JP2003249279A - Producing method of porous semiconductor layer, and dye sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make different dyes co-adsorbed on a surface of a porous semiconductor layer efficiently. <P>SOLUTION: It is a manufacturing method of the porous semiconductor layer in which two or more kinds of dyes which are different from each other are co-adsorbed on the surface, and it includes at least a production process in which a coat film soluble to a specific solvent is formed on a part of the surface of the porous semiconductor layer, subsequently, the production process in which first dye dissolved is adsorbed on the surface of the porous semiconductor layer, the production process in which subsequently the dye on the coat film is removed together with the coat film using the solvent, and further, the production process in which a second dye is adsorbed on the surface of the porous semiconductor layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a porous semiconductor layer and a dye-sensitized solar cell. Specifically, the present invention is a porous semiconductor layer for a dye-sensitized solar cell having high efficiency and a wide spectral sensitization region by efficiently co-adsorbing different dyes on the surface of the porous semiconductor layer. To a method of manufacturing.

[0002]

2. Description of the Related Art Due to recent industrial development, the amount of energy and electric power used has increased rapidly. Therefore, the emission of global warming substances such as carbon dioxide has increased, and the amount is not negligible in order to protect the global environment. A solar cell that converts solar energy into electricity can produce electric power without directly emitting carbon dioxide, and thus is expected to be widely used. However, the conventional solar cell using silicon has a problem of high manufacturing cost, and has not been widely used as expected for large-scale electric power.

As a solar cell having a low manufacturing cost, which is an alternative to the solar cell using silicon, a wet type solar cell in which a dye that absorbs visible light is adsorbed on a semiconductor electrode is attracting attention. The principle of photoelectric conversion in the energy region lower than the original light absorption region of the semiconductor itself, in other words, on the long wavelength side, is called photosensitization and has been known for a long time. However, when it was applied to a photoelectric conversion element to form a solar cell, the conversion efficiency was low.

M. Graetzel et al., Nature
e, vol. 357, p. 737 (1991),
Titanium oxide, which is an n-type semiconductor, is made into fine particles and formed into a film, and a ruthenium complex (RuL
₂ (NCS) ₂ , L = 4,4-dicarboxyl-2,2 ′
A photoelectric conversion device in which (bipyridine) is adsorbed on the surface has been announced. By using fine particles of titanium oxide, the roughness factor (actual surface area in the electrode / projected area), which is the surface roughness coefficient, increases. As a result, the light receiving area is increased, and the conversion efficiency is greatly improved.

However, J. Am. Chem. Soc, V
ol. 115, No. 14, page 6382 (1993
Year). As in the article by Graetzel et al., This dye has a peak at a wavelength of 530 to 550 nm and a wavelength of 400 to
Only the wavelength of 800 nm is used. Sunlight has a wide energy spectral distribution from ultraviolet light to infrared light. Therefore, this method has a problem that only a part of the energy of sunlight can be used. It is important to absorb enough solar energy to improve the conversion efficiency.

As prior art 1, Japanese Patent Laid-Open No. 9-19974
Japanese Unexamined Patent Publication (Kokai) No. 4 discloses a new sensitizing dye that expands the absorption wavelength range of the dye and a wet solar cell using the same. This is a novel dye adsorbed on an oxide semiconductor having a nanostructure.

As prior art 2, Jpn. J. App
l. Phys. Vol. 37, L132-135 page
J. Part2, No2A (1998) discloses a technique of adsorbing a plurality of dyes on titanium oxide.
That is, two dyes, tetrasulfonidogallium phthalocyanine (GaTsPc) and tetrasulfonido zinc porferin (ZnTsPP) were dissolved in a DMSO solution and adsorbed on titanium oxide.

As the prior art 3, Japanese Patent Laid-Open No. 2000-245
Japanese Patent No. 466 discloses a new sensitizing dye that expands the absorption wavelength region of the optical spectrum and improves the conversion characteristic of light energy into electric energy, and a wet solar cell using the same. This is provided by stacking a plurality of semiconductor layers on a conductive substrate, a catalyst is adsorbed on the conductive substrate that is the opposite electrode of the conductive substrate, and an electrolyte layer is provided between the conductive substrates. A photoelectric conversion element in which a dye having a different absorption wavelength is adsorbed, and the absorption wavelength of the dye in the semiconductor layer located on the incident light side is shorter than the absorption wavelength of the dye in the semiconductor layer behind the semiconductor layer. is there.

As the prior art 4, there is disclosed a dye-sensitized solar cell in which a plurality of colors are arranged at a plurality of parts such as a display element or a signboard. This is a transparent electrode, a transparent semiconductor layer provided on the transparent electrode, sensitizing dye adsorbing parts of plural colors adsorbed on plural parts of the transparent semiconductor layer surface, and carrier transfer provided on the sensitizing dye adsorbing part. A dye-sensitized solar cell comprising a layer and another transparent electrode provided on the carrier transfer layer.

[0010]

However, since the porous semiconductor layer and the method for producing the same according to the prior art 1 use a single dye, the range of the absorption spectrum is limited even for a new dye. Therefore, when utilizing sunlight, only a small part of the spectrum of sunlight can be absorbed, and as a result, the photoelectric conversion efficiency of the entire photoelectric conversion element using this porous semiconductor layer becomes low.

