JP2011040288A - Method of manufacturing semiconductor film, the semiconductor film, and dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a flexible semiconductor film which is less apt to peel off, when bent, to provide the semiconductor film which is produced in the same, and to provide a dye-sensitized solar battery including the same produced in the method. <P>SOLUTION: The method of manufacturing the semiconductor film includes applying a solution containing semiconductor particles and a binder onto a first conductive substrate, drying the application liquid, and then warming it in a range of 130-300°C; while by giving a pressure of 20-40 MPa thereto, a semiconductor layer is formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a semiconductor film manufacturing method, a semiconductor film, and a dye-sensitized solar cell.

Research and development of dye-sensitized solar cells have been conducted globally since Gretzell announced a new type of photovoltaic cell (dye-sensitized photocell) with a conversion efficiency of 7.9% in Non-Patent Document 1. The dye-sensitized solar cell announced by Gretzer has a structure in which a TiO ₂ (titanium oxide) electrode and a counter electrode are opposed to each other and an electrolyte solution is disposed therebetween. As the TiO ₂ electrode, a glass plate with a transparent conductive film made of fluorine-doped tin oxide, a porous TiO ₂ film provided on the transparent conductive film, and having a ruthenium sensitizing dye usually called N3 adsorbed on the surface, Is used. In addition, as the counter electrode, a conductive glass substrate formed with a platinum film is used, and as the electrolyte solution, an oxidation-reduction solution containing I ⁻ / I ₃ ⁻ in a solvent such as acetonitrile is used.

Conventionally, in order to manufacture a TiO ₂ electrode of a dye-sensitized solar cell, for example, first, a paste is prepared by dispersing TiO ₂ powder having a size of several tens of nanometers in polyethylene glycol or a cellulose-based binder. Is coated on a transparent conductive film on a glass substrate to form a coating film. Thereafter, the binder is decomposed by baking at a high temperature of about 500 ° C., the TiO ₂ powder particles are bonded to each other, and then a dye (pigment) is adsorbed on the TiO ₂ surface.

In recent years, in order to expand applications, it has been demanded to develop a thin, lightweight and flexible photovoltaic cell by plasticizing a base material in an electrode. It is also considered to reduce costs by plasticizing the base material of the electrode to give flexibility and continuously producing dye-sensitized solar cells. However, in the method for producing an electrode using TiO ₂ powder as described above, it is necessary to sinter at a high temperature, and thus it is difficult to produce an electrode based on a plastic film.

Therefore, as a method of producing an electrode based on a plastic film at a low temperature, instead of the paste, a solution containing titanium oxide and a binder is applied on a transparent conductive film, dried, and then at a predetermined pressure. A method of press-pressing is disclosed (for example, see Patent Document 1).

Gretzell, “Nature”, Volume 353, 1991, p. 737

Patent No. 4086037

By the method described in Patent Document 1, a titanium oxide film can be formed on a flexible plastic film. However, the obtained titanium oxide film was insufficiently adhered to the base material and easily peeled off. The problem is likely to occur when the substrate on which the titanium oxide film is formed is bent. That is, even if a flexible substrate is used, the titanium oxide film is peeled off by bending, and thus it has been difficult to sufficiently exhibit the advantages of the flexible substrate. Therefore, in the method described in Patent Document 1, since the flexibility is insufficient, it is difficult to continuously produce a dye-sensitized solar cell.

Method for manufacturing flexible semiconductor film in which peeling of semiconductor film does not occur even when semiconductor film is bent, semiconductor film obtained by the manufacturing method, and dye sensitization comprising semiconductor film obtained by the manufacturing method An object is to provide a solar cell.

The present invention has solved the above problems by the following technical configuration.

