JP2010108855A - Photoelectric cell, and coating for forming porous metal oxide semiconductor film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric cell from which a photosensitive material is never separated even if it is heat-treated at low temperatures. <P>SOLUTION: In the photoelectric cell having a porous metal oxide semiconductor film formed by adsorbing the photosensitive material on an electrode layer surface, the porous metal oxide semiconductor film is made of (i) titanium oxide particles prepared by adsorbing a visible light absorbing photosensitive material, (ii) titanium oxide particles to adsorb photosensitive material formed by absorbing rays from a near infrared ray to an infrared ray, and/or (iii) titanium oxide particles formed by absorbing a near ultraviolet ray absorbing rays of photosensitive material. The titanium oxide particles to adsorb the photosensitive materials of (i) to (iii) are respectively made of a mixture of titanium oxide particulates of which the average particle size is in a range of 5 to 200 nm, and a porous titanium oxide particulate aggregates of which the average particle size is in the range 0.5 to 10 μm, and the pore volume is in the range 0.1 to 0.8 ml/g, while the porous metal oxide semiconductor film (1) is obtained by being subjected to heat treatment at 80 to 200°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photoelectric cell having a semiconductor film capable of photoelectric conversion over a wide wavelength range and excellent in photoelectric conversion efficiency, and a coating material for forming a porous semiconductor film for the photoelectric cell.

Metal oxide semiconductor materials having a high band gap are used for other optical sensors such as photoelectric conversion materials and photocatalyst materials, and power storage materials (batteries).
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. Are listed.

As another method, a two-layer semiconductor film is provided in order to increase the utilization rate of sunlight, a photosensitizer having absorption in the visible light region is adsorbed on one semiconductor film, and infrared light is absorbed on the other semiconductor film. Attempts have also been made to improve the photoelectric conversion efficiency by providing a semiconductor film in which a photosensitizer having absorption in the region or a photosensitizer having absorption in the ultraviolet and infrared region is adsorbed.
Japanese Patent Laid-Open No. 1-220380 Japanese National Patent Publication No. 5-504023

However, solar cells using a semiconductor film adsorbing a conventional spectral sensitizing dye (photosensitizer) having absorption in the visible light region still have insufficient light conversion efficiency, and further improvements are required.
Therefore, in order to use ultraviolet and infrared rays, in addition to the photosensitizer that absorbs in the visible region, the photosensitizer that absorbs in the infrared region or the photosensitizer that absorbs in the ultraviolet region is mixed and adsorbed. However, the absorption characteristics are different, and when a photosensitizer having absorption in the visible light region is adsorbed, it has absorption in the infrared region or absorption in the ultraviolet and infrared region. There are problems such as insufficient adsorption of the photosensitizer and vice versa, and the photoelectric conversion efficiency cannot be sufficiently improved.

  In addition to forming a two-layer semiconductor film as in the prior art, there is a problem in terms of productivity and economy, and the photosensitizer adsorbed on the first semiconductor film is altered. However, there is a problem that the photosensitizer to be adsorbed on the semiconductor film formed later is adsorbed on the semiconductor film formed first, and the object could not be achieved.

Under such circumstances, the present inventors have intensively studied to solve the above problems, and as a result, (i) titanium oxide particles adsorbed with a visible light absorbing photosensitizer in advance, and (ii) near infrared rays in advance. Porous titanium oxide having a large particle diameter using titanium oxide particles adsorbing an infrared absorbing photosensitizer and / or (iii) titanium oxide particles adsorbing a near ultraviolet absorbing photosensitizer from It has been found that the above-mentioned problems can be solved by including a fine particle aggregate. And when a semiconductor film is formed using the coating material for forming a porous metal oxide semiconductor film for electric cells containing such titanium oxide particles, the photosensitizer can be subjected to heat treatment (sometimes referred to as curing) at a lower temperature than in the past. The present invention has been completed by finding that an optoelectric cell having excellent semiconductor strength and photoelectric conversion efficiency can be obtained without desorption.

  That is, an object of the present invention is to provide a photoelectric cell having a semiconductor film capable of photoelectric conversion over a wide wavelength range of the ultraviolet region and / or the infrared region in addition to the visible light region, and having excellent photoelectric conversion efficiency, and the light. An object of the present invention is to provide a coating material for forming a porous semiconductor film for an electric cell.

The configuration of the present invention is as follows.
[1] 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); A substrate (2) having an electrode layer (2) on the surface, the electrode layer (1) and the electrode layer (2) are disposed so as to face each other, and the porous metal oxide semiconductor film (1) In the photoelectric cell in which an electrolyte layer is provided between the electrode layer (2),
Porous metal oxide semiconductor film (1)
(i) titanium oxide particles adsorbed with a visible light absorbing photosensitizer,
comprising (ii) titanium oxide particles adsorbing an infrared absorbing photosensitizer from near infrared and / or (iii) titanium oxide particles adsorbing a near ultraviolet absorbing photosensitizer,
Titanium oxide particles that adsorb the photosensitizers (i) to (iii) are each titanium oxide fine particles having an average particle diameter in the range of 5 to 200 nm,
It consists of a mixture with an aggregate of porous titanium oxide fine particles having an average particle diameter in the range of 0.5 to 10 μm and a pore volume in the range of 0.1 to 0.8 ml / g,
And the photoelectric cell which is obtained by heat-processing the said porous metal oxide semiconductor film (1) at 80-200 degreeC.
[2] (ii) The titanium oxide particles that adsorb the infrared absorbing photosensitizer from the near infrared are doped with one or more elements selected from Nb, Zr, Ge, Hf, W, Ce, Sn, and Fe. Containing titanium oxide fine particles (A),
(Iii) Titanium oxide fine particles coated with one or more oxides selected from aluminum oxide, silicon oxide, zirconium oxide, magnesium oxide, calcium oxide and yttrium oxide as titanium oxide particles adsorbing the near-ultraviolet absorbing photosensitizer The photoelectric cell according to [1], including (B).
[3] The photoelectric cell according to [1] or [2], wherein the porous titanium oxide aggregate includes fine titanium oxide particles and a peroxotitanate binder.
[4] Photoelectricity of [1] to [3], wherein 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) cell.
[5] The thickness of the titanium oxide thin film (1) is in the range of 10 to 70 nm, and the pore volume is 0.01 to
The photoelectric cell according to [1] to [4], which has a range of 0.20 ml / g and an average pore diameter of 0.5 to 5.0 nm.
[6] (i) titanium oxide particles adsorbed with a visible light absorbing photosensitizer,
(ii) titanium oxide particles adsorbing an infrared absorbing photosensitizer from near infrared and / or (iii)
Titanium oxide particles adsorbed with a near-ultraviolet absorbing photosensitizer,
A dispersion medium;
A thickener and
Titanium oxide particles that adsorb the photosensitizers (i) to (iii) are each titanium oxide fine particles having an average particle diameter in the range of 5 to 200 nm,
Porous metal for photoelectric cells comprising a mixture with porous titanium oxide fine particle aggregates having an average particle diameter in the range of 0.5 to 10 μm and a pore volume in the range of 0.1 to 0.8 ml / g A coating for forming an oxide semiconductor film.
[7] The coating material for forming a porous metal oxide semiconductor film for photoelectric cells according to [6], wherein the porous titanium oxide aggregate includes fine titanium oxide particles and a peroxotitanate binder.
[8] (ii) The titanium oxide particles that adsorb the infrared absorbing photosensitizer from the near infrared are doped with one or more elements selected from Nb, Zr, Ge, Hf, W, Ce, Sn, and Fe. Titanium oxide particles (A),
(Iii) Titanium oxide particles in which the titanium oxide particles adsorbing the near-ultraviolet absorbing photosensitizer are coated with one or more oxides selected from aluminum oxide, silicon oxide, zirconium oxide, magnesium oxide, calcium oxide, and yttrium oxide [6] or [7] The coating material for forming a photoelectric cell porous metal oxide semiconductor film according to (B).

  According to the present invention, in addition to the visible light region, a photoelectric film having a semiconductor film capable of photoelectric conversion over a wide wavelength range of the ultraviolet region and / or the infrared region, and having excellent photoelectric conversion efficiency, and the photoelectric device A coating material for forming a porous semiconductor film for a cell can be provided.

Hereinafter, the present invention will be specifically described.
[Photoelectric cell]
The photovoltaic 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 disposed so that the electrode layer (1) and the electrode layer (2) face each other, and the porous metal oxide semiconductor film (1) and the electrode layer ( In the photoelectric cell in which an electrolyte layer is provided between
Porous metal oxide semiconductor film (1)
(i) titanium oxide particles adsorbed with a visible light absorbing photosensitizer,
It consists of (ii) titanium oxide particles adsorbing an infrared absorbing photosensitizer from near infrared and / or (iii) titanium oxide particles adsorbing a near ultraviolet absorbing photosensitizer.

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 the photovoltaic cell of the present invention, which has an electrode layer (1) on the surface and, if necessary, a titanium oxide thin film (1) on the electrode layer (1). (I) titanium oxide particles adsorbing a visible light absorbing photosensitizer on the electrode layer (1) or titanium oxide thin film (1), and (ii) infrared absorbing photosensitization from near infrared rays A substrate (1) having a porous metal oxide semiconductor film (1) formed of titanium oxide particles adsorbing a material and / or (iii) a titanium oxide particle adsorbing a near-ultraviolet absorbing photosensitizer, and a surface A substrate (2) having an electrode layer (2) on the electrode layer (1) and the electrode layer (2) so as to face each other, the porous metal oxide semiconductor film (1) and the electrode layer An electrolyte is enclosed between (2) and (2).

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 (1).
The photoelectric cell of the present invention is not limited to the illustrated photoelectric cell, and may be a photoelectric cell having two or more semiconductor films and another electrode layer and electrolyte layer provided therebetween. Good.

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, and both of them may be 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. The photoelectric conversion efficiency when the resistance value of the electrode layer is increased beyond 100 [Omega / cm ² may decrease.

Titanium oxide thin film In the present invention, a titanium oxide thin film (1) can be formed on the electrode layer (1) as necessary, and this titanium oxide thin film (1) uses a peroxy titanic acid aqueous solution containing a thickener. This is a dense film. When the titanium oxide thin film is formed, the contact between the electrolytic solution and the electrode can be suppressed, and there is an effect of suppressing the backflow of electrons and the recombination of electrons. Moreover, even if such a titanium oxide thin film is formed, the movement of electrons is not inhibited.

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. Although it is possible to obtain a dense titanium oxide thin film by a method such as sputtering, it is too dense to inhibit the movement of electrons, or with a porous metal oxide semiconductor film formed on the surface of the titanium oxide thin film. Adhesion may be insufficient.