In addition, the porous semiconductor layer and the method for manufacturing the same according to the prior art 2 have a photon-electron conversion quantum efficiency (IPC).
E) is drastically reduced at the wavelength of 400 to 500 nm on the short wavelength side as compared with the above-mentioned dye ZnTsPP, and 600 to 750 n on the long wavelength side.
It is slightly improved with m and the absorption wavelength range is expanded. However, the photoelectric conversion element using this does not have a large photocurrent, so that the overall photoelectric conversion efficiency is low. As a cause of this, it is conceivable that not all charges are injected into the semiconductor electrode from the dye photoexcited by the association of the dyes and the resulting interaction between the dyes.

Further, in the porous semiconductor layer and the method for manufacturing the same according to the prior art 3, since the semiconductor layer is not baked, carrier transfer in the semiconductor layer is hindered and recombination is promoted.
High electron transport efficiency cannot be realized, and a photoelectric conversion element using this cannot obtain high conversion efficiency.
From a structural point of view, in photoelectric conversion elements using multiple dyes, it is essential to control the amount of dye adsorption based on the light absorption characteristics of the dyes, suppress wasteful absorption for each wavelength, and achieve high collection efficiency. Is. However, in the manufacturing method according to the conventional technique, the same solvent is used to form a plurality of semiconductor layers, so that an overlap between layers actually occurs and it is impossible to form a systematic semiconductor layer. Alternatively, a third layer is formed between the two layers. Therefore, it is difficult to adsorb multiple dyes to the porous electrode as designed.

Further, the porous semiconductor layer and the method for producing the same according to the prior art 4 have a high designability, but the dye adsorption in the form of stacking a plurality of dyes in the light incident direction cannot be performed even by the tissue, and therefore The photoelectric conversion element using is unable to obtain high conversion efficiency.

[0014]

Means for Solving the Problems As a result of various investigations for solving the above problems, the inventors of the present invention have found that the optical spectrum of an optical spectrum can be obtained without hindering carrier transport in the semiconductor layer or photoelectron transfer on the surface of the semiconductor layer. The inventors have found a method for producing a porous semiconductor layer that expands the absorption wavelength region, improves photoelectric conversion collection efficiency, and also has a function as a display device, and arrived at the present invention.

Thus, according to the present invention, there is provided a method for producing a porous semiconductor layer in which two or more kinds of different dyes are co-adsorbed on the surface, wherein a part of the surface of the porous semiconductor layer is soluble in a specific solvent. A film, a step of adsorbing the dissolved first dye on the surface of the porous semiconductor layer, a step of removing the dye on the film together with the film with the solvent, and a second dye Provided is a method for producing a porous semiconductor layer, which includes at least a step of adsorbing it on the surface of the porous semiconductor layer.

Further, according to the present invention, there is provided a dye-sensitized solar cell using the porous semiconductor layer obtained by the above method as a photoelectric conversion layer.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the following technical means are adopted in order to adsorb different dyes on the surface of a porous semiconductor layer to a site designed in advance. A film that dissolves in a specific solvent is provided in advance on the portion of the porous semiconductor layer where the first dye is to be adsorbed. After adsorbing the second dye on the surface of the porous semiconductor layer provided with the film, the film and the second dye on the film are removed by the solvent, and then the first dye is adsorbed on the part where the film is removed. By doing so, the two kinds of dyes can be adsorbed to the intended portion.

The porous semiconductor that can be used in the present invention is not particularly limited as long as it is generally used for photoelectric conversion materials. For example, titanium oxide, zinc oxide,
One or more known semiconductors such as tungsten oxide, tin oxide, barium titanate, strontium titanate, and cadmium sulfide can be used. Above all,
Titanium oxide is preferable in terms of stability and safety. In addition,
Titanium oxide used in the present invention, anatase type titanium oxide, rutile type titanium oxide, amorphous titanium oxide, metatitanic acid, various titanium oxide such as orthotitanic acid, or titanium hydroxide, titanium oxide etc. Included. For some dyes such as EOSIN Y, the photoelectron transfer characteristics can be improved by mixing and using zinc oxide / tin oxide in an appropriate ratio.

The shape of the porous semiconductor layer is not particularly limited, and may be an aggregate of particles, a plate shape or the like.

Next, a film is formed on a part of the surface of the porous semiconductor layer. The film is preferably composed of a substance that does not dissolve in a specific solvent but dissolves, peels off or precipitates together with the dye attached or adsorbed on the surface of the film. Also, the film is
It is preferable to use a material that does not interfere with the adsorption of the dye on the surface of the porous semiconductor which is not covered with the film. Specific examples include compounds containing alkaline earth metals such as magnesium oxide, calcium oxide, and cesium oxide. For example, the film may include a substance having a composition different from that of the substance forming the film.

The porous semiconductor layer having a film on a part of its surface may be prepared by a coating method which allows patterning by preparing a paste containing a fine particle semiconductor having no film and a paste containing a fine particle semiconductor having a film. it can.
As a coating method, a squeegee method, a printing method, or a non-impact method such as inkjet is applied. Further, it can be formed by spraying a solution containing a material capable of forming a film on a desired position of the porous semiconductor layer or by partially immersing the solution in a solution containing the material.

In the present invention, by using a plurality of types of films, it is possible to adsorb three or more types of dyes to the intended portion of the porous semiconductor layer.

In the case of a solar cell, the dye that can be used in the present invention is limited to a long wavelength side from the viewpoint of power generation efficiency and a short wavelength side from the durability of the solar cell.
It makes sense to use a wavelength of 1200 nm. In the case of a dye with excellent photoelectron transfer performance, it is 300-400n by itself.
Considering that photoelectron transfer can be realized in the wavelength range of about m, the number of kinds of dyes to be adsorbed on the semiconductor porous layer is 2
3 to 3 are suitable.