(1) A solution containing semiconductor fine particles and a binder is applied onto the first conductive substrate, and the coating solution is dried, and then pressurized at 20 to 40 MPa, and 130 in parallel with the pressing. A method for producing a semiconductor film, wherein the semiconductor layer is formed by heating within a range of ˜300 ° C.
(2) The method for manufacturing a semiconductor film according to (1), wherein the heating is performed such that the temperature becomes higher as the temperature approaches the first conductive substrate side.
(3) The method for producing a semiconductor film according to (1), wherein the semiconductor fine particles adsorb a dye.
(4) The method for producing a semiconductor film as described in (1) above, wherein the first conductive substrate is formed by forming a transparent conductive layer on a flexible substrate.
(5) A semiconductor film obtained by the method according to any one of (1) to (4).
(6) Using the semiconductor film obtained by the method according to any one of (1) to (4) above, an electrolyte layer and a second conductive substrate are formed on the semiconductor layer constituting the semiconductor film. A dye-sensitized solar cell, which is sequentially laminated.

According to the present invention, there is provided a method for manufacturing a flexible semiconductor film in which the semiconductor film does not easily peel even when the semiconductor film is bent, a semiconductor film obtained by the manufacturing method, and a semiconductor film obtained by the manufacturing method. Thus, a dye-sensitized solar cell can be provided.

It is sectional drawing of a dye-sensitized solar cell.

<Dye-sensitized solar cell>
The dye-sensitized solar cell of this invention is demonstrated using figures.
As shown in FIG. 1, the dye-sensitized solar cell 50 constituting the present invention includes a semiconductor layer 20, an electrolyte layer 40, and a second conductive base material in which a dye is supported on the first conductive base material 10. 11 are sequentially laminated. The semiconductor film 30 is obtained by forming the semiconductor layer 20 on the first conductive base material 10 by hot pressing described later. As shown in FIG. 1, the electrolyte layer 40 may be provided between the semiconductor layer 20 and the second base material 11, or is made to penetrate into the porous semiconductor layer 20 using a capillary phenomenon. There may be.
The dye-sensitized solar cell 50 of the present invention is preferable because after the semiconductor layer 20 is filled with an electrolyte, the entire dye-sensitized solar cell can be sealed with a resin component to prevent leakage and volatilization of the electrolyte.

<Semiconductor film manufacturing method>
In the method for producing a semiconductor film of the present invention, a solution containing semiconductor fine particles and a binder is applied onto a first conductive substrate, the coating solution is dried, and then pressurized at 20 to 40 MPa, A porous semiconductor layer is formed by heating in the range of 130 to 300 ° C. in parallel with the pressurization.
In the present invention, semiconductor fine particles are sintered by performing pressurization and heating in parallel (hot pressing). Therefore, since it is not necessary to perform high-temperature firing at about 500 ° C., which has been conventionally required for sintering of semiconductor fine particles, a flexible plastic film or the like can be used as a base material.
The pressurization is preferably 25 to 35 MPa. When the pressure is less than 20 MPa, there is a problem of poor necking between the fine particles. When the pressure exceeds 40 MPa, there is a problem of damage to the base material (first conductive base material).
The heating is preferably 130 to 160 ° C, and more preferably 140 to 150 ° C. When the heating temperature is less than 130 ° C., there is a problem of poor necking between fine particles. When the heating temperature exceeds 300 ° C., there is a problem that a flexible substrate such as a transparent plastic film is damaged.
Note that performing pressurization and heating in parallel may be performed simultaneously with pressurization and warming, but may be performed during or after pressurization, or after pressurization. Including those that perform In the present invention, it is preferable to perform pressurization and warming simultaneously, or warming during or after pressurization.

The kind of the pressurizing device that applies pressure to form the semiconductor layer is not particularly limited as long as it can generate a predetermined pressure. Specifically, for example, a flat plate press or a roll press can be used. A roll press is preferable when a plastic film having flexibility is used as a base material because it can be continuously produced roll-to-roll.

