JP5199587B2 - Photoelectric cell and method for manufacturing the same - Google Patents

Description

  The present invention relates to a photoelectric cell having high photoelectric conversion efficiency and a manufacturing method thereof, in which backflow of electrons (referred to as dark current or back current), recombination of electrons, short circuit due to adhesion between electrodes, and the like are suppressed.

Metal oxide semiconductor materials having a high band gap are used for other optical sensors such as photoelectric conversion materials and photocatalyst materials, power storage materials (batteries), and the like.
Among these, the photoelectric conversion material is a material that can continuously extract light energy as electric energy, and is a material that converts light energy into electric energy using an electrochemical reaction between electrodes. When such a photoelectric conversion material is irradiated with light, electrons are generated on one electrode side, move to the counter electrode, and the electrons moved to the counter electrode move as ions in the electrolyte and return to the one electrode. Since this energy conversion is continuous, it is used, for example, for solar cells.

  In general solar cells, a semiconductor film for a photoelectric conversion material is first formed on a support such as a glass plate on which a transparent conductive film is formed, and then another transparent conductive film is used as a counter electrode. A support such as a formed glass plate is provided, and an electrolyte is sealed between these electrodes.

  When the photosensitizer adsorbed on the photoelectric conversion material semiconductor is irradiated with, for example, sunlight, the photosensitizer absorbs light in the visible region and is excited. The electrons generated by this excitation move to the semiconductor, then move to the transparent conductive glass electrode, move to the counter electrode through the conducting wire connecting the two electrodes, and the electrons transferred to the counter electrode are oxidized in the electrolyte. Reduce the reduction system. On the other hand, the photosensitizer that has moved electrons to the semiconductor is in an oxidant state, but this oxidant is reduced by the redox system in the electrolyte and returns to its original state. In this way, electrons flow continuously, and the photoelectric conversion material functions as a solar cell.

  As this photoelectric conversion material, a material obtained by adsorbing a spectral sensitizing dye having absorption in the visible light region on the semiconductor surface is used. For example, JP-A-1-220380 (Patent Document 1) describes a solar cell having a spectral sensitizing dye layer made of a transition metal complex such as a ruthenium complex on the surface of a metal oxide semiconductor. Japanese Patent Application Laid-Open No. 5-504023 (Patent Document 2) discloses a solar cell having a spectral sensitizing dye layer made of a transition metal complex such as a ruthenium complex on the surface of a titanium oxide semiconductor layer doped with metal ions. Have been described.

  In the solar cell as described above, it is important to improve the light conversion efficiency that electrons are rapidly transferred from a spectral sensitizing dye layer such as a ruthenium complex excited by absorbing light to the titanium oxide semiconductor layer. If no electron transfer is performed, recombination of the ruthenium complex with the electrons or backflow of electrons (referred to as a dark current or a back current) occurs and the light conversion efficiency is lowered.

For this reason, it has been studied to increase the amount of the spectral sensitizing dye adsorbed on the surface of the titanium oxide semiconductor film or to improve the mobility of electrons in the titanium oxide semiconductor film.
For example, when forming a titanium oxide semiconductor film, a titania sol is applied on an electrode substrate, dried, and then fired repeatedly to form a porous thick film, and the semiconductor film is made porous. It has been proposed to increase the amount of Ru complex supported on the surface. It has also been proposed to improve conductivity by firing between titania fine particles at a temperature of 400 ° C. or higher. Further, in JP-A-6-511113 (Patent Document 3), in order to increase the effective surface, it is immersed in an aqueous solution of titanium chloride or electrochemically deposited on a titania film using a hydrolyzed solution of titanium chloride. It has been proposed.

However, conventional solar cells still have insufficient light conversion efficiency, and further improvements are required.
In Patent Document 3, a barrier layer is provided between the conductive glass layer and the porous titanium oxide layer in order to prevent the influence of ion diffusion from the transparent electrode to the porous titanium oxide film due to annealing during the formation of the porous titanium oxide film. It is described. At this time, as a barrier layer forming method, it is described that a titanium alkoxide alcohol solution is applied and a solvent is evaporated in humid air to form a titanium oxide layer (non-porous layer) having a thickness of less than 0.1 μm. ing. Further, it is described that vapor deposition is performed from about 500 ° C. dry air containing titanium chloride vapor by heating a titanium chloride aqueous solution. However, it is difficult to control the film thickness by the above method, it is difficult to form on a substrate with a large area electrode layer, or the apparatus is corroded by gas generated when it is decomposed into a titanium oxide film. There is a problem to be solved, and there is a problem to be solved in consideration of manufacturing at an industrial level.

Furthermore, the inventors of the present application form a porous semiconductor film formed later when a non-porous metal oxide semiconductor film is formed between the electrode layer and the porous metal oxide semiconductor film composed of metal oxide particles and a binder. It discloses that the photoelectric conversion efficiency of the solar cell obtained is improved while the adhesion is improved. (Patent Document 4: Japanese Patent Laid-Open No. 2002-319439)
However, in Patent Document 4, although the film thickness of the nonporous metal oxide semiconductor film is relatively uniform, there are cases where the film is cracked and the effect as the barrier film cannot be obtained. In addition, further improvement in photoelectric conversion efficiency is required.
Japanese Patent Laid-Open No. 1-220380 Japanese National Patent Publication No. 5-504023 JP-T 6-511113 JP 2002-319439 A

As a result of intensive studies by the present inventors in view of the above problems, the porous titanium oxide semiconductor film is made into a porous titanium oxide semiconductor film made of only metal oxide particles without using a binder, and the electrode layer and the porous metal oxide When a titanium oxide thin film (sometimes called a barrier) is formed using peroxotitanic acid containing cellulose between the semiconductor film and the porous semiconductor film to be formed later has high adhesion, the photoelectric conversion efficiency of the resulting solar cell is high. The present invention was completed by finding further improvements.

In addition, the applicant of the present invention is disclosed in JP 2006-93002 A, JP 2006-19190 A, and JP 2003-308891 A.
No., JP-A-2003-168495, JP-A-2001-185245, JP-A-2001-155791,
Photoelectric cells have been proposed, both of which disclose using titanium oxide and peroxotitanic acid as a binder in the semiconductor film. However, they do not disclose any technical idea of forming a dense titanium oxide thin film between the electrode layer and the porous metal oxide semiconductor film, and the same problem as in Patent Document 1 described above. There was a point.

As a result of intensive studies to solve the above problems, the present inventors have found that the use of peroxotitanic acid containing a thickener between the transparent electrode layer and the porous semiconductor film results in uniform film thickness and cracks. There can be provided a dense titanium oxide thin film excellent in adhesion with the electrode layer and the porous semiconductor film, and therefore, backflow of electrons, recombination of electrons, short circuit due to adhesion between electrodes, etc. are suppressed, It has been found that a photoelectric cell with improved photoelectric conversion efficiency can be provided.