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 peroxytitanic 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 peroxytitanic acid aqueous solution used for forming the titanium oxide thin film (1) is 0 as TiO _2.
. It is preferably in the range of 1 to 2.0% by weight, more preferably 0.3 to 1.0% by weight. If the concentration of the peroxytitanic acid aqueous solution is low, the titanium oxide thin film (1) having a desired film thickness may not be obtained, and it is necessary to repeatedly apply and dry the titanium oxide thin film (1). If the concentration of the peroxytitanic acid aqueous solution is low, cracks may occur during drying or a dense film may not be formed, and the effects of suppressing dark current and suppressing recombination of electrons may not be obtained.

  Here, peroxytitanic 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 peroxytitanic acid aqueous solution.
In preparing the peroxytitanic 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 is too high, it takes a long time to dissolve the solution, and an undissolved gel may precipitate, or the resulting peroxytitanic 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 peroxytitanic 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 peroxytitanic acid aqueous solution used in the present invention contains a thickener, and as the thickener, ethylene glycol, polyethylene glycol, polyvinyl pyrrolidone, hydroxypropyl cellulose, polyacrylic acid, ethyl cellulose, polyvinyl alcohol, methanol, ethanol , Isopropyl alcohol, normal butanol, tertiary butanol and the like may be contained. When such a thickener is contained in the peroxytitanic acid aqueous solution, the viscosity of the coating solution increases, and this enables 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 peroxytitanic 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 peroxytitanic 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.

(I) Titanium oxide particles adsorbing a visible light absorbing photosensitizer on the electrode layer (1) or a titanium oxide thin film (1) provided as necessary, and (ii) a porous metal oxide semiconductor film; A porous metal oxide semiconductor film comprising titanium oxide particles adsorbing an infrared absorbing photosensitizer from near infrared and / or (iii) titanium oxide particles adsorbing a near ultraviolet absorbing photosensitizer is formed.
(i) Titanium oxide particles adsorbed with a visible light absorbing photosensitizer (titanium oxide particles)
As the titanium oxide particles used in the present invention, a mixture of titanium oxide fine particles (1) and porous titanium oxide fine particle aggregates (2) is used.
(1) Titanium oxide fine particles The average particle diameter of the titanium oxide fine particles is 5 to 200 n, preferably 10 to 100 nm. It is difficult to obtain particles with titanium oxide particles smaller than the above range, and even if obtained, the crystallinity is low, and depending on the heat treatment at the time of forming the semiconductor film, it may be sintered, which makes it porous. In some cases, the specific surface area of the metal oxide semiconductor film decreases, the amount of adsorption of the photosensitizer decreases, and the photoelectric conversion efficiency becomes insufficient.

If the average particle size of the titanium oxide fine particles is too large, the strength of the resulting porous metal oxide semiconductor film will be insufficient, and the large particle size will decrease the specific surface area and decrease the adsorption of the photosensitizer. As a result, the photoelectric conversion efficiency may be insufficient.
(2) Porous titanium oxide fine particle aggregate In the present invention, together with the titanium oxide fine particles, the average particle diameter is in the range of 0.5 to 10 μm, and the pore volume is in the range of 0.1 to 0.8 ml / g. A certain porous titanium oxide fine particle aggregate is used.

  When such a porous titanium oxide fine particle aggregate is included, a thick film can be formed and cured at a low temperature, so that the adsorbed photosensitizer is also desorbed and decomposed. It is possible to obtain a photoelectric cell excellent in photoelectric conversion efficiency. Moreover, it is also possible to use a resin substrate having a low softening point instead of the glass substrate as a base material.

The porous titanium oxide fine particle aggregate is an aggregate composed of at least one of granular titanium oxide fine particles, fibrous titanium oxide fine particles, and tubular titanium oxide fine particles.
The granular titanium oxide fine particles include spherical particles, dice particles, and the like, and are distinguished from fibrous particles described later, and mean particles having an aspect ratio of approximately 4 or less, preferably 2 or less.

The granular titanium oxide fine particles preferably have an average particle diameter in the range of 5 to 200 nm, more preferably 10 to 100 nm. The granular titanium oxide fine particles may be the same as the (1) titanium oxide fine particles, or may be larger than the (1) titanium oxide fine particles.

It is difficult to obtain particles smaller than the granular titanium oxide fine particles (1). Even if they are obtained, the pore volume of the aggregate of titanium oxide fine particles obtained by using them becomes smaller and the surface area is reduced. The adsorbed amount of the light-sensitive material is reduced, and the diffusibility of the electrolyte is lowered to cause back current, which may result in insufficient photoelectric conversion efficiency.

When the average particle diameter of the granular titanium oxide fine particles (1) exceeds 200 nm, the strength of the resulting porous titanium oxide fine particle aggregate becomes insufficient, and the granular titanium oxide fine particles (1) have a large particle diameter. Since the surface area is reduced and the adsorption of the photosensitizer is reduced, the photoelectric conversion efficiency may be insufficient.

  Such granular titanium oxide fine particles are not particularly limited as long as the average particle diameter is in the above range, and conventionally known titanium oxide fine particles can be used. For example, the anatase-type titanium oxide particles disclosed in JP-A-63-229139 filed by the applicant of the present application can be suitably used.

The fibrous titanium oxide fine particles have an aspect ratio (W _F ) / (L _F ) in the range of 5 to 200, and more preferably in the range of 10 to 100.
Those having a small aspect ratio (W _F ) / (L _F ) of the fibrous titanium oxide fine particles are classified as the granular titanium oxide fine particles and are difficult to obtain. Those having a large aspect ratio (W _F ) / (L _F ) require a large amount of titanium oxide that acts as a binder such as peroxytitanic acid described later in order to obtain a porous titanium oxide fine particle aggregate. In some cases, the pore volume of the aggregate of fine titanium oxide particles becomes small, and the amount of adsorption of the photosensitizer becomes insufficient.

The average width (W _F ) of the fibrous titanium oxide fine particles is 5 to 40 nm, more preferably 10 to 30 nm.
It is preferable that it exists in the range. When the average width (W _F ) is small, it is difficult to obtain, and if it is too large, the specific surface area of the resulting porous titanium oxide fine particle aggregate is reduced, and the adsorption amount of the photosensitizer is insufficient. There is a case.

The average length (L _F ) of the fibrous titanium oxide fine particles is 25 to 1000 nm, and further 50 to 5
It is preferably in the range of 00 nm. If the average length (L _F ) is too short, the aspect ratio becomes small, and the particles are classified into the granular titanium oxide fine particles. If the average length of the fibrous titanium oxide fine particles is too long, a large amount of titanium oxide acting as a binder such as peroxytitanic acid described later is required to obtain a porous titanium oxide fine particle aggregate, and the porous oxidation obtained in this case In some cases, the pore volume of the titanium fine particle aggregate becomes small, and the amount of adsorption of the photosensitizer becomes insufficient.

Such fibrous titanium oxide fine particles are not particularly limited as long as the average width (W _F ), average length (L _F ), and aspect ratio (W _F ) / (L _F ) are within the above ranges. The fibrous titanium oxide fine particles can be used. For example, the anatase type fibrous titanium oxide fine particles disclosed in Japanese Patent Application Laid-Open No. 2005-68001 filed by the applicant of the present application can be suitably used.

The tubular titanium oxide fine particles have an aspect ratio (L _P ) / (D _ouT ) of 5 to ₂₀₀ , preferably 10 to 100 nm, and are tubular (that is, hollow).
Tubular titanium oxide fine particles having a small aspect ratio (L _P ) / (D _ouT ) are difficult to obtain. If the aspect ratio (L _P ) / (D _ouT ) is too large, the same as the fibrous titanium oxide fine particles. In addition, in order to obtain a porous titanium oxide fine particle aggregate, a large amount of titanium oxide acting as a binder such as peroxytitanic acid described later is required. In this case, the pore volume of the resulting porous titanium oxide fine particle aggregate is reduced, The amount of adsorption of the photosensitizer may be insufficient.

The average tube _outer diameter (D _ouT ) of the tubular titanium oxide fine particles is 5 to 40 nm, preferably 10 to 30
It is desirable to be in the range of nm.
It is difficult to obtain a _{tube having an} average _{tube outer} diameter (D _ouT ) that is too small. If (D _ouT ) is too large, the specific surface area of the resulting porous titanium oxide fine particle aggregate depends on the tube thickness. In some cases, the amount of adsorption of the photosensitizer becomes insufficient.

The average length (L _P ) of the tubular titanium oxide fine particles is preferably in the range of 25 to 1000 nm and 50 to 500 nm. It is difficult to obtain a material having a short average length (L _P ),
If the average length (L _P ) is too long, a large amount of titanium oxide acting as a binder such as peroxytitanic acid described later is required to obtain a porous titanium oxide fine particle aggregate, and the porous titanium oxide fine particles obtained in this case In some cases, the pore volume of the aggregate becomes small, and the amount of adsorption of the photosensitizer becomes insufficient.

The average tube thickness of the tubular titanium oxide fine particles is desirably in the range of 0.5 to 10 nm, preferably 1 to 8 nm. The tube thickness does not exceed 1/2 of the average tube outer diameter.
The tubular titanium oxide fine particles are not particularly limited as long as the average _{tube outer} diameter (D _ouT ), average length (L _P ), and aspect ratio aspect ratio (L _P ) / (D _ouT ) are within the above ranges. Conventionally known fibrous titanium oxide fine particles can be used. For example, the anatase type tubular titanium oxide fine particles disclosed in Japanese Patent Application Laid-Open No. 2003-137549 filed by the applicant of the present application can be suitably used.

The porous titanium oxide fine particle aggregate is an aggregate of at least one kind of titanium oxide fine particles of the granular titanium oxide fine particles, fibrous titanium oxide fine particles, and tubular titanium oxide fine particles.
The average particle diameter of the porous titanium oxide fine particle aggregate is preferably in the range of 0.5 to 10 μm, more preferably 1 to 5 μm. If the average particle size of the aggregate is small, it is difficult to form a uniform porous porous metal oxide semiconductor film for photovoltaic cells with a small number of times. If the average particle size of the porous titanium oxide fine particle aggregate is too large, the strength of the resulting metal oxide semiconductor film may be insufficient or cracks may occur. In addition, a semiconductor film having a uniform film thickness may not be obtained. For this reason, it may be difficult to control the distance between the electrodes of the counter electrode, and sufficient photoelectric conversion efficiency may not be obtained.

  The pore volume of the porous titanium oxide fine particle aggregate is preferably in the range of 0.1 to 0.8 ml / g, more preferably 0.2 to 0.65 ml / g. When the pore volume of the porous titanium oxide fine particle aggregate is small, the specific surface area of the porous titanium oxide fine particle aggregate becomes low (that is, the voids are reduced), and therefore the adsorption amount of the photosensitizer is reduced, and The diffusibility of the electrolyte may be lowered to cause a back current, and the photoelectric conversion efficiency may be insufficient. If the pore volume of the porous titanium oxide fine particle aggregate is too large, the strength of the porous titanium oxide fine particle aggregate becomes insufficient and the strength of the resulting porous metal oxide semiconductor film becomes insufficient, causing cracks. There is a case. When the pore volume of the porous titanium oxide fine particle aggregate is in the above range, a sufficient amount of the photosensitizer can be adsorbed and has sufficient strength and is free from cracks. A semiconductor film can be obtained.