On the first conductive substrate, a solution containing semiconductor fine particles and a binder is applied, and after the application liquid is dried, when pressurizing, between the pressurizer and the dried application liquid. It is preferable to sandwich a release material. As a result, the semiconductor fine particles constituting the formed semiconductor layer are less likely to adhere to the pressure device, and therefore, the semiconductor fine particles are less likely to be peeled off from the semiconductor layer, and the conductivity is easily maintained.
As the release material, polytetrafluoroethylene (PTFE), polychlorotrifluoride ethylene (PCTFE), tetrafluoroethylene hexafluoropropylene copolymer (FEP), perfluoroalkoxy fluororesin (PFA), Fluorine resins such as polyvinylidene fluoride (PVDF), ethylene tetrafluoride ethylene copolymer (ETFE), ethylene chlorotrifluoride ethylene copolymer (ECTFE), and polyvinyl fluoride (PVF) can be preferably used.

The solvent for dispersing the semiconductor fine particles and the binder is not particularly limited, but it is preferable if it becomes a paste (emulsion) when added to these mixed materials. As the dispersion solvent, for example, water, acetic acid, alcohols, acetone or the like can be used. Among these dispersion solvents, use of a solvent that does not contain a carboxyl group is preferable from the viewpoint of improving power generation efficiency because the adsorption reaction does not compete with the dye.

The heating performed in parallel with the pressurization is preferably performed so that the temperature becomes higher as the first conductive substrate side is approached (temperature gradient is added), because the power generation efficiency of the dye-sensitized solar cell is improved. . By heating with a temperature gradient, the bonding ability between the first conductive substrate and the semiconductor layer is improved. In addition, since the bonding ability between the semiconductor layer and the pressure device (or release material) is reduced, the semiconductor fine particles constituting the semiconductor layer are less likely to adhere to the pressure device (or release material), and the surface of the formed semiconductor layer Will have a smoother shape.
Specifically, for example, the temperature gradient can be set by changing the heating temperature on the first conductive base material side and the semiconductor layer side constituting the semiconductor film differently or without heating the semiconductor layer side. It is only necessary to heat only one conductive substrate side, heat the first conductive substrate side, cool the semiconductor layer side, or the like.

The temperature gradient is preferably such that the temperature on the first conductive substrate side and the semiconductor layer side is 10 to 60 ° C. apart, and more preferably 20 to 50 ° C. apart.
If it is less than 10 degreeC, there exists a problem of a semiconductor layer peeling.
Above 60 ° C., there is a problem of destabilization of conditions due to a temperature decrease on the first conductive substrate side and a temperature increase on the semiconductor layer side.

With the above temperature gradient, the temperature on the first conductive substrate side is preferably 130 to 300 ° C, more preferably 130 to 160 ° C, and more preferably 140 to 150 ° C. Particularly preferred.
If it is less than 130 degreeC, there exists a problem of a 1st electroconductive base material-semiconductor interlayer adhesion defect.
Above 300 ° C., there is a problem of the first conductive substrate damage.

The temperature on the semiconductor layer side is preferably 100 to 130 ° C, more preferably 110 to 120 ° C, with the above temperature gradient.
Below 100 ° C., there is a problem of poor necking between the semiconductor fine particles.
Above 130 ° C., there is a problem of peeling of the semiconductor layer.

The adsorption of the dye to the semiconductor fine particles may be performed before the semiconductor layer is formed or after the semiconductor layer is formed. It is preferable to perform dye adsorption on the semiconductor fine particles before forming the semiconductor layer, because continuous production is easy on a roll-to-roll basis. In the present invention, since high temperature baking of about 500 ° C., which has been essential in the past, is not required, even if dye adsorption is performed on the semiconductor fine particles before forming the semiconductor layer, there is little dye decomposition during hot pressing, There is no problem in light conversion efficiency.
In addition, it is preferable to perform dye adsorption on the semiconductor fine particles before forming the semiconductor layer because adhesion between the semiconductor layer and the first conductive base material is improved. The reason why the adhesion is improved is presumed that the familiarity of the semiconductor fine particles and the NBR which is the binder is improved by the dye adsorption.