The dye that can be used here is a dye that functions as a spectral sensitizer, and there is no problem as long as it has absorption in the visible light region and / or the infrared light region. Specifically, xanthene-based dyes such as rose bengal and rhodamine B; triflumethane dyes such as malachite green and crystal violet, [perylene]
-Bis (4-dicarboxylphenyl)-
3,4,9,10-tetraCarboxylici
perene-based dyes such as copper, phthalocyanine, and Phys. Rev. Lett V81, N14, p
Zinc phthalocyanine [2,9,16,23-tet as disclosed in 2154-2957 (1998).
ra (4-Carboxyphenoxy) phtha
locyanine Zinc (II)] and other metal phthalocyanines, chlorophyll, hemin, or ruthenium,
Complex containing at least one of osmium, iron and zinc
-220380, JP-A-5-504023) and the like, metal complex salts, EOSINY, and the like.

Of the above dyes, the metal complex salt, in particular, has a characteristic that the absorption wavelength range is remarkably extended to a long wavelength range when adsorbed on the porous semiconductor layer made of an oxide semiconductor, so that a wide absorption wavelength range is required. It is preferable to produce a photoelectric conversion element having

The method of adsorbing the dye is not particularly limited, and any known method can be used. For example, a method of immersing the porous semiconductor layer on which a film is formed in a solution in which a dye is dissolved and then drying it can be mentioned.

As a method of removing the film, a method of immersing in a removing solution selected according to the type of the corresponding film can be mentioned. Examples of the removal solution include inorganic acid solutions such as hydrochloric acid, nitric acid, phosphoric acid, and dilute sulfuric acid, or mixed acid thereof, and organic acid solutions such as acetic acid, phenol, and trifluoromethylsulfonic acid.

The porous semiconductor layer obtained by the method of the present invention can be suitably used for a photoelectric conversion layer of a solar cell. That is, the porous semiconductor layer can carry out sufficient electron transport. Furthermore, by having a film on the site designed in advance, the adsorption site of the dye can be controlled as designed. In addition, by selecting a preferable combination of a porous semiconductor and a dye, an oxide semiconductor electrode for a dye-sensitized solar cell having high photoelectric conversion efficiency can be provided.

Further, since different kinds of dyes are adsorbed at different sites in the porous semiconductor layer and there is no association or interaction between different kinds of dyes, photoelectron transfer is not hindered. Further, since it is sensitized by a plurality of dyes, a solar cell using a wide wavelength region of incident light can be manufactured.

[0030]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1 FIG. 1 shows a method for producing a porous semiconductor layer in which two kinds of dyes are adsorbed on different porous semiconductor films.
This will be described with reference to (A) to FIG. 1A to 2F, 1 is a titanium oxide porous film, 2 is a titanium oxide porous film that adsorbs a dye different from 1, and 3 is Sol.
ruthenium 535 [cis-dith made by aronix
iocyanine-n-bis (2,2'-bipy
rigid-4,4'-dicarboxylicaci
d) ruthenium] (hereinafter ruthenium dye), 4
Is [perylene-bis (4-dicarbox
ylphenyl) -3,4,9,10-tetraC
Arboxylicimide] (hereinafter referred to as perylene dye), 5 is a magnesium oxide film, 6 is a transparent substrate, and 7 is a transparent conductive film. The titanium oxide porous film having the magnesium oxide film is A, and the titanium oxide porous film which is the source of A is Al.

The coating liquid for forming the titanium oxide porous film A, which is the basis of the titanium oxide porous film 1, is a commercially available titanium oxide particle (trade name AMT-600 manufactured by Teika Co., Ltd., anatase type crystal, average). Particle size 30 nm, specific surface area 50 mm ²
/ G) 4.0 g and diethylene glycol monomethyl ether 20 ml were dispersed for 6 hours with a paint shaker using glass beads to prepare a titanium oxide suspension. This titanium oxide suspension was applied onto the transparent conductive film 7 using a doctor blade, pre-dried at 100 ° C. for 30 minutes, and then baked at 460 ° C. for 40 minutes under oxygen to give 10 m.
mx30mm area, film thickness 8μm, specific surface area 48mm
² / g, density 2.1 g / cm ³ titanium oxide porous film Al
(See FIG. 1 (A)) Next, a magnesium oxide film 5 is formed on the surface of the titanium oxide porous film Al. 20 g of commercially available magnesium ethoxide is diluted with 250 ml of absolute ethanol and stirred. Prepare 5 g of water and 20 g of acetic acid diluted with 250 ml of absolute ethanol, add to the liquid prepared above, and stir well. 0.1 ml of the prepared liquid is dropped on the surface of the titanium oxide porous film. It was kept at 280 ° C. for 12 hours to prepare a titanium oxide porous film A having a magnesium oxide film on its surface (see FIG. 1 (a)).

On the titanium oxide porous film A having the magnesium oxide film 5 on its surface, the above titanium oxide suspension was further applied by using a doctor blade, pre-dried at 100 ° C. for 30 minutes, and then at 460 ° C. 40. The titanium oxide porous film 2 was produced by firing under oxygen for a minute (see FIG. 1C).

