JP5119624B2 - Transfer body for metal oxide electrode production - Google Patents

Description

  The present invention relates to a metal oxide electrode of a dye-sensitized solar cell, and relates to a high-performance dye-sensitized solar cell without a short circuit between a counter electrode and a power generation layer.

  In recent years, environmental problems such as global warming have progressed globally. In recent years, photovoltaic power generation has attracted attention as a clean energy with a small environmental load, and active research and development has been promoted. As such solar cells, single crystal silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells and the like have already been put into practical use, but have problems such as high manufacturing costs and high energy consumption in the manufacturing stage. ing. In response to such problems, dye-sensitized solar cells are currently attracting attention as new solar cells that have a high potential for cost reduction, and are actively researched and developed.

  Dye-sensitized solar cells carry a transparent conductive substrate with a transparent conductive layer on a transparent substrate such as a glass substrate or resin film substrate from the light incident side, and a sensitizing dye for the solar wavelength region A photoelectric conversion layer composed of the oxide semiconductor layer and the electrolyte layer, and a counter electrode base material are sequentially laminated to constitute a cell.

Dye-sensitized solar cells can produce flexible solar cells by using a resin film on the substrate. In this case, the oxide semiconductor layer must be in contact with the counter electrode and short-circuited when the substrate is bent. There is a need to provide an insulating layer made of an insulating material so that there is no problem.
On the other hand, Patent Document 1 discloses a method for producing a dye-sensitized solar cell using a high-performance resin film substrate. When a resin film substrate is used as the substrate, the oxide semiconductor layer cannot be baked to a high temperature of about 600 ° C. due to the limitation of the temperature of the substrate. Document 1 discloses a technique for forming an oxide semiconductor layer on a substrate having high heat resistance and transferring it onto a resin film substrate after firing, in order to solve the above problems.
However, in the production method according to Patent Document 1, when the metal oxide layer is transferred onto the surface of the resin film substrate by the transfer body, the peelability between the heat resistant substrate and the metal oxide film is removed when the heat resistant substrate is peeled off. However, it was difficult to accurately transfer the metal oxide film onto the substrate to be transferred. Moreover, in the manufacturing process of a dye-sensitized solar cell, it was necessary to provide the above-mentioned insulating layer after transfer, and there existed a subject that a process was complicated and a yield was bad.
JP 2002-184475 A

  The present invention has been made in view of the above object, and a first object thereof is to provide a transfer body capable of producing a highly stable metal oxide electrode.

In order to achieve the above object, the present invention provides a semiconductor electrode manufacturing transfer comprising a first metal oxide layer, a second metal oxide layer, and a transparent electrode layer sequentially laminated on one surface of a heat-resistant substrate. a body, said first metal oxide layer is Ri Do metal oxide fine particles of the insulator, the value of the volume resistivity of the first metal oxide layer having a volume resistivity of said second metal oxide layer Provided is a transfer body for producing a metal oxide electrode, characterized by being larger than the value .
According to the metal oxide production transfer member of the present invention, the first metal oxide layer is formed by firing a mixture of metal oxide fine particles and an organic resin, and has good releasability and a metal oxide electrode layer. When the heat-resistant substrate is peeled off after the resin film is bonded to the resin film substrate, the metal oxide electrode layer is accurately formed on the substrate to be transferred without occurrence of defective peeling between the heat-resistant substrate and the metal oxide electrode film. Can be transferred. Furthermore, since the metal oxide fine particles are made of an insulating material, it is not necessary to newly provide an insulating layer after transfer, the process can be simplified, and the yield can be improved.

  Moreover, the present invention is characterized in that the transparent electrode layer of the transfer body for producing a metal oxide electrode according to claim 1 and a resin film base material having flexibility are bonded via an adhesive layer. A laminate for producing a metal oxide electrode is provided.

Further, according to the present invention, after bonding the resin film substrate having flexibility and a transparent electrode layer side of the metal oxide electrode prepared for transfer body according to claim 1 with an adhesive layer, wherein The metal oxide electrode is produced by transferring the first metal oxide layer , the second metal oxide layer and the transparent electrode layer to the resin film substrate by peeling off the heat-resistant substrate.
According to the production method of the present invention, since a metal oxide layer is formed on a substrate having high heat resistance once and is baked and then transferred onto the resin film substrate, the temperature of the resin film substrate is adjusted. The metal oxide layer can be fired at a high temperature of about 600 ° C. without being restricted, and a metal oxide electrode with high conversion efficiency can be obtained. Further, as described above, according to the method of the present invention, the first metal oxide layer of the transfer body for producing a metal oxide electrode has both peelability and insulation properties, and there are few transfer defects, and the process is simplified. Is possible, and the yield can be improved.