Hereinafter, the material constituting the present invention will be mainly described.

<Conductive substrate>
The first conductive substrate and the second conductive substrate need to have conductivity and at least one of them needs to be transparent, but one of them has transparency. You don't have to. As the conductive substrate having no transparency, for example, a metal substrate can be used. By using a metal substrate, the resistance of the electrode can be reduced, so that electrons generated from the dye supported on the semiconductor layer can be taken out as power without loss.
Specific examples of the metal substrate include copper, aluminum, gold, silver, platinum, chromium, nickel, tungsten, and the like and a substrate made of two or more metals selected from these metals.
The metal substrate is preferably used for the second conductive substrate (counter electrode).

The first conductive substrate and the second conductive substrate preferably have flexibility. This facilitates continuous production on a roll-to-roll basis. The thickness of the first conductive substrate and the second conductive substrate is preferably 5 μm to 3 mm, and more preferably 10 μm to 300 μm. By setting the thickness within the range of 5 μm to 3 mm, appropriate strength and flexibility can be provided.

You may use what formed the transparent conductive layer or the conductive layer on the transparent base material as a 1st conductive base material or a 2nd conductive base material. The transparent substrate is not particularly limited as long as it does not interfere with incident light and has an appropriate strength, but examples thereof include flexible substrates such as organic films and clay films in addition to glass. Can do. The glass may be a plate-like glass plate, a sheet containing glass as a fiber, or a glass formed in a spiral shape.

(Base material having flexibility)
As the substrate having flexibility, a metal substrate, an organic film, a clay film, or the like can be used. Among these, organic films and clay films are preferable because they are more flexible. A semiconductor film using a flexible substrate can be formed into a sheet and is preferable because it can be easily produced continuously in a roll-to-roll manner.
Specific examples of the organic film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polyamide, polyamideimide, polyethersulfone, polyphenylene sulfide, polyetherketone, polyetherimide, triacetylcellulose, Organic films such as polytetrafluoroethylene, polyarylate, cyclic polyolefin, and aramid can be used. In addition, since an organic film has transparency, it can also be used as a transparent base material.
In addition, a clay film may be used as a flexible base material (for example, JP 2009-137833 A). Since the clay film can withstand heating of about 300 ° C., necking between semiconductor fine particles can be effectively performed by raising the heating temperature higher than that of the organic film even during hot pressing. In addition, since a clay film has transparency, it can also be used as a transparent base material.
The thickness of the flexible substrate is preferably 5 μm to 3 mm, and more preferably 10 μm to 300 μm. By setting the thickness within the range of 5 μm to 3 mm, appropriate strength and flexibility can be provided.

(Transparent conductive layer)
There are no particular restrictions on the transparent conductive layer, from the viewpoint of light transmittance, for example, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), tin oxide _(SnO 2), zinc oxide (ZnO) It is preferable to use a transparent oxide semiconductor such as. These oxide semiconductors may be used alone or in combination.

As a method for forming a transparent conductive layer on a transparent substrate, a method corresponding to the material of the transparent conductive layer may be used. For example, when an oxide semiconductor such as ITO is formed on a transparent substrate, a sputtering method is used. And thin film forming methods such as CVD, SPD, and vapor deposition. The thickness of the transparent conductive layer is preferably 0.05 to 2.0 μm in consideration of light transmittance and conductivity.

(Conductive layer)
As the conductive layer, any conductive material can be used. For example, a metal such as Cu, Pt, ITO, FTO, carbon, or the like can be used. Examples of the method for applying the conductive layer to the substrate include thin film forming methods such as sputtering, CVD, SPD, and vapor deposition. The thickness of the conductive layer is preferably 0.05 to 2.0 μm in consideration of light transmittance and conductivity.
Further, unlike the transparent conductive layer, the conductive layer is not necessarily required to have transparency.

