 0.2M are most preferred. In preparing the electrolytic solution, it is preferable to add the isothiocyanate ion as a salt. The counter ion of the salt is preferably a guanidinium ion. If necessary, an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant may be added to the electrolytic solution.

The photoelectrode layer described above preferably has pores in its porous structure filled with an electrolytic solution. Specifically, the ratio of the pores of the photoelectrode layer filled with the electrolyte is preferably 20% by volume or more, and more preferably 50% by volume or more. The thickness of the electrolytic solution layer can be adjusted by, for example, the size of the spacer provided between the photoelectrode layer and the counter electrode layer. The thickness of the portion where the electrolytic solution exists alone outside the photoelectrode is preferably 1 μm to 50 μm, more preferably 1 μm to 30 μm, still more preferably 1 μm to 20 μm, and most preferably 1 μm to 15 μm.

The light transmittance of the electrolyte layer is preferably 70% or more (in the optical path length of 30 μm) when the thickness of the electrolyte layer is 30 μm at a measurement wavelength of 400 nm, and preferably 80% or more. Is more preferable, and 90% or more is most preferable. The light transmittance preferably has the above-described transmittance in the entire wavelength region of 350 nm to 900 nm. In order to form the electrolytic solution layer of the present invention, a method of applying the electrolytic solution on the photoelectrode layer by a casting method, a bar coating method, a spray coating method, a dipping method or the like, or a cell having a photoelectrode and a counter electrode is produced. For example, a method of injecting an electrolyte into the gap may be used.

When an electrolyte layer is formed by a coating method, an additive such as a coating property improver (leveling agent, etc.) is added to the electrolyte containing a molten salt, and this is applied to a spin coating method, a dip coating method, an air knife coating. Apply by the following methods, such as coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method, extrusion coating method using hopper, spray coating method using spray nozzle, multilayer simultaneous coating method, etc. It may be heated according to the condition. The heating temperature for heating may be appropriately selected depending on the heat-resistant temperature of the dye and the like, but is usually preferably 10 ° C to 150 ° C, more preferably 10 ° C to 100 ° C. The heating time depends on the heating temperature and the like, but is preferably about 5 minutes to 72 hours.

When introducing iodine or the like into the electrolyte composition to produce a redox couple, the method of adding to the electrolyte solution described above, or placing the support on which the electrolyte layer has been formed in an airtight container together with iodine or the like, A technique for diffusing the film can be used. It is also possible to introduce or deposit iodine or the like on the counter electrode into the electrolyte layer when the photoelectric conversion element is assembled. In addition, it is preferable that the water | moisture content in an electrolyte solution layer is 10,000 ppm or less, More preferably, it is 2000 ppm or less, Most preferably, it is 100 ppm or less.

[3] Counter electrode layer (1) Counter electrode substrate The counter electrode functions as a positive electrode when the photoelectric conversion element is a photochemical battery. The counter electrode substrate is preferably composed of a transparent substrate and a transparent conductive layer. The details of the transparent substrate and the transparent conductive layer are the same as those of the transparent substrate and the transparent conductive layer of the photoelectrode layer.

(2) It is preferable to provide a catalyst layer on the conductive film of the catalyst layer counter electrode substrate. For the catalyst layer applied to the counter electrode substrate, noble metal particles having a catalytic action or carbon materials are preferably used. The noble metal particles are not particularly limited as long as they have a catalytic action, but are preferably composed of at least one of metal platinum, metal palladium and metal ruthenium having a relatively high catalytic action. Moreover, as a carbon material, although the shape is not specifically limited, a carbon fiber, a carbon nanotube, etc. can be mentioned. The size of the carbon nanotube is 0.5 to 100 nm, preferably 0.5 to 50 nm, and more preferably 1 to 20 nm. The length is 10 to 5000 nm, preferably 20 to 4000 nm, and more preferably 50 to 4000 nm. The carbon nanotube may be a single-walled carbon nanotube or a multi-walled carbon nanotube. Furthermore, a material having high conductivity is particularly preferable.

The method for applying the catalyst layer is not particularly limited. For example, there are a method of applying a noble metal by vapor deposition or sputtering, and a method of applying a dispersion in which noble metal fine particles or carbon nanotubes are dispersed in a solvent by coating or spraying. When the dispersion method is used, a binder may be further added to the dispersion, and a conductive polymer is preferably used as the binder. The conductive polymer is not particularly limited as long as it has conductivity and can disperse noble metal particles.