  A method for producing such a porous titanium oxide fine particle aggregate is obtained by using the granular titanium oxide fine particles, fibrous titanium oxide fine particles, and tubular titanium oxide fine particles, and the titanium oxide fine particle aggregate having the average particle diameter and pore volume. Can be produced according to the method disclosed in Japanese Patent Application Laid-Open No. 61-174103 filed by the applicant's application.

Specifically, it can be obtained by spray-drying a dispersion of at least one of the granular titanium oxide fine particles, fibrous titanium oxide fine particles, and tubular titanium oxide fine particles.

  The spraying conditions vary depending on the type and size of the titanium oxide fine particles used, the concentration of the dispersion, and the like. For example, the spray drying atmosphere temperature is generally 10 to 150 ° C, preferably 40 to 120 ° C, and the humidity is 3 to 13% by volume. It can be obtained by spraying and drying in an airflow of preferably 5 to 9% by volume. When spray-dried under these conditions, a spherical porous titanium oxide fine particle aggregate is obtained, a uniform thick film is easily obtained, the amount of dye adsorbed is sufficient, and the electron mobility is good. A metal oxide semiconductor film can be obtained.

  The concentration of the dispersion of fine titanium oxide particles to be sprayed is preferably in the range of 1.0 to 40% by weight, more preferably 5.0 to 20% by weight as the solid content. If the solid sentence concentration of the titanium oxide fine particle dispersion is too low, it is difficult to obtain an aggregate, and even if it is obtained, the average particle size becomes small, making it difficult to achieve the object of the present application. If the solid content concentration of the titanium oxide fine particle dispersion is too high, the dispersion may have a high viscosity and may not be spray dried.

  The dispersion of the fine titanium oxide particles to be sprayed is obtained by heating and aging peroxytitanic acid obtained by dissolving fine particles of orthotitanic acid gel or sol with hydrogen peroxide or further dissolving it with hydrogen peroxide. It is desirable to include a titania sol. Oxytitanic acid and peroxytitanic acid are as described above. These act as a binder, and can combine the granular, fibrous, and tubular titanium oxide fine particles to easily obtain a porous titanium oxide fine particle aggregate. The resulting porous titanium oxide fine particle aggregate is easily obtained In addition, it is suitable for the anatase-type titanium oxide by calcining the obtained aggregate as needed without contributing to the adsorption of the photosensitizer and reducing the photoelectric conversion efficiency. Can be used. Use of such a binder is necessary and effective when the granular, fibrous, and tubular titanium oxide fine particles are large.

The amount of the binder used is 1/100 of the weight of the titanium oxide fine particles as solid content (TiO ₂ ).
It is preferable to be in the range of -30/100, more preferably 2 / 100-20 / 100.
When the amount of the binder used is small, the strength of the porous titanium oxide fine particle aggregate may become insufficient, may easily collapse, and the effect of using the porous titanium oxide fine particle aggregate cannot be obtained sufficiently There is. Even if the amount of the binder is too large, the pore volume of the resulting titanium oxide fine particle aggregate becomes too small, and the adsorption amount of the photosensitizer may be insufficient.

Also when using a binder, it is set as the solid content of the said range.
The porous titanium oxide fine particle aggregate obtained by spray-drying can be used as it is, but is then preferably fired (heat treatment). The firing temperature is preferably in the range of 200 to 800 ° C, more preferably 300 to 700 ° C. If the firing temperature is low, the bonding force between the particles is weak and sufficient strength may not be obtained, or the binder component is insufficiently crystallized to anatase-type titanium oxide, and sufficient photoelectric conversion efficiency is obtained. There may not be. If the firing temperature is high, the adsorption amount of the photosensitizer may decrease due to a decrease in specific surface area, or anatase-type titanium oxide may crystallize to rutile-type titanium oxide, which may reduce photoelectric conversion efficiency.

When the titanium oxide fine particles and aggregates in the mixture are used as a titanium oxide particle, the above-mentioned (1) titanium oxide fine particles and (2) porous titanium oxide fine particle aggregates are used in combination. The content of the porous titanium oxide fine particle aggregate (2) in the semiconductor film is preferably in the range of 30 to 70% by weight, more preferably 35 to 50% by weight as the solid content (TiO ₂ ). When the content of the porous titanium oxide fine particle aggregate (2) in the porous metal oxide semiconductor film is small,
A porous metal oxide semiconductor film having a desired thickness may not be formed with a small number of times, and a repeated operation is required. Porous titanium oxide fine particle aggregates in porous metal oxide semiconductor films (2)
If the amount is too large, the amount of the titanium oxide fine particles (1) is small, so that the strength of the porous semiconductor film may be insufficient or the photoelectric conversion efficiency may be insufficient.

The content of the porous titanium oxide fine particle aggregate (2) in the titanium oxide particles used in the present invention is 30% by weight or more, preferably 50% by weight or more. Within this range, a porous metal oxide semiconductor film having a desired thickness can be sufficiently formed with a small number of times.

When components other than titanium oxide particles are included, the amount of titanium oxide particles is desirably 77% by weight or more, preferably 87% by weight or more.
Such titanium oxide particles (including titanium oxide fine particles (1) and porous titanium oxide fine particle aggregates (2)) adsorb the visible light absorbing photosensitizer.

The visible light absorbing photosensitizer is not particularly limited as long as it absorbs and excites light in the visible light region (wavelength = 480 to 600 nm). For example, an organic dye or a metal complex Etc. can be used.

  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. Is used.

Examples of the metal complex include ruthenium-tris (2,2′-bispyridyl-4,4′-dicarboxylate), cis- (SCN ⁻ ) -bis (2,2′-bipyridyl-4,4′-dicarboxylate). Mention may be made of complexes such as ruthenium-cis-diaqua-bipyridyl complexes such as carboxylate) ruthenium, ruthenium-cis-diaqua-bis (2,2′-bipyridyl-4,4′-dicarboxylate).

  The adsorption amount of the photosensitizer to titanium oxide particles (including titanium oxide fine particles (1) and porous titanium oxide fine particle aggregates (2)) is 100 μg or more per unit weight (mg) of titanium oxide particles, It is preferably 150 μg or more. When the adsorption amount of the photosensitizer is small, the photoelectric conversion efficiency is insufficient. The adsorption method of such a photosensitizer is not particularly limited, and a general method such as absorption of a solution obtained by dissolving the photosensitizer in a solvent into titanium oxide particles and then drying can be employed. Furthermore, you may repeat the said absorption process as needed. Alternatively, the photosensitizer can be adsorbed by bringing the photosensitizer solution into contact with the titanium oxide particles 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.

(ii) Titanium oxide particles adsorbing infrared absorbing photosensitizer from near infrared rays As titanium oxide particles, (i) titanium oxide particles adsorbing visible light absorbing photosensitizer, that is, (1) titanium oxide fine particles, or Titanium oxide particles similar to titanium oxide particles comprising (1) titanium oxide fine particles and (2) an aggregate of porous titanium oxide fine particles are used.

The titanium oxide particles used for the titanium oxide particles adsorbing the infrared absorbing photosensitizer from the near infrared of the present invention are doped with one or more elements selected from Nb, Zr, Ge, Hf, W, Ce, Sn, and Fe. It is preferable to use the oxidized titanium oxide particles.

  Titanium oxide doped with such an element selectively and strongly adsorbs a photosensitizer capable of absorbing near infrared rays to infrared rays, which will be described later, and absorbs light in the near infrared to infrared wavelength region as electrical energy. Can be converted to That is, photoelectric conversion is possible over a wide wavelength range compared to conventional visible light alone.

  The content of the doping component in the doped titanium oxide particles is preferably in the range of 0.5 to 20% by weight, more preferably 1 to 8% by weight in terms of oxide. When the content of the doping component is small, the photosensitizer of the titanium oxide particles adsorbed to the photosensitizer that absorbs light in other wavelength regions is adsorbed in the coating material for forming a porous semiconductor film, which will be described later. The photosensitizer capable of absorbing infrared rays may be detached, and conversion of light in the near infrared to infrared wavelength range into electrical energy may be insufficient. Even if the content of the doping component is too large, the adsorption amount of the photosensitizer capable of absorbing near-infrared light to infrared light does not increase further. Conversion may not be improved and movement of electrons excited by the photosensitizer may be hindered.

The method for producing titanium oxide particles doped with the element includes the compound of the element to be doped when the titanium oxide particles ((1) titanium oxide fine particles, (2) porous titanium oxide fine particle aggregates) are prepared. For example, after mixing a titanium tetrachloride aqueous solution and a compound solution such as a chloride containing an element to be doped and neutralizing with ammonia water or the like, a titanium hydroxide gel containing the above element is prepared and washed with water The gel can be obtained by reslurry and hydrothermal treatment. Further, when (2) an aggregate of porous titanium oxide fine particles is included, a doping component may be added to the granular, fibrous, and tubular titanium oxide fine particles before forming the aggregate by the same method.

From near infrared to infrared absorbing photosensitizer, the near infrared to infrared absorbing photosensitizer is not particularly limited as long as it absorbs and excites light in the infrared region (wavelength = 600 to 850) from near infrared, For example, an organic dye or a metal complex can be used.

  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. Specifically, D149 dye made by Mitsubishi Paper Industries or the like is used.

  Metal complexes include (2,2 ': 6', 2 '' -terpyridine-4,4 ', 4' '-tricarbosichelate) ruthenium-tris (tetrabutylammonium) tris (isocyanate), etc. Metal complexes can be used.

  Adsorption amount of photosensitizer of titanium oxide particles (including titanium oxide fine particles (1) and porous titanium oxide fine particle aggregates (2)) is 100 μg or more per unit weight (mg) of titanium oxide particles, and more than 150 μg It is preferable that When the adsorption amount of the photosensitizer on the titanium oxide particles is small, the photoelectric conversion efficiency becomes insufficient.

The adsorption method of the near-infrared to infrared absorption sensitizer is the same as the adsorption method of the visible light absorption sensitizer.
(iii) Titanium oxide particles adsorbing a near-ultraviolet absorbing photosensitizer The titanium oxide particles are the same as the titanium oxide particles used for the titanium oxide particles adsorbing the visible light absorbing photosensitizer (i). Use.

The titanium oxide particles adsorbing the near-ultraviolet absorbing photosensitizer are titanium oxide particles coated with one or more oxides selected from aluminum oxide, silicon oxide, zirconium oxide, magnesium oxide, calcium oxide, and yttrium oxide. Preferably there is. In the case of an aggregate, the whole may be coated, or granular titanium oxide fine particles constituting the aggregate may be coated.