On the conductive layer, it is preferable to apply at least one selected from the group of polypyrrole, polythiophene, polyaniline and derivatives thereof as an electrode active substance.
Examples of polythiophene derivatives include polyalkylthiophene, PEDOT (poly (3,4-ethylenedioxythiophene), PEDOT-TsO (PEDOT doped with p-toluenesulfonic acid), and PEDOT-PSS (PEDOT doped with polystyrene sulfonic acid). ).

Examples of a method of applying polypyrrole or polythiophene include a method of applying a monomer solution containing these raw material monomers, pyrrole, thiophene, and derivatives thereof, and a polymerization agent to an object to be coated by spin coating or the like. And after application | coating, a monomer can be polymerized by heating, for example.

Although there is no restriction | limiting in particular as a polymerization agent, When a raw material monomer is pyrrole and its derivative (s), iron (III) chloride and its hydrate can be used. Further, when the raw material monomer is thiophene and its derivatives, iron (III) chloride, iron (III) tris-p-toluenesulfonate, iron (III) p-dodecylbenzenesulfonate, iron methanesulfonate (III ), Iron (III) p-ethylbenzenesulfonate, iron (III) naphthalenesulfonate (and hydrates thereof) can be used.

Further, a polymerization rate adjusting agent may be added to the monomer solution. The polymerization rate adjusting agent is not particularly limited as long as it is a weak complexing agent for the Fe (III) ion of the polymerization agent and can easily form a film by reducing the polymerization rate. In the case of iron (III) and its hydrate, aromatic oxysulfonic acid (such as 5-sulfosalicylic acid) can be used. Polymerization agents are iron (III) tris-p-toluenesulfonate, iron (III) p-dodecylbenzenesulfonate, iron (III) methanesulfonate, iron (III) p-ethylbenzenesulfonate, iron naphthalenesulfonate (III ) And hydrates thereof, imidazole or the like can be used as a polymerization rate adjusting agent.

The solvent of the monomer solution in which these components are mixed is not particularly limited. For example, when the raw material monomer, the polymerization agent, and the polymerization rate adjusting agent are pyrrole, iron (III) chloride, and 5-sulfosalicylic acid, Water can be used as the solvent. When the raw material monomer, the polymerization agent, and the polymerization rate adjusting agent are combinations of 3,4-ethylenedioxythiophene, tris-p-toluenesulfonic acid iron (III), and imidazole, respectively, normal butanol can be used as a solvent.

The mixing ratio of the raw material monomer, the polymerization agent, and the polymerization rate adjusting agent in the monomer solution can be appropriately adjusted according to the components, the degree of polymerization, the polymerization rate, and the like.

As conditions for conducting the polymerization reaction, for example, the heating temperature can be 25 to 120 ^° C., and the heating time can be 5 minutes to 24 hours.

<Semiconductor layer>
The semiconductor layer contains semiconductor fine particles and a binder. The first conductive substrate and the semiconductor fine particles are in close contact with each other through the binder, and the semiconductor fine particles are in close contact with each other through the binder in the formed semiconductor layer. Thus, even when the semiconductor film is bent, the semiconductor film is hardly peeled off, and a flexible semiconductor film can be provided. The compounding ratio of the semiconductor fine particles and the binder is preferably within the range of 0.1 to 10 for the binder with respect to 100 parts by mass of the semiconductor fine particles.
When the binder is less than 0.1 part by mass, there are problems of reduced paste dispersibility and first conductive substrate-semiconductor interlayer adhesion.
When the amount of the binder exceeds 10 parts by mass, there is a problem of a decrease in necking between semiconductor fine particles and an increase in electric resistance of the semiconductor layer.
The thickness of the semiconductor layer is preferably a thin film of about 0.5 to 50 μm.