Examples of such highly conductive polymers include Poly (thiophene-2,5-diyl), Poly (3-butylthiophene-2,5-diyl),
Polythiophene such as Poly (3-hexylthiophene-2,5-diyl), poly (2,3-dihydrothieno- [3,4-b] -1,4-dioxin), polyacetylene and its derivatives, polyaniline and its derivatives, polypyrrole And its derivatives, Poly (p-xylenetrahythrophenium
choride), Poly [(2-methoxy-5- (2'ethylhexyloxy))-1,4-phenylvinylene]], Poly [(2-methoxy-5- (3 ', 7'-dimethyloxy))-1,4-phenylenevine. )], Poly [2-2 ′, 5′-bis (2 ″ -ethylhexyloxy) phenyl] -1,4-phenylenevinylene] and the like can be used. Among these, a particularly preferable conductive polymer is Poly (2,3-dihydrothieno- [3,4-b] -1,4-dioxin) / Poly (styreneenesulfonate).
(PEDOT / PSS).

Further, the catalyst layer can further contain a binder other than the conductive polymer from the viewpoint of improving the adhesion to the conductive layer. The binder may be an organic resin or an inorganic material. Examples of organic resins include polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, polypropylene glycol, polyacrylic acid, acrylic resin, polyester resin, polyurethane resin, polyolefin resin, polystyrene resin, cellulose and derivatives, butyral resin, alkyd resin, and vinyl chloride resin. Thermosetting or thermoplastic organic polymer compounds, ultraviolet (UV) curable organic polymer compounds, electron beam (EB) curable organic polymer compounds, inorganic polymer compounds such as polysiloxane, etc., alone or in combination Can be used.

Examples of the inorganic substance include silica sol, silicate such as M ₂ O · nSiO ₂ (M: Li, Na, K), phosphate, silicon oxide, zirconium oxide, titanium oxide, aluminum oxide particle colloid, A metal alkoxide of silicon, zirconium, titanium, or aluminum, a partially hydrolyzed polycondensation product thereof, a molten frit, water glass, or the like can be used alone or in combination.

Furthermore, in addition to the binder described above, for the purpose of further improving the film adhesion strength and conductivity of the catalyst layer, for example, silicon, aluminum, zirconium, cerium, titanium, yttrium, zinc, magnesium, indium In addition, particles of oxides or composite oxides such as tin, antimony, gallium, and ruthenium, and conductive oxide particles such as tin oxide, fluorine-doped tin oxide, and tin-doped indium oxide can also be included. The thickness of the catalyst layer is preferably 100 nm to 1 μm, more preferably 50 nm to 5 μm, and particularly preferably 30 nm to 5 μm.

[4] Functional layers such as a protective layer, an antireflection layer, and a gas barrier layer on the outer surface of one or both of the photoelectrode and the counter electrode that act as other layer electrodes, between the conductive layer and the substrate, or in the middle of the substrate May be provided. These functional layers can be formed by a coating method, a vapor deposition method, a bonding method, or the like depending on the material. When such a functional layer is formed in multiple layers, a simultaneous multilayer coating method or a sequential coating method can be used.

[5] Sealing layer The sealing layer of the present invention is provided around the electrolyte layer and has a function of sealing the electrolyte layer. The sealing layer is a spacer for forming an electrolyte layer by adjusting a necessary gap between the photoelectrode substrate and the counter electrode substrate, and a sealing material for bonding the photoelectrode substrate and the counter electrode substrate. It is comprised by.

(1) Sealing material The sealing material of the present invention is not particularly limited as long as it can adhere the photoelectrode substrate and the counter electrode substrate and seal the electrolyte layer. It is preferable that it is excellent in the adhesiveness between board | substrates, the tolerance (chemical resistance) with respect to electrolyte solution, and high temperature, high humidity durability (moisture-heat resistance). This is because, in order to effectively and continuously suppress the leakage of the electrolytic solution, it is necessary to have excellent chemical resistance and wet heat resistance in addition to adhesiveness.

Examples of the sealing material excellent in adhesiveness, chemical resistance, and wet heat resistance include thermoplastic resins, thermosetting resins, and active radiation (light, electron beam) curable resins. Examples of the material include an acrylic resin, a fluorine resin, a silicone resin, an olefin resin, and a polyamide resin. From the viewpoint of excellent handleability, a photocurable acrylic resin is preferred.

(2) Spacer The spacer of the present invention is not particularly limited as long as a necessary gap can be adjusted to a desired range between the photoelectrode substrate and the counter electrode substrate. Usually, spherical resin particles, inorganic particles, glass beads and the like can be appropriately selected. In the present invention, it is preferable to use perfect circle resin particles. As a particle size, 1 micrometer-100 micrometers are preferable, 1 micrometer-50 micrometers are more preferable, and 1 micrometer-20 micrometers are especially preferable. This is because the photoelectrode substrate and the counter electrode substrate are not in contact with each other, and the shorter gap is kept uniform, thereby reducing the electrolyte resistance and improving the photoelectric conversion efficiency.

It is preferable that the thickness of the sealing layer of the present invention is substantially the same as the thickness of the porous semiconductor fine particle layer. This is to maintain stable power generation efficiency by keeping the gap between the photoelectrode substrate and the counter electrode substrate uniform. Further, the width (thickness) of the sealing layer of the present invention is not particularly limited, but is preferably in the range of 0.5 mm to 5 mm, and more preferably in the range of 0.8 mm to 3 mm. If the width of the sealing layer is too small, sufficient durability against the electrolyte may not be exhibited. If the width of the sealing layer is too large, the element area contributing to power generation in the dye-sensitized solar cell element This is because the effective area with respect to the module area decreases and the effective power generation efficiency may decrease.

