JP2008084829A - Manufacturing method of dye sensitized solar battery, and dye sensitized solar battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a dye sensitized solar battery which can secure a smooth electron flow in an electrolyte solution for a long period and can maintain a high energy conversion efficiency, and to provide a dye sensitized solar battery. <P>SOLUTION: A photo electrode layer 2 is cleansed by an electrolyte solution which is used for filling the layer as an electrolyte solution 1 and a sensitized dye which is feared to be dissolved into the electrolyte solution 1 after the filling is certainly washed out and a smooth electron flow by the electrolyte solution 1 can be secured for a long period and a high energy conversion efficiency can be maintained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dye-sensitized solar cell that has improved durability and can maintain high energy conversion efficiency over a long period of time.

  As a commonly used dye-sensitized solar cell, for example, a porous photoelectric conversion semiconductor having a specific surface area of 1 to 100 m <2> / g is obtained by immersing a conductive surface substrate in a metal inorganic acid salt solution and using an electrochemical method. A layer is formed on a conductive surface, a metal inorganic acid salt solution contains a water-soluble dye, and a porous photoelectric conversion semiconductor layer having a water-soluble dye supported on the surface is formed by an electrochemical method. A method for producing a photosensitive photoelectric conversion semiconductor layer and a dye-sensitized solar cell using a porous photoelectric conversion semiconductor layer formed by the production method are disclosed (for example, Patent Document 1).

JP 2002-184476 A

  However, in the conventional dye-sensitized solar cell as described in Patent Document 1, when the amount of the sensitizing dye carried on the porous photoelectric conversion semiconductor layer is not the optimum amount, The sensitizing dye flows out into the electrolytic solution, and the flow of electrons through the electrolytic solution may be hindered by the outflowing sensitizing dye, and it is difficult to maintain high energy conversion efficiency over a long period of time.

  The present invention has been made in view of the above problems, and a method for producing a dye-sensitized solar cell that can ensure a smooth flow of electrons in an electrolyte and maintain high energy conversion efficiency over a long period of time. And a dye-sensitized solar cell.

  In order to achieve the above object, the present invention is configured as follows. That is, in the method for producing a dye-sensitized solar cell according to the present invention, a photoelectrode layer formed by supporting a sensitizing dye on a semiconductor layer formed on a first conductive film of a transparent substrate is used as a counter group. A method for producing a dye-sensitized solar cell, which is disposed opposite to a second conductive film of a material, and is filled with an electrolytic solution containing an electrolyte in a space between the photoelectrode layer and the second conductive film Then, the photoelectrode layer is washed with the electrolytic solution, and the electrolytic solution is newly filled after the washing.

  According to the dye-sensitized solar cell of the present invention, by washing with the same electrolytic solution that fills the photoelectrode layer, the sensitizing dye that can be eluted into the electrolytic solution after filling is surely washed away. Therefore, it is possible to secure a smooth flow of electrons by the electrolyte over a long period of time and maintain high energy conversion efficiency.

  Further, if the washing is performed while irradiating light containing light having a wavelength suitable for power generation, it is preferable that a sensitizing dye that may be eluted in a state where the photoelectrode layer is activated by light can be removed in advance. .

  The washing is performed in a state where the dye-sensitized solar cell is assembled. If the electrolyte solution is once extracted and then filled with the electrolyte solution again, the dye-sensitized solar cell in the actual use state is subjected to light. The electrode layer can be washed, and the photoelectrode layer can be washed without excess or deficiency.

  The dye-sensitized solar cell according to the present invention is formed by the method for producing a dye-sensitized solar cell according to any one of claims 1 to 3.

  According to the dye-sensitized solar cell according to the present invention, the elution of the sensitizing dye from the photoelectrode layer hardly occurs, so that a smooth electron flow by the electrolyte is ensured over a long period of time, and high energy conversion efficiency is achieved. Can be held.

  According to the dye-sensitized solar cell of the present invention, by washing with the same electrolytic solution that fills the photoelectrode layer, the sensitizing dye that can be eluted into the electrolytic solution after filling is surely washed away. Therefore, it is possible to secure a smooth flow of electrons by the electrolyte over a long period of time and maintain high energy conversion efficiency.