The configuration of the present invention is as follows.
[1] (A) providing a transparent electrode on the surface of the transparent substrate;
(B) preparing a peroxotitanic acid aqueous solution having a TiO ₂ concentration of 0.1 to 2.0% by weight and a thickener concentration of 1 to 60% by weight;
(C) applying the peroxotitanic acid aqueous solution on the transparent electrode to form a titanium oxide thin film;
(D) forming a porous metal oxide semiconductor film consisting only of metal oxide particles adsorbing a photosensitizer on the titanium oxide thin film;
(E) producing a counter substrate having a counter electrode on the surface;
(F) a step of opposing the transparent substrate and the counter substrate, and providing an electrolyte layer between the porous metal oxide semiconductor film and the counter electrode;
Including
A method for producing a photoelectric cell, wherein the titanium oxide thin film is formed in a thickness of 10 to 70 nm.
[2] The method for producing a photovoltaic cell according to [1], wherein the peroxotitanic acid aqueous solution is aged at 50 to 90 ° C. for 1 to 25 hours before the step (C).
[3] The light of [1] or [2], wherein the titanium oxide thin film has a pore volume in the range of 0.01 to 0.20 ml / g and an average pore diameter in the range of 0.5 to 5.0 nm. Electric cell manufacturing method.

  According to the present invention, since it has a titanium oxide thin film formed using peroxotitanic acid containing a thickener between the electrode layer and the porous metal oxide semiconductor film, backflow of electrons (dark current or back current) And short circuit due to recombination of electrons and adhesion between electrodes are suppressed or prevented, and thus a photoelectric cell with improved photoelectric conversion efficiency can be provided.

The photoelectric cell according to the present invention will be specifically described below.
Photoelectric cell The photoelectric cell according to the present invention comprises:
A substrate (1) having an electrode layer (1) on the surface and a porous metal oxide semiconductor film (1) having a photosensitizer adsorbed on the surface of the electrode layer (1); The substrate (2) having the electrode layer (2) is arranged so that the electrode layer (1) and the electrode layer (2) face each other,
In the photoelectric cell comprising an electrolyte layer between the porous metal oxide semiconductor film (1) and the electrode layer (2),
A titanium oxide thin film (1) derived from peroxotitanic acid is provided between the electrode layer (1) and the porous metal oxide semiconductor film (1), and the porous metal oxide semiconductor film (1) is a metal. It is characterized by comprising only oxides.

As a photoelectric cell obtained by the present invention, for example, the one shown in FIG.
FIG. 1 is a schematic cross-sectional view showing an example of a photoelectric cell obtained by the present invention, which has an electrode layer (1) on the surface and a titanium oxide thin film (1) on the electrode layer (1). A substrate (1) having a porous metal oxide semiconductor film (1) adsorbing a photosensitizer on the titanium oxide thin film (1), and a substrate having an electrode layer (2) on the surface ( 2) is disposed so that the electrode layer (1) and the electrode layer (2) face each other, and an electrolyte is enclosed between the porous metal oxide semiconductor film (1) and the electrode layer (2). Has been.

In FIG. 1, 1 is an electrode layer (1), 2 is a semiconductor film (1), 3 is an electrode layer (2), 4 is an electrolyte layer (2), 5 is a substrate (1), 6 is a substrate (2), Reference numeral 7 denotes a titanium oxide thin film.
The photoelectric cell obtained by the present invention is not limited to the illustrated photoelectric cell, and is a photoelectric cell having two or more semiconductor films and another electrode layer and electrolyte layer interposed therebetween. May be.

As the one substrate, a transparent and insulating substrate such as a glass substrate or an organic polymer substrate such as PET can be used.

  The other substrate is not particularly limited as long as it has enough strength to withstand use. In addition to insulating substrates such as glass substrates and organic polymer substrates such as PET, metal titanium, metal aluminum, metal copper, metal A conductive substrate such as nickel can be used.

Further, it is sufficient that at least one of the substrates is transparent.
The electrode layer (1) formed on the surface of the electrode layer substrate (1) includes tin oxide, tin oxide doped with Sb, F or P, indium oxide doped with Sn and / or F, antimony oxide, oxidation Conventionally known electrodes such as zinc and noble metals can be used.

Such an electrode layer (1) can be formed by a conventionally known method such as a thermal decomposition method or a CVD method.
In addition, the electrode layer (2) formed on the surface of the other substrate (2) is not particularly limited as long as it has a reduction catalytic ability, and is composed of platinum, rhodium, ruthenium metal, ruthenium oxide. The electrode material was plated or deposited on the surface of a conductive material such as tin oxide, tin oxide doped with Sb, F or P, indium oxide doped with Sn and / or F, or antimony oxide. Conventionally known electrodes such as electrodes and carbon electrodes can be used.

  Such an electrode layer (2) was formed by directly coating, plating or vapor-depositing the electrode on the substrate (2), and forming a conductive layer by a conventionally known method such as a thermal decomposition method or a CDV method. Thereafter, the electrode material can be formed on the conductive layer by a conventionally known method such as plating or vapor deposition.

The substrate (2) may be a transparent substrate similarly to the substrate (1), and the electrode layer (2) may be a transparent electrode similarly to the electrode layer (1). Furthermore, the substrate (2) may be the same as the substrate (1), and the electrode layer (2) may be the same as the electrode layer (1).

  The visible light transmittance of the transparent substrate (1) and the transparent electrode layer (1) is preferably higher, specifically 50% or more, particularly preferably 90% or more. When the visible light transmittance is less than 50%, the photoelectric conversion efficiency may be lowered.

The resistance values of the electrode layer (1) and the electrode layer (2) are each preferably 100 Ω / cm ² or less. When the resistance value of the electrode layer exceeds 100 Ω / cm ² , the photoelectric conversion efficiency may be lowered.

Titanium oxide thin film The titanium oxide thin film (1) used in the present invention is a dense film formed using a peroxotitanic acid aqueous solution containing a thickener.

The titanium oxide thin film (1) preferably has a thickness of 10 to 70 nm, more preferably 20 to 40 nm. If the thickness of the titanium oxide thin film (1) is small, the suppression of dark current and the suppression of electron recombination by the titanium oxide film (1) are insufficient. If the film thickness of the titanium oxide thin film (1) is too thick, the energy barrier becomes too large to suppress the movement of electrons, and conversely, the photoelectric conversion efficiency may decrease.

Further, the titanium oxide thin film (1) has a pore volume of 0.01 to 0.20 ml / g, more preferably 0.0.
It is preferably in the range of 2 to 0.15 ml / g. When the pore volume is larger than the above upper limit, the denseness is lowered, the contact between the electrolytic solution and the electrode occurs, and the effect of suppressing the backflow of electrons and the recombination of electrons may be insufficient. It is possible to obtain a dense titanium oxide thin film even by a method such as sputtering, but it is too dense to inhibit the movement of electrons or has insufficient adhesion to a porous metal oxide semiconductor film to be formed later. It may become.

The titanium oxide thin film (1) has an average pore diameter of 0.5 to 5.0 nm, more preferably 1.0 to 3.5 nm.
It is preferable that it exists in the range. When the average pore size of the titanium oxide thin film (1) is larger than the above upper limit, contact between the electrolytic solution and the electrode may occur, and the effect of suppressing the backflow of electrons and recombination of electrons may be insufficient.