Titanium oxide coated with such an oxide selectively and strongly absorbs a photosensitizer capable of absorbing near ultraviolet rays, which will be described later, and converts light in the near ultraviolet wavelength region into electrical energy. be able to. That is, photoelectric conversion is possible over a wide wavelength range compared to conventional visible light alone.

  The content of the coating oxide in the titanium oxide particles coated with the oxide is preferably 0.5 to 20% by weight, more preferably 1 to 5% by weight. If the coating oxide is small, the photosensitizer that absorbs light in other wavelength regions is absorbed in the coating for forming a porous semiconductor film. In some cases, the photosensitive material may be detached, or conversion of light in the near ultraviolet wavelength region into electrical energy may be insufficient. When there are too many coating oxides, the amount of adsorption of the photosensitizer does not increase, and the conversion of light in the near ultraviolet wavelength region into electrical energy does not improve.

  The method for producing the oxide-coated titanium oxide particles is, for example, dissolving the titanium oxide particles well dispersed in an alcohol solvent and the metal alkoxide compound corresponding to the oxide in an alcohol solvent, and then mixing them. It can be produced by depositing a hydroxide of the oxide on the surface of the titanium oxide particles, and then aging or hydrothermal treatment as necessary.

The near-ultraviolet absorbing photosensitizer is not particularly limited as long as it absorbs and excites light in the near-ultraviolet region (wavelength = 410 to 480 nm). For example, an organic dye or a metal complex Etc. can be used.

  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. Specifically, D131 pigment manufactured by Mitsubishi Paper Industries is used.

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.

  Adsorption amount of photosensitizer of titanium oxide particles (including titanium oxide fine particles (1) and porous titanium oxide fine particle aggregates (2)) is 100 μg or more per unit weight (mg) of titanium oxide particles, and more than 150 μg It is preferable that

When the adsorption amount of the photosensitizer on the titanium oxide particles is small, the photoelectric conversion efficiency becomes insufficient. The adsorption method of the near-ultraviolet absorbing sensitizer is the same as that of the visible light absorbing photosensitizer.
In the porous metal oxide semiconductor film, the ratio of (i) the titanium oxide particles adsorbing the visible light absorbing photosensitizer in the total titanium oxide particles adsorbing each of the photosensitizers (i) to (iii) is 30 to 90% by weight, more preferably 40 to 80% by weight.

(i) When the proportion of the titanium oxide particles adsorbing the visible light absorbing photosensitizer is small, there is a case where the light in the visible light region cannot be sufficiently photoelectrically converted. (i) Even if the proportion of the titanium oxide particles adsorbing the visible light absorption photosensitizer is too large, the absorption of light outside the visible light region becomes insufficient, and the use of near infrared rays, infrared rays, near ultraviolet rays, etc. becomes insufficient. The effect of the present application may not be sufficiently obtained.

Also, (ii) titanium oxide particles adsorbing infrared absorbing photosensitizer from near infrared in all titanium oxide particles adsorbing photosensitizer, or (iii) titanium oxide particles adsorbing near ultraviolet absorbing photosensitizer (The total amount if both (ii) and (iii) are included) is 10 to 70% by weight, and further 20
It is preferably in the range of ˜60% by weight.

When both (ii) and (iii) are included, (ii) the weight of the titanium oxide particles adsorbing the infrared absorbing photosensitizer from near infrared (W _T2 ) and (iii) adsorbing the near ultraviolet absorbing photosensitizer the weight ratio of the weight (W _T3) of the titanium oxide particles _{(W T2) / (W T3} ) from 0.1 to 10, more preferably in the range of 0.2 to 5.

  When the ratio of the titanium oxide particles adsorbing each photosensitizer in the porous metal oxide semiconductor film is within the above range, the wavelength region of infrared rays, ultraviolet rays, etc. is 410 to 850 nm without reducing the visible light photoelectric conversion efficiency. Can be effectively converted into electric energy, and a photoelectric cell with high photoelectric conversion efficiency can be obtained.

  The porous metal oxide semiconductor film contains titanium oxide particles adsorbing the photosensitizers (i) to (iii) in a total amount of 77% by weight or more, preferably 87 to 98% by weight. Is desirable.

Moreover, if necessary, a titanium oxide component other than the titanium oxide particles adsorbing each photosensitizer may be included.
Further, the adsorption amount (total amount) of the photosensitizer on the porous semiconductor film is 150 μg or more, preferably 200 μg or more per specific surface area (cm ² ).
Titanium oxide component The porous metal oxide semiconductor film of the present invention may contain titanium oxide derived from peroxytitanic acid, if necessary.

  When titanium oxide derived from peroxytitanic acid is contained, a porous metal oxide semiconductor film that is dense and excellent in strength and excellent in electron mobility can be obtained, and the adsorption amount of the photosensitizer is further increased. As a result, the photoelectric conversion efficiency may be improved.

  The content of titanium oxide derived from peroxytitanic acid in the porous metal oxide semiconductor film is 30% by weight or less of the total solid content of the titanium oxide particles adsorbing the photosensitizers (i) to (iii). Further, it is preferably in the range of 15% by weight or less.

By including a titanium oxide component derived from peroxytitanic acid, it is possible to improve the adhesion between the semiconductor film and the titanium oxide thin film (1) formed as necessary, and further the strength of the semiconductor film itself. The effect of increasing the adsorption amount of the photosensitizer and the effect of improving the photoelectric conversion efficiency can be sufficiently exhibited.

The film thickness of the porous metal oxide semiconductor film is preferably in the range of 0.1 to 50 μm, more preferably 0.5 to 25 μm.
If the porous metal oxide semiconductor film is thin, the semiconductor film is too thin to obtain sufficient photoelectric conversion efficiency. Even if the porous metal oxide semiconductor film is too thick, electron transfer is suppressed and the photoelectric conversion efficiency tends to decrease.

The pore volume of the porous metal oxide semiconductor film is preferably in the range of 0.10 to 0.80 ml / g, more preferably 0.20 to 0.65 ml / g. If the pore volume is too small, the diffusibility of the electrolyte may be reduced, causing back current, and conversion efficiency may be insufficient. If it is too large, the strength of the porous metal oxide semiconductor film may be insufficient.

Such a porous metal oxide semiconductor film can be produced by applying and drying a porous metal oxide semiconductor film-forming paint described later on the electrode layer surface.
The electrolyte layer electrolyte, a mixture of at least one compound forming a redox system is used in conjunction with electrochemically active salt.

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, water, alcohols, oligoethers, carbonates such as propionate carbonate, phosphate esters, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, N-vinylpyrrolidone, sulfolane 66 sulfur compound, ethylene carbonate, acetonitrile , Γ-butyrolactone and the like.
[Porous metal oxide semiconductor film-forming paint for photovoltaic cells]
The coating for forming a porous metal oxide semiconductor film for photoelectric cells according to the present invention comprises (i) titanium oxide particles adsorbing a visible light absorbing photosensitizer, and (ii) an infrared absorbing photosensitizer from near infrared. And / or (iii) titanium oxide particles adsorbing a near-ultraviolet absorbing photosensitizer,
It is characterized by comprising a dispersion medium and a thickener.
Titanium oxide particles
As the titanium oxide particles adsorbing the photosensitizers (i) to (iii), the titanium oxide particles adsorbing the above-described photosensitizer are used, and the ratio thereof is also used as described above.
As the dispersion medium of the dispersion medium coating, at least one selected from water, alcohols, ketones, glycols, ethers, and terpines is used.

  Specifically, methanol, ethanol, isopropyl alcohol, butanol, etc. as alcohols, glycols, such as acetone, ethylene glycol, propylene glycol, etc. as ketones, butyl carbitol, butyl carbitol acetate, etc. as ethers, terpine Examples include terpineol, dihydroterpineol, terpineolene and the like.

The solvent is appropriately selected according to the coating method. In the screen printing method, a paint dispersed in a solvent such as terpineol or butyl carbitol is preferably used. Further, in a printing method that requires quick drying, an aqueous dispersion medium containing water and relatively low boiling point alcohols such as methanol, ethanol, isopropyl alcohol, and butanol is used as the titanium oxide particles, which are used as necessary. It can be preferably used because it can uniformly disperse or dissolve the adhesive, and after the titanium oxide particle layer is formed on the base material, the dispersion medium easily evaporates during drying.
Thickener The paint of the present invention may contain a thickener. Examples of the thickener include polyethylene glycol, polyacetylene, polyethylene oxide, polyvinylpyrrolidone, hydroxypropylcellulose, polyacrylic acid, ethylcellulose, methylcellulose, carboxy. Examples include methyl methyl cellulose, polyvinyl alcohol, acrylic resin, ketone resin, and melamine resin. When such a thickener is contained in the coating material for forming a porous metal oxide semiconductor film, the viscosity of the coating material is increased, thereby enabling uniform application, and the pore volume and pore diameter described above. A porous metal oxide semiconductor film having the following can be obtained.

  The concentration of the thickener in the coating material for forming a porous metal oxide semiconductor film varies depending on the type of the thickener, but is preferably 30% by weight or less, more preferably 5% by weight or less. If the concentration of the thickening agent is too low, the effect of using the thickening agent is insufficient, and if the coating film exceeds 30% by weight, the coatability decreases and the strength of the resulting semiconductor film becomes insufficient. It may be difficult to completely remove the thickener, and a sufficient photoelectric conversion efficiency improvement effect may not be obtained.

  The concentration of the titanium oxide particles in the coating for forming a porous metal oxide semiconductor film (total concentration when peroxytitanic acid is included) is in the range of 1 to 30% by weight, further 2 to 20% by weight as titanium oxide. Preferably there is. If the concentration is low, a porous metal oxide semiconductor film having a desired thickness may not be formed by a single operation, and a repeated operation is required. If the concentration is too high, the viscosity of the dispersion increases, the density of the resulting porous 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.

  The porous metal oxide semiconductor film-forming coating material may contain peroxytitanic acid. When peroxytitanic acid is contained, a porous metal oxide semiconductor film that is dense and excellent in strength and excellent in electron mobility is obtained, and the adsorption amount of the photosensitizer is increased, resulting in photoelectric conversion efficiency. Will improve. The amount of peroxytitanic acid used in the paint is preferably 30% by weight or less, more preferably 15% by weight or less of titanium oxide particles as titanium oxide.

  If the amount of peroxytitanic acid used is small, the adhesion with the titanium oxide thin film or electrode to be provided, the effect of improving the strength of the semiconductor film, the effect of increasing the adsorption amount of the photosensitizer, the effect of improving the photoelectric conversion efficiency, etc. It may be insufficient. If the amount of peroxytitanic acid used is too large, the above effect will not be further improved and the photoelectric conversion efficiency may decrease.