[6] Current Collection In the present invention, the surface resistivity of the transparent transparent electrode made of a transparent conductive film is lowered by disposing a current collection wire made of a metal (good conductor) on the transparent conductive film. The current collector is preferably provided outside the dye-sensitized photoelectric conversion element composed of a photoelectrode layer, an electrolytic solution layer, and a counter electrode layer separated by a sealing layer. This is to protect the collecting electrode from corrosion by the electrolytic solution. The material of the current collector is not particularly limited as long as it has conductivity, but at least one selected from metal materials having a relatively low resistivity, for example, silver, copper, aluminum, tungsten, nickel, and chromium. It is preferably made of the above metals or alloys thereof, and silver is more preferable from the viewpoint of low resistivity and easy formation as a line. The current collector may be formed in a lattice shape on the transparent conductive layer. As a method for forming the current collector, sputtering, vapor deposition, plating, screen printing, or the like is used. The width of the current collector is 0.5 mm to 5 mm, more preferably 0.7 mm to 3 mm, and the thickness of the current collector is 5 μm to 50 μm, more preferably 6 μm to 20 μm. In addition to ensuring a sufficient electric conductivity per line cross-sectional area, and an appropriate width for securing a necessary gap between the photoelectrode substrate and the counter electrode substrate in combination with conductive fine particles described later. This is because a thickness is required.

[7] Extraction electrode In the present invention, the photoelectric conversion element includes a pair of extraction electrodes. When the photoelectric conversion element is covered with an exterior or barrier package described later, a lead material can be attached to the extraction electrode. The material of the extraction electrode is not particularly limited as long as it has conductivity. It is preferably made of a metal material having a relatively low resistivity, for example, at least one metal selected from gold, platinum, silver, copper, aluminum, nickel, zinc, titanium, and chromium, or an alloy thereof. The thickness of the extraction electrode is preferably 50 nm to 100 μm. This is because it is necessary that the thickness of the extraction electrode is not too thin so that the yield of the dye-sensitized photoelectric conversion element does not decrease due to disconnection, and it is not necessary to increase the thickness excessively from the viewpoint of cost. The shape of the extraction electrode is not particularly limited. For example, any of metal foil, a metal tape, plate shape, and string shape may be sufficient. A metal tape is preferable from the viewpoint of workability.

[8] Exterior, barrier package In the present invention, the substrate is designed to reduce its permeability to water vapor and gas, but there is a possibility that output degradation may be seen due to severe environmental conditions. In particular, it is important to provide durability under high temperature and high humidity environmental conditions. These improvement methods can be achieved by making the substrate a substrate having a barrier property against gas or water vapor, or enclosing the dye-sensitized photoelectric conversion element of the present invention in a package having a barrier property. Hereinafter, the barrier film preferably used in the present invention, particularly the water vapor barrier property will be described below.

As described above, the dye-sensitized photoelectric conversion element of the invention preferably has a layer having a barrier property against gas and water vapor outside the substrate. Furthermore, it is preferable that it is packaged or wrapped with a packaging material having a water vapor barrier property. At that time, there may be a space between the dye-sensitized photoelectric conversion element of the present invention and the high barrier packaging material, or the dye-sensitized photoelectric conversion element may be bonded with an adhesive. Furthermore, the dye-sensitized photoelectric conversion element is packaged in a packaging material using a liquid or solid (eg, liquid or gel paraffin, silicon, phosphate ester, aliphatic ester, etc.) that is difficult to pass water vapor or gas. May be.

The preferable water vapor permeability of the substrate or packaging material having a barrier property preferably used in the present invention is 0.1 g / m 2 / day or less in an environment of 40 ° C. and a relative humidity of 90% (90% RH), more preferably. Is 0.01 g / m 2 / day or less, more preferably 0.0005 g / m 2 / day or less, and particularly preferably 0.00001 g / m 2 / day or less. Further, even when the environmental temperature is 60 ° C. and 90% RH, the water vapor permeability of the substrate or packaging material having a barrier property is more preferably 0.01 g / m 2 / day or less, and still more preferably. 0.0005 g / m 2 / day or less, particularly preferably 0.00001 g / m 2 / day or less. The oxygen permeability of the substrate or packaging material having a barrier property is preferably about 0.001 g / m 2 / day or less, more preferably 0.00001 g / m 2 / day in an environment of 25 ° C. and 0% RH. preferable.

Although there is no particular limitation on imparting via properties to water vapor or gas to the substrate or packaging material having barrier properties for the dye-sensitized solar cell of the present invention, it is necessary not to interfere with the amount of light necessary for the solar cell. Therefore, it is a substrate or packaging material that is permeable and has a barrier property, and its transmittance is preferably 50% or more, more preferably 70% or more, still more preferably 85% or more, and particularly preferably. 90% or more. The board | substrate or packaging material which has the said characteristic with a barrier property is not specifically limited in the structure and material, If it has this characteristic, it will not specifically limit.