  Further, according to the dye-sensitized solar cell according to the present invention, since the elution of the sensitizing dye from the photoelectrode layer hardly occurs, a smooth electron flow by the electrolyte is ensured over a long period of time, and high energy conversion efficiency is achieved. Can be held.

  BEST MODE FOR CARRYING OUT THE INVENTION The best embodiment according to the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of a dye-sensitized solar cell according to the present invention, exaggerating the thickness in one embodiment. In the dye-sensitized solar cell 10, a translucent transparent substrate 32 is provided on the light incident side α from the photoelectrode layer 2 in which a sensitizing dye is supported on a porous semiconductor material. A first conductive film 31 made of ITO (tin-doped indium oxide) is provided between the transparent substrate 32 and the photoelectrode layer 2, and a second conductive film 31 also made of platinum provided on the counter substrate 33. And between the photoelectrode layers 2 are filled with an electrolytic solution 1 that is an aqueous iodine solution.

  In the method for producing a dye-sensitized solar cell according to the present invention, the electrolytic solution 1 is extracted from the state in which the electrolytic solution 1 is filled by an appropriate method, and is newly filled with the electrolytic solution 1 to thereby form a photoelectrode layer. 2 is performed. In addition, after the cleaning electrolyte solution 1 is filled, after irradiation for a certain period of time with visible light including light having a wavelength suitable for power generation, that is, light having a wavelength at which the sensitizing dye to be used is excited, the electrolyte solution If 1 is extracted, a sensitizing dye that may be more efficiently eluted can be removed.

  Further, the cleaning of the photoelectrode layer 2 is not limited to the above method, and the transparent substrate 32 on which the photoelectrode layer 2 in which the sensitizing dye has been lamented is immersed in a cleaning solution having the same component as the electrolytic solution 1 or You may make it wash | clean by irradiating the light containing the light of the wavelength suitable for electric power generation in the immersed state.

  As the electrolytic solution 1, a liquid electrolyte such as a mixed solution of acetonitrile and ethylene carbonate, or a solvent such as methoxypropionitrile and a halogen simple substance such as iodine, or an electrolyte such as lithium iodide or metallic iodine is suitably used. Can be used.

  As a sensitizing dye, yellow can be expressed by using a carotenoid pigment such as gardenia pigment or honeysuckle pigment or a coumarin pigment such as coumarin 343. In developing other color tones, it can be expressed using dyes such as eosin and the like for red, and Scarylium for blue, and various combinations of these three primary colors at appropriate ratios. It may be possible to set different color tones.

  Depending on the application used, ruthenium metal complex dyes generally known as sensitizing dyes include N3, black dye, bipyridine-carboxylic acid group, bipyridine series, phenanthroline, quinoline, β-diketonate complex, and other Os metal complexes, Metal complex dyes such as Fe metal complex, Cu metal complex, Pt metal complex, Re metal complex, methine dyes such as cyanine dyes and merocyanine dyes, mercurochrome dyes, xanthene dyes, porphyrin dyes, phthalocyanine dyes, azo dyes, coumarins Organic dyes such as dyes can also be used.

  The transparent substrate 32 is not particularly limited as long as it is translucent. However, it is easy to mold, such as polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polymethacrylate, acrylic resin, polyvinyl chloride, and ABS. A thermoplastic synthetic resin having light properties can be preferably used, but a cyclic polyolefin resin having high resistance to the iodine solution as the electrolytic solution 1 can be most preferably used. Moreover, you may make it mix | blend durability further by mix | blending a ultraviolet absorber. The optimum combination for exhibiting the effect of reducing translucency and the amount of ultraviolet rays is obtained by blending a cyclic polyolefin-based resin with a benzotriazole-based one as an ultraviolet absorber.

  The first conductive coating 31 is vacuum-deposited with tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), gold, platinum, etc., which are excellent in transparency and high conductivity, and combinations thereof. The film is formed on the substrate 11 by an appropriate method such as a sputtering method, a sputter deposition method, an ion plating method, a CVD method, or an electrophoretic electrodeposition method, or a film on which these thin films are formed is adhered to the substrate 11. Or the like.