  Such a coating material for forming a porous metal oxide semiconductor film is applied on the electrode layer or a titanium oxide thin film provided as necessary, dried and then cured by ultraviolet irradiation or cured by heat treatment and annealed. Can be formed.

As a coating method, a dip method, a spinner method, a roll coater method, flexographic printing, a screen printing method, and the like are suitable.
The drying may be performed at any temperature as long as the dispersion medium can be removed, and a conventionally known method can be adopted. Air drying can also be performed, and drying is performed at a temperature lower than the heat treatment temperature. Dry for about 5 hours.

Irradiation with ultraviolet rays varies depending on the content of peroxotitanic acid and the like, but it is sufficient to irradiate the amount necessary to decompose and cure peroxotitanic acid.
In the present invention, the heat treatment is preferably performed at 80 to 200 ° C., more preferably 110 to 160 ° C. for about 1 to 24 hours.

When the heat treatment temperature is high, the photosensitizer may be detached or decomposed, and sufficient photoelectric conversion efficiency may not be obtained. If the heat treatment temperature is too low, the porous metal oxide semiconductor film may be insufficiently cured, depending on the previous drying temperature, and the film strength may be insufficient.

The film thickness of the porous metal oxide semiconductor film thus obtained is preferably in the range of 0.1 to 50 μm.
[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to an Example by these.
[Example 1]
Preparation of Visible Light Absorbing Photosensitizer Adsorbed Titanium Oxide Fine Particles (1), Titanium Oxide Fine Particles (1) Preparation of Ethanol Dispersion Titanium Oxide Sol (manufactured by Catalyst Chemical Industry Co., Ltd .: HPW-18NR, average particle diameter 20 nm, TiO ₂ The solvent was replaced with ethanol by an ultrafiltration membrane method to prepare titanium oxide fine particles (1) ethanol dispersion liquid with a TiO ₂ concentration of 20% by weight.
Preparation of porous titanium oxide fine particle aggregate (1) Titanium oxide sol (manufactured by Catalyst Kasei Kogyo Co., Ltd .: HPW-18NR, average particle diameter 20 nm, TiO ₂ concentration 20% by weight) in 500 g of concentration 4.0 as TiO ₂ A 250% by weight aqueous solution of peroxotitanic acid was mixed and diluted by adding water to prepare a titanium oxide fine particle dispersion having a TiO ₂ concentration of 8% by weight. Next, the dispersion liquid is supplied to the opposed two-fluid nozzle, and the processing liquid amount is 60 L / Hr, the air / liquid ratio is 2000, the air flow rate is Mach 1.1, the drying atmosphere temperature is 120 ° C., and the humidity is 7.2 vol% Spray dried.

The obtained particles were calcined at 550 ° C. for 3 hours to prepare porous titanium oxide fine particle aggregates (1).
The average particle diameter and pore volume of the porous titanium oxide fine particle aggregate (1) were measured, and the results are shown in the table.
-Preparation of Visible Light Absorbing Photosensitizer Solution Separately, an ethanol solution having a B2 dye concentration of 0.1% manufactured by DYESOL was prepared as a photosensitizer.
・ Adsorption of visible light absorption photosensitizer Porous titanium oxide fine particle aggregate (1) and titanium oxide fine particle (1) A mixture of ethanol dispersion in a solid content ratio of 8: 2 is mixed well. dispersed, an ethanol solution 200g of photosensitizer added to a solution 200g prepared as a TiO ₂ concentration of 20 wt% in ethanol, washed with ethanol by ultrafiltration method incidentally stirring for 24 h, TiO ₂ A visible light absorption photosensitizer adsorbed titanium oxide fine particle (1) ethanol dispersion having a concentration of 25% by weight was prepared. The adsorption amount of the photosensitizer is shown in the table.
Preparation of near-infrared absorbing photosensitizer adsorbed titanium oxide fine particles (1) and SnO ₂ doped titanium oxide particles (1-1) Preparation of ethanol dispersion Tin chloride (IV) pentahydrate in weight ratio of titanium chloride aqueous solution The mixture was mixed so that TiO ₂ / SnO ₂ = 92/8, and diluted with pure water to prepare an aqueous solution having a concentration of 5% by weight as a solid content. This aqueous solution was neutralized and hydrolyzed by adding it to 15% by weight ammonia water whose temperature was adjusted to 5 ° C. The pH after addition of the aqueous solution was 10.5. Subsequently, the produced gel was filtered and washed to obtain a complex oxide gel having a solid content of 9% by weight.

The composite oxide gel was diluted with pure water to a solid content concentration of 3% by weight, and 15% by weight.
Prepare a dispersion of titanium oxide fine particles (1) doped with SnO ₂ by hydrothermal treatment at 175 ° C. for 18 hours with an aqueous ammonia solution of pH 10.5, and perform ultrafiltration. The solvent was replaced with ethanol by a membrane method to prepare SnO ₂ doped titanium oxide fine particles (1) ethanol dispersion liquid with a solid content concentration of 20% by weight.
・ Preparation of Porous Titanium Oxide Fine Particle Aggregate (1) The obtained SnO ₂ -doped titanium oxide fine particles (1) were ultrafiltered to a solid content concentration of 25% by weight, and separately prepared ethanol dispersion To 500 g, 250 g of a peroxotitanic acid aqueous solution having a concentration of 4.0% by weight as TiO ₂ was mixed, and diluted by adding water to prepare a titanium oxide fine particle dispersion having a TiO ₂ concentration of 8% by weight. The obtained dispersion liquid is supplied to the opposed two-fluid nozzle, and the processing liquid amount is 60 L / Hr, the air / liquid ratio is 2000, the air flow rate is Mach 1.1, the drying atmosphere temperature is 120 ° C., and the humidity is 7.2 vol%. Spray dried below.

The obtained particles were fired at 450 ° C. for 3 hours to prepare porous SnO ₂ -doped titanium oxide fine particle aggregates (1). The average particle diameter and pore volume of the porous SnO ₂ -doped titanium oxide fine particle aggregate (1) were measured, and the results are shown in Table 1.
-Preparation of near-infrared absorbing photosensitizer solution Separately, an ethanol solution having a concentration of 0.1% by weight of DBL BlackDye manufactured by DYESOL was prepared as a photosensitizer.
Adsorption of near-infrared absorption photosensitizer Porous SnO ₂ doped titanium oxide fine particle aggregate (1) and SnO ₂ doped titanium oxide fine particle (1) ethanol dispersion were mixed so that the solid content ratio was 8: 2. The mixture was thoroughly stirred and dispersed, and 200 g of a photosensitizer ethanol solution was added to 200 g of a solution prepared with ethanol to give a TiO ₂ concentration of 20% by weight. After stirring for 24 hours, ultrafiltration membrane method was used. After washing with ethanol, a near-infrared absorbing photosensitizer-adsorbed SnO ₂ -doped titanium oxide fine particle (1) ethanol dispersion having a TiO ₂ concentration of 25 wt% was prepared. The amount of adsorption of the photosensitizer is shown in Table 1.
Preparation of paint for forming porous metal oxide semiconductor film (1) Visible light absorbing photosensitizer adsorbed titanium oxide fine particles having a TiO ₂ concentration of 20% by weight (1) Ethanol dispersion liquid 75g and a solid concentration of 20% by weight Infrared absorbing photosensitizer adsorbed SnO ₂ doped titanium oxide fine particles (1) Ethanol dispersion 25g was mixed with this, and 1.0g of polyethylene oxide as a thickener was dissolved in ethanol to a concentration of 10% by weight. Mix the solution
Dilution with methanol was performed so that the solid content concentration was 15% by weight to prepare a coating material (1) for forming a porous metal oxide semiconductor film.

Preparation of Peroxytitanic Acid Coating Solution 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 TiO ₂ concentration was 0.5% and the ethylene glycol concentration was 20% to obtain a peroxotitanic acid coating solution.

Formation of Titanium Oxide Thin Film (1) A peroxotitanic acid coating solution (1) was coated on a transparent glass substrate formed with fluorine-doped tin oxide as an electrode by flexographic printing, dried naturally, and then 6000 mJ using a low-pressure mercury lamp. The film was cured by irradiating UV light of / cm ² to decompose the peroxoacid. Furthermore, the titanium oxide thin film (1) was formed by heating and curing at 450 ° C. for 30 minutes for curing and annealing.

The obtained titanium oxide thin film (1) had a thickness of 40 nm, a pore volume determined by a nitrogen adsorption method of 0.12 ml / g, and an average pore diameter of 2 nm.
Formation of porous metal oxide semiconductor film (1) On the transparent glass substrate on which the titanium oxide thin film (1) is formed, that is, the surface of the titanium oxide thin film (1) is coated with a paint for forming a porous metal oxide semiconductor film (1). Coating was performed by a doctor blade method so that the printed film thickness was about 100 μm, and then heat treatment was performed at 150 ° C. for 2 hours to form a porous metal oxide semiconductor film (1).

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: ×
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]
Preparation of near-ultraviolet absorbing photosensitizer adsorbed titanium oxide fine particles (1) Aluminum oxide coated titanium oxide fine particles (1) Preparation of ethanol dispersion Titanium oxide sol (manufactured by Catalyst Chemical Industry Co., Ltd .: HPW-18NR, average particle size 20 nm) , TiO ₂ concentration 20% by weight) in a solution obtained by substituting the ethanol solvent with an ultrafiltration device, a solution obtained by dissolving aluminum triethoxide in ethanol so that the Al ₂ O ₃ concentration becomes 10% by weight is An aluminum oxide precursor is deposited on the surface of titania particles added so that TiO ₂ / Al ₂ O ₃ = 95/5, kept at 50 ° C. for 8 hours, washed with ethanol in an ultrafiltration apparatus, and solid. The partial concentration was adjusted to 20% by weight to obtain an ethanol dispersion of aluminum oxide-coated titanium oxide fine particles (1).
-Preparation of porous aluminum oxide-coated titanium oxide fine particle aggregate (1) The aluminum oxide-coated titanium oxide fine particle (1) was replaced with an aqueous solvent in an ultrafiltration device, and 500 g of a solution prepared to a solid content concentration of 20% by weight was added. 250 g of a 4.0 wt% peroxotitanic acid aqueous solution as TiO ₂ was mixed and diluted with water to prepare a titanium oxide fine particle dispersion having a TiO ₂ concentration of 8 wt%. Next, the dispersion liquid is supplied to the opposed two-fluid nozzle, and the processing liquid amount is 60 L / Hr, the air / liquid ratio is 2000, the air flow rate is Mach 1.1, the drying atmosphere temperature is 120 ° C., and the humidity is 7.2 vol%. Spray dried.