Next, ruthenium dye 3 was dissolved in absolute ethanol at a concentration of 4 × 10 ^-4 mol / liter to prepare a dye solution for adsorption. Titanium oxide porous membrane A, 2 obtained above
The transparent substrate 6 provided with the transparent conductive film 7 is immersed in the dye solution for adsorption for 10 hours to adsorb the dye. afterwards,
It was washed several times with absolute ethanol and dried at about 60 ° C. for about 20 minutes (see FIG. 2D).

Here, the substrate on which the dye is adsorbed is
The magnesium oxide film on the titanium oxide porous film A is removed by immersing it in hydrochloric acid adjusted to H2 to 5 for 30 minutes. The ruthenium dye 3 adsorbed on the titanium oxide porous film A is also removed, and the titanium oxide porous film 1 is formed (see FIG. 2E).

Next, perylene dye 4 was dissolved in absolute ethanol at a concentration of 4 × 10 ^-4 mol / liter to prepare a dye solution for adsorption. The transparent substrate 6 having the titanium oxide porous films 1 and 2 and the transparent conductive film 7 obtained above is dipped in the adsorbing dye solution for 10 hours to adsorb the dye. Then, it was washed several times with absolute ethanol and dried at about 60 ° C. for about 20 minutes. The perylene dye 4 is hardly adsorbed on the titanium oxide porous film 2 on which the ruthenium dye 3 has already been adsorbed, but is mainly adsorbed on the titanium oxide porous film 1. This makes it possible to produce a porous semiconductor layer in which two kinds of dyes are adsorbed on different porous semiconductor films (see FIG. 2F).

A method for producing a dye-sensitized solar cell using this porous semiconductor layer to improve the conversion efficiency by improving the short-circuit current value will be described below with reference to FIG. In FIG. 3, 11 is a porous semiconductor layer on which a dye is adsorbed, 12 is a transparent substrate, 13 is a transparent conductive film, 14 is a conductive substrate, 15 is a platinum film, 16 is a redox electrolytic solution, 17
Indicates a spacer.

The spacer 17 is placed on the transparent conductive film 13 as shown in FIG. The spacer at this time must be thicker than the porous semiconductor layer 11. Specifically, polyethylene heat fusion film (Mitsui DuPont,
A product having a thickness of 50 μm) molded into 30 mm × 2 mm is used. After that, a platinum film 15 having a thickness of about 1 μm is vapor-deposited on the conductive surface of the conductive substrate 4, and the platinum film 15 and the porous semiconductor layer 11 having the dye adsorbed thereon are overlapped with each other. Fix it with a clip as it is and place it at 90 ° C for 10 minutes.
The porous semiconductor layer 11 adsorbing 5 and the dye is fused and fixed by the spacer 17.

The redox electrolytic solution 16 to be injected was prepared by dissolving lithium iodide having a concentration of 0.3 mol / liter and iodine having a concentration of 0.03 mol / liter using acetonitrile as a solvent. The redox electrolytic solution 16 is injected between the platinum film 15 and the porous semiconductor layer 11.

A short circuit current value of 18.2 m was obtained by the above method.
A / cm ² , open voltage 0.65 V, F.A. F. 0.68,
A dye-sensitized solar cell having a conversion efficiency of 8.04% was obtained. Characteristics of a dye-sensitized solar cell using a porous semiconductor layer made of titanium oxide prepared by a conventional method (short-circuit current value 14.0 mA / cm ² , open-circuit voltage 0.67).
V, F. F. 0.63 and conversion efficiency 5.90%), the conversion efficiency of the solar cell is improved because the short-circuit current is particularly improved.

Example 2 A method for producing a porous semiconductor layer in which two kinds of dyes are adsorbed on different porous semiconductor films to improve designability will be described below with reference to FIGS. 4 (a) to 5 (k). Explained. 4 (A) to 5 (K),
21 is a titanium oxide porous film, 22 is a titanium oxide porous film which adsorbs a dye different from 21, a ruthenium dye, 24 is a coumarin dye, 25 is a magnesium oxide film, 26 is a transparent substrate, 27 is a transparent conductive film, 28 is a polyethylene thin film. Further, a titanium oxide porous film having a magnesium oxide film is referred to as B, and a titanium oxide porous film which is a source of B is referred to as Bl.

The coating liquid for forming the titanium oxide porous film Bl, which is the basis of the titanium oxide porous film 21, is titanium oxide paste (Ti-Nanox manufactured by Solaronix Co., Ltd.).
ide D / SP) was used. This is screen-printed on a portion of the transparent conductive film 23 where the titanium oxide porous film 21 is to be produced. After being dried at 130 ° C. for 10 minutes, it is baked at 500 ° C. for 20 minutes to produce a titanium oxide porous film Bl (see FIG. 1A). Then, a coating solution prepared by dissolving 1% by weight of commercially available polystyrene (molecular weight: 100,000) in commercially available benzene is applied to a site where the titanium oxide porous film 2 is to be formed, to form a polystyrene thin film 28 (FIG. 4). (See (a)).

Next, on the surface of the titanium oxide porous film Bl,
A magnesium oxide film is prepared. 20 g of commercially available magnesium ethoxide is diluted with 250 ml of absolute ethanol and stirred. 250g of water and 20g of acetic acid
Prepare a solution diluted with ml of absolute ethanol, add to the solution prepared above, and stir well. 0.1 ml of the prepared liquid is dropped on the surface of the titanium oxide porous film. It was kept at 280 ° C. for 12 hours to prepare a titanium oxide porous film B having a magnesium oxide film on its surface (see FIG. 4C).