  As the second conductive film 31 provided on the counter substrate 33 side, platinum, carbon, conductive polymer, metal oxide such as tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), and the above substances are used. These composite materials are used to form on the substrate 11 by an appropriate method such as a vacuum deposition method, a sputter deposition method, an ion plating method, a CVD method, an electrophoretic deposition method, or a thin film thereof. The film can be formed by sticking the film to the base material 11 or the like.

The semiconductor layers forming the photoelectrode layer 2 are Fe ₂ O ₃ , Cu ₂ O, In ₂ O ₃ , WO ₃ , Fe ₂ TiO ₃ , PbO, V ₂ O ₅ , FeTiO ₃ , Bi ₂ O ₃ , Nb. It can be formed by supporting a sensitizing dye on a thin film formed using a semiconductor material such as ₂ O ₃ , SrTiO ₃ , ZnO, BaTiO ₃ , CaTiO ₃ , KTaO ₃ , SnO ₂ , ZrO _2, and keep it porous. Is preferred. Of these, titanium oxide (TiO ₂ ) or zinc oxide (ZnO), which is excellent in the formation of a transparent thin layer and can be electrodeposited, is preferable as the semiconductor material. The present invention is not limited to this, and appropriate ones can be used.

  The time for irradiating visible light containing light having a wavelength at which the sensitizing dye to be used is excited at least in the state where the electrolytic solution 1 for cleaning is filled is preferably about 70 to 100 hours. Table 1 shows the light based on JIS C8917 “Environmental test method and durability test method for crystalline solar cell module” by irradiating pseudo-sunlight on the dye-sensitized solar cell listed in Example 1 described later with a solar simulator. After the irradiation test, the change in absorbance of light at a wavelength of 500 nm of the photoelectrode layer 2 measured by UV-VIS (visible / ultraviolet absorptiometry) is shown. The vertical axis represents absorbance and the horizontal axis represents light. It represents the irradiation time (time).

  As shown in Table 1, as the time of the light irradiation test elapses, the absorbance initially increases, that is, the red color of the photoelectrode layer 2 decreases due to the desorption of the dye. Therefore, the absorbance is almost constant. Therefore, by taking a light irradiation test for at least about 70 hours and taking the allowance for about 100 hours to extract and fill the electrolyte, sensitizing dyes with weak adsorptive power are sufficiently removed as aggregates and the like. Can be estimated.

  The effects obtained by the method for producing a dye-sensitized solar cell according to the present invention will be described in the following examples.

(Example 1)
A thin semiconductor layer made of porous zinc oxide is formed on a first conductive film made of ITO (tin-doped indium oxide) deposited on the surface of a cyclic polyolefin resin plate, and a coumarin sensitizing dye is formed on the semiconductor layer. (D102) was immersed in 500 μM for 1 hour to form a transparent substrate. Similarly, a counter conductive substrate was formed by providing a second conductive film in which platinum was vapor-deposited on ITO (tin-doped indium oxide) vapor-deposited on the surface of the cyclic polyolefin resin plate. The photoelectrode layer and the second conductive film are arranged opposite to each other, and between the photoelectrode layer and the second conductive film, iodine is 0.025M and tetrapropylammonium iodide is 0. An electrolyte solution dispersed in an acetonitrile-based solvent as a bulky electrolyte at a concentration of 5 M was once filled, and the periphery of the electrolyte layer was sealed with an epoxy-based sealing material. In this state, after performing a light irradiation test based on JIS C8917 described later for 72 hours, the electrolyte solution was taken out and newly filled with the electrolyte solution, whereby the dye-sensitized solar cell according to Example 1 of the present invention was obtained. It was.

(Comparative Example 1)
A dye-sensitized solar cell of Comparative Example 1 was obtained in the same manner as in Example 1 except that the light irradiation test, extraction of the electrolytic solution, and no new filling were performed (the electrolytic solution was filled as it was first).

  For the dye-sensitized solar cell of Example 1 and Comparative Example 1, the initial energy conversion efficiency was measured, and further simulated sunlight was irradiated with a solar simulator, and JIS C8917 “Environmental test method for crystalline solar cell module and A light irradiation test based on the “endurance test method” was conducted, and the energy conversion efficiency at the time of irradiation for 144 hours (equivalent to actual outdoor exposure for 2 years) and 316 hours (equivalent to actual outdoor exposure for 5 years) was converted to an IV curve. Measurement was performed with a tracer MP-160 (manufactured by Eiko Seiki Co., Ltd.). Table 2 shows the retention rate of the energy conversion efficiency after the light irradiation test.