(Semiconductor fine particles)
Semiconductor fine particles include titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), zinc oxide (ZnO), niobium oxide (Nb ₂ O ₅ ), indium oxide (In ₂ O ₃ ), oxidation Zirconium (ZrO ₂ ), tantalum oxide (Ta ₂ O ₅ ), lanthanum oxide (La ₂ O ₃ ), strontium titanate (SrTiO ₃ ), yttrium oxide (Y ₂ O ₃ ), holmium oxide (Ho ₂ O ₃ ), Bismuth oxide (Bi ₂ O ₃ ), cerium oxide (CeO ₂ ), alumina (Al ₂ O ₃ ), or the like can be used. These semiconductor fine particles may be used alone or in combination of two or more. Semiconductor fine particles having an average particle diameter of 1 to 1000 nm can be preferably used.

(binder)
As the binder, those having properties as a dispersant and an adhesive can be used. Specifically, for example, carboxymethyl cellulose can be used.
From the viewpoint of increasing power generation efficiency, it is preferable that no carboxyl group is present in the binder molecule. It is considered that the surface of the semiconductor fine particles is covered with a hydroxyl group, and the carboxyl group of the dye is expected to be adsorbed by dehydration condensation on the hydroxyl group. Therefore, when the carboxyl group of the binder is adsorbed on the surface of the semiconductor fine particles, the amount of the dye adsorbed on the semiconductor fine particles is reduced, so that the power generation efficiency may be reduced. Examples of the binder having no carboxyl group include rubber components such as styrene butadiene rubber and naphthalene butadiene rubber. Rubber components such as styrene butadiene rubber and naphthalene butadiene rubber are preferable in improving the adhesion of a semiconductor film by a hot press method because the adhesion performance is greatly improved by applying pressure while heating.

As a method for forming the semiconductor layer on the first conductive substrate, for example, a dispersion in which semiconductor fine particles are dispersed in a desired dispersion medium or a colloidal solution that can be adjusted by a sol-gel method is used as necessary. After adding a desired additive, it can be applied on the first conductive substrate by a screen printing method, an ink jet printing method, a roll coating method, a doctor blade method, a spin coating method, a spray coating method or the like. Alternatively, an electrophoretic electrodeposition method may be used in which the first conductive substrate is immersed in a colloidal solution, and the semiconductor fine particles are deposited on the first conductive substrate by electrophoresis. In addition, after mixing polymer microbeads in a colloidal solution or dispersion and applying the mixture on the first conductive substrate, the polymer microbeads are removed by heat treatment or chemical treatment to form voids to make it porous. A method may be applied.

(Dye)
The pigment is adsorbed on the semiconductor fine particles before or after the formation of the semiconductor layer. The dye to be carried on the semiconductor layer is not particularly limited as long as it absorbs visible light. For example, a ruthenium complex or iron complex having a ligand containing a bipyridine structure, a terpyridine structure, or the like, a porphyrin type, From phthalocyanine-based metal complexes, eosin, rhodamine, merocyanine, organic dyes such as coumarin, and the like, they can be appropriately selected and used depending on the application and the material of the semiconductor layer.
The addition amount of the dye is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the semiconductor fine particles.
If the amount is less than 0.1 parts by mass, there is a problem of reduction in light absorption efficiency.
If it exceeds 10 parts by mass, there is a problem of a decrease in photoelectric conversion efficiency due to multilayer adsorption.
Examples of the method for adsorbing the dye to the semiconductor layer include a method for impregnating the semiconductor layer on the transparent conductive layer with the dye solution, a method for impregnating the semiconductor fine particles with the dye solution, and the like.

By adsorbing the dye to the semiconductor layer in the coexistence of cholic acid such as deoxycholic acid and chenodeoxycholic acid (coadsorption), a semiconductor film with high adhesion can be produced by low-temperature firing, thus improving the photoelectric conversion efficiency. It can be further increased. Further, the presence of the coadsorbed material is preferable because aggregation of the dyes and multilayer adsorption to the semiconductor fine particles can be prevented.