Such a titanium oxide thin film (1) is a peroxotitanic acid aqueous solution containing a thickener on the electrode layer (1), (A) spin coating method, (B) dip coating method, (C) flexographic printing method, It can be formed by applying, drying and curing by one or more methods selected from (D) roll coater method and (E) electrophoresis method.

The concentration of the peroxotitanic acid aqueous solution used for forming the titanium oxide thin film (1) is preferably 0.1 to 2.0% by weight, more preferably 0.3 to 1.0% by weight as TiO ₂ . When the concentration of the peroxotitanic acid aqueous solution is low, a titanium oxide thin film (1) having a desired film thickness may not be obtained, and it becomes necessary to repeatedly apply and dry. If the concentration of the peroxotitanic acid aqueous solution is low, cracks may occur during drying or a dense film may not be formed, and the effect of suppressing dark current and recombination of electrons may not be obtained.

Here, peroxotitanic acid refers to hydrated titanium peroxide, and can be prepared, for example, by adding hydrogen peroxide to an aqueous solution of a titanium compound or a sol or gel of hydrated titanium oxide and heating. Specifically, first, a titanium compound is hydrolyzed to prepare a sol or gel of orthotitanic acid.

  The orthotitanic acid gel can be obtained by using a titanium salt such as titanium chloride, titanium sulfate, or titanyl sulfate as a titanium compound, neutralizing the aqueous solution by adding an alkali, and washing. In addition, the sol of orthotitanic acid is used to remove anions by passing an aqueous solution of a titanium salt through an ion exchange resin, or water of titanium alkoxide such as titanium tetramethoxide, titanium tetraethoxide, titanium tetraisopropoxide and the like. It can be obtained by adding an acid or alkali to an organic solvent and hydrolyzing it.

  The pH of the titanium compound solution during neutralization or hydrolysis is preferably in the range of 7-13. When the pH of the titanium compound solution is in the above range, fine particles of orthotitanic acid gel or sol are obtained, and the reaction with hydrogen peroxide described later becomes easy.

  Furthermore, the temperature at the time of neutralization or hydrolysis is preferably in the range of 0 to 60 ° C, and particularly preferably in the range of 0 to 50 ° C. When the temperature at the time of neutralization or hydrolysis is within the above range, fine particles of orthotitanic acid gel or sol are obtained, and the reaction with hydrogen peroxide described later becomes easy. The orthotitanic acid particles in the obtained gel or sol are preferably amorphous.

Next, hydrogen peroxide is added to the orthotitanic acid gel or sol or a mixture thereof to dissolve the orthotitanic acid to prepare a peroxotitanic acid aqueous solution. In preparing the peroxotitanic acid aqueous solution, it is preferable to heat or stir the orthotitanic acid gel or sol or a mixture thereof to about 50 ° C. or higher as necessary. At this time, if the concentration of orthotitanic acid becomes too high, it takes a long time to dissolve the solution, and undissolved gel may precipitate, or the resulting peroxotitanic acid aqueous solution may become viscous. . For this reason, the TiO ₂ concentration is preferably about 10% by weight or less, and more preferably about 5% by weight or less.

If the amount of hydrogen peroxide to be added is 1 or more in terms of the weight ratio of H ₂ O ₂ / TiO ₂ (ortho titanic acid is converted to TiO ₂ ), the ortho titanic acid can be completely dissolved. If the H ₂ O ₂ / TiO ₂ weight ratio is less than 1, orthotitanic acid may not be completely dissolved, and an unreacted gel or sol may remain. In addition, as the H ₂ O ₂ / TiO ₂ weight ratio is larger, the dissolution rate of orthotitanic acid is larger and the reaction time is completed in a shorter time. Remains in the system and is not economical. When hydrogen peroxide is used in such an amount, orthotitanic acid dissolves in about 0.5 to 20 hours. The aqueous peroxotitanic acid solution used in the present invention is preferably aged at 50 to 90 ° C. after dissolution. When this aging is carried out, it is substantially amorphous but exhibits an anatase-like X-ray diffraction pattern, and particles having an average particle diameter in the range of 10 to 50 nm are generated, and have the pore volume and the average pore diameter. A titanium oxide thin film can be obtained with good reproducibility.

The aging time varies depending on the aging temperature, but is usually 1 to 25 hours.
Further, the peroxotitanic acid aqueous solution used in the present invention contains a thickener. Examples of the thickener include ethylene glycol, polyethylene glycol, polyvinyl pyrrolidone, hydroxypropyl cellulose, polyacrylic acid, ethyl cellulose, polyvinyl alcohol, methanol, and ethanol. , Isopropyl alcohol, normal butanol, tertiary butanol and the like may be contained. If such a thickener is contained in the peroxotitanic acid aqueous solution, the viscosity of the coating solution increases, and this allows uniform coating, resulting in a titanium oxide thin film having a uniform thickness without cracks. Thus, a titanium oxide thin film having high adhesion to the lower electrode layer can be obtained.

The concentration of the thickener in the peroxotitanic acid aqueous solution varies depending on the type of the thickener, but is preferably in the range of 1.0 to 60.0% by weight, more preferably 3.0 to 35.0% by weight. When the concentration of the thickener is less than 1.0% by weight, the effect of using the thickener is insufficient, and when it exceeds 60.0% by weight, the coatability is lowered and the film thickness becomes too thick. Cracks may occur, and the effect of providing the titanium oxide thin film may not be obtained.

If the coating method of the peroxotitanic acid aqueous solution is any one of (A) spin coating method, (B) dip coating method, (C) flexographic printing method, (D) roll coater method (E) electrophoresis method, electrode layer It is possible to form a titanium oxide thin film (1) that has excellent adhesion with the film, has a uniform film thickness, is free of cracks, and is excellent in strength, and is particularly suitable for industrial use in flexographic printing. it can.

The drying may be performed at a temperature that can remove water as a dispersion medium, and a conventionally known method can be adopted and air drying is also possible. Usually, drying is performed at 50 to 200 ° C. for about 0.2 to 5 hours. To do. In the present invention, a porous metal oxide semiconductor film to be described later can be formed after drying, but the porous metal oxide semiconductor film may be formed after curing after drying.

Although it hardens | cures only by a drying process, it irradiates with an ultraviolet-ray as needed and then anneals by heat processing.
Irradiation with ultraviolet rays may be performed in an amount necessary to decompose and cure peroxotitanic acid.
The heat treatment is usually performed at 200 to 500 ° C., further at 300 to 450 ° C. for about 1 to 48 hours.

Porous metal oxide semiconductor film A porous metal oxide semiconductor film is formed on the titanium oxide thin film (1). The thickness of the porous metal oxide semiconductor film is preferably in the range of 0.1 to 50 μm.

  The porous metal oxide semiconductor film may be composed of one or more metal oxides of titanium oxide, lanthanum oxide, zirconium oxide, niobium oxide, tungsten oxide, strontium oxide, zinc oxide, tin oxide, and indium oxide. preferable. Among these, crystalline titanium oxides such as anatase type titanium oxide, brookite type titanium oxide, and rutile type titanium oxide can be suitably used.