By joining the transparent electrode layer side of the transfer body for metal oxide electrode production according to claim 1 and a flexible resin film substrate through an adhesive layer, and then peeling off the heat-resistant substrate. A step of producing a metal oxide electrode by transferring the first metal oxide layer, the second metal oxide layer and the transparent electrode layer to a resin film substrate, and producing a counter electrode facing the metal oxide electrode There is provided a method for producing a dye-sensitized solar cell, comprising: a step; and a step of forming an electrolyte layer interposed between the metal oxide electrode and a counter electrode.
According to the present invention, conventionally, in the manufacturing process of the dye-sensitized solar cell by the transfer method, it has been necessary to provide the above-described insulating layer after the transfer, but according to the present invention, the insulating layer made of an insulating material is used. Since the layer is provided before transfer, the process can be simplified and the yield can be improved.

  The transfer body for producing a metal oxide electrode of the present invention comprises a first metal oxide layer having excellent releasability, whereby the transfer accuracy is increased, and insulating metal oxide fine particles are formed on the metal oxide layer. Therefore, it is not necessary to newly provide an insulating layer after transfer to the resin film substrate, the process can be simplified, and a substrate for a dye-sensitized solar cell can be manufactured with high yield.

  Hereinafter, the transfer body for producing a metal oxide electrode of the present invention, a method for producing a metal oxide electrode, and a dye-sensitized solar cell will be described.

A. First, the transfer body for producing a metal oxide electrode of the present invention will be described.

The transfer body for producing a metal oxide electrode of the present invention is a metal oxide electrode obtained by sequentially laminating a first metal oxide layer, a second metal oxide layer, and a transparent electrode layer on one surface of a heat-resistant substrate. a manufacturing transcript, the volume of the first metal oxide layer is Ri Do metal oxide fine particles of the insulator, the value of the volume resistivity of the first metal oxide layer said second metal oxide layer It is characterized by being larger than the value of resistivity .

Such a transfer body for producing a metal oxide electrode of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of a transfer member for producing a metal oxide electrode of the present invention. As illustrated in FIG. 1, the metal oxide electrode production transfer body of the present invention includes a first metal oxide layer (2) composed of insulating metal oxide fine particles on a heat resistant substrate (1), a metal A second metal oxide layer (3) made of oxide fine particles is laminated, and further has a transparent electrode layer (4) on the second metal oxide layer.
Hereafter, each structure of the transfer body for metal oxide layer electrode manufacture of such this invention is demonstrated in detail.

(Heat resistant substrate)
Further, the heat-resistant substrate used in this step is not particularly limited as long as it has excellent heat resistance. Specifically, a heat-resistant substrate made of glass, ceramics, a metal plate, or the like can be given. By using a heat-resistant substrate made of such a material, baking can be performed at a sufficiently high temperature in a baking process described later, so that the binding property between the metal oxide semiconductor fine particles can be increased.

(First metal oxide layer)
The first metal oxide layer used in the present invention is formed by firing a mixture of insulating metal oxide fine particles and an organic resin, and has a function of peeling from a heat-resistant substrate and a metal oxide after transfer. It has a function as an insulating layer that prevents the physical layer from coming into contact with the counter electrode and short-circuiting.

The term “insulation” as used herein means that the volume resistivity (Ω · cm) of the first metal oxide layer is larger than the value of the second metal oxide layer described later, and is used for the first metal oxide layer. The insulating metal oxide fine particles to be formed are not particularly limited as long as they satisfy the above requirements when forming a layer. Specifically, Al ₂ O ₃ , ZrO ₂ , MgO, Y ₂ O ₃ , Ta Fine particles such as ₂ O ₅ , Nb ₂ O ₅ and La ₂ O ₃ can be used, and among them, Al ₂ O ₃ and ZrO ₂ can be preferably used. Any one kind of the above fine particles may be used, or two or more kinds may be mixed and used. Further, the particle diameter of the metal oxide fine particles contained in the first metal oxide layer is not particularly limited, and specifically, the average particle diameter is preferably 5 nm or more, and particularly preferably 10 nm or more, Moreover, it is more preferable that it is larger than the average particle diameter of the metal oxide fine particles in the second metal oxide layer described later. When the particle size of the metal oxide fine particles of the first metal oxide layer is larger than the particle size of the metal oxide fine particles of the second metal oxide layer, the first metal oxide layer has a function as a scattering layer. As a result, in the solar cell using this transfer body, the light incident from the transparent electrode side and passed without being absorbed by the second metal oxide layer functioning as the photoelectric conversion layer is the first metal oxide layer. As a result, the light absorption rate of the second metal oxide layer can be improved.

  In addition, the organic resin is not particularly limited as long as it is easily decomposed in a baking step described later. Specific examples include resins. Such a resin is not particularly limited as long as it is difficult to dissolve in the solvent used when forming the second metal oxide layer described later. Among these, in the present invention, a resin having a molecular weight in the range of 2,000 to 600,000 is preferable, and a resin having a molecular weight in the range of 10,000 to 200,000 is more preferable. This is because a resin having a molecular weight in the above range is easily decomposed in a baking step described later, and the first metal oxide layer can be easily formed into a film having communication holes.