A preferred substrate or packaging material having a barrier film of the present invention is preferably a film in which a barrier layer having low water vapor and gas permeability is provided on a plastic support. Examples of the gas barrier film include those obtained by vapor-depositing silicon oxide and aluminum oxide (Japanese Patent Publication No. Sho 53-12953, Japanese Patent Laid-Open Publication No. 58-217344), and those having an organic-inorganic hybrid coating layer (Japanese Patent Laid-Open No. 2000-323273, Japanese Patent Laid-Open Publication No. 2004) 25732), those having an inorganic layered compound (Japanese Patent Laid-Open No. 2001-205743), those obtained by laminating inorganic materials (Japanese Patent Laid-Open No. 2003-206361, Japanese Patent Laid-Open No. 2006-263389), those obtained by alternately laminating organic layers and inorganic layers (special features) No. 2007-30387, US Pat. No. 6413645, Affinito et al., Thin Solid Films 1996, pages 290-291), and organic layers and inorganic layers laminated continuously (US Pat. No. 2004-46497).

When the dye-sensitized photoelectric conversion element of the present invention is in the form of a plastic film, the overall thickness of the discharge conversion element is 150 μm to 1000 μm, preferably 250 μm, for the purpose of ensuring mechanical flexibility and performance stability. ˜750 μm is preferable, and 300 μm to 600 μm is more preferable. Moreover, a separator for preventing a short circuit can be included as required. The material forming the separator is an electrically insulating material, and the form thereof may be any of a film form, a particle form, and a form integrated with the electrolyte layer. It is preferable to use a separator in the form of a film.

When used in the form of a film, the film is made of a porous film that permeates an electrolytic solution, for example, an organic material such as a resin film, a nonwoven fabric, or paper. Such a porous film may be a hydrophilic film formed by hydrophilizing the surface. The thickness of this film needs to be 80 μm or less, and it is necessary to use a film whose porosity is 50% to 85%.

When used in the form of particles, various inorganic materials and organic materials can be used as the particles. As the inorganic material, silica, alumina, fluorine-based resin and the like are preferable, and as the organic material, nylon, polystyrene, polyethylene, polypropylene, polyester, polyimide and the like are preferable, and it is preferable that a component having a crosslinking group is contained as the component. This is because swelling due to the electrolytic solution can be prevented. The average particle size of these particles is preferably 10 μm to 50 μm, more preferably 15 μm to 30 μm. When the separator is integrated with the electrolyte, for example, an electrolytic solution gelled with a polymer or the like, an electrolytic solution whose viscosity is increased by crosslinking the electrolytic solution by a crosslinking reaction of a compound in the electrolytic solution, and the like are used. These so-called quasi-solidified electrolytes are also included in a broad sense.

2. Dye-sensitized solar cell module Since the electromotive force that can be obtained with a single dye-sensitized photoelectric conversion element is limited, multiple dye-sensitized photoelectric conversion elements can be connected in series or in parallel to extract a practical voltage. Need to connect. The upper part of FIG. 2 is a cross-sectional view of the dye-sensitized solar cell module 100 of the present invention in which six dye-sensitized photoelectric conversion elements of the present invention are connected in series at predetermined intervals, and the lower part of FIG. 3 is a plan view of the sensitive solar cell module 100. FIG. This is an example of the embodiment, and the present invention is not limited to this.
As shown in the upper part of FIG. 2, the individual dye-sensitized photoelectric conversion elements 1 are connected in series by an electrode connection portion 23 including a current collecting line 20 and conductive fine particles 22. Further, the electrode connection portion 23 is partitioned by a non-conductive sealing layer 19. The sealing layer 19 serves to seal the electrolyte solution layer 16 of each dye-sensitized photoelectric conversion element 1. In addition, the extraction electrode 21 is provided on the current collecting line 20 at both ends of the dye-sensitized solar cell module 100. A lead wire is joined to the extraction electrode and connected to a desired electrical device to be used as a power generation source.

[1] Conductive fine particles Here, the conductive fine particles 22 are elastic conductive fine particles obtained by applying gold plating to plastic fine particles having a sharp particle size distribution. Excellent elasticity with the current collector because of its elasticity. In addition, the thickness of the electrolyte layer can be controlled by selecting conductive fine particles having a particle size 1 to 1.5 times, preferably 1.1 to 1.3 times that of the spacer.
In the present invention, the electrode connection portion is a combination of the current collector and the conductive fine particles. Specifically, after the current collector is formed, the conductive fine particles including the sealing material are laminated on the current collector, so that the transparent conductive This is to ensure the conductivity between the photoelectrode and the counter electrode due to the formation of the undercoat layer on the conductive layer.