Such a metal oxide has a high band gap (approximately in the range of 1.7 to 3.8 eV), and can generate electrons when the photosensitizer is excited by absorption of visible light.
As the porous metal oxide semiconductor film, one made of metal oxide particles is used. The average particle diameter of the metal oxide particles is preferably 5 to 800 nm, more preferably 10 to 600 nm, and particularly preferably 10 to 200 nm. When the average particle diameter of the metal oxide particles is small, cracks are likely to occur in the formed metal oxide semiconductor film, and it becomes difficult to form a crack-free thick film having a film thickness described later with a small number of times. In addition, the pore diameter and pore volume of the metal oxide semiconductor film may decrease, and the amount of adsorption of the photosensitizer may decrease. Even if the average particle size of the metal oxide particles is too large, the gap between the particles becomes large, so that the amount of transmitted light increases and the light utilization rate decreases, or the strength of the metal oxide semiconductor film is insufficient. It may become.

Such metal oxide particles have a specific surface area of 10 to 400 m ² / g, more preferably 20 to 30.
It is preferably in the range of 0 m ² / g. Those having a small specific surface area do not increase the photoelectric conversion efficiency because the amount of adsorption of the photosensitizer is small, and even if the specific surface area is too large, the photoelectric conversion efficiency does not increase further.

  The pore volume of the porous metal oxide semiconductor film is preferably in the range of 0.25 to 0.8 ml / g, more preferably 0.3 to 0.6 ml / g. When the pore volume of the porous metal oxide semiconductor film is smaller than 0.25 ml / g, the adsorption amount of the photosensitizer is low, and when it is higher than 0.8 ml / g, the electron transfer in the semiconductor film is reduced. May decrease the photoelectric conversion efficiency.

  The average pore diameter of the porous metal oxide semiconductor film is preferably in the range of 6 to 250 nm, more preferably 10 to 200 nm. When the average pore diameter is less than 6 nm, the adsorption amount of the photosensitizer decreases, and when it exceeds 250 nm, the electron mobility in the semiconductor film decreases and the photoelectric conversion efficiency may decrease.

The method for producing the porous metal oxide semiconductor film is not particularly limited as long as the above-described porous metal oxide semiconductor film can be obtained. However, the porous metal oxide semiconductor film forming coating solution described below is used. The method for producing a metal oxide semiconductor film disclosed in Japanese Patent Application Laid-Open No. 11-33867 filed by the applicant of the present application can be suitably applied.

  Specifically, a coating solution for forming a porous metal oxide semiconductor film composed of metal oxide particles, a thickener used as necessary, and a dispersion medium is applied onto the titanium oxide thin film formed on the electrode layer, After drying, it can be formed by curing by ultraviolet irradiation or heat curing.

In particular, it is preferable to use colloidal particles of anatase-type titanium oxide particles as the metal oxide particle particles.
In the metal oxide particle dispersion, the above-described metal oxide particles, a thickener used as necessary, and one or more selected from water, alcohols, ketones, and glycols as a dispersion medium are used. .
Specifically, alcohols include methanol, ethanol, isopropyl alcohol, butanol and the like, and ketones include glycols such as acetone such as ethylene glycol and propylene glycol.

  Among them, an aqueous dispersion medium containing water and a relatively low boiling point alcohol such as methanol, ethanol, isopropyl alcohol, butanol or the like uniformly disperses the metal oxide particles, and a thickener used as necessary. Since the dispersion medium can be dissolved and the dispersion medium is easily evaporated when the metal oxide particle layer is laminated on the substrate and then dried, it can be suitably used.

  As the thickener, the aforementioned polyethylene glycol, polyvinyl pyrrolidone, hydroxypropyl cellulose, polyacrylic acid, ethyl cellulose, methyl cellulose, carboxymethyl methyl cellulose, polyvinyl alcohol, acrylic resin, ketone resin, melamine resin, and the like may be included. . When such a thickener is contained in the coating liquid for forming a porous metal oxide semiconductor film, the viscosity of the coating liquid is increased, whereby it can be applied uniformly, and the pore volume and A porous metal oxide semiconductor film having an average pore diameter can be obtained.

  The concentration of the thickener in the coating solution for forming the porous metal oxide semiconductor film varies depending on the type of the thickener, but is 1.0 to 40.0% by weight, more preferably 4.0 to 10.0% by weight. It is preferable to be in the range.

  When the concentration of the thickener is less than 1.0% by weight, the effect of using the thickener is insufficient, and when it exceeds 40.0% by weight, the coatability is lowered and the strength of the resulting semiconductor film is increased. May be insufficient, and it may be difficult to completely remove the thickener, and the factory effect of sufficient photoelectric conversion efficiency may not be obtained.

The solid content concentration of the metal oxide particles in the coating solution for forming a porous metal oxide semiconductor film is preferably in the range of 1 to 30% by weight, more preferably 2 to 20% by weight.
When the concentration is less than 1% by weight, the concentration may be too low to form a metal oxide semiconductor film having a desired thickness in a single operation, which requires repeated operations.

  When the concentration exceeds 30% by weight, the viscosity of the dispersion increases, the density of the resulting metal oxide semiconductor film decreases, and the strength and wear resistance of the semiconductor film become insufficient. Mobility may decrease and photoelectric conversion efficiency may be insufficient.

Such a coating liquid for forming a porous metal oxide semiconductor film can be applied on a titanium oxide thin film, dried and then heat-cured and annealed.
As a coating method, a dip method, a spinner method, a roll coater method, a flexographic printing method, and the like are suitable.

  The drying may be performed at a temperature at which the dispersion medium can be removed, and a conventionally known method can be adopted, and air drying can also be performed. The heat treatment is usually performed at 200 to 600 ° C., and further at 300 to 500 ° C. for about 1 to 48 hours.

The film thickness of the porous metal oxide semiconductor film thus obtained is preferably in the range of 0.1 to 50 μm.
In the photoelectric cell according to the present invention, the porous metal oxide semiconductor film (1) adsorbs the photosensitizer.
The photosensitizer is not particularly limited as long as it absorbs and excites light in the visible light region, ultraviolet light region, and infrared light region. For example, an organic dye or a metal complex is used. Can do.

  As the organic dye, a conventionally known organic dye having a functional group such as a carboxyl group, a hydroxyalkyl group, a hydroxyl group, a sulfone group, or a carboxyalkyl group in the molecule can be used. Specific examples include metal-free phthalocyanines, cyanine dyes, methocyanine dyes, triphenylmethane dyes, and xanthene dyes such as uranin, eosin, rose bengal, rhodamine B, and dibromofluorescein. These organic dyes have a characteristic that the adsorption rate to the metal oxide semiconductor film is fast.

Examples of the metal complex include metal phthalocyanines such as copper phthalocyanine and titanyl phthalocyanine described in JP-A-1-220380 and JP-A-5-504023, chlorophyll, hemin, ruthenium-tris (2,2 ′ -Bispyridyl-4,4′-dicarboxylate), cis- (SCN ⁻ ) -bis (2,2′-bipyridyl-4,4′-dicarboxylate) ruthenium, ruthenium-cis-diaqua-bis (2, Ruthenium-cis-, such as 2'-bipyridyl-4,4'-dicarboxylate)
Examples include complexes of ruthenium, osmium, iron, zinc and the like, such as diaqua-bipyridyl complexes, porphyrins such as zinc-tetra (4-carboxyphenyl) porphine, and iron-hexocyanide complexes. These metal complexes are excellent in the effect of spectral sensitization and durability.