By leaving this substrate in acetone for 1 hour, the magnesium oxide at the site where the titanium oxide porous film 22 is formed can be removed (see FIG. 4D).

Subsequently, the titanium oxide porous film 22 is prepared as follows. Titanium oxide paste (Solaroni
Ti-Nanoxide D / SP manufactured by X Co. was used. This is printed by screen printing on the site where the titanium oxide porous film 2 is to be produced. After being dried at 130 ° C. for 10 minutes, it is baked at 500 ° C. for 20 minutes to form the titanium oxide porous film 22 (see FIG. 5E).

Subsequent operations were carried out according to Example 1, and different dyes were adsorbed on the titanium oxide porous films 21 and 22, and two kinds of dyes were adsorbed on different porous semiconductor films to improve the design. A porous semiconductor layer can be produced. Further, a dye sensitized solar cell can be prepared by performing the same modification as in Example 1. According to the above method, the short circuit current value is 16.2 mA / cm ² and the open circuit voltage is 0.7.
2V, F.I. F. A dye-sensitized solar cell having a performance of 0.64 and a conversion efficiency of 7.46% was obtained. Characteristics of a dye-sensitized solar cell using a porous semiconductor electrode made of titanium oxide manufactured by a conventional method (short-circuit current value 14.0 mA /
cm ² , open-circuit voltage 0.67 V, F.I. F. 0.63, conversion efficiency 5.90%), the conversion efficiency of the solar cell is improved because the value of the short-circuit current is particularly improved. In addition, ruthenium dye (red) and coumarin dye (yellow) are adsorbed at pre-designed positions on the transparent conductive film side of the titanium oxide porous film. And the design is improved as compared with the structure in which the dye is laminated in the incident light direction as seen in Example 1.

Example 3 A method for producing an oxide porous film having a function as a display by improving the design by adsorbing a plurality of dyes at arbitrary positions on the porous semiconductor film is shown in FIG. ) To FIG. 8 (X) will be described below. In FIGS. 6A to 8C, 31 is a titanium oxide porous film, 32 is a titanium oxide porous film that adsorbs a dye different from 31, and 33 is a titanium oxide porous film that adsorbs a dye different from 31 and 32. Membrane, 34 is ruthenium dye, 35
Is [2, 9, 16, 23-tetra (4-Carbo
xyphenoxy) phthalocyanine
Zinc (II)] (hereinafter zinc phthalocyanine dye),
36 is a perylene dye, 37 is a magnesium oxide film, 3
8 is a barium oxide film, 39 is a transparent substrate, and 40 is a transparent conductive film. Further, the titanium oxide porous film having the barium oxide film is C, the titanium oxide porous film which is the source of C is Cl,
A titanium oxide porous film having a magnesium oxide film is designated as D.

The coating liquid for forming the titanium oxide porous film Cl, which is the basis of the titanium oxide porous film 31, is a titanium oxide paste (Ti-Nanoxid manufactured by Solaronix Co., Ltd.).
eD / SP) was used. By screen printing this,
Printing is performed on the transparent conductive film 40 on the site where the titanium oxide porous film 31 is to be produced. After drying at 130 ° C for 10 minutes,
It is baked at 500 ° C. for 20 minutes to produce a titanium oxide porous film Cl (see FIG. 6A).

Next, a barium oxide film 38 is formed on the surface of the titanium oxide porous film Cl. 15 g of commercial barium isopropoxide are diluted with 250 ml of 2-propanol and stirred. Acetylacetone 10m
In addition, 15 ml of acetic acid and 250 ml (0.1 vol%) of 2-propanol solution of water are added, and stirring is continued.
The prepared liquid was applied to the surface of the titanium oxide porous membrane Cl in an amount of 0.
Add 1 ml dropwise. It was kept at 280 ° C. for 12 hours to prepare a titanium oxide porous film C having a barium oxide film 38 on its surface (see FIG. 6A).

The coating liquid for forming the titanium oxide porous film 32 is a titanium oxide paste (T-type, manufactured by Solaronix).
i-Nanoxide T / SP) was used. This is printed by screen printing on the site where the titanium oxide porous film 2 is to be produced (at this time, part or all may be on the titanium oxide porous film 1). After being dried at 130 ° C. for 10 minutes, it is baked at 500 ° C. for 20 minutes to produce a titanium oxide porous film 32 (see FIG. 6C).

The titanium oxide porous film D, which is the basis of the titanium oxide porous film 33, is manufactured as follows.

2 g of 20 g of commercially available magnesium ethoxide
Dilute with 50 ml absolute ethanol and stir. Prepare 5 g of water and 20 g of acetic acid diluted with 250 ml of absolute ethanol, add to the liquid prepared above, and stir well. Titanium oxide particles (trade name AMT-600, manufactured by Teika Co., Ltd., anatase type crystal, average particle size 30 nm, specific surface area 50 mm ² / g) were added to 10 ml of the prepared liquid.
After adding 4.0 g and stirring well, the mixture is left at 80 ° C. for 2 days.
Only the precipitate was taken out and kept at 280 ° C. for 12 hours to prepare titanium oxide particles having a magnesium oxide film. 20m of this particle and diethylene glycol monomethyl ether
1 and 6 using glass beads with a paint shaker
It was dispersed for a time to prepare a titanium oxide suspension. This titanium oxide suspension was applied onto the titanium oxide porous films 31 and 32 using a doctor blade. After predrying at 100 ° C for 30 minutes, calcination at 460 ° C for 40 minutes under oxygen,
A titanium oxide porous film D having a magnesium film is produced (see FIG. 7D).