  The resin that can be specifically used is preferably a resin that is easily pyrolyzed by baking and does not remain in the intervening film. For example, ethyl cellulose, methyl cellulose, nitrocellulose, acetyl cellulose, acetyl ethyl cellulose, cellulose propionate, hydroxypropyl cellulose Cellulose resins such as butylcellulose, benzylcellulose, nitrocellulose, or methyl methacrylate, ethyl methacrylate, tertiary butyl methacrylate, normal butyl methacrylate, isobutyl methacrylate, isopropyl methacrylate, 2-ethyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxy Acrylic resin consisting of a polymer or copolymer such as ethyl methacrylate, polyethylene glycol, etc. Examples thereof include polyhydric alcohols.

  In addition, the solid content ratio (weight ratio) between the insulating metal oxide fine particles forming the first metal oxide layer and the organic resin is specifically in the range of particle / resin = 2/8 to 8/2. Among them, it is preferable that the particle / resin is within the range of 3/7 to 7/3. Within the above range, the first metal oxide layer formed after firing has a structure in which insulating metal fine particles are appropriately scattered, and becomes a layer having peelability and insulation.

  The thickness of the first metal oxide layer is not particularly limited as long as the first metal oxide film can be formed on the heat-resistant substrate with appropriate adhesion. When formed as a porous body in the firing step described later, it is preferable to adjust and determine the film thickness as described in “3. Specifically, it is preferably in the range of 0.01 μm to 30 μm, more preferably in the range of 0.05 μm to 6 μm, and more preferably smaller than the second metal oxide layer described later. When the film thickness of the first metal oxide layer is larger than the film thickness of the first metal oxide layer functioning as a photoelectric conversion layer, the diffusibility of the electrolyte ions is reduced in the solar cell using this transfer body. Because.

(Second metal oxide layer)
The second metal oxide layer used in the present invention is composed of metal oxide fine particles and an organic resin. For example, after applying a coating solution for forming a second metal oxide layer containing the above-mentioned material. It means a product formed as a porous body through solidification and firing steps, and further having a dye sensitizer supported on the pores. When manufactured as a dye-sensitized solar cell, it constitutes a photoelectric conversion layer that functions as a member that conducts the charge generated by light irradiation from the dye sensitizer carried in the pores to the transparent electrode layer described later. Is.

As the metal oxide fine particles of the second metal oxide layer, the volume resistivity (Ω · cm) of the second metal oxide layer is smaller than the value of the first metal oxide layer, and the first metal oxide layer There is no particular limitation as long as the charge generated from the dye sensitizer can be conducted to the transparent electrode layer. _{Specifically,} mention may be made of TiO _2, SnO 2, ZnO, and ITO. These metal oxide fine particles are suitable for forming a porous second metal oxide layer, and are preferable because energy conversion efficiency can be improved and costs can be reduced. In addition, any one of the above fine particles may be used, or two or more kinds may be mixed and used. Among these, TiO ₂ and ZnO can be preferably used. Further, one of these may be a core fine particle, and a core-shell structure in which the core fine particle is included to form a shell with other metal oxide semiconductor fine particles.

  Resins usable for forming the second metal oxide layer include cellulose resins, polyester resins, polyamide resins, polyacrylate resins, polyacryl resins, polycarbonate resins, polyurethane resins, polyolefin resins. In addition to resins, polyvinyl acetal resins, fluorine resins, polyimide resins, polyhydric alcohols such as polyethylene glycol, and the like can be given.

  Further, the particle size of the metal oxide semiconductor fine particles contained in the second metal oxide layer is not particularly limited, but specifically, it is in the range of 1 nm to 1 μm, and in particular, in the range of 10 nm to 500 nm. Preferably there is. When the particle diameter is smaller than the above range, it is difficult to produce such fine particles per se, and each particle aggregates to form secondary particles, which is not preferable. On the other hand, when the particle diameter is larger than the above range, the second metal oxide layer may be thickened, which is not preferable because the resistance becomes high.

  In addition, the same or different kinds of metal oxide semiconductor fine particles having a particle diameter within the above range and different particle diameters may be mixed and used. As a result, the light scattering effect can be enhanced and more light can be confined in the finally obtained second metal oxide layer, so that light absorption in the dye sensitizer can be efficiently performed. Because. For example, the metal oxide semiconductor fine particles in the range of 10 to 50 nm and the metal oxide semiconductor fine particles in the range of 50 to 200 nm can be mixed and used.