  The organic dye or metal complex as the above-mentioned photosensitizer may be used alone, or may be used by mixing two or more kinds of organic dyes or metal complexes. Further, the organic dye and the metal complex are used in combination. Also good.

The adsorption amount of the photosensitizer on the porous metal oxide semiconductor film is preferably 100 μg or more, more preferably 150 μg or more per 1 cm ² of the specific surface area of the porous metal oxide semiconductor film.
When the adsorption amount of the photosensitizer on the porous metal oxide semiconductor film is less than 100 μg, the photoelectric conversion efficiency is insufficient.

  The adsorption method of such a photosensitizer is not particularly limited, and a solution obtained by dissolving the photosensitizer in a solvent is absorbed into the porous metal oxide semiconductor film by a method such as a dipping method, a spinner method, or a spray method. General methods such as drying and then drying can be employed. Furthermore, you may repeat the said absorption process as needed. Alternatively, the photosensitizer can be adsorbed to the porous metal oxide semiconductor film by bringing the photosensitizer solution into contact with the substrate while heating and refluxing.

  As the solvent for dissolving the photosensitizer, any solvent that dissolves the photosensitizer can be used. Specifically, water, alcohols, toluene, dimethylformamide, chloroform, ethyl cellosolve, N-methylpyrrolidone, Tetrahydrofuran or the like can be used.

The concentration of the photosensitizer in the photosensitizer solution is preferably 100 μg or more, more preferably 200 μg or more per 1 cm ² of the specific surface area of the porous metal oxide semiconductor film.
In the present invention, the electrode layer (1) is provided on the surface, the titanium oxide thin film (1) is provided on the electrode layer (1), and the photosensitizer is provided on the surface of the titanium oxide thin film (1). A substrate (1) having an adsorbed porous metal oxide semiconductor film and a substrate (2) having an electrode layer (2) on the surface are arranged so that the electrode layer (1) and the electrode layer (2) face each other. The side surface is sealed with a resin, the electrolyte is sealed between the porous metal oxide semiconductor film (1) and the electrode layer (2), and the electrodes are connected with lead wires to connect the photoelectric cell. Can be manufactured.

As the electrolyte layer electrolyte, a mixture of at least one compound that forms an oxidation-reduction system with an electrochemically active salt is used.

Examples of the electrochemically active salt include quaternary ammonium salts such as tetrapropylammonium iodide. Examples of the compound forming the redox system, quinone, hydroquinone, iodine _{^{(I - / I - 3)}} , potassium iodide, bromine _{^{(Br - / Br - 3)}} , potassium bromide, and the like. In some cases, these may be used in combination.

The amount of the electrolyte used is preferably approximately in the range of 0.1 to 5 mol / liter, although it varies depending on the type of electrolyte and the type of solvent described later.
A conventionally well-known solvent can be used for an electrolyte layer. Specifically, carbonates such as water, alcohols, oligoethers, propionate carbonate, phosphate esters, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, N-vinylpyrrolidone, sulfur compounds of sulfolane 66, ethylene carbonate, acetonitrile , Γ-butyrolactone and the like.
Photoelectric cell manufacturing method The photoelectric cell manufacturing method according to the present invention comprises an electrode layer (1) on the surface, a titanium oxide thin film (1), and a porous material in which a photosensitizer is adsorbed on the titanium oxide thin film. The substrate (1) on which the metal oxide semiconductor film (1) is formed and the substrate (2) having the electrode layer (2) on the surface are opposed to the electrode layer (1) and the electrode layer (2). The electrolyte layer is provided between the porous metal oxide semiconductor film (1) and the electrode layer (2), and the electrode layer (1) and the porous metal oxide semiconductor film (1) In the method for producing a photovoltaic cell, comprising a titanium oxide thin film (1) derived from peroxotitanic acid between and a porous metal oxide semiconductor film (1) made of only a metal oxide, an electrode layer ( peroxo titanic acid aqueous solution containing a thickener 1) on, (a) spin coating method, (B) dip coating method, (C) flexographic printing method, (D) roll coater method (E) electrophoresis It was coated with one or more method selected from the group consisting of, dried, and characterized by forming a titanium oxide thin film (1) is cured.

The concentration of the peroxotitanic acid aqueous solution containing the thickener for forming the titanium oxide thin film is preferably in the range of 0.1 to 2.0% by weight, more preferably 0.3 to 1.0% by weight as TiO ₂ . When the concentration of the peroxotitanic acid aqueous solution for forming the titanium oxide thin film is less than 0.1% by weight as TiO ₂ , the titanium oxide thin film (1) having a desired film thickness may not be obtained. There is a need to do it.

If the concentration of the peroxotitanic acid aqueous solution containing a thickener for forming a titanium oxide thin film exceeds 2.0% by weight as TiO ₂ , cracking may occur during drying or a dense film may not be formed, and dark current can be suppressed. In some cases, the effect of suppressing recombination of electrons cannot be obtained.

The concentration of the thickener in the peroxotitanic acid aqueous solution varies depending on the type of the thickener, but is preferably in the range of 1.0 to 60.0% by weight, more preferably 3.0 to 35.0% by weight. When the concentration of the thickener is less than 1.0% by weight, the effect of using the thickener is insufficient, and when it exceeds 60.0% by weight, the coatability is lowered and the film thickness becomes too thick. Cracks may occur, and the effect of providing the titanium oxide thin film may not be obtained.

The application method of the peroxotitanic acid aqueous solution containing the thickener is any one of (A) spin coating method, (B) dip coating method, (C) flexographic printing method, (D) roll coater method (E) electrophoresis method If present, it is possible to form a titanium oxide thin film (1) having excellent adhesion to the electrode layer, uniform film thickness, and excellent strength, and the flexographic printing method is particularly preferably employed industrially. Can do.

Note that the method (E) and the electrophoresis, which was immersed the substrate formed with the electrode layer to the peroxo titanic acid solution, a DC voltage is applied to the electrode layer and the peroxo titanic acid solution, to stack peroxo titanic acid on the electrode layer It is. When employed in the present invention, the applied voltage varies depending on the type and size of the electrode layer, but is generally in the range of 0.5 to 100 V (DC), more preferably 1 to 50 V (DC).

The drying may be performed at any temperature that can remove the water as a dispersion medium, and a conventionally known method can be adopted and air drying is possible. Usually, drying is performed at 50 to 200 ° C. for about 0.2 to 5 hours. To do. In the present invention, a porous metal oxide semiconductor film to be described later can be formed after drying, but the porous metal oxide semiconductor film may be formed after curing after drying.
As a curing method, ultraviolet rays are irradiated as necessary, and then annealing is performed by heat treatment.

Irradiation with ultraviolet rays may be performed in an amount necessary to decompose and cure peroxotitanic acid.
The heat treatment is usually performed at 200 to 500 ° C., further at 300 to 450 ° C. for about 1 to 48 hours.