  Although there is not much difference between Example 1 and Comparative Example 1 at the time of light irradiation test 144 hours, there is a significant difference between Comparative Example 1 and Example 1 after 312 hours of light irradiation test. In the light irradiation test of 312 hours, that is, at the time corresponding to outdoor exposure for 5 years, in the dye-sensitized solar cell manufactured by the conventional manufacturing method of Comparative Example 1, the energy conversion efficiency is improved by elution of the sensitizing dye into the electrolyte. A significant decrease is inevitable, and the superiority of the manufacturing method according to the present invention is clearly manifested.

  Further, the following examples will be shown to explain the advantages obtained by the method for producing a dye-sensitized solar cell according to the present invention.

(Example 2)
A dye-sensitized solar cell of Example 2 according to the present invention was obtained in the same manner as Example 1 except that the iodine concentration of the electrolytic solution was changed to 0.25M.

(Comparative Example 2)
A dye-sensitized solar cell of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that the iodine concentration of the electrolytic solution was changed to 0.25M.

  About the dye-sensitized solar cell of Example 2 and Comparative Example 2, the initial energy conversion efficiency was measured, and further, simulated sunlight was irradiated with a solar simulator, and JIS C8917 “Environmental test method for crystalline solar cell module and Light irradiation test based on "Durability Test Method", and the irradiation time of the light irradiation test 24 hours, 72 hours, 144 hours (equivalent to actual outdoor exposure 2 years), 216 hours and 316 hours (equivalent to actual outdoor exposure 5 years) The energy conversion efficiency was measured with an IV curve tracer MP-160 (manufactured by Eiko Seiki Co., Ltd.). Table 3 shows the transition of the retention rate of the energy conversion efficiency after the light irradiation test.

  Also in this example, the degree of decrease in the conversion efficiency of Comparative Example 2 by increasing the iodine concentration was made smaller than that of Comparative Example 1, but after 312 hours of the light irradiation test, Example 2 and Comparative Example 2 In the light irradiation test of 312 hours, that is, at the time corresponding to 5 years of outdoor exposure, in the dye-sensitized solar cell manufactured by the conventional manufacturing method of Comparative Example 2, the sensitizing dye A significant decrease in energy conversion efficiency is inevitable due to elution into the electrolytic solution, and the superiority of the production method according to the present invention is clearly manifested. Further, the difference in conversion efficiency between Example 2 and Comparative Example 2 starts from around 72 hours of the light irradiation test. The desorption of the sensitizing dye shown in Table 1 and the energy conversion efficiency shown in Table 3 are shown. It can also be estimated that there is a correlation.

It is the longitudinal cross-sectional view which exaggerated and represented the thickness in one Embodiment of the dye-sensitized solar cell concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolyte layer 2 Photoelectrode layer 31 (1st and 2nd) electroconductive film 32 Transparent substrate 33 Opposite substrate 10 Dye-sensitized solar cell

Claims (4)

A photoelectrode layer formed by supporting a sensitizing dye on a semiconductor layer formed on the first conductive film of the transparent substrate is disposed opposite to the second conductive film of the counter substrate, A method for producing a dye-sensitized solar cell in which a space between a photoelectrode layer and a second conductive coating is filled with an electrolyte containing an electrolyte, and the photoelectrode layer is washed with the electrolyte, A method for producing a dye-sensitized solar cell, which is newly filled with an electrolytic solution after the washing. The method for producing a dye-sensitized solar cell according to claim 1, wherein the cleaning is performed while irradiating light including light having a wavelength suitable for power generation. The dye sensitization according to claim 1 or 2, wherein the washing is performed in a state where the dye-sensitized solar cell is assembled, and only the electrolytic solution is once extracted and filled again. Type solar cell manufacturing method. It forms with the manufacturing method of the dye-sensitized solar cell in any one of Claims 1-3, The dye-sensitized solar cell characterized by the above-mentioned.

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