(Transparent electrode)
The material for forming the transparent electrode layer is not particularly limited as long as it is excellent in conductivity and does not corrode with respect to the electrolyte. For example, it is manufactured using the metal oxide electrode of the present invention. In the dye-sensitized solar cell, when the transparent electrode layer is located on the light receiving surface side, it is preferable that the light transmissive property is excellent. For example, SnO2, ITO, IZO, ZnO etc. can be mentioned as a material excellent in the light transmittance. Among these, fluorine-doped SnO 2 and ITO are preferable. It is because it is excellent in both electroconductivity and permeability.

  Furthermore, the material for forming the transparent electrode layer is the work of the material for forming the counter electrode layer provided as an opposing electrode when a dye-sensitized solar cell is manufactured using the metal oxide electrode manufactured according to the present invention. It is preferable to select a material in consideration of a function or the like. For example, examples of the material having a high work function include Au, Ag, Co, Ni, Pt, C, ITO, SnO2, and fluorine doped SnO2, ZnO. On the other hand, examples of the material having a low work function include Li, In, Al, Ca, Mg, Sm, Tb, Yb, Zr, and LiF.

  Further, the transparent electrode layer may be a single layer, or may be laminated using materials having different work functions. As the film thickness of such a transparent electrode layer, in the case of a transparent electrode layer composed of a single layer, the film thickness is within a range of 0.1 to 2000 nm when composed of a plurality of layers, It is preferably in the range of 1 nm to 500 nm.

  Furthermore, the base material provided by this process is not particularly limited, whether it is transparent or opaque, and is manufactured using, for example, a metal oxide electrode manufactured according to the present invention. In the dye-sensitized solar cell thus formed, when the substrate is located on the light receiving surface side, it is preferable that the substrate has transparency excellent in light transmission. Furthermore, it is preferable that it is excellent in heat resistance, weather resistance, water vapor, and other gas barrier properties. Specifically, transparent flexible materials such as quartz glass, Pyrex (registered trademark), synthetic quartz plate, etc. that are not flexible, ethylene / tetrafluoroethylene copolymer film, biaxially stretched polyethylene terephthalate film, polyethersulfone (PES) film, polyetheretherketone (PEEK) film, polyetherimide (PEI) film, polyimide (PI) film, polyester naphthalate (PEN) and other plastic films. In the present invention, among these, a film substrate using a plastic film is preferable. This is because the processability is excellent, so it is easy to combine with other devices, and the range of applications can be expanded. It is also effective in improving productivity and reducing manufacturing costs.

Such a film may be used alone or may be a composite film in which two or more kinds of films are laminated.

(Method for producing transfer body for metal oxide electrode production)
The method for producing the metal oxide production transfer member (5) of the present invention will be specifically described with reference to the drawings. FIG. 2 is a process diagram illustrating an example of a method for producing a transfer body for producing a metal oxide electrode according to the present invention. First, as the first metal oxide-forming coating liquid, a liquid or slurry in which insulating metal oxide fine particles and a resin binder are dispersed in water, an organic solvent, or a mixed solvent thereof is prepared. The concentration of the solid content in the coating solution is preferably 1 to 70% by weight. Next, as shown in FIG. 2 (a), the coating solution is applied onto a heat resistant substrate by spin coating, dip coating, screen printing, blade coating, or the like, and dried as necessary. One metal oxide layer forming layer (2 ') can be formed. In addition, you may add additives, such as surfactant, a viscosity modifier, and a dispersing agent, to a coating liquid as needed. Next, in the same manner as the first metal oxide layer forming layer, a coating solution for forming the second metal oxide layer is prepared from the metal oxide fine particles and the binder resin, and as shown in FIG. On the metal oxide layer forming layer (2 '), the second metal oxide layer forming coating solution is applied in the same manner as the first metal oxide layer forming layer and solidified to form the second metal oxide layer. A layer (3 ') is formed.

  Next, as shown in FIG. 2C, the heat-resistant substrate 1 on which the first metal oxide layer forming layer (2 ′) and the second metal oxide layer forming layer (3 ′) are laminated is heated and fired. . Thereby, as shown in FIG. 2D, the first metal oxide layer forming layer (2 ′) and the second metal oxide layer forming layer (3 ′) become a porous body having communication holes. The porous body is defined as a first metal oxide layer (2) and a second metal oxide layer (3). In addition, it is preferable that the temperature of baking is in the range of 300 degreeC-700 degreeC, and it is preferable that it is in the range of 350 degreeC-600 degreeC especially. In the present invention, since a heat-resistant substrate having excellent heat resistance is used, firing at a high temperature within the above range is possible, and the first metal oxide layer (2) and the second metal oxide layer (3 ) Can be formed with good binding between the metal oxide semiconductor fine particles.

Next, a transparent electrode (4) for taking out current is arranged on the metal oxide film formed in this way. The transparent electrode is preferably formed after the heat-firing treatment, and examples thereof include wet coating, spray pyrolysis, vapor deposition, sputtering, and CVD, and the most preferable method is spray heat. A decomposition method is mentioned.