The obtained particles were fired at 450 ° C. for 3 hours to prepare porous aluminum oxide-coated titanium oxide fine particle aggregates (1).
The average particle diameter and pore volume of the porous aluminum oxide-coated titanium oxide fine particle aggregate (1) were measured, and the results are shown in the table.
-Preparation of near-ultraviolet absorbing photosensitizer solution Separately, an ethanol solution having a D131 dye concentration of 0.1% made by Mitsubishi Paper Industries was prepared as a photosensitizer.
-Adsorption of near-ultraviolet absorbing photosensitizer Porous aluminum oxide coated titanium oxide fine particle aggregate (1) and aluminum oxide coated titanium oxide fine particle (1) ethanol dispersion were mixed so that the solid content ratio was 8: 2. The mixture was thoroughly stirred and dispersed, and 200 g of a photosensitizer ethanol solution was added to 200 g of a solution prepared with ethanol to give a TiO ₂ concentration of 20% by weight. After stirring for 24 hours, ultrafiltration membrane method was used. It was washed with ethanol to prepare a near-ultraviolet photosensitizer adsorbed aluminum oxide coated titanium oxide fine particle (1) ethanol dispersion having a TiO ₂ concentration of 25% by weight.
The adsorption amount of the photosensitizer is shown in the table.

Preparation of paint for forming porous metal oxide semiconductor film (2) Next, in the same manner as in Example 1, visible light absorbing photosensitizer adsorbed titanium oxide fine particles having a TiO ₂ concentration of 20% by weight (1) Ethanol dispersion 65 g And 20 g of a near-infrared absorbing photosensitizer adsorbed with a solid concentration of 20 wt%, SnO ₂ -doped titanium oxide fine particles (1) 20 g of an ethanol dispersion, and a near-ultraviolet absorbing photosensitizer with a solid concentration of 20 wt% obtained above. Adsorbed aluminum oxide coated titanium oxide fine particles (1) Ethanol dispersion (15 g) was mixed, and a solution obtained by dissolving 1.0 g of polyethylene oxide as a thickener in ethanol to a concentration of 10% by weight was mixed. Dilution with methanol was performed so that the solid content concentration was 15% by weight to prepare a coating material (2) for forming a porous metal oxide semiconductor film.
Formation of porous metal oxide semiconductor film (2) In Example 1, the porous metal oxide semiconductor film (2) was formed in the same manner except that the paint (2) for forming a porous metal oxide semiconductor film was used. did.

The film thickness, pore volume, average pore diameter and adhesion of the obtained porous metal oxide semiconductor film (2) were evaluated, and the results are shown in Table 1.
Production of Photoelectric Cell (2) A photoelectric cell (2) was produced in the same manner as in Example 1 except that the porous metal oxide semiconductor film (2) was used.

With respect to the photoelectric cell (2), Voc, Joc, FF and η were measured, and the results are shown in Table 1.
[Example 3]
Preparation of Visible Light Absorbing Photosensitizer Adsorbed Titanium Oxide Particles (2) Preparation of Ethanol Dispersion of Porous Titanium Oxide Fine Particle Aggregate (2) The titanium oxide sol used in Example 1 was manufactured by JGC Catalysts & Chemicals Co., Ltd. HPW-18NR, average particle size 20 nm, TiO ₂ concentration 20% by weight, manufactured by JGC Catalysts & Chemicals, Inc .: HPW-200C
, HPW-18NR / HPW with an average particle diameter of 200 nm and a TiO ₂ concentration of 20 wt% in a weight ratio
It was prepared in the same manner except that a mixture of -200C = 4/1 was used. The average particle diameter of the porous titanium oxide fine particle aggregate (2) is 2.5 μm, and the pore volume is 0.52 ml / g.
Met.

Next, the porous titanium oxide fine particle aggregate (2) is dispersed in ethanol to obtain a TiO ₂ concentration of 20
A weight% porous titanium oxide fine particle aggregate (2) ethanol dispersion was prepared.
Separately, an ethanol solution having a concentration of 0.1% by weight of B2 dye manufactured by DYESOL was prepared as a photosensitizer.
-Adsorption of visible light absorption photosensitizer Porous titanium oxide fine particle aggregate (2) and titanium oxide fine particle (1) A mixture of ethanol dispersion in a solid content ratio of 8: 2 is mixed well. 200 g of the photosensitizer ethanol solution was added to 200 g of a solution prepared by dispersing and preparing a TiO ₂ concentration of 20% by weight in ethanol, stirred for 24 hours, and then washed with ethanol by the ultrafiltration membrane method. Then, a visible light absorption photosensitizer adsorbed titanium oxide particle (2) ethanol dispersion having a TiO ₂ concentration of 25% by weight was prepared.
The adsorption amount of the photosensitizer is shown in the table.
Preparation of near-infrared absorption photosensitizer adsorbed titanium oxide fine particles (2) and preparation of porous SnO ₂ doped titanium oxide fine particles aggregate (2) The solid content concentration of SnO ₂ doped titanium oxide fine particles (1) is 20% by weight. Then, 100 g of HPW-200C manufactured by JGC Catalysts Co., Ltd. was added to 400 g of the prepared solution, and 250 g of a peroxotitanic acid aqueous solution having a concentration of 4.0% by weight as TiO ₂ was mixed. The mixture was diluted with water to prepare a titanium oxide fine particle dispersion having a TiO ₂ concentration of 8% by weight. Next, the dispersion liquid is supplied to the opposed two-fluid nozzle, and the processing liquid amount is 60 L / Hr, the air / liquid ratio is 2000, the air flow rate is Mach 1.1, the drying atmosphere temperature is 120 ° C., and the humidity is 7.2 vol%. Spray dried.

The obtained particles were calcined at 450 ° C. for 3 hours to prepare porous SnO ₂ -doped titanium oxide fine particle aggregates (2). The average particle diameter and pore volume of the porous SnO ₂ -doped titanium oxide fine particle aggregate (2) were measured, and the results are shown in the table.
-Adsorption of near-infrared absorbing photosensitizer Separately, an ethanol solution having a concentration of 0.1 wt% DBL BlackDye manufactured by DYESOL was prepared as a photosensitizer. Porous SnO ₂ -doped titanium oxide fine particle aggregate (2) and SnO ₂ -doped titanium oxide fine particle (1) Ethanol dispersion mixed to a solid content ratio of 8: 2 was thoroughly stirred and dispersed to obtain ethanol. 200 g of a photosensitizer ethanol solution was added to 200 g of the solution prepared so as to have a TiO ₂ concentration of 20% by weight, stirred for 24 hours, washed with ethanol by an ultrafiltration membrane method, and a TiO ₂ concentration of 25 wt. % Near-infrared absorbing photosensitizer adsorbed SnO ₂ doped titanium oxide particles (2) ethanol dispersion. The adsorption amount of the photosensitizer is shown in the table.
Preparation of Porous Metal Oxide Semiconductor Film Forming Paint (3) In the same manner as in Example 1, TiO ₂ concentration 20 wt% visible light absorbing photosensitizer adsorbed titanium oxide particles (2) 65 g ethanol dispersion, Near-infrared absorption photosensitizer adsorption S with a solid content of 20% by weight
nO ₂ -doped titanium oxide particles (2) 20 g of an ethanol dispersion and a near-ultraviolet absorbing photosensitizer adsorbed aluminum oxide coated titanium oxide fine particles (1) 15 g of an ethanol dispersion with a solid concentration of 20% by weight were mixed. Then, a solution prepared by dissolving 1.0 g of polyethylene oxide as a thickener in ethanol so that the concentration becomes 10% by weight is mixed, diluted with methanol so that the solid content concentration becomes 15% by weight, and porous metal oxide A coating for forming a semiconductor film (3) was prepared.

Formation of porous metal oxide semiconductor film (3) In Example 1, the porous metal oxide semiconductor film (3) was formed in the same manner except that the paint (3) for forming a porous metal oxide semiconductor film was used. did.

The film thickness, pore volume, average pore diameter and adhesion of the obtained porous metal oxide semiconductor film (3) were evaluated, and the results are shown in Table 1.
Production of Photoelectric Cell (3) A photoelectric cell (3) was produced in the same manner as in Example 1 except that the porous metal oxide semiconductor film (3) was used.

With respect to the photoelectric cell (3), Voc, Joc, FF and η were measured, and the results are shown in Table 1.
[Example 4]
Visible light absorption photosensitizer adsorbed acid porous titanium oxide fine particles (3)
In Example 3, a visible light absorbing photosensitizer adsorbing acid was used in the same manner except that a DYESOL B4 dye was used instead of DYESOL B2 dye as a photosensitizer and an ethanol solution having a concentration of 0.1% by weight was used. Porous titanium oxide fine particles (3) ethanol dispersion was prepared. The adsorption amount of the photosensitizer is shown in the table.
Preparation of near-infrared absorption photosensitizer adsorbed titanium oxide particles (3) Preparation of Nb ₂ O ₅ doped titanium oxide particles (3) Niobium chloride (V) in a titanium chloride aqueous solution by weight ratio TiO ₂ / Nb ₂ O ₅ = 92/8 was mixed and diluted with pure water to prepare an aqueous solution having a concentration of 5% by weight as a solid content. This aqueous solution was neutralized and hydrolyzed by adding it to 15% by weight ammonia water whose temperature was adjusted to 5 ° C. The pH after addition of the aqueous solution was 10.0. Subsequently, the produced gel was filtered and washed to obtain a complex oxide gel having a solid content of 9% by weight.

The composite oxide gel was diluted with pure water to a solid content concentration of 3% by weight, and 15% by weight.
The aqueous solution was adjusted to pH 10.5 with an aqueous ammonia solution, and then hydrothermally treated at 175 ° C. for 18 hours to prepare a dispersion of titanium oxide particles (3) doped with Nb ₂ O ₅ . The solvent was replaced with ethanol by an ultrafiltration membrane method to prepare Nb ₂ O ₅ doped titanium oxide particles (3) ethanol dispersion liquid having a solid content concentration of 20% by weight.
・ Preparation of porous Nb ₂ O ₅ doped titanium oxide fine particle aggregate (3) Ultrafiltration of Nb ₂ O ₅ doped titanium oxide particles (3) to a solid content concentration of 20% by weight, and 500 g of the prepared solution The mixture was mixed with 250 g of a peroxotitanic acid aqueous solution having a concentration of 4.0% by weight as TiO ₂ , and diluted by adding water to prepare a titanium oxide fine particle dispersion having a TiO ₂ concentration of 8% by weight. Next, the dispersion liquid is supplied to the opposed two-fluid nozzle, and the processing liquid amount is 60 L / Hr, the air / liquid ratio is 2000, the air flow rate is Mach 1.1, the drying atmosphere temperature is 120 ° C., and the humidity is 7.2 vol%. Spray dried.