The titanium oxide thin film (1) thus obtained has a film thickness of 10 to 70 nm, more preferably 20 to
It is preferable to be in the range of 40 nm.
Further, the titanium oxide thin film (1) has a pore volume of 0.01 to 0.20 ml / g, more preferably 0.0.
It is preferably in the range of 1 to 0.15 ml / g.

The titanium oxide thin film (1) preferably has an average pore diameter in the range of 0.5 to 5.0 nm, more preferably 1.0 to 3.5 nm.
[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to an Example by these.
[Example 1]
Preparation of aqueous peroxotitanic acid solution (1) 18.3 g of titanium tetrachloride was diluted with pure water to obtain an aqueous solution containing 1.0% by weight as TiO ₂ . While stirring this, ammonia water having a concentration of 15% by weight was added to obtain a white slurry having a pH of 9.5. This slurry was washed by filtration to obtain a hydrated titanium oxide gel cake having a concentration of 10.2% by weight as TiO ₂ . This cake was mixed with 400 g of a 5% hydrogen peroxide solution and dissolved by heating at 80 ° C. for 2 hours to obtain a 1.0 wt% aqueous peroxotitanic acid solution (1) as TiO ₂ . Further, ethylene glycol was added to water and a peroxotitanic acid aqueous solution so that the TiO2 concentration was 0.5% and the ethylene glycol concentration was 20% to obtain a peroxotitanic acid coating solution (1).

Formation of titanium oxide thin film (1) Peroxotitanic acid coating solution (1) was applied to a transparent glass substrate formed with fluorine-doped tin oxide as an electrode by flexographic printing, followed by natural drying, followed by low-pressure mercury lamp Was used to irradiate ultraviolet rays of 6000 mJ / cm ² to decompose the peroxo acid and harden the film. Furthermore, the titanium oxide thin film (1) was formed by heating and curing at 450 ° C. for 30 minutes for curing and annealing.

Table 1 shows the film thickness of the obtained titanium oxide thin film (1) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
Formation of porous metal oxide semiconductor film (1) Paint for forming porous metal oxide semiconductor film (catalyst chemical industry Co., Ltd .: PST-18NR, titanium oxide colloid average particle size: 20 nm, TiO ₂ concentration 17% by weight , Ethyl cellulose concentration 7.0% by weight) is screen printed and dried until the film thickness shown in the table is repeated, followed by baking annealing at 450 ° C. to form a porous metal oxide semiconductor film (1) did.

The film thickness of the obtained porous metal oxide semiconductor film (1) and the pore volume and average pore diameter determined by the nitrogen adsorption method are shown in the table. Also, evaluate the adhesion of the porous metal oxide semiconductor film (1),
The results are shown in Table 1.

The surface of the adhesive porous metal oxide semiconductor film (1) is made with 11 parallel scratches with a knife at intervals of 1 mm in length and width to make 100 squares, and a cellophane tape is bonded to this, and then the cellophane tape is attached. Adhesiveness was evaluated by classifying the number of squares remaining without peeling of the film when the film was peeled into the following four stages. The results are shown in the table.

Number of remaining squares: ◎
Number of remaining squares 90-99: ○
Number of remaining squares: 85 to 89: Δ
Number of remaining squares: 84 or less: ×
As an adsorption photosensitizer for the photosensitizer, an ethanol solution was prepared so that the concentration of B2 dye manufactured by DYESOL was 0.1%. The glass on which the porous metal oxide semiconductor film (1) was formed was immersed in this solution for 5 hours, taken out, washed with an aqueous ethanol solution, and the dye was adsorbed.
Preparation of photoelectric cell (1) First, tetrapropylammonium iodide and iodine are mixed in a solvent prepared by mixing acetonitrile and ethylene carbonate in a volume ratio of 1: 4 as a solvent, and each concentration is 0.46.
An electrolyte solution was prepared by dissolving at a mol / L of 0.06 mol / L.

  The electrode prepared above is used as one electrode, and fluorine-doped tin oxide is formed as the other electrode. The transparent glass substrate carrying platinum is placed on the opposite side, and the sides are sealed with resin. Then, the above-described electrolyte solution was sealed between the electrodes, and the electrodes were connected with lead wires to produce a photoelectric cell (1).

Photoelectric cell (1) is a solar simulator that irradiates light with an intensity of 100 W / m ^{2 at} an incident angle of 90 ° (90 ° with the cell surface), Voc (voltage in open circuit state), Joc (short circuit) Table 1 shows the results of measurement of the density of the current that flows when the test was performed, FF (fill factor), and η (conversion efficiency).
[Example 2]
Formation of titanium oxide thin film (2) A titanium oxide thin film (2) was formed in the same manner as in Example 1 except that it was applied by a spin coater.

Table 1 shows the film thickness of the obtained titanium oxide thin film (2) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
Formation of porous metal oxide semiconductor film (2) In Example 1, a porous metal oxide semiconductor film (2) was prepared in the same manner as in Example 1 except that the coating liquid (A) for forming a semiconductor film was applied onto the titanium oxide thin film (2). 2) was formed.

The film thickness of the obtained porous metal oxide semiconductor film (2), the pore volume and the average pore diameter determined by the nitrogen adsorption method are shown in the table. Also, evaluate the adhesion of the porous metal oxide semiconductor film (2),
The results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was applied onto the porous metal oxide semiconductor film (2).

The adsorption amount of the photosensitizer on the obtained porous metal oxide semiconductor film (2) was measured, and the results are shown in the table.
Production of photoelectric cell (2) Photoelectric cell (2) except that the titanium oxide thin film (2) prepared above and the electrode on which the porous metal oxide semiconductor film (2) was formed were used as one electrode. )created.

Voc, Joc, FF and η were measured for the photoelectric cell (2), and the results are shown in the table.
[Example 3]
Formation of Titanium Oxide Thin Film (3) A titanium oxide thin film (3) was formed in the same manner as in Example 1 except that flexographic printing was repeated twice. Table 1 shows the film thickness of the titanium oxide thin film (3) and the pore volume and average pore diameter determined by the nitrogen adsorption method.

Formation of Porous Metal Oxide Semiconductor Film (3) In Example 1, a porous metal oxide semiconductor film (3) was prepared in the same manner except that the coating liquid (A) for forming a semiconductor film was applied onto the titanium oxide thin film (3). 3) was formed.

Table 1 shows the film thickness of the obtained porous metal oxide semiconductor film (3) and the pore volume and average pore diameter determined by the nitrogen adsorption method. Further, the adhesion of the porous metal oxide semiconductor film (3) was evaluated, and the results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was applied onto the porous metal oxide semiconductor film (3).

The adsorption amount of the photosensitizer of the obtained porous metal oxide semiconductor film (3) was measured, and the results are shown in Table 1.
Production of photoelectric cell (3) Photoelectric cell (3) was prepared in the same manner except that the titanium oxide thin film (3) prepared above and the electrode on which the porous metal oxide semiconductor film (3) was formed were used as one electrode. )created.