<Electrolyte layer>
The electrolyte layer does not necessarily have to be a clear layer, and may be one obtained by immersing an electrolyte solution on the surface of a semiconductor film, or one obtained by semi-solidifying an electrolyte solution with a gelling agent. The electrolyte layer is not particularly limited as long as it is a substance that can transport electrons, holes, ions, and the like. For example, a p-type semiconductor solid hole transport material such as CuI, CuSCN, NiO, Cu ₂ O, and KI, iodine A solution in which a redox electrolyte such as / iodide and bromine / bromide is dissolved in an organic solvent can be used.
Examples of the organic solvent include polyhydric alcohols such as nitrile acetonitrile, methoxypropionitrile, hydrocarbon propylene carbonate, diethyl carbonate, γ-butyrolactan, and polyethylene glycol.
In these, since the pigment | dye adsorb | sucked to the metal oxide semiconductor porous layer is bulky and it is hard to remove | eliminate, the solution which melt | dissolved the oxidation reduction electrolyte in the organic solvent is preferable.

EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not restrict | limited to these.

(Production Example 1: Preparation of dye solution)
40 ml of ethanol was added to 3.0 mg of Eosin Y dye (manufactured by Aldrich), and ultrasonically stirred for 30 minutes under light-shielding conditions to prepare a 5 × 10 ⁻⁴ mol / l Eosin Y dye solution. The structure of Eosin Y is shown in Chemical Formula 1.

(Production Example 2: Preparation of dyed zinc oxide)
To 1 g of zinc oxide powder (product name: Nanofine-50, manufactured by Sakai Chemical Industry Co., Ltd .; surface untreated product, average particle size 20 nm), the Eosin Y dye solution prepared in Production Example 1 above is added, and is shielded with a magnetic stirrer. Stir for 24 hours under sealed conditions. The colloidal solution was suction filtered with 5 types C filter paper and Kiriyama funnel, and dried with a dryer to obtain a dye-adsorbed zinc oxide powder (hereinafter referred to as pre-dyed zinc oxide).

(Production Example 3: Production of zinc oxide paste using NBR emulsion)
3 ml of ethanol and 0.1 ml of acetylacetone were placed in a mortar and mixed well. To this was added 1 g of the pre-dyed zinc oxide obtained in the above Production Example 2, and after further mixing, 0.1 ml of NBR emulsion (product name: 1562 manufactured by Nippon Zeon Co., Ltd.) was added and further mixed to prepare a paste.

(Production Example 4: Preparation of electrolyte)
Tetra-n-propylammonium iodide (3.1 g) and iodine (0.25 g) were dissolved in 20 ml of a 1: 4 mixed solvent of acetonitrile: ethylene carbonate to obtain an electrolytic solution.

As a first conductive substrate, an ITO-coated PET sheet (manufactured by Tobi Co., 30-50Ω / □) was cut into approximately 10 × 2.5 mm, and the surface was washed with ethanol (Kanto Chemical) and then dried. Was used. Two pieces of cello tape (registered trademark) were pasted as spacers on the long side of the PET sheet, and the paste produced in Production Example 3 was applied by the squeegee method. After the solvent contained in the paste is dried with a dryer and the cello tape (registered trademark) is peeled off, the laminate in which the PET sheet, the Teflon (registered trademark) tape and the filter paper are sequentially stacked is formed into a heat press (product name: AH-1T (made by Matsuura Seisakusho Co., Ltd.) was placed between two metal plates for heating and pressing, and hot pressing was performed at 150 ° C./30 MPa for 15 minutes to produce a flexible semiconductor film.

The area of the obtained semiconductor film was shaved off to 0.25 cm ² (0.5 cm × 0.5 cm). In order to prevent direct contact between the semiconductor film and the second conductive substrate, a polymer film (Surlyn film thickness 25 μm) was cut into a concave shape as a spacer and placed on the semiconductor film. The electrolytic solution prepared in Production Example 4 was dropped on the surface of the semiconductor film, and allowed to penetrate into the porous semiconductor film by capillary action. A platinum-sputtered FTO glass substrate was used as the second conductive base material, and was superposed on a semiconductor film infiltrated with an electrolytic solution and fixed with a clip to prepare a dye-sensitized solar cell.