Next, the zinc phthalocyanine dye 35 was dissolved in acetone at a concentration of 4 × 10 ^-4 mol / liter to prepare a dye solution for adsorption. A transparent substrate 39 having the titanium oxide porous films C, 32 and D obtained above and a transparent conductive film 40.
Is immersed in this dye solution for adsorption for 10 hours to adsorb the dye (see FIG. 7E).

After that, it was washed several times with absolute ethanol to about 6
It was dried at 0 ° C. for about 20 minutes. At this time, since barium oxide on the titanium oxide porous film C is removed, the dye on the titanium oxide porous film C can be removed. As a result, the titanium oxide porous film 31 is formed (FIG. 7).
(See (f)).

Next, the ruthenium dye 34 was dissolved in absolute ethanol at a concentration of 4 × 10 ^-4 mol / liter to prepare a dye solution for adsorption. Titanium oxide porous film 3 obtained above
1, 32, D and a transparent substrate 39 having a transparent conductive film 40
Is immersed in this adsorption dye solution for 10 hours to adsorb the dye. After that, wash several times with absolute ethanol and about 60 ℃
And dried for about 20 minutes (see FIG. 8 (ki)).

The ruthenium dye 34 is hardly adsorbed on the titanium oxide porous film 32 on which the zinc phthalocyanine dye 35 has already been adsorbed. Here, the substrate on which the dye is adsorbed is immersed in hydrochloric acid adjusted to pH 2 to 5 for 30 minutes,
The magnesium oxide film on the titanium oxide porous film D is removed. The ruthenium dye adsorbed on the titanium oxide porous film D is also removed. Therefore, the ruthenium dye 34 is mainly adsorbed on the titanium oxide porous film 31.
Further, as a result, the titanium oxide porous film 33 is formed (see FIG. 8C).

Next, the perylene dye 36 was dissolved in absolute ethanol at a concentration of 4 × 10 ^-4 mol / liter to prepare a dye solution for adsorption. The titanium oxide porous film 31 obtained above,
The transparent substrate 12 provided with 32 and 33 and the transparent conductive film 13 is immersed in the dye solution for adsorption for 10 hours to adsorb the dye. Then, it was washed several times with absolute ethanol and dried at about 60 ° C. for about 20 minutes. The perylene dye 36 is almost not adsorbed to the titanium oxide porous films 31 and 32 to which the zinc phthalocyanine 35 and the ruthenium dye 34 have already been adsorbed, but is mainly adsorbed to the titanium oxide porous film 33 (see FIG. 8 (v)).

As a result, a plurality of dyes are adsorbed on arbitrary positions of the porous semiconductor layer to increase photocurrent, thereby improving photoelectric conversion efficiency and improving designability, and a porous oxide film having a function as a display body. Can be made.

Furthermore, a dye-sensitized solar cell can be prepared by performing the same operation as in Example 1. According to the method described above, the short circuit current value is 22.4 mA / cm ² , the open circuit voltage is 0.68 V, the F.S. F. A dye-sensitized solar cell having a performance of 0.64 and a conversion efficiency of 9.75% was obtained. Characteristics of a dye-sensitized solar cell using a porous semiconductor electrode made of titanium oxide produced by a conventional method (short circuit current value 20.3
mA / cm ² , open voltage 0.67 V, F.I. F. 0.6
3, the conversion efficiency is 8.56%), and the conversion efficiency of the solar cell is improved because the value of the short-circuit current is particularly improved. Further, as compared with Example 2, since the ruthenium dye (red), the perylene dye (yellow) and the zinc phthalocyanine dye (green) are used, the designability and conversion efficiency can be further improved.

(Example 4) A porous semiconductor having a function as a display body is improved by adsorbing a plurality of dyes on an arbitrary position of a porous semiconductor film composed of a plurality of porous semiconductors. Figure 9 (a) about the manufacturing method of the layer
~ It demonstrates below using FIG. Figure 9 (a) ~
In FIG. 11 (K), 41 is a tin oxide / zinc oxide porous film, 42 is a titanium oxide porous film, 43 is a titanium oxide porous film that adsorbs a dye different from 42, and 44 is EOSI.
NY, 45 is a zinc phthalocyanine dye, 46 is a perylene dye, 47 is a magnesium oxide film, 48 is a barium oxide film, 49 is a transparent substrate, and 50 is a transparent conductive film.
Further, the titanium oxide porous film having the magnesium oxide film is E, the tin oxide / zinc oxide porous film having the barium oxide film is F, and the tin oxide / zinc oxide porous film which is the source of F is F.
Let l.

The coating liquid for forming the tin oxide / zinc oxide porous film Fl, which is the base of the tin oxide / zinc oxide porous film 41, is a tin oxide colloid aqueous solution (1) of Alla Aesar.
(5 w%) 1.5 ml of glacial acetic acid with a dropper, and zinc oxide powder (Aldrich, 99.9%).
3g, Triton X (4 drops with dropper), methanol 20
It was prepared by adding ml and stirring well.