  A dye may be adsorbed (chemical adsorption, physical adsorption, deposition, etc.) as a sensitizer on the metal oxide film thus formed. The dye is preferably adsorbed after being transferred to the transfer substrate. As a method for adsorbing the dye, for example, the substrate on which the metal oxide film is formed may be immersed in a solution in which the dye is dissolved in an organic solvent. If necessary, the solution may be heated for the purpose of performing pressure reduction treatment or promoting adsorption so that the solution quickly enters the inside of the metal oxide film.

(Method for producing metal oxide electrode)
Next, the process of transferring the metal oxide electrode production transfer body to a flexible resin film substrate (6) will be described. The resin film substrate having flexibility is not particularly limited as long as it is light transmissive. For example, polyolefins such as polyethylene, polypropylene, polyisobutylene, polystyrene, ethylene-propylene rubber, polyethylene terephthalate, polybutylene terephthalate. Polyester resins such as ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, cellulose derivatives such as ethyl cellulose and cellulose triacetate, poly (meth) acrylic acid and its ester compounds, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral Polyvinyl acetal, polyacetal, polyamide, polyimide, nylon, urethane resin, epoxy resin, silicone resin, fluorine resin, polycarbonate, urea resin, melamine resin, pheno Le resins, resorcinol resins, furan resins. Among these synthetic resins, polyolefins or polyester resins are preferable because they have good light transmittance, resistance to an electrolytic solution, and little gas permeation.

  As a method for transferring the metal oxide electrode production transfer body (5) to the flexible resin film substrate (6), the transparent body (4) side of the transfer body (5) and the substrate to be transferred (6) ) And the like through the adhesive or the like (7), and then peeled off from the heat-resistant substrate. (Figure 3)

  The adhesive (7) that can be used in the above transfer step is not particularly limited, and various synthetic resins, inorganic adhesives, thermosetting adhesives, and UV curable adhesives can be used. Synthetic resins include, for example, polyethylene, polypropylene, polyisobutylene, polystyrene, ethylene-propylene rubber, cellulose derivatives such as cellulose triacetate, copolymers of poly (meth) acrylic acid and esters thereof, polyvinyl acetate, polyvinyl Examples thereof include polyvinyl acetals such as alcohol and polyvinyl butyral, polyacetals, polyamide resins and the like, and examples of the inorganic adhesive include alkali metal silicates such as low melting point glass and sodium silicate. Examples of the thermosetting adhesive include epoxy resin, diallyl phthalate resin, silicone resin, phenol resin, unsaturated polyester resin, polyimide resin, polyurethane resin, melamine resin, urea resin, fluorine resin, and UV curing. Examples of the mold adhesive include acrylate monomers, methacrylate monomers, cationic polymerization monomers, acrylate oligomers, polyester oligomers, epoxy acrylate oligomers, urethane acrylate oligomers, and the like. Among these adhesives, synthetic resin polyolefin, ethylene-vinyl acetate copolymer, thermosetting adhesive polyurethane resin, epoxy resin from the viewpoint of adhesion, resistance to electrolyte, light transmission and transferability Silicone resins and acrylate monomers and acrylate oligomers of UV curable adhesives are preferred. Moreover, an additive can be used for these adhesives as needed. Examples of the additive include a crosslinking agent, a dispersant, a tackifier, a leveling agent, a plasticizer, and an antifoaming agent.

  The method for adhering the metal oxide electrode production transfer body (5) and the transferred substrate (6) using such an adhesive (7) will be described with reference to some examples. Or an adhesive dissolved or dispersed in water is applied on the electrode layer (4) of the transfer body for producing metal oxide electrodes or on the transfer substrate (6), and the transfer body for producing metal oxide electrodes (5) A method in which the substrate to be transferred (6) is bonded and dried, and a heat-melted adhesive is applied onto the electrode layer (4) of the metal oxide electrode production transfer body or the substrate to be transferred (6). A method of cooling after bonding, a method of sandwiching a resin film made of a synthetic resin as described above between a transfer body for metal oxide electrode production (5) and a substrate to be transferred (6), heating and bonding, etc. Is mentioned. Although the thickness of an adhesive bond layer is not specifically limited, 5-300 micrometers, Preferably it is 10-200 micrometers.

(Method for producing dye-sensitized solar cell)
Next, the manufacturing method of the dye-sensitized solar cell of this invention is demonstrated. The manufacturing method of the dye-sensitized solar cell of the present invention includes the above-described metal oxide electrode manufacturing step, a counter electrode forming step of providing a counter electrode facing the metal oxide electrode, and the metal oxide electrode. And an electrolyte layer forming step of forming an electrolyte layer between the counter electrode and the counter electrode.

  Hereinafter, the present invention will be described in detail for each step.

1. Metal Oxide Electrode Manufacturing Process Since this process is the same as that described in the above “Metal Oxide Electrode Manufacturing Method”, description thereof is omitted here.