[2] Formation of current collector A photoelectrode substrate in which a current collector is arranged on a conductive electrode substrate constituting the photoelectrode, and a dye-sensitized semiconductor fine particle layer is formed on the conductive electrode substrate divided by the current collector; A counter electrode provided with a current collector on a conductive electrode substrate constituting the counter electrode is bonded to a seal portion provided on a transparent conductive film on the current collector to provide a cell portion, and an electrolyte layer is provided on the cell portion. A dye-sensitized solar cell module made of a plastic substrate in which is encapsulated is preferable.

  The material of the current collector is preferably made of at least one metal selected from silver, copper, aluminum, tungsten, nickel, and chromium, or an alloy thereof. The current collector is preferably formed in a lattice shape on the transparent conductive substrate. Examples of the method for forming the current collector include sputtering, vapor deposition, plating, and screen printing.

[3] Modularization In order to assemble the dye-sensitized photoelectric conversion element of the present invention as a dye-sensitized solar cell, it is necessary to modularize it. Described below. In the case of modularization, a porous semiconductor fine particle layer is formed on a transparent conductive film separated by a current collecting line, and a dye is adsorbed thereon to produce a photoelectrode, and a conductive film is formed on the substrate. A step of forming a counter electrode, a step of forming a seal portion on a transparent conductive film on a current collecting line, adhering the photoelectrode and the counter electrode to form a cell portion, and a step of encapsulating an electrolyte in the cell portion It is preferable to prepare a dye-sensitized solar cell module. Even if the step of encapsulating the electrolyte in the cell portion is performed in advance, and then the step of forming the cell portion by forming the seal portion on the transparent conductive film on the current collector and bonding the photoelectrode and the counter electrode is performed. Good. The generated power collected by the power collecting wire is joined to a lead wire and connected to desired electrical equipment and used as a power generation source. At this time, it is possible to use only each unit cell, and it is more preferable to combine two or more cells with lead wires to form a module. At that time, each cell may be connected in series or in parallel, and further, a combination of series and parallel may be used.

[4] Exterior and barrier package As for the exterior and barrier package of the dye-sensitized photoelectric conversion element formed into a module, the exterior and barrier package were prepared in the same manner as the photoelectric conversion element.

[5] Use The use of the dye-sensitized photoelectric conversion element and dye-sensitized solar cell module of the present invention is not particularly limited. If the available light source is in the visible light region, it has a power generation function. In addition, even if illuminance unevenness exists in the light source, it has a feature that the output characteristics are not greatly hindered. Furthermore, the dependency on the irradiation angle is also small. As an application, it can be used as a power source for generating electricity all day long from sunrise to sunset as a general solar battery for a household power source. Moreover, since it has the feature that it can generate electric power without problems even in the sun or indoors where silicon-based solar cells are not good, it can be used as a power source for various uses in the sun and indoors. In addition, since a plastic substrate is used, it is characterized by being lightweight and not easily damaged, and can be used as a portable battery for charging a mobile phone or a portable information terminal (mobile). As a medical use, it can be used as a power supply for infusion pumps and syringe pumps, and as a portable battery for charging a monitor power supply for monitoring extracorporeal circulation such as dialysis, for emergency power supply during a power outage or at night. In particular, it is also useful as an emergency charging battery in the event of a disaster.

Further, the dye-sensitized photoelectric conversion element can be produced in an arbitrary shape, and the shape is not particularly limited. The dye-sensitized photoelectric conversion element and the dye-sensitized solar cell module of the present invention can be used as a power source, for example, used in an electronic device, a moving body, a power device, a construction machine, a machine tool, a power generation system, etc. I get out. The desired output, size, shape, etc. can be designed arbitrarily according to the application. The dye-sensitized photoelectric conversion element can also be used for applications such as a dye-sensitized photosensor. Moreover, as an electronic device using the dye-sensitized photoelectric conversion element and the dye-sensitized solar cell module of the present invention, both a portable type and a stationary type can be used, and mobile phones, mobile devices, robots, personal computers, Examples include game machines, in-vehicle devices, home appliances, and industrial products. Examples of mobile use using a dye-sensitized photoelectric conversion element and a dye-sensitized solar cell module include automobiles, motorcycles, aircraft, rockets, and space ships.

Next, the form for implementing this invention is shown in Table 1 and Table 2 as an Example.
[1] Example 1
(1) Preparation of electrolyte solution 2.6 g of N-methylbenzimidazole, 3.3 g of potassium iodide, and 6.6 g of 1,3-butylmethylimidazolium iodide are placed in a 50 mL volumetric flask, and the whole amount of γ-butyrolactone is obtained. To 50 mL. After stirring for 1 hour by vibration with an ultrasonic cleaner, leave it in the dark for more than 24 hours to prepare an electrolyte solution containing no redox couple (I- / I3-) consisting of a combination of iodine and iodide. did.