This tin oxide / zinc oxide suspension was applied to a masked transparent electrode by a spray method to obtain 100
After pre-drying at 30 ° C for 30 minutes, calcination at 460 ° C for 40 minutes under oxygen, and 10 mm x 30 mm area, film thickness 15μ
A tin oxide / zinc oxide porous film Fl of m was prepared (FIG. 9).
(See (a)). In addition, it is particularly preferable to use the dye EOSIN Y described later for the porous film made of tin oxide or zinc oxide.

Next, the tin oxide / zinc oxide porous film Fl
A barium oxide film 48 is formed on the surface. 15 g of commercial barium isopropoxide are diluted with 250 ml of 2-propanol and stirred. Acetylacetone 1
In addition to 0 ml, acetic acid 15 ml and water 2-propanol solution 250 ml (0.1 vol%) are added and stirring is continued. 0.1 ml of the prepared liquid is dropped on the surface of the tin oxide / zinc oxide porous film. Hold at 280 ° C for 12 hours,
A tin oxide / zinc oxide porous film F having a barium oxide film 48 on its surface was prepared (see FIG. 9A).

The coating liquid for forming the titanium oxide porous film 42 is a titanium oxide paste (T-type, manufactured by Solaronix).
i-Nanoxide T / SP) was used. This is printed by screen printing on the site where the titanium oxide porous film 41 is to be produced (at this time, part or all may be on the tin oxide / zinc oxide porous film F). 130
After being dried at 0 ° C. for 10 minutes, it is baked at 500 ° C. for 20 minutes to produce a titanium oxide porous film 42 (see FIG. 9C).

The titanium oxide porous film E, which is the basis of the titanium oxide porous film 43, is manufactured as follows.

2 g of 20 g of commercially available magnesium ethoxide
Dilute with 50 ml absolute ethanol and stir. Prepare 5 g of water and 20 g of acetic acid diluted with 250 ml of absolute ethanol, add to the liquid prepared above, and stir well. Titanium oxide particles (trade name AMT-600, manufactured by Teika Co., Ltd., anatase type crystal, average particle size 30 nm, specific surface area 50 mm ² / g) were added to 10 ml of the prepared liquid.
After adding 4.0 g and stirring well, the mixture is left at 80 ° C. for 1 day.
Only the precipitate was taken out and kept at 230 ° C. for 12 hours to prepare titanium oxide particles having a magnesium oxide appearance. 20m of this particle and diethylene glycol monomethyl ether
1 and 15 g of ethyl cellulose (molecular weight 40,000) dissolved in 20 ml of ethanol are dispersed for 6 hours with a paint shaker using glass beads. Then, ethanol was evaporated to prepare a titanium oxide paste. This titanium oxide paste was applied by screen printing onto the substrate on which the tin oxide / zinc oxide porous film F and the titanium oxide porous film 42 were formed (at this time, a part or all of the tin oxide / zinc oxide porous film was formed). F, may be on the titanium oxide porous film 42). After preliminary drying at 100 ° C. for 30 minutes, firing was performed at 460 ° C. for 40 minutes under oxygen to prepare a titanium oxide porous film E having a magnesium oxide film (see FIG. 9D).

Next, zinc phthalocyanine was dissolved in acetone at a concentration of 4 × 10 ^-4 mol / liter to prepare a dye solution for adsorption. The transparent substrate 49 provided with the tin oxide / zinc oxide porous film F, the titanium oxide porous film 2, F and the transparent conductive film 50 obtained above is immersed in this adsorbing dye solution for 10 hours to adsorb the dye. (See FIG. 10E).

After that, it was washed several times with absolute ethanol to about 6
It was dried at 0 ° C. for about 20 minutes. At this time, since barium oxide on the tin oxide / zinc oxide porous film F is removed, the dye on the tin oxide / zinc oxide porous film F can be removed. As a result, the tin oxide / zinc oxide porous film 41 is formed (see FIG. 10F).

Next, EOSIN Y44 was dissolved in absolute ethanol at a concentration of 4 × 10 ^-4 mol / liter to prepare a dye solution for adsorption. The tin oxide / zinc oxide porous film 41, the titanium oxide porous film 42, E obtained above and the transparent conductive film 5
The transparent substrate 49 containing 0 is added to the dye solution for adsorption in an amount of 10
Dip for a time to adsorb the dye. Then, it was washed several times with absolute ethanol and dried at about 60 ° C. for about 20 minutes (see FIG. 10 (K)).

EOSIN Y44 is hardly adsorbed on the titanium oxide porous film 42 on which the zinc phthalocyanine 45 has already been adsorbed. Here, the substrate on which the dye is adsorbed is immersed in hydrochloric acid adjusted to pH 2 to 5 for 30 minutes to remove the magnesium oxide film on the titanium oxide porous film E. EOSIN adsorbed on the titanium oxide porous film E
Y44 is also removed. Therefore, EOSIN Y
44 is mainly adsorbed on the tin oxide / zinc oxide porous film 41. By this step, the titanium oxide porous film 43 is formed (see FIG. 11C).

Next, the perylene dye 46 was dissolved in absolute ethanol at a concentration of 4 × 10 ^-4 mol / liter to prepare a dye solution for adsorption. The tin oxide / zinc oxide porous film 41, the titanium oxide porous films 42 and 43, and the transparent conductive film 5 obtained above.
The transparent substrate 49 containing 0 is added to the dye solution for adsorption in an amount of 10
Dip for a time to adsorb the dye. Then, it was washed several times with absolute ethanol and dried at about 60 ° C. for about 20 minutes (see FIG. 11 (X)).