The obtained particles were fired at 450 ° C. for 3 hours to prepare porous Nb ₂ O ₅ -doped titanium oxide fine particle aggregates (3).
-Adsorption of near-infrared absorbing photosensitizer Separately, an ethanol solution having a concentration of 0.1 wt% DBL BlackDye manufactured by DYESOL was prepared as a photosensitizer. A mixture of porous Nb ₂ O ₅ -doped titanium oxide fine particle aggregate (3) and Nb ₂ O ₅ -doped titanium oxide particles (3) ethanol dispersion in a solid content ratio of 8: 2 was thoroughly stirred. 200 g of an ethanol solution of a photosensitizer was added to 200 g of a solution prepared by dispersing and preparing a 20% by weight TiO ₂ concentration in ethanol, stirred for 24 hours, and then washed with ethanol by an ultrafiltration membrane method. ₂ Nb ₂ O ₅ doped titanium oxide particles (3) ethanol dispersion liquid with a near infrared absorption photosensitizer adsorbing concentration of 25% by weight was prepared. The adsorption amount of the photosensitizer is shown in the table.

Preparation of paint for forming porous metal oxide semiconductor film (4) In the same manner as in Example 1, TiO ₂ concentration 20 wt% visible light absorbing photosensitizer adsorbed titanium oxide particles (3) ethanol dispersion 65 g, Adsorption N of near-infrared absorption photosensitizer with a solid content of 20% by weight
b ₂ O ₅ doped titanium oxide particles (3) 20 g of ethanol dispersion and solid content concentration of 20 in Example 2
Weight% near UV absorption photosensitizer adsorbed aluminum oxide coated titanium oxide fine particles (1)
Ethanol dispersion (15 g) was mixed, and polyethylene oxide 1.
A solution prepared by dissolving 0 g in ethanol so that the concentration becomes 10% by weight is mixed, diluted with methanol so that the solid content concentration becomes 15% by weight, and a coating for forming a porous metal oxide semiconductor film (4)
Was prepared.

Formation of porous metal oxide semiconductor film (4) The porous metal oxide semiconductor film (4) was formed in the same manner as in Example 1 except that the paint (4) for forming a porous metal oxide semiconductor film was used. did.

The film thickness, pore volume, average pore diameter and adhesion of the obtained porous metal oxide semiconductor film (4) were evaluated, and the results are shown in Table 1.
Production of Photoelectric Cell (4) A photoelectric cell (4) was produced in the same manner as in Example 1 except that the porous metal oxide semiconductor film (4) was used.

With respect to the photoelectric cell (4), Voc, Joc, FF and η were measured and the results are shown in Table 1.
[Example 5]
As the visible light absorbing photosensitizer adsorbing acid porous titanium oxide fine particles, the same visible light absorbing photosensitizer adsorbing acid porous titanium oxide fine particles (3) as in Example 4 were used, and an ethanol dispersion was similarly prepared. did. The adsorption amount of the photosensitizer is shown in the table.
Preparation of near-infrared absorbing photosensitizer adsorbed titanium oxide particles (4) Preparation of ZrO ₂ -doped titanium oxide particles (4) Zirconium oxychloride in a titanium chloride aqueous solution has a weight ratio of TiO ₂ / ZrO ₂ = 92/8 Then, the mixture was diluted with pure water to prepare an aqueous solution having a concentration of 5% by weight as a solid content. This aqueous solution was neutralized and hydrolyzed by adding it to 15% by weight ammonia water whose temperature was adjusted to 5 ° C. The pH after addition of the aqueous solution was 10.3. Subsequently, the produced gel was filtered and washed to obtain a complex oxide gel having a solid content of 9% by weight.

The composite oxide gel was diluted with pure water to a solid content concentration of 3% by weight, and 15% by weight.
Then, a pH of 10.5 was adjusted with an aqueous ammonia solution, followed by hydrothermal treatment at 175 ° C. for 18 hours to prepare a dispersion of titanium oxide particles (4) doped with ZrO ₂ .
Subsequently, the solvent was replaced with ethanol by an ultrafiltration membrane method, and ZrO ₂ having a solid content concentration of 20% by weight.
Doped titanium oxide particles (4) An ethanol dispersion was prepared.
- porous ZrO ₂ performs doped titanium oxide fine particle aggregates ultrafiltration as (4) Preparation of ZrO ₂ doped titanium oxide particles (4) that the solid content concentration of 20 wt%, as TiO ₂ in the prepared solution 500g A peroxotitanic acid aqueous solution (250 g) having a concentration of 4.0% by weight was mixed and diluted with water to prepare a titanium oxide fine particle dispersion having a TiO ₂ concentration of 8% by weight. Next, the dispersion liquid is supplied to the opposed two-fluid nozzle, and the processing liquid amount is 60 L / Hr, the air / liquid ratio is 2000, the air flow rate is Mach 1.1, the drying atmosphere temperature is 120 ° C., and the humidity is 7.2 vol%. Spray dried.

The obtained particles were fired at 450 ° C. for 3 hours to prepare porous ZrO ₂ -doped titanium oxide fine particle aggregates (4).
-Adsorption of near-infrared absorbing photosensitizer Separately, an ethanol solution having a concentration of 0.1 wt% DBL BlackDye manufactured by DYESOL was prepared as a photosensitizer.

A mixture of porous ZrO ₂ -doped titanium oxide fine particle aggregate (4) and ZrO ₂ -doped titanium oxide particles (4) in an ethanol dispersion having a solid content ratio of 8: 2 is thoroughly stirred and dispersed to obtain ethanol. 200 g of a photosensitizer ethanol solution was added to 200 g of the solution prepared so as to have a TiO ₂ concentration of 20% by weight, stirred for 24 hours, washed with ethanol by an ultrafiltration membrane method, and a TiO ₂ concentration of 25 wt. % Near infrared absorption photosensitizer adsorbed ZrO ₂ doped titanium oxide particles (4) ethanol dispersion liquid was prepared.
Preparation of near-UV absorbing photosensitizer adsorbed titanium oxide particles (2) and magnesium oxide coated titanium oxide particles (2).

In a solution in which titanium oxide sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: HPW-18NR, average particle size 20 nm, TiO ₂ concentration 20% by weight) is replaced with ethanol solvent by an ultrafiltration device, magnesium ethoxide is ethanol and MgO concentration A magnesium oxide precursor was deposited on the surface of titania particles added with a solution of 10% by weight so that the weight ratio was TiO ₂ / MgO = 95/5, and held at 50 ° C. for 8 hours. Then, it was washed with ethanol in an ultrafiltration device, and the solid content concentration was adjusted to 20% by weight to obtain magnesium oxide-coated titanium oxide particles (2).
Preparation of porous magnesium oxide coated titanium oxide fine particles (2) Magnesium oxide coated titanium oxide particles (2) were replaced with an aqueous solvent by an ultrafiltration device, and TiO ₂ was added to 500 g of a solution prepared to a solid content concentration of 20% by weight. As a mixture, 250 g of a peroxotitanic acid aqueous solution having a concentration of 4.0 wt% was mixed and diluted with water to prepare a titanium oxide fine particle dispersion having a TiO ₂ concentration of 8 wt%. Next, the dispersion liquid is supplied to the opposed two-fluid nozzle, and the processing liquid amount is 60 L / Hr, the air / liquid ratio is 2000, the air flow rate is Mach 1.1, the drying atmosphere temperature is 120 ° C., and the humidity is 7.2 vol%. Spray dried.

The obtained particles were calcined at 450 ° C. for 3 hours to prepare porous magnesium oxide-coated titanium oxide fine particle aggregates (2).
The average particle diameter and pore volume of the porous magnesium oxide-coated titanium oxide fine particle aggregate (2) were measured, and the results are shown in the table.
-Adsorption of visible light absorption photosensitizer Separately, an ethanol solution with a concentration of 0.1% of D131 dye manufactured by Mitsubishi Paper Industries was prepared as a photosensitizer.

Porous magnesium oxide-coated titanium oxide fine particle aggregate (2) and magnesium oxide-coated titanium oxide particles (2) Ethanol dispersion mixed to a solid content ratio of 8: 2 is thoroughly stirred and dispersed to obtain ethanol. 200 g of a photosensitizer ethanol solution was added to 200 g of the solution prepared so as to have a TiO ₂ concentration of 20% by weight, stirred for 24 hours, washed with ethanol by an ultrafiltration membrane method, and a TiO ₂ concentration of 25 wt. % Visible light absorption photosensitizer adsorbed magnesium oxide coated titanium oxide particles (2) ethanol dispersion liquid was prepared.

Preparation of paint for forming porous metal oxide semiconductor film (5) Next, in the same manner as in Example 1, visible light absorbing photosensitizer adsorbed titanium oxide particles having a TiO ₂ concentration of 20% by weight (3) Ethanol dispersion 65 g And 20 g of near-infrared absorbing photosensitizer adsorbed ZrO ₂ doped titanium oxide particles (4) ethanol dispersion liquid with a solid content concentration of 20% by weight and a near-UV absorbing photosensitizer adsorbed magnesium oxide coating with a solid content concentration of 20 wt% Titanium oxide particles (2) 15 g of an ethanol dispersion was mixed, and a solution obtained by dissolving 1.0 g of polyethylene oxide as a thickener in ethanol to a concentration of 10% by weight was mixed. It was diluted with methanol so as to be 15% by weight, and a coating material (5) for forming a porous metal oxide semiconductor film was prepared.

Formation of porous metal oxide semiconductor film (5) In Example 1, the porous metal oxide semiconductor film (5) was formed in the same manner except that the paint (5) for forming a porous metal oxide semiconductor film was used. did.

The film thickness, pore volume, average pore diameter and adhesion of the obtained porous metal oxide semiconductor film (5) were evaluated, and the results are shown in Table 1.
Production of Photoelectric Cell (5) A photoelectric cell (5) was produced in the same manner as in Example 1 except that the porous metal oxide semiconductor film (5) was used.

With respect to the photoelectric cell (5), Voc, Joc, FF and η were measured, and the results are shown in Table 1.
[Comparative Example 1]
Preparation of Porous Metal Oxide Semiconductor Film Coating (R1) Visible Light Absorbing Photosensitizer Adsorbed Titanium Oxide Particles (R1) Ethanol Dispersion 100 g Prepared as in Example 1 with a TiO ₂ Concentration of 20% by Weight Polyethylene oxide 1.0 as a thickener
A solution in which g is dissolved in ethanol so that the concentration becomes 10% by weight is mixed, and further diluted with methanol so that the solid content concentration becomes 15% by weight, and the coating for forming a porous metal oxide semiconductor film (R1) Was prepared.

Formation of porous metal oxide semiconductor film (R1) In Example 1, the porous metal oxide semiconductor film (R1) was formed in the same manner except that the coating material (R1) for forming the porous metal oxide semiconductor film was used. did.

The film thickness, pore volume, average pore diameter and adhesion of the obtained porous metal oxide semiconductor film (R1) were evaluated, and the results are shown in Table 1.
Production of Photoelectric Cell (R1) A photoelectric cell (R1) was produced in the same manner as in Example 1 except that the porous metal oxide semiconductor film (R1) was used.