(2) Preparation of dye solution 72 mg of a ruthenium complex dye (N719, manufactured by Solaronics) was placed in a 200 mL volumetric flask. 190 mL of dehydrated ethanol was mixed and stirred. After stoppering the volumetric flask, the mixture was stirred for 60 minutes by vibration with an ultrasonic cleaner. After keeping the solution at room temperature, dehydrated ethanol was added to make a total volume of 200 mL to prepare a dye solution.

(3) Creation of photoelectrode On a conductive electrode substrate (sheet resistance 15 Ω / sq) obtained by laminating a transparent conductive layer (indium-tin oxide (ITO)) on a transparent substrate (polyethylene naphthalate film, thickness 200 μm), Conductive silver paste (K3105, manufactured by Pernox Co., Ltd.) is printed and applied at intervals according to the photoelectrode cell width by screen printing, and heated and dried for 15 minutes in a 150 degree hot air circulation oven to produce a current collector. did.
The undercoat layer was set on a coating coater with the current collector surface of the conductive electrode substrate facing up, and an organic PC-600 solution (manufactured by Matsumoto Fine Chemical) diluted to 1.6% was swept with a wire bar (10 mm). / Second) and dried at room temperature for 10 minutes, and then further dried by heating at 150 ° C. for 10 minutes. On the undercoat layer forming surface of the transparent conductive substrate on which the undercoat layer was formed, laser treatment was performed at intervals according to the photoelectrode cell width to form insulating lines.
A mask film (bottom: PC-542PA manufactured by Fujimori Kogyo Co., Ltd., upper: NBO-0424 manufactured by Fujimori Kogyo Co., Ltd.) in which a protective film having an adhesive layer coated on a polyester film is stacked is an opening for forming a porous semiconductor fine particle layer. A part (length: 60 mm, width 5 mm) was punched out. The processed mask film was bonded to the current collector forming surface of the transparent conductive substrate on which the undercoat layer was formed so that air bubbles would not enter.
A high-pressure mercury lamp (rated lamp power 400 W) is placed at a distance of 10 cm from the mask bonding surface, and immediately after irradiation with electromagnetic waves for 1 minute, a binder-free titanium oxide paste that does not contain polymer components (PECC-C01-06, Pexel Technologies) Co., Ltd.) was applied with a Baker type applicator. After the paste is dried at room temperature for 10 minutes, the protective film on the upper side of the mask film (NBO-0424, manufactured by Fujimori Kogyo Co., Ltd.) is peeled and removed, and further heated and dried in a hot air circulation oven at 150 degrees for 5 minutes. A fine particle layer (length: 60 mm, width 5 mm) was formed.
Thereafter, the conductive electrode substrate on which the porous semiconductor fine particle layer (length: 60 mm, width 5 mm) was formed was immersed in the prepared dye solution (40 ° C.), and the dye was adsorbed while gently stirring. After 90 minutes, the dye-adsorbed titanium oxide film was taken out from the dye-adsorption container, washed with ethanol and dried, and the remaining mask film was peeled and removed to produce a photoelectrode.

(4) Production of counter electrode Conductive surface of conductive electrode substrate (sheet resistance 150 Ω / sq) in which transparent conductive layer (indium-tin oxide (ITO)) is laminated on transparent substrate (polyethylene naphthalate film, thickness 200 μm) A metal mask in which an opening (length: 60 mm, width 5 mm) is punched is overlapped, and a platinum film pattern (catalyst layer) is formed by a sputtering method. The light transmittance of the catalyst layer forming portion is about 72%. A counter electrode layer having was obtained. At this time, when the photoelectrode layer and the counter electrode layer are overlapped with their conductive surfaces facing each other, the titanium oxide pattern (porous semiconductor fine particle layer forming portion) and the platinum pattern (catalyst layer forming portion) are Matched structure.

(5) Production of photoelectric conversion element With the catalyst layer forming surface of the counter electrode layer as the surface, it is fixed on an aluminum adsorption plate using a vacuum pump, and a liquid photocurable sealant (manufactured by ThreeBond Co., Ltd.) is used. The coating was applied to the outer peripheral portion of the platinum film pattern by an automatic coating robot. After that, apply a predetermined amount of the electrolyte prepared as described above to the platinum film pattern part, and use an automatic laminating device in a reduced pressure environment so that the rectangular platinum pattern and the same type of titanium oxide pattern face each other. Superimposing and irradiating light from the photoelectrode side with a metal halide lamp, followed by irradiating light from the platinum electrode side. After that, a plurality of photoelectric conversion elements arranged in the substrate after bonding are cut out, and a dye is increased by sticking a conductive copper anchor tape (CU7636D, manufactured by Sony Chemical & Information Device Co., Ltd.) to the extraction electrode part. A photoelectric conversion element was produced.