The perylene dye 46 is hardly adsorbed to the tin oxide / zinc oxide porous film 41 and the titanium oxide porous film 43 to which the zinc phthalocyanine 45 and the EOSIN Y44 have been adsorbed, but is mainly adsorbed to the titanium oxide porous film 42. To do. As a result, it is possible to improve the designability by adsorbing a plurality of dyes at an arbitrary position of a porous semiconductor film composed of a plurality of porous semiconductors, and to manufacture a porous semiconductor layer having a function as an indicator. It can be done (see FIG. 11 (K)).

Furthermore, a dye-sensitized solar cell can be produced by performing the same operation as in Example 1. According to the method described above, the short-circuit current value was 22.5 mA / cm ² , the open circuit voltage was 0.69 V, and the F.I. F. 0.68, conversion efficiency 10.56%
A dye-sensitized solar cell having the above performance was obtained. Conversion of the solar cell by improving the value of the short-circuit current in comparison with the characteristics of the dye-sensitized solar cell using the porous semiconductor electrode made of titanium oxide produced by the conventional method and the method described in Examples 1 to 3 Efficiency is improving. Further, by using three kinds of dyes, it has a design property equivalent to that of Example 3.

[0074]

Industrial Applicability As described above, according to the present invention, in order to adsorb different dyes to different parts of the porous semiconductor layer, a porous semiconductor having a film which is dissolved in a specific solvent in advance is formed on a part of the surface. After adsorbing molecules on the surface of the layer, the solvent and the dye on it are removed, and a dye different from the one previously adsorbed is adsorbed on the part where the film has been removed, so that multiple dyes are intended. It can be adsorbed to a part.

By using this method, it is possible to use a porous semiconductor layer that sufficiently transports electrons even when operating as a solar cell. Furthermore, by producing a porous semiconductor layer having a film on a predesigned site, the dye adsorption site can be controlled as designed.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a method for manufacturing a porous semiconductor layer according to Example 1 of the present invention.

FIG. 2 is a schematic view illustrating a method for manufacturing a porous semiconductor layer according to Example 1 of the present invention.

FIG. 3 is a configuration diagram of a dye-sensitized solar cell using a porous semiconductor layer produced according to an example of the present invention.

FIG. 4 is a schematic view illustrating a method for manufacturing a porous semiconductor layer according to Example 2 of the present invention.

FIG. 5 is a schematic view illustrating a method for manufacturing a porous semiconductor layer according to Example 2 of the present invention.

FIG. 6 is a schematic diagram illustrating a method for manufacturing a porous semiconductor layer according to Example 3 of the present invention.

FIG. 7 is a schematic diagram illustrating a method for manufacturing a porous semiconductor layer according to Example 3 of the present invention.

FIG. 8 is a schematic view illustrating a method for manufacturing a porous semiconductor layer according to Example 3 of the present invention.

FIG. 9 is a schematic view illustrating a method for producing a porous semiconductor layer according to Example 4 of the present invention.

FIG. 10 is a schematic diagram illustrating a method for manufacturing a porous semiconductor layer according to Example 4 of the present invention.

FIG. 11 is a schematic view illustrating a method for manufacturing a porous semiconductor layer according to Example 4 of the present invention.

[Explanation of symbols]

1, 21, 31, 42 Titanium oxide porous film 21 Titanium oxide porous film for adsorbing a dye different from 1 3, 23, 34 Ruthenium dye 4, 36, 46 Perylene dye 5, 25, 37, 47 Magnesium oxide film 6 , 12, 26, 39, 49 Transparent substrate 7, 13, 27, 40, 50 Transparent conductive film 11 Porous semiconductor layer 15 adsorbing dye 15 Platinum film 16 Redox electrolyte 17 Spacer 22 21 Adsorbing dye different from Titanium oxide porous film 24 Coumarin dye 28 Polyethylene thin film 32 31 Titanium oxide porous film 33 that adsorbs a dye different from 31 31 Titanium oxide porous film 35 that adsorbs a dye different from 31, 32 Zinc phthalocyanine dye 38, 48 Oxidation Barium film 41 Tin oxide / zinc oxide porous film 43 42 Titanium oxide porous film that adsorbs a different dye Membrane 44 EOSIN Y A, B, D, E Titanium oxide porous film A1 having a magnesium oxide film as a source Titanium oxide porous film B1 B as a source of titanium oxide porous film C B having a barium oxide film as an oxide Titanium oxide porous film F that is the source of titanium porous film C1 C Tin oxide / zinc oxide porous film F1 that has a barium oxide film Tin oxide / zinc oxide porous film that is the source of F1 F

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Claims (4)

[Claims] 1. A method for producing a porous semiconductor layer in which two or more kinds of different dyes are co-adsorbed on the surface, wherein a film soluble in a specific solvent is provided on a part of the surface of the porous semiconductor layer. A step of adsorbing the dissolved first dye on the surface of the porous semiconductor layer, a step of removing the dye on the film together with the film by the solvent, and a second dye on the surface of the porous semiconductor layer A method for producing a porous semiconductor layer, comprising at least the step of adsorbing onto a porous semiconductor layer. 2. The method for producing a porous semiconductor layer according to claim 1, wherein the specific solvent contains at least an organic acid compound or an inorganic acid compound. 3. The method for producing a porous semiconductor layer according to claim 1, wherein the film is composed of an alkaline earth metal. 4. A dye-sensitized solar cell using a porous semiconductor layer obtained by the method according to claim 1 as a photoelectric conversion layer.