METAL OXIDE SEMICONDUCTOR ELECTRODE HAVING POROUS THIN FILM, DYE-SENSITIZED SOLAR CELL USING SAME, AND METHOD FOR MANUFACTURING SAME

The present invention relates to a dye-sensitized solar cell and to a method for manufacturing same, and more specifically, to a novel dye-sensitized solar cell for preventing photoelectron recombination due to a triiodide, and to a method for manufacturing same. The dye-sensitized solar cell, according to the present invention, comprises a metal oxide which is produced by co-adsorption of a reactive compound, which can react with iodine, with a dye on a surface of the dye-sensitized solar cell. The dye-sensitized solar cell can achieve high efficiency by preventing the photoelectron recombination due to the triiodide while using a small amount of the dye.

MODE FOR INVENTION

A composition for forming a TiO2(solaronix) porous film was applied using a doctor blade process on a transparent glass substrate having a substrate resistance of 15Ω/□ and coated with fluorine-doped ITO. Drying and then heat treatment at 500° C. for 30 min were carried out, thus forming a porous film having TiO2. The thickness of the formed porous film was about 6 μm. Subsequently, a first electrode having the porous film was immersed for 18 hr in a solution comprising acetonitrile and tert-butanol (1:1 volume ratio) solvents and 0.30 mM ruthenium(4,4-dicarboxy-2,2′-bipyridine)2(NCS) as a dye and 0.30 mM methacryloyl-4-aminobutyric acid as a co-adsorbent, so that the dye was adsorbed on the porous film. Subsequently, a solution comprising methylmethacrylate and 1,6-hexanediol diacrylate at a molar ratio of 2 was applied on the first electrode having the porous film adsorbed with the dye and the co-adsorbent, and was then cross-linked at 80° C. for 30 min.FIGS. 4 and 5are images illustrating the cross-section of the porous polymer thin film formed while surrounding the TiO2particles as observed by SEM at 6,000 and 150,000 magnifications.

A platinum paste (solaronix) was applied using a doctor blade process on a transparent glass substrate having a substrate resistance of 15Ω/□ and coated with fluorine-doped ITO. Drying and then heat treatment at 450° C. for 30 min were carried out, thus manufacturing a catalyst electrode to form a second electrode. A bore was formed in the second electrode using a 0.75 mm drill.

0.6M 1-butyl-3-methylimidazolium iodide, 0.03M iodine, 0.10M guanidinium thiocyanate, and 0.5M 4-tert-butylpyridine were dissolved in acetonitrile and valeronitrile (85:15 volume ratio) solvents, thus preparing an electrolyte, which was then injected via the bore, after which the bore was sealed with an adhesive, thereby manufacturing a dye-sensitized solar cell.

A dye-sensitized solar cell was manufactured in the same manner as in Example 1, with the exception that the electrolyte was prepared by dissolving 0.8M 1-butyl-3-methylimidazolium iodide, 0.03M iodine, and 0.2M 4-tert-butylpyridine in a methoxypropionitrile solvent.

A dye-sensitized solar cell was manufactured in the same manner as in Example 2, with the exception that the electrolyte was prepared by mixing the electrolyte of Example with a solution comprising methylmethacrylate and 1,6-hexanediol diacrylate at a ratio of 4, and was then cross-linked again, thereby manufacturing a semi-solid dye-sensitized solar cell.

A dye-sensitized solar cell was manufactured in the same manner as in Example 1, with the exception that the solution comprising methylmethacrylate and 1,6-hexanediol diacrylate at a molar ratio of 4 was used.

A dye-sensitized solar cell was manufactured in the same manner as in Example 1, with the exception that the solution comprising methylmethacrylate and 1,6-hexanediol diacrylate at a molar ratio of 0.5 was used.

A dye-sensitized solar cell was manufactured in the same manner as in Example 1, with the exception that styrene was used, instead of methylmethacrylate.

A dye-sensitized solar cell was manufactured in the same manner as in Example 1, with the exception that 1,4-butanediol diacrylate was used instead of 1,6-hexanediol diacrylate.

A dye-sensitized solar cell was manufactured in the same manner as in Example 1, with the exception that methacryloyl-4-aminolauric acid was used as the co-adsorbent, instead of methacryloyl-4-aminobutyric acid.

Comparative Example 1

A composition for forming a TiO2(solaronix) porous film was applied using a doctor blade process on a transparent glass substrate having a substrate resistance of 15Ω/□ and coated with fluorine-doped ITO. Drying and then heat treatment at 500° C. for 30 min were carried out, thus forming a porous film having TiO2. The thickness of the formed porous film was about 6 μm.

Subsequently, a first electrode having the porous film was immersed for 18 hr in a solution comprising acetonitrile and tert-butanol (1:1 volume ratio) solvents and 0.30 mM ruthenium(4,4-dicarboxy-2,2′-bipyridine)2(NCS) as a dye, so that the dye was adsorbed on the porous film.

A platinum paste (solaronix) was applied using a doctor blade process on a transparent glass substrate having a substrate resistance of 15Ω/□ and coated with fluorine-doped ITO. Drying and then heat treatment at 450° C. for 30 min were performed, thus manufacturing a catalyst electrode to form a second electrode. A bore was formed in the second electrode using a 0.75 mm drill.

0.6M 1-butyl-3-methylimidazolium iodide, 0.03M iodine, 0.10M guanidinium thiocyanate, and 0.5M 4-tert-butylpyridine were dissolved in acetonitrile and valeronitrile (85:15 volume ratio) solvents, thus preparing an electrolyte, which was then injected via the bore, after which the bore was sealed with an adhesive, thereby manufacturing a dye-sensitized solar cell.

Comparative Example 2

A dye-sensitized solar cell was manufactured in the same manner as in Comparative Example 1, with the exception that the electrolyte was prepared by dissolving 0.8M 1-butyl-3-methylimidazolium iodide, 0.03M iodine, and 0.2M 4-tert-butylpyridine in a methoxypropionitrile solvent, thus preparing a solution and then mixing this solution with a solution of methylmethacrylate and 1,6-hexanediol diacrylate at a ratio of 4, and was then cross-linked again, thus manufacturing a semi-solid dye-sensitized solar cell.

The dye-sensitized solar cell of Example 1 was stored at 80° C., and taken out at 200 hr, 400 hr, 600 hr, 800 hr, 1000 hr, and 1200 hr, and the solar cell efficiency thereof was measured.

Comparative Example 3

The dye-sensitized solar cell of Comparative Example 1 was stored at 80° C., and taken out at 200 hr, 400 hr, 600 hr, 800 hr, 1000 hr, and 1200 hr, and the solar cell efficiency thereof was measured.

The porous polymer thin film according to the present invention is formed to surround the surface of the metal oxide adsorbed with the dye, thus minimizing desorption of dye molecules and recombination, which are regarded as the most serious causes of decreased durability of the cell, thereby improving both open-circuit voltage and short-circuit current, thus significantly increasing photoelectric conversion efficiency and drastically improving durability of the cell. Therefore the present invention provides a technique for developing a dye-sensitized solar cell having high efficiency, low cost and long-term stability. Specifically, the technique for developing the dye-sensitized solar cell able to simultaneously achieve high efficiency, low cost, and long-term stability is provided, thus exhibiting very high industrial applicability.