(6) Evaluation of photoelectric conversion element (conversion efficiency)
As a light source, a pseudo solar irradiation device (PEC-L11 type, manufactured by Pexel Technologies Co., Ltd.) light source in which an AM1.5G filter is attached to a 150 W xenon lamp light source was used. The amount of light was adjusted to 100,000, 50,000, and 25,000 lux. The produced dye-sensitized solar cell was connected to a source meter (type 2400 source meter, manufactured by Keithley). For the current-voltage characteristics, the output current was measured while changing the bias voltage under each light irradiation from 0 V to 0.9 V in units of 0.01 V. The output current was measured by integrating the values from 0.05 seconds to 0.15 seconds after changing the voltage in each voltage step. Measurement was also performed by stepping the bias voltage from 0.9 V to 0 V in the reverse direction, and the average value of the forward and reverse measurements was taken as the photocurrent. Table 1 shows the initial output (Pmax) and maximum voltage (Vmax) of the above-described various samples.

[2] Examples 2 and 3
The same procedure as in Example 1 was performed except that a conductive electrode substrate having a sheet resistance of 300Ω / sq or 400Ω / sq was used as the conductive electrode substrate of the counter electrode.

[3] Examples 4, 5, and 6
Example 1 was the same as Example 1 except that the conductive electrode substrate for the photoelectrode used was a sheet resistance of 30Ω / sq, 50Ω / sq, or 80Ω / sq.

[4] Examples 7, 8, and 9
A conductive electrode substrate with a sheet resistance of 15 Ω / sq was used as the conductive electrode substrate for the counter electrode, and a conductive electrode substrate with a sheet resistance of 150 Ω / sq, 300 Ω / sq, or 400 Ω / sq was used as the conductive electrode substrate for the photoelectrode. The same as in Example 1.

[5] Examples 10, 11, 12
Except that the conductive electrode substrate for the photoelectrode has a sheet resistance of 150 Ω / sq, and the conductive electrode substrate for the counter electrode has a sheet resistance of 30 Ω / sq, 50 Ω / sq, 80 Ω / sq. The same as in Example 1.

[6] Comparative Examples 1-6
As the sheet resistance combination of the conductive electrode substrate of the photoelectrode and the conductive electrode substrate of the counter electrode, (light: 15Ω / sq, pair: 15Ω / sq), (light: 90Ω / sq, pair: 90Ω / sq), ( Light: 150Ω / sq, Pair: 150Ω / sq), (Light: 150Ω / sq, Pair: 600Ω / sq), (Light: 600Ω / sq, Pair: 15Ω / sq), (Light: 600Ω / sq, Pair: Example 1 except that 600Ω / sq) was used.

[7] Results As shown in Table 1, the comparative samples 1013 to 1018 in which the conductivity of the photoelectrode or the counter electrode is outside the scope of the present invention have a fluctuation amount of power generation amount of 2 or more between high irradiation and low irradiation. large. In contrast, the conductivity of the photoelectrode of the present invention is less than 100Ω and the counter electrode is 100 to 500Ω, and the samples 1001 to 1006 of the present invention are 100 to 500Ω and the counter electrode is 100Ω. Samples 1007 to 1012 of the present invention, which are less than 1, show the feature that the amount of power generation variation between high and low irradiation is as small as around 1, and the power generation amount is constant regardless of the amount of irradiation of the present invention. Met. Furthermore, it was confirmed that the voltage (Vmax) also has excellent characteristics with small fluctuations. It was also confirmed that the film strength of the obtained photoelectrode and counter electrode was sufficient, and that there was no problem with the adhesion between the substrate and the conductive layer and the titanium oxide layer or the catalyst layer. Therefore, it was proved that the sample of the present invention is an excellent dye-sensitized photoelectric conversion element and dye-sensitized solar cell with small illumination dependency.

[8] Example 21
Example 1 was the same as Example 1 except that the counter electrode was produced by the following method.
(1) Production of counter electrode Conductive electrode substrate (sheet resistance 200Ω / sheet) in which a transparent conductive layer (carbon nanotube (SG65 manufactured by Aldrich (product application No. 704148))) is laminated on a transparent substrate (polyethylene naphthalate film, thickness 200 μm) sq) is overlaid with a metal mask punched with openings (length: 60 mm, width 5 mm) to form a platinum film pattern (catalyst layer) by sputtering, with a catalyst layer formation portion of 72%. A counter electrode layer having a light transmittance of a certain degree was obtained. At this time, when the photoelectrode layer and the counter electrode layer are overlapped with their conductive surfaces facing each other, the titanium oxide pattern (porous semiconductor fine particle layer forming portion) and the platinum pattern (catalyst layer forming portion) are Matched structure.

[9] Example 22
Example 21 was the same as Example 21 except that carbon nanotubes (SG65 manufactured by Aldrich (product application No. 704148)) were used as the catalyst layer.

[10] Example 23
The same as Example 21 except that indium-tin oxide (ITO) was used as the conductive layer.