2. Next, the counter electrode manufacturing process will be described. The counter electrode manufacturing process is a process of providing a counter electrode (8) facing the transparent electrode layer (4) on the metal oxide electrode formed in the metal oxide electrode manufacturing process.

  This step is performed either before or after the electrolyte layer forming step, depending on the method of forming the electrolyte layer in the electrolyte layer forming step described later. That is, as will be described later, the electrolyte layer is formed by applying an electrolyte layer forming coating solution used for forming the electrolyte layer on the first metal oxide layer of the metal oxide electrode and drying it (hereinafter referred to as the following). In some cases, such a method for forming an electrolyte layer may be referred to as a coating method.) In the method for forming a dye-sensitized solar cell, an electrolyte layer forming step described later is performed first, followed by this step. Can be produced. Alternatively, when an electrolyte layer is formed by disposing a transparent electrode layer and a counter electrode layer with a predetermined gap so as to face each other and injecting an electrolyte layer forming coating solution into the gap (hereinafter referred to as the electrolyte layer). In some cases, such a method for forming an electrolyte layer may be referred to as an injection method.) In this case, this step is first performed, and then an electrolyte layer forming step described later is performed to manufacture a dye-sensitized solar cell. be able to.

  For example, when it is formed by a coating method in the electrolyte layer forming step described later, the method of forming the counter electrode layer in this step is not particularly limited, but specifically, the counter group on which the counter electrode layer is formed is not limited. It can be formed by preparing a material and bonding such a facing substrate on the electrolyte layer.

  In this case, the gap between the transparent electrode layer and the counter electrode layer is not particularly limited as long as an electrolyte layer can be formed in this gap, but generally within the range of 0.01 μm to 100 μm, It is preferably within a range of 0.1 μm to 50 μm. If the gap is narrower than the above range, it is not preferable because it may take a long time to inject the electrolyte layer forming coating solution. If the gap is wider than the above range, the electrolyte formed in such a gap is not preferable. This is not preferable because the thickness of the layer may increase.

    Conventionally, it has been necessary to provide an insulating layer between the transparent electrode and the counter electrode. In the present invention, however, this step can be omitted because the release layer contains insulating metal oxide fine particles. The process can be simplified.

(A) Opposing base material The opposing base material in the present invention is opposed to the base material constituting the transparent electrode. Such a facing substrate in the present invention is not particularly limited as long as it is transparent or opaque, but when it is located on the light receiving surface side, it transmits light. It is preferable that it has the transparency excellent in the property. Furthermore, it is preferable that it is excellent in heat resistance, weather resistance, water vapor, and other gas barrier properties.

  Note that the materials that can be specifically used when forming the counter substrate are the same as those used for the transparent electrode manufactured by the above-described “metal oxide electrode manufacturing method”. Description of is omitted.

(B) Counter electrode layer The counter electrode layer in this invention is formed on the said opposing base material, and is an electrode facing the transparent electrode formed in the base material for dye-sensitized solar cells.

  The material for forming such a counter electrode layer is not particularly limited as long as it is excellent in conductivity and does not corrode with respect to the electrolyte. It is preferable that it is excellent in light transmittance. In addition, it is preferable to select a material in consideration of the work function of the material for forming the transparent electrode layer which is an electrode facing the counter electrode layer.

  The materials that can be used when specifically forming the counter electrode layer are the same as the transparent electrode layer described in the above-mentioned “metal oxide electrode manufacturing method transparent electrode forming step”, so the explanation here is as follows. Omitted.

3. Electrolyte Layer Formation Step The electrolyte layer formation step in the present invention is a step of forming an electrolyte layer (9) between the transparent electrode layer and the counter electrode.

  The electrolyte layer (9) formed in this step is located between the transparent electrode and the counter electrode, and the charge conducted by the metal oxide layer (photoelectric conversion layer) passes through the transparent electrode layer and the counter electrode layer. Thus, transport is performed when transported to the metal oxide layer (photoelectric conversion layer). Therefore, the electrolyte layer formed by this step is not particularly limited as long as it has such a function, and may be an electrolyte layer in any form of solid, gel, or liquid.

  In such an electrolyte layer, for example, when it is in a gel form, there is no particular limitation whether it is a physical gel or a chemical gel. A physical gel is gelled near room temperature due to physical interaction, and a chemical gel is a gel formed by chemical bonding by a crosslinking reaction or the like.

  Furthermore, when the electrolyte layer is formed by this step, the film thickness is not particularly limited, but since the electrolyte layer is formed by filling the photoelectric conversion layer, the film thickness of the photoelectric conversion layer is also included. Within the range of 2 μm to 100 μm, among them, it is preferable to be within the range of 2 μm to 50 μm. If the film thickness is thinner than the above range, the metal oxide layer (photoelectric conversion layer) and the counter electrode layer are likely to come into contact with each other, causing a short circuit. If the film thickness is thicker than the above range, the internal resistance increases and the performance is increased. This leads to a decline.