Voc, Joc, FF, and η were measured for the photoelectric cell (3), and the results are shown in Table 1.
[Example 4]
In forming <br/> Example 1 of the titanium oxide thin film (4), a TiO ₂ concentration of peroxotitanate coating liquid prepared 0.3
A titanium oxide thin film (4) was formed in the same manner except that the concentration was 8% and the ethylene glycol concentration was 23%.
Table 1 shows the thickness of the titanium oxide thin film (4) obtained and the pore volume and average pore diameter determined by the nitrogen adsorption method.

Formation of porous metal oxide semiconductor film (4) In Example 1, a porous metal oxide semiconductor film (in the same manner as in Example 1) except that the coating liquid (A) for forming a semiconductor film was applied onto the titanium oxide thin film (4). 4) was formed.

The film thickness of the obtained porous metal oxide semiconductor film (4) and the pore volume and average pore diameter determined by the nitrogen adsorption method are shown in the table. Also, evaluate the adhesion of the porous metal oxide semiconductor film (4),
The results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was applied onto the porous metal oxide semiconductor film (4).

The adsorption amount of the photosensitizer on the obtained porous metal oxide semiconductor film (4) was measured, and the results are shown in Table 1.
Production of photoelectric cell (4) Photoelectric cell (4) was prepared in the same manner except that the titanium oxide thin film (4) prepared above and the electrode on which the porous metal oxide semiconductor film (4) was formed were used as one electrode. )created.

Voc, Joc, FF and η were measured for the photoelectric cell (4), and the results are shown in Table 1.
[Example 5]
Formation of Titanium Oxide Thin Film (5) In Example 1, the TiO ₂ concentration of the prepared peroxotitanic acid coating solution was set to 0.
A titanium oxide thin film (5) was formed in the same manner except that the concentration was 5% and the ethylene glycol concentration was 12%.
Table 1 shows the film thickness of the obtained titanium oxide thin film (5) and the pore volume and average pore diameter determined by the nitrogen adsorption method.

Formation of Porous Metal Oxide Semiconductor Film (5) In Example 1, a porous metal oxide semiconductor film (5) was prepared in the same manner except that the coating liquid (A) for forming a semiconductor film was applied on the titanium oxide thin film (5). 5) was formed.

The film thickness of the obtained porous metal oxide semiconductor film (5), the pore volume and the average pore diameter determined by the nitrogen adsorption method are shown in the table. Also, evaluate the adhesion of the porous metal oxide semiconductor film (5),
The results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was coated on the porous metal oxide semiconductor film (5).

The adsorption amount of the photosensitizer on the obtained porous metal oxide semiconductor film (5) was measured, and the results are shown in Table 1.
Production of photoelectric cell (5) Photoelectric cell (5) was prepared in the same manner except that the titanium oxide thin film (5) prepared above and the electrode on which the porous metal oxide semiconductor film (5) was formed were used as one electrode. )created.

Voc, Joc, FF and η were measured for the photoelectric cell (5), and the results are shown in Table 1.
[Example 6]
Formation of titanium oxide thin film (1) A titanium oxide thin film (1) was formed in the same manner as in Example 1.
Formation of porous metal oxide semiconductor film (6) Paint for forming porous metal oxide semiconductor film (manufactured by Catalyst Kasei Kogyo Co., Ltd .: PST-30NRD, titanium oxide colloid average particle size: 35 nm, TiO ₂ concentration 16% by weight Then, screen printing was performed using an ethylcellulose concentration of 10% by weight, and drying was repeated until the film thickness shown in the table was obtained, followed by baking annealing at 450 ° C. to form a porous metal oxide semiconductor film (6).

The film thickness of the obtained porous metal oxide semiconductor film (6), the pore volume and the average pore diameter determined by the nitrogen adsorption method are shown in the table. Also, evaluate the adhesion of the porous metal oxide semiconductor film (6),
The results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was applied onto the porous metal oxide semiconductor film (6).

The adsorption amount of the photosensitizer of the obtained porous metal oxide semiconductor film (6) was measured, and the results are shown in Table 1.
Production of photoelectric cell (6) Photoelectric cell (6) was prepared in the same manner except that the titanium oxide thin film (6) prepared above and the electrode on which the porous metal oxide semiconductor film (6) was formed were used as one electrode. )created.

Voc, Joc, FF, and η were measured for the photoelectric cell (6), and the results are shown in Table 1.
[Comparative Example 1]
Formation of Porous Metal Oxide Semiconductor Film (R1) In Example 1, the coating liquid for forming a semiconductor film (A) was formed by directly forming fluorine doped tin oxide as an electrode without forming a titanium oxide thin film. A porous metal oxide semiconductor film (R1) was formed in the same manner except that it was applied to a glass substrate.

The film thickness of the obtained porous metal oxide semiconductor film (R1) and the pore volume and average pore diameter determined by the nitrogen adsorption method are shown in the table. Further, the adhesion of the porous metal oxide semiconductor film (R1) was evaluated, and the results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was applied onto the porous metal oxide semiconductor film (R1).

The adsorption amount of the photosensitizer on the obtained porous metal oxide semiconductor film (R1) was measured, and the results are shown in Table 1.
Production of Photoelectric Cell (R1) Photoelectric cell (R1) was produced in the same manner except that the electrode on which the porous metal oxide semiconductor film (R1) was formed was used as one electrode.

Voc, Joc, FF and η were measured for the photoelectric cell (R1), and the results are shown in Table 1.
[Comparative Example 2]
Formation of Titanium Oxide Thin Film (R2) Spray method on transparent glass substrate formed by using fluorine doped tin oxide heated to 450 ° C as a solution of titanium tetraisopropoxide diluted to 0.5% TiO ₂ with isopropanol The titanium oxide thin film (2) was formed by spraying with and causing thermal decomposition.

Table 1 shows the film thickness of the obtained titanium oxide thin film (R2) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
Formation of Porous Metal Oxide Semiconductor Film (R2) In Example 1, a porous metal oxide semiconductor film (R2) was formed in the same manner except that the coating liquid (A) for forming a semiconductor film was applied onto the titanium oxide thin film (R2). R2) was formed.

The film thickness of the obtained porous metal oxide semiconductor film (R2), the pore volume and the average pore diameter determined by the nitrogen adsorption method are shown in the table. Further, the adhesion of the porous metal oxide semiconductor film (R2) was evaluated, and the results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was applied onto the porous metal oxide semiconductor film (R2).

The adsorption amount of the photosensitizer on the obtained porous metal oxide semiconductor film (R2) was measured, and the results are shown in the table.
Production of photoelectric cell (R2) Photoelectric cell (R2) in the same manner except that the titanium oxide thin film (R2) prepared above and the electrode on which the porous metal oxide semiconductor film (R2) was formed were used as one electrode. )created.

Voc, Joc, FF and η were measured for the photoelectric cell (R2), and the results are shown in Table 1.
[Comparative Example 3]
Formation of Porous Metal Oxide Semiconductor Film (R3) In Example 6, the porous metal oxide semiconductor film-forming coating material was formed directly using fluorine-doped tin oxide as an electrode without forming a titanium oxide thin film. A porous metal oxide semiconductor film (R3) was formed in the same manner except that it was applied to a transparent glass substrate.

The film thickness of the obtained porous metal oxide semiconductor film (R3) and the pore volume and average pore diameter determined by the nitrogen adsorption method are shown in the table. Further, the adhesion of the porous metal oxide semiconductor film (R3) was evaluated, and the results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was coated on the porous metal oxide semiconductor film (R3).