With respect to the photoelectric cell (R1), Voc, Joc, FF and η were measured and the results are shown in Table 1.
[Comparative Example 2]
Preparation of paint for forming porous metal oxide semiconductor film (R2)
Preparation of titanium oxide fine particle (1) alcohol dispersion liquid In Example 1, the porous titanium oxide fine particle aggregate (1) and the titanium oxide fine particle (1) ethanol dispersion liquid had a solid content ratio of 8: 2. In this way, a titanium oxide particle ethanol dispersion (R2) was prepared so that the solid concentration was 20% by weight.

Preparation of SnO ₂ -doped titanium oxide fine particles (1) alcohol dispersion In Example 1, porous SnO ₂ -doped titanium oxide fine particles aggregate (1) and SnO ₂ -doped titanium oxide fine particles (1) ethanol dispersion in solid content ratio A mixture prepared so as to have a ratio of 8: 2 and a solid content concentration of 20% by weight was used as an SnO ₂ -doped titanium oxide particle alcohol dispersion (R2).

Preparation of aluminum oxide-coated titanium oxide fine particles (1) alcohol dispersion In Example 1, porous aluminum oxide-coated titanium oxide fine particle aggregate (1) and aluminum oxide-coated titanium oxide fine particles (1) A mixture prepared so as to be 8: 2 and having a solid content concentration of 20% by weight was used as an aluminum oxide-coated titanium oxide particle alcohol dispersion (R2).
Next, 65 g of titanium oxide particle ethanol dispersion (R2), 20 g of SnO ₂ doped titanium oxide particle alcohol dispersion (R2), and 15 g of aluminum oxide-coated titanium oxide particle alcohol dispersion (R2) were mixed. A porous metal oxide semiconductor is prepared by mixing a solution obtained by dissolving 1.0 g of polyethylene oxide as a thickener with ethanol so that the concentration becomes 10% by weight and diluting with methanol so that the solid content concentration becomes 15% by weight. A film-forming paint (R2) was prepared.

Formation of porous metal oxide semiconductor film (R2) In Example 1, the porous metal oxide semiconductor film (R1) was formed in the same manner except that the coating material (R2) for forming the porous metal oxide semiconductor film was used. did.

The film thickness, pore volume, average pore diameter, and adhesion of the obtained porous metal oxide semiconductor film (R2) were evaluated, and the results are shown in Table 1.
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%. Porous metal oxide semiconductor film (R2) formed glass is immersed in this solution for 5 hours, taken out, washed with an aqueous ethanol solution, and adsorbed with a visible light absorbing photosensitizer. (R2) was prepared. The adsorption amount of the visible light absorbing photosensitizer was calculated from the difference in concentration of the dye solution after use and is shown in the table.

  Next, an ethanol solution was prepared so that DBL BlackDye manufactured by DYESOL as a photosensitizer had a concentration of 0.1% by weight. A porous metal oxide semiconductor film (R2) adsorbed with a visible light absorbing photosensitizer in this solution was immersed for 5 hours, then taken out and washed with an aqueous ethanol solution to adsorb a near infrared absorbing photosensitizer. A porous metal oxide semiconductor film (R2) was prepared. The adsorption amount of the near-infrared absorbing photosensitizer was calculated from the difference in concentration of the dye solution used and shown in the table.

  Next, an ethanol solution was prepared so that the concentration of D131 dye manufactured by Mitsubishi Paper Industries was 0.1 wt% as a photosensitizer. A porous metal oxide semiconductor film (R2) adsorbed with a visible light absorbing photosensitizer / near infrared absorbing photosensitizer is immersed in this solution for 5 hours, taken out, washed with an aqueous ethanol solution, and absorbed by near ultraviolet rays. A porous metal oxide semiconductor film (R2) adsorbed with a photosensitizer was prepared. The adsorption amount of the near-ultraviolet absorbing photosensitizer obtained from the difference in concentration of the photosensitizer before and after the immersion is shown in the table.

Next, the porous metal oxide semiconductor film (R2) adsorbing three kinds of photosensitizers was dried at 450 ° C. for 2 hours.
Preparation of photoelectric cell (2) In Example 1, a photoelectric cell (R2) was prepared in the same manner except that a porous metal oxide semiconductor film (R2) adsorbing three kinds of photosensitizers was used. did.

With respect to the photoelectric cell (R2), Voc, Joc, FF and η were measured and the results are shown in Table 1.
[Comparative Example 3]
Formation of Porous Metal Oxide Semiconductor Film (R3) In Example 2, the porous metal oxide semiconductor film (R3) was formed by performing heat treatment (baking annealing) at 250 ° C. when creating the porous metal oxide semiconductor film. Formed.

The film thickness, pore volume, average pore diameter and adhesion of the obtained porous metal oxide semiconductor film (R3) were evaluated, and the results are shown in Table 1.
Production of Photoelectric Cell (R3) A photoelectric cell (R3) was produced in the same manner as in Example 1 except that the porous metal oxide semiconductor film (R3) was used.

With respect to the photoelectric cell (R3), Voc, Joc, FF and η were measured and the results are shown in Table 1.
[Comparative Example 4]
Preparation of Porous Metal Oxide Semiconductor Film Forming Paint (R4 ) 100 g of titanium oxide sol (manufactured by Catalyst Kasei Kogyo Co., Ltd .: HPW-18NR, average particle diameter 20 nm, TiO ₂ concentration 20% by weight) is used as an ultrafiltration membrane method. Then, the solvent was replaced with ethanol to prepare a titanium oxide fine particle (1) ethanol dispersion liquid having a TiO ₂ concentration of 20% by weight. To this, a solution obtained by dissolving 1.0 g of polyethylene oxide as a thickener in ethanol so that the concentration becomes 10% by weight is mixed, and diluted with methanol so that the solid content concentration becomes 15% by weight. A paint (R4) for forming an oxide semiconductor film was prepared.

Formation of porous metal oxide semiconductor film (R4) On the transparent glass substrate on which the titanium oxide thin film (1) was formed in the same manner as in Example 1, the coating for forming the porous metal oxide semiconductor film (R4) Was applied by a doctor blade method so as to be about 100 μm, followed by heat treatment at 150 ° C. for 2 hours to form a porous metal oxide semiconductor film (R4).

The film thickness, pore volume, average pore diameter and adhesion of the obtained porous metal oxide semiconductor film (R4) were evaluated, and the results are shown in Table 1.
As an adsorption photosensitizer for the photosensitizer, an ethanol solution was prepared so that a concentration of 0.1% by weight of B2 dye manufactured by DYESOL was used. Porous metal oxide semiconductor film (R4) formed glass is immersed in this solution for 5 hours, then taken out and washed with an aqueous ethanol solution to adsorb the visible light absorbing photosensitizer. (R4) was prepared. The adsorption amount of the visible light absorbing photosensitizer was calculated from the difference in concentration of the dye solution used, and is shown in the table.
Production of Photoelectric Cell (R4) A photoelectric cell (R4) was produced in the same manner as in Example 1 except that the porous metal oxide semiconductor film (R4) was used.

  With respect to the photoelectric cell (R4), Voc, Joc, FF and η were measured and the results are shown in Table 1.

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 (8)

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 disposed so that the electrode layer (1) and the electrode layer (2) face each other, and the porous metal oxide semiconductor film (1)
In the photoelectric cell in which an electrolyte layer is provided between the electrode layer (2) and
Porous metal oxide semiconductor film (1)
(i) titanium oxide particles adsorbed with a visible light absorbing photosensitizer,
comprising (ii) titanium oxide particles adsorbing an infrared absorbing photosensitizer from near infrared and / or (iii) titanium oxide particles adsorbing a near ultraviolet absorbing photosensitizer,
Titanium oxide particles that adsorb the photosensitizers (i) to (iii) are each titanium oxide fine particles having an average particle diameter in the range of 5 to 200 nm,
It consists of a mixture with an aggregate of porous titanium oxide fine particles having an average particle diameter in the range of 0.5 to 10 μm and a pore volume in the range of 0.1 to 0.8 ml / g,
A photoelectric cell comprising the porous metal oxide semiconductor film (1) obtained by heat treatment at 80 to 200 ° C. (Ii) Titanium oxide particles adsorbing an infrared absorbing photosensitizer from near infrared rays are Nb, Zr, Ge
Including fine titanium oxide particles (A) doped with one or more elements selected from Hf, W, Ce, Sn, and Fe,
(Iii) Titanium oxide fine particles coated with one or more oxides selected from aluminum oxide, silicon oxide, zirconium oxide, magnesium oxide, calcium oxide and yttrium oxide as titanium oxide particles adsorbing the near-ultraviolet absorbing photosensitizer The photoelectric cell according to claim 1, comprising (B).   The photoelectric cell according to claim 1, wherein the porous titanium oxide aggregate includes titanium oxide fine particles and a peroxotitanate binder. The titanium oxide thin film (1) derived from peroxotitanic acid is provided between the electrode layer (1) and the porous metal oxide semiconductor film (1). A photoelectric cell according to claim 1. The thickness of the titanium oxide thin film (1) is in the range of 10 to 70 nm, and the pore volume is 0.01 to
The photoelectric cell according to any one of claims 1 to 4, wherein the photoelectric cell is in the range of 0.20 ml / g and the average pore diameter is in the range of 0.5 to 5.0 nm. (i) titanium oxide particles adsorbed with a visible light absorbing photosensitizer,
(ii) titanium oxide particles adsorbing an infrared absorbing photosensitizer from near infrared and / or (iii)
Titanium oxide particles adsorbed with a near-ultraviolet absorbing photosensitizer,
A dispersion medium;
A thickener and
Titanium oxide particles that adsorb the photosensitizers (i) to (iii) are each titanium oxide fine particles having an average particle diameter in the range of 5 to 200 nm,
Photoelectricity comprising a mixture of porous titanium oxide fine particle aggregates having an average particle diameter in the range of 0.5 to 10 μm and a pore volume in the range of 0.1 to 0.8 ml / g Paint for forming porous metal oxide semiconductor film for cells.   The said porous titanium oxide aggregate contains a titanium oxide fine particle and a peroxotitanate binder, The coating material for porous metal oxide semiconductor film formation for photoelectric cells of Claim 6 characterized by the above-mentioned. (Ii) Titanium oxide particles adsorbing an infrared absorbing photosensitizer from near infrared rays are Nb, Zr, Ge
Including fine titanium oxide particles (A) doped with one or more elements selected from Hf, W, Ce, Sn, and Fe,
(Iii) Titanium oxide fine particles coated with one or more oxides selected from aluminum oxide, silicon oxide, zirconium oxide, magnesium oxide, calcium oxide, and yttrium oxide as the titanium oxide particles that adsorb the near-ultraviolet absorbing photosensitizer The coating material for forming a photoelectric cell porous metal oxide semiconductor film according to claim 6 or 7, comprising (B).

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