  As described above, as a method for forming the electrolyte layer, an electrolyte layer forming coating solution used for forming the electrolyte layer is applied to the first metal oxide layer (2) of the metal oxide electrode (10) and dried. Before forming the coating method or this step, the transparent electrode layer and the counter electrode layer are arranged with a predetermined gap so as to face each other, and an electrolyte layer forming coating solution is placed in the gap. An injection method for forming an electrolyte layer can be given by injecting. Hereinafter, the method for forming the electrolyte layer will be described by taking a coating method as an example.

(A) Coating method First, an electrolyte layer is applied by applying a coating liquid for forming an electrolyte layer to the first metal oxide layer (2) of the metal oxide electrode (10) and solidifying it. A coating method to be formed will be described. By such a forming method, a solid electrolyte layer can be mainly formed.

  In such a coating method, a known coating method can be used as a coating method for the second metal oxide layer forming coating solution, specifically, die coating, gravure coating, gravure reverse coating, roll coating. , Reverse roll coating, bar coating, blade coating, knife coating, air knife coating, slot die coating, slide die coating, dip coating, micro bar coating, micro bar reverse coating, screen printing (rotary method), and the like.

  In addition, when an electrolyte layer is formed by a coating method, the electrolyte layer forming coating solution for forming the electrolyte layer retains an oxidation-reduction counter electrolyte and an oxidation-reduction counter electrolyte as necessary in order to impart coatability. A gelling agent can be used.

  Specifically, the redox counter electrolyte is not particularly limited as long as it is generally used in an electrolyte layer. Specifically, a combination of iodine and iodide and a combination of bromine and bromide are preferable. For example, as a combination of iodine and iodide, a combination of metal iodide such as LiI, NaI, KI, and CaI2 and I2 can be given. Further, examples of the combination of bromine and bromide include a combination of a metal bromide such as LiBr, NaBr, KBr, and CaBr2 and Br2.

  Furthermore, as the polymer for holding the redox counter electrolyte, it is preferable to use a conductive polymer having a high hole transporting property such as CuI, polypyrrole, or polythiophene.

  In addition, a crosslinking agent, a photopolymerization initiator, or the like may be contained as an additive. In the case of an electrolyte layer forming coating solution containing such an additive, after applying the electrolyte layer forming coating solution, an actinic ray is irradiated and cured to form a solid electrolyte layer. be able to.

Hereinafter, the present invention will be described more specifically by showing examples.

(1) Example 1
As the coating solution for forming the first metal oxide layer, 15.2% by weight of Al ₂ O ₃ fine particles (Nanotek CII Kasei) with an average particle diameter of 31 nm, 10.6% by weight of ethyl cellulose (Nisshin Kasei), and terpineol 74. A coating solution containing 2% by weight was prepared. This coating solution was applied onto a glass substrate (thickness 1 mm) by screen printing and dried at 120 ° C. for 10 minutes.

Thereafter, Ti Nanoxide T / SP (TiO ₂ fine particle average particle diameter 13 nm) manufactured by Solaronix SA was prepared as a coating solution for forming the second metal oxide layer, and the glass on which the first metal oxide layer forming layer was formed. It laminated | stacked on the board | substrate by the screen printing method. It was allowed to stand at room temperature for 20 minutes and then dried at 100 ° C. for 30 minutes.

  Thereafter, it was baked in an atmospheric atmosphere at 500 ° C. for 30 minutes using an electric muffle furnace (P90 manufactured by Denken). Thereby, the 1st metal oxide layer and 2nd metal oxide layer which were formed as a porous body were obtained. Thereafter, a coating solution in which indium chloride 0.1 mol / 1 and tin chloride 0.005 mol / 1 were dissolved in ethanol was prepared, and the above-mentioned baked glass substrate was placed on a hot plate (400 The above-mentioned coating solution is sprayed on the heated second metal oxide layer with an ultrasonic sprayer to form an ITO film as a transparent electrode layer having a thickness of 500 nm, thereby producing a metal oxide electrode. A transfer body was obtained.

(2) Example 2
A heat sealant (Toyobo MD1985) was applied onto a PET film (Toyobo E5100125μ) as a transfer electrode substrate and allowed to air dry. The heat-sealant-coated surface of the substrate to be transferred and the IT0 surface of the metal oxide electrode production transfer body laminated with IT0 described in Example 1 were bonded at 120 ° C. Obtained.

(3) Example 3
Further, the ITO, the second metal oxide layer, and the first metal oxide layer are transferred from the transfer body for producing the metal oxide electrode to the transfer electrode substrate by peeling off the transfer substrate, and the metal oxide electrode is transferred. Obtained.