The laminated body produced in Example 1 is placed between two metal plates for heat and pressure constituting a heat and pressure apparatus (product name: AH-1T manufactured by Matsuura Seisakusho Co., Ltd.), and is in contact with an ITO-coated PET sheet. A flexible semiconductor film was produced in the same manner as in Example 1 except that the temperature of the pressing metal plate was 150 ° C., the temperature of the heating and pressing metal plate in contact with the filter paper was 100 ° C., and pressing was performed at 30 MPa.
A dye-sensitized solar cell was produced in the same manner as in Example 1 except that the obtained semiconductor film was used.

[Comparative Example 1]
The ITO-coated PET sheet used in Example 1 was used as the first conductive substrate. Two pieces of cello tape (registered trademark) were pasted as spacers on the long side of the PET sheet, and the paste produced in Production Example 3 was applied by the squeegee method. After drying with a drier and removing the cellotape (registered trademark), the glass substrate was placed on a hot plate and sintered at 150 ° C. for 15 minutes to produce a flexible semiconductor film not subjected to hot pressing.
A dye-sensitized solar cell was produced in the same manner as in Example 1 except that the obtained semiconductor film was used.

<Evaluation>
Under simulated sunlight (AM-1.5, 100 mW / cm ² ) irradiation using a solar cell characteristic measurement system (spectrometer), short-circuit current density (Jsc), open-circuit voltage (Voc), The form factor (FF) and the quantum yield (Eff) in photoelectric conversion were measured.
The results obtained are summarized in Table 1.

Comparative Example 1 uses a flexible ITO-coated PET sheet as the first conductive substrate, but it cannot be said to be a battery because zinc oxide was not adsorbed to ITO at all. Conversion efficiency decreased to the level.
On the other hand, although the conversion efficiency of Example 1 increased as compared with Comparative Example 1 by performing hot pressing, a part of the film or the entire film may be adsorbed to the Teflon (registered trademark) tape side when hot pressing is performed. Observed. The semiconductor film of Example 1 was flexible.

In Example 2, the temperature gradient was generated and hot pressing was performed, so that zinc oxide was adsorbed on ITO and exhibited high conversion efficiency. In addition, the semiconductor film produced in Example 2 has flexibility, and zinc oxide did not peel off to some extent.

According to the present invention, there is provided a method for manufacturing a semiconductor film having flexibility (flexibility) in which the semiconductor film does not easily peel even when the semiconductor film is bent, the semiconductor film obtained by the manufacturing method, and the semiconductor film. Thus, a dye-sensitized solar cell can be provided.

DESCRIPTION OF SYMBOLS 10 1st electroconductive base material 11 2nd electroconductive base material 20 Semiconductor layer 30 Semiconductor film 40 Electrolyte layer 50 Dye-sensitized solar cell

Claims (6)

On the 1st electroconductive base material, after apply | coating the solution containing semiconductor fine particles and a binder and drying this coating liquid, it pressurizes at 20-40 Mpa, 130-300 degreeC in parallel with this pressurization. A method for producing a semiconductor film, wherein the semiconductor layer is formed by heating within a range of. 2. The method of manufacturing a semiconductor film according to claim 1, wherein the heating is performed such that the temperature increases as the temperature approaches the first conductive substrate side. The method of manufacturing a semiconductor film according to claim 1, wherein the semiconductor fine particles adsorb a dye. 2. The method of manufacturing a semiconductor film according to claim 1, wherein the first conductive base material is formed by forming a transparent conductive layer on a flexible base material. The semiconductor film obtained by the method in any one of Claims 1-4. Using the semiconductor film obtained by the method according to any one of claims 1 to 4, an electrolyte layer and a second conductive base material are sequentially laminated on the semiconductor layer constituting the semiconductor film. A dye-sensitized solar cell characterized by

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