[11] Results As shown in Table 2, even when the conductive layer is changed to CNT, the fluctuation amount of the power generation amount between the high irradiation and the low irradiation is as small as about 1, and the power generation amount regardless of the irradiation amount of the present invention. Was characteristic of being constant. Furthermore, it was confirmed that the voltage (Vmax) had excellent characteristics with small fluctuations. In the sample 2002, it was also confirmed that the CNT itself exhibits conductivity and excellent catalytic action.

[12] Example 31
The sample 1001 produced based on Example 1 was enclosed in the following barrier package, and the module sample 3001 of this invention was produced.
(1) Production of Module Encapsulated in Barrier Package Body Sample 1001 produced in Example 1 was sealed in a barrier package body having a moisture permeability of 10 ⁻⁴ g / day · cm 2 as described below, and the dye increase enclosed in the packaging material A solar cell element 3001 was produced.

(2) Production of packaging material A deposited thin film layer of silicon oxide having a thickness of 30 nm is laminated on one surface of a base material made of a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm, and a coating amount of 3 g is formed on the deposited thin film layer. A 15 μm thick biaxially stretched nylon film is laminated via a polyurethane adhesive of / m ² (dry state), and a polyurethane adhesive of 3 g / m ² (dry state) is applied to the biaxially stretched nylon film surface. agent laminating an unstretched polypropylene film having a thickness of 30μm through the other _C to the surface _{3 F 7 - (OC 3 F} 6) 24 -O- (CF 2) 2 -C 2 H 4 -O-CH 2 Si _{(OCH 3)} 3 a perfluoropolyether group-containing silane coupling agent made of diluted 0.5 wt% in perfluorohexane was applied a coating solution and dried to a film thickness 3μm proof of To obtain a laminate material obtained by laminating a layer.

(3) Manufacture of a module enclosing a packaging material Three-sided seal with two unstretched polypropylene film surfaces of two laminated materials slit into the predetermined dimensions, heat-sealed on three sides, and an opening on one side Create a bag (packaging bag), insert a sample 3001 with a cable through the opening of the three-side sealed bag, take one end of the cable out of the bag, suck the air in the bag under vacuum, and heat seal Thus, a module sample 3001 encapsulated in the packaged barrier package of the present invention was obtained.

(4) Durability Evaluation The module sample 3001 encapsulated in the barrier package of the present invention was allowed to stand for 1000 hours at 40 ° C. and 90% relative humidity. It was confirmed that it showed a good characteristic. From the above, it was confirmed that the dye-sensitized photoelectric conversion element having the conductive layer of the present invention has excellent durability.

The dye-sensitized photoelectric conversion element according to the present invention has a photoelectrode having a specific conductivity and a counter electrode, and develops a certain power generation property even with respect to illuminance fluctuations. It has stable and excellent output. In addition, according to the present invention, it is possible to obtain a dye-sensitized photoelectric conversion element and a dye-sensitized solar cell that have excellent durability, low cost, excellent environmental circulation, and low environmental load.

DESCRIPTION OF SYMBOLS 1 Dye-sensitized photoelectric conversion element 11 Transparent substrate 12 Transparent conductive layer 13 Undercoat layer 14 Porous semiconductor fine particle layer 15 carrying sensitizing dye 15 Photoelectrode layer 16 Electrolyte layer 17 Catalyst layer 18 Counter electrode layer 19 Sealing layer 20 Current collector 21 Extraction electrode 22 Conductive fine particle 23 Electrode connection portion 100 Dye-sensitized solar cell module

Claims (4)

In the dye-sensitized photoelectric conversion element having a photoelectrode layer composed of dye-sensitized semiconductor particles, an electrolytic solution layer, a catalyst layer, and a conductive counter electrode substrate in this order on a conductive photoelectrode substrate, the conductive property A dye-sensitized photoelectric conversion characterized in that the sheet resistance of one of the photoelectrode substrate and the conductive counter electrode substrate is less than 100Ω, and the sheet resistance of the other electrode substrate is 150Ω to 500Ω. element. In the dye-sensitized photoelectric conversion element having a photoelectrode layer composed of dye-sensitized semiconductor particles, an electrolytic solution layer, a catalyst layer, and a conductive counter electrode substrate in this order on a conductive photoelectrode substrate, the conductive property A dye-sensitized photoelectric conversion characterized in that the sheet resistance of one of the photoelectrode substrate and the conductive counter electrode substrate is 50Ω or less and the sheet resistance of the other electrode substrate is 150Ω to 300Ω. element. The ratio (P10max / P2.5max) of the power generation amount (P10max) at a light amount of 100,000 looks to the power generation amount (P2.5max) at a light amount of 25,000lux is 1.0 to 1.5. 3. The dye-sensitized photoelectric conversion element according to 1 or 2. Either or both of the conductive photoelectrode substrate and the conductive counter electrode substrate are plastic substrates, and the material constituting the plastic substrate is polyethylene terephthalate, polyethylene naphthalate, cycloolefin copolymer, alicyclic polyolefin The dye-sensitized photoelectric conversion element according to claim 1, wherein the dye-sensitized photoelectric conversion element is selected from any one of the above.