(4) Example 4
After that, ruthenium complex (RuL, Kojima Chemical Co., Ltd. (NCS)) as a dye sensitizer was dissolved in absolute ethanol solution to a concentration of 3 × 1O ^-4 mol / 1 to prepare a dye solution for adsorption The sensitizing dye was held by the second metal oxide layer by immersing the transfer electrode substrate provided with ITO and the second metal oxide layer and the first metal oxide layer described in Example 2. A dye-sensitized solar cell was produced as follows using the obtained electrode substrate for a dye-sensitized solar cell. The electrolyte layer forming coating solution for forming the electrolyte layer was prepared as follows. Using methoxyacetonitrile as a solvent, dissolve 0.1 mol / 1 lithium iodide, 0.05 mol / 1 iodine, 0.3 mol / 1 dimethylpropylimidazolium iotide, 0.5 mol / 1 dark butylpyridine. This was used as an electrolyte. After trimming the above-mentioned dye-sensitized solar cell electrode substrate to 1 cm x 1 cm, the opposing substrate is bonded with a 20 μm-thick ionomer resin (DuPont Co., Ltd., Surlyn). A device impregnated with a working solution was used as an element. As the counter substrate, a 50 nm thick platinum film formed by sputtering on a counter film substrate having an ITO sputter layer having a film thickness of 150 nm and a surface resistance of 7Ω / □ was used.

The evaluation of the fabricated element was performed using AM1.5, pseudo-sunlight (incident light intensity of 100 mW / Cm ² ) as a light source, incident from the substrate side having the oxide semiconductor layer adsorbed with the dye, and the source measure unit (Keithley 2400 The current-voltage characteristics were measured by applying voltage with a mold. As a result, the short-circuit current was 15.2 mA / cm ² , the open-circuit voltage was 710 mV, and the conversion efficiency was 6.2%.

The first metal oxide layer-forming coating solution was applied on a glass substrate (thickness 1 mm) by screen printing and dried at 120 ° C. for 10 minutes, and then an electric muffle furnace (P90 manufactured by Denken) was used. The first metal oxide layer laminate having a thickness of 1 μm was obtained by firing at 500 ° C. for 30 minutes in an atmospheric pressure atmosphere. Moreover, the 2nd metal oxide layer laminated body was also formed by the same method from the said 2nd metal oxide layer forming coating liquid. The volume resistivity (Ω · cm) of the obtained first metal oxide layer laminate and the second metal oxide layer laminate was measured by Hiresta UP MCP-HT450 manufactured by Dia Instruments Co., Ltd. The volume resistivity of the oxide layer stack (Al ₂ O ₃ layer) is 2.0 × 10 ¹⁴ (Ω · cm), and the volume resistivity of the second metal oxide layer stack is 2.0 × 10 ¹² (Ω Cm).

It is a schematic sectional drawing which shows an example of the transfer body for metal oxide electrode manufacture of this invention. It is process drawing which showed an example of the manufacturing method of the transfer body for metal oxide electrode manufacture of this invention. It is process drawing which showed an example of the manufacturing method of the metal oxide electrode of this invention. It is process drawing which showed an example of the manufacturing method of the dye-sensitized solar cell of this invention.

Explanation of symbols

1: Heat-resistant substrate 2: First metal oxide layer 3: Second metal oxide layer 4: Transparent electrode layer 5: Transfer body for producing metal oxide electrode 6: Flexible resin film substrate 7: Adhesive Layer 8: Counter electrode layer 9: Electrolyte layer 10: Metal oxide electrode 11: Dye-sensitized solar cell

Claims (4)

A transfer body for producing a metal oxide electrode in which a first metal oxide layer, a second metal oxide layer, and a transparent electrode layer are sequentially laminated on one surface of a heat-resistant substrate, the first metal oxide metal object layer being greater than the value of the metal oxide Do from the microparticles Ri, the volume resistivity of the first metal oxide layer volume resistivity value said second metal oxide layer of the insulator A transfer body for producing an oxide electrode.   The transparent electrode layer of the transfer body for producing a metal oxide electrode according to claim 1 and a resin film base material having flexibility are bonded via an adhesive layer. Laminated body. By joining the transparent electrode layer side of the transfer body for metal oxide electrode production according to claim 1 and a flexible resin film substrate through an adhesive layer, and then peeling off the heat-resistant substrate. A method for producing a metal oxide electrode, comprising transferring a first metal oxide layer , a second metal oxide layer, and a transparent electrode layer to a resin film substrate. By joining the transparent electrode layer side of the transfer body for metal oxide electrode production according to claim 1 and a flexible resin film substrate through an adhesive layer, and then peeling off the heat-resistant substrate. A step of producing a metal oxide electrode by transferring the first metal oxide layer, the second metal oxide layer and the transparent electrode layer to a resin film substrate, and producing a counter electrode facing the metal oxide electrode And a step of forming an electrolyte layer interposed between the metal oxide electrode and the counter electrode. A method for producing a dye-sensitized solar cell, comprising:

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