Transparency Effect of Electrolyte on Light Back-Scattering in Dye-Sensitized Solar Cells

Author

Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan, Iran

Abstract

Conventionally, a film of TiO2 particles of ~300 nm size is employed in DSCs as the back reflector film to enhance the light harvesting. In this study, two electrolytes with different transparencies, iodide-based and cobalt-based electrolytes, were used to investigate the transparency effect of electrolytes on light back-scattering from back scattering layer and also to study its effect on the performance of DSCs. The use of cobalt-based electrolyte is recommended from the view point of optical properties as due to the light absorption in electrolytes, the current density losses are 2.9mA/cm2 and 4.2 mA/cm2 in cobalt- and iodide-based electrolytes, respectively, and the transmission of 100% is observed for cobalt-based electrolyte in 500-600 nm in spite of iodide-based electrolyte. Use of light back-scattering layer, unlike iodide-based cell, causes external quantum efficiency in cobalt-base cell to increase for the wavelengths lower than 350 nm since cobalt-base electrolyte has transparency in this region. In addition, optical calculations demonstrate that in the range 400-500 nm, in which dye has a noticeable absorption, absorption loss is 40% and 30% for iodide- and cobalt-based electrolytes, respectively.

Keywords


O’Regan, B.C. and Graetzel, M., “A Low-Cost, High-Efficiency Solar Cell Based on Dye-Sensitized Colloidal TiO2 Films”, Nature, Vol. 353, pp. 737–740, 1991.
2. Tachibana, Y., Hara, K., Sayama, K. and Arakawa, H., “Quantitative Analysis of Light-Harvesting Efficiency and Electron-Transfer Yield in Ruthenium-Dye-Sensitized Nanocrystalline TiO2 Solar Cells”, Solar Cells, Vol. 14, pp. 2527–2535, 2002.
3. Graetzel, M., “Solar Energy Conversion by Dye-Sensitized Photovoltaic Cells”, Inorganic Chemistry, Vol. 44, pp. 6841–51, 2005.
4. Ito, S., Murakami, T., Comte, P. and Liska, P., “Fabrication of Thin Film Dye Sensitized Solar Cells with Solar to Electric Power Conversion Efficiency over 10%”, Thin Solid Films, Vol. 516, pp. 4613–4619, 2008.
5. Sevilla, M. and Fuertes, A.B., “Chemical and Structural Properties of Carbonaceous Products Obtained by Hydrothermal Carbonization of Saccharides”, Chemistry (Easton), Vol. 15,
pp. 4195–4203, 2009.
6. Feldt, S.M., Gibson, E.A., Gabrielsson, E., Sun, L., Boschloo, G. and Hagfeldt, A., “Design of Organic Dyes and Cobalt Polypyridine Redox mediators for High-Efficiency Dye-Sensitized Solar Cells”, Journal of the American Chemical Society, Vol. 132,
pp. 16714–24, 2010.
7. Giribabu, L., Bessho, T., Srinivasu, M., Vijaykumar, C., Soujanya, Y., Reddy, V.G., Reddy, P.Y., Yum, J., Graetzel, M. and Nazeeruddin, M.K., “A New Familiy of Heteroleptic Ruthenium(Ii) Polypyridyl Complexes for Sensitization of Nanocrystalline TiO2 Films”, Dalton Transactions: An International Journal of Inorganic Chemistry, Vol. 40, pp. 4497–4504, 2011.

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