The adsorption amount of the photosensitizer on the obtained porous metal oxide semiconductor film (R3) was measured, and the results are shown in Table 1.
Preparation of Photoelectric Cell (R3) A photoelectric cell (R3) was prepared in the same manner except that the electrode on which the porous metal oxide semiconductor film (R3) was formed was used as one electrode.

Voc, Joc, FF and η were measured for the photoelectric cell (R1), and the results are shown in Table 1.
[Comparative Example 4]
Formation of Titanium Oxide Thin Film (R4) A titanium oxide thin film (R4) was formed on a transparent glass substrate formed by using a Ti target and using fluorine-doped tin oxide as an electrode by sputtering.

Table 1 shows the film thickness of the obtained titanium oxide thin film (R4) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
Formation of porous metal oxide semiconductor film (R4) In Example 6, a porous metal oxide semiconductor film was formed in the same manner as in Example 6 except that a coating for forming a porous metal oxide semiconductor film was applied on the titanium oxide thin film (R4). (R4) was formed.

The film thickness of the obtained porous metal oxide semiconductor film (R4), the pore volume and the average pore diameter determined by the nitrogen adsorption method are shown in the table. Further, the adhesion of the porous metal oxide semiconductor film (R4) was evaluated, and the results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was coated on the porous metal oxide semiconductor film (R4).

The adsorption amount of the photosensitizer on the obtained porous metal oxide semiconductor film (R4) was measured, and the results are shown in Table 1.
Production of photoelectric cell (R4) Photoelectric cell (R4) was prepared in the same manner except that the titanium oxide thin film (R4) prepared above and the electrode on which the porous metal oxide semiconductor film (R4) was formed were used as one electrode. )created.

Voc, Joc, FF and η were measured for the photoelectric cell (R4), and the results are shown in the table.
[Comparative Example 5]
Preparation of aqueous peroxotitanic acid solution (R5) In the same manner as in Example 1, an aqueous peroxotitanic acid solution (1) having a concentration of 1.0% by weight as TiO ₂ was obtained. Water was added thereto to obtain a peroxotitanic acid coating solution (R5) having a concentration of 0.5% by weight as TiO ₂ .

Formation of Titanium Oxide Thin Film (R5) A titanium oxide thin film (R5) was formed in the same manner as in Example 1 except that the peroxotitanic acid coating solution (R5) was used.

Table 1 shows the film thickness of the obtained titanium oxide thin film (R5) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
Formation of porous metal oxide semiconductor film (R5) (In Example 1, the semiconductor film contains peroxotitanic acid)
Porous metal oxide semiconductor film-forming coating (manufactured by Catalyst Kasei Kogyo Co., Ltd .: HPW-18NR, titanium oxide colloid average particle size: 20 nm, peroxotitanic acid content: 10% by weight of titanium oxide colloid as TiO ₂ , total The porous metal oxide semiconductor film is subjected to screen printing using a TiO ₂ concentration of 10% by weight and a polyethylene glycol concentration of 14% by weight, and drying is repeated to the film thickness shown in the table, followed by baking annealing at 450 ° C. (R5) was formed.

The film thickness of the obtained porous metal oxide semiconductor film (R5) and the pore volume and average pore diameter determined by the nitrogen adsorption method are shown in the table. Further, the adhesion of the porous metal oxide semiconductor film (R5) was evaluated, and the results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was applied onto the porous metal oxide semiconductor film (R5).

The adsorption amount of the photosensitizer of the obtained porous metal oxide semiconductor film (R5) was measured, and the results are shown in Table 1.
Preparation of photoelectric cell (R5) Photoelectric cell (R5) was prepared in the same manner except that the electrode formed with the titanium oxide thin film (R5) and the porous metal oxide semiconductor film (R5) prepared above was used as one electrode. )created.

Voc, Joc, FF and η were measured for the photoelectric cell (R5), and the results are shown in the table.
[Comparative Example 6]
Formation of Titanium Oxide Thin Film (R6) A titanium oxide thin film (R6) was formed in the same manner as in Comparative Example 5 except that the peroxotitanic acid coating solution (R5) was used.

Table 1 shows the film thickness of the obtained titanium oxide thin film (R6) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
Formation of porous metal oxide semiconductor film (R6) Paint for forming porous metal oxide semiconductor film (catalyst chemical industry Co., Ltd .: PST-18NR, titanium oxide colloid average particle size: 20 nm, TiO ₂ concentration 17% by weight Screen printing using an ethylcellulose concentration of 7.0% by weight) and drying until the film thickness shown in the table is repeated, followed by baking annealing at 450 ° C. to form a porous metal oxide semiconductor film (R6) did.

The thickness of the porous metal oxide semiconductor film (R6) obtained and the pore volume and average pore diameter determined by the nitrogen adsorption method are shown in the table. Further, the adhesion of the porous metal oxide semiconductor film (R6) was evaluated, and the results are shown in Table 1.
Adsorption of photosensitizer The photosensitizer was adsorbed in the same manner as in Example 1 except that it was coated on the porous metal oxide semiconductor film (R6).

The adsorption amount of the photosensitizer of the obtained porous metal oxide semiconductor film (R5) was measured, and the results are shown in Table 1.
Production of photoelectric cell (R6) Photoelectric cell (R6) was prepared in the same manner except that the electrode formed with the titanium oxide thin film (R6) and the porous metal oxide semiconductor film (R6) prepared above was used as one electrode. )created.

Voc, Joc, FF, and η were measured for the photoelectric cell (R6), and the results are shown in the table.

It is a schematic sectional drawing which shows one example of the photoelectric cell of this invention.

Explanation of symbols

1. Electrode layer (1)
2 ... Semiconductor film (1)
3. Electrode layer (2)
4 ... Electrolyte layer (2)
5 ... Board (1)
6 ... Board (2)
7. Titanium oxide thin film

Claims (3)

(A) providing a transparent electrode on the surface of the transparent substrate;
(B) preparing a peroxotitanic acid aqueous solution having a TiO ₂ concentration of 0.1 to 2.0% by weight and a thickener concentration of 1 to 60% by weight;
(C) applying the peroxotitanic acid aqueous solution on the transparent electrode to form a titanium oxide thin film;
(D) forming a porous metal oxide semiconductor film consisting only of metal oxide particles adsorbing a photosensitizer on the titanium oxide thin film;
(E) producing a counter substrate having a counter electrode on the surface;
(F) a step of opposing the transparent substrate and the counter substrate, and providing an electrolyte layer between the porous metal oxide semiconductor film and the counter electrode;
Including
A method of manufacturing a photoelectric cell, wherein the titanium oxide thin film is formed in a thickness of 10 to 70 nm.   The method for producing a photovoltaic cell according to claim 1, wherein the peroxotitanic acid aqueous solution is aged at 50 to 90 ° C for 1 to 25 hours before the step (C).   The pore volume of the titanium oxide thin film is in the range of 0.01 to 0.20 ml / g, and the average pore diameter is in the range of 0.5 to 5.0 nm. Manufacturing method for photovoltaic cells.

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