Light scattering of nanocrystalline TiO2 film used in dye-sensitized solar cells

This paper studies the light scattering and adsorption of nanocrystalline TiOlight scattering, modelling, films, dye-sensitized solar cellsProject supported by the Program of Science and Technology Commission of Shanghai Municipality (Grant No 03DZ12032) and the Program for New Century Excellent Talents in University in China (Grant No NCET-04-0406).4225F, 61463/7/2008 12:00:00 AMThis paper studies the light scattering and adsorption of nanocrystalline TiOlight scattering, modelling, films, dye-sensitized solar cellsProject supported by the Program of Science and Technology Commission of Shanghai Municipality (Grant No 03DZ12032) and the Program for New Century Excellent Talents in University in China (Grant No NCET-04-0406).4225F, 61463/7/2008 12:00:00 AMThis paper studies the light scattering and adsorption of nanocrystalline TiOlight scattering, modelling, films, dye-sensitized solar cellsProject supported by the Program of Science and Technology Commission of Shanghai Municipality (Grant No 03DZ12032) and the Program for New Century Excellent Talents in University in China (Grant No NCET-04-0406).4225F, 61463/7/2008 12:00:00 AMThis paper studies the light scattering and adsorption of nanocrystalline TiO$_2$ porous films used in dye-sensitized solar cells composed of anatase and/or rutile particles by using an optical four-flux radiative transfer model. These light properties are difficult to measure directly on the functioning solar cells and they can not be calculated easily from the first-principle computational or quantitative theoretical evaluations. These simulation results indicate that the light scattering of 1--25\,nm TiO$_{2}$ particles is negligible, but it is effective in the range of 80 and 180\,nm. A suitable mixture of small particles (10\,nm radius), which are resulted in a large effective surface, and of larger particles (150\,nm radius), which are effective light scatterers, have the potential to enhance solar absorption significantly. The rutile crystals have a larger refractive index and thus the light harvest of the mixtures of such larger rutile and relatively small anatase particles is improved in comparison with that of pure anatase films. The light absorption of the 10\,$\mu$m double-layered films is also examined. A maximal light absorption of double-layered film is gotten when the thickness of the first layer of 10\,nm-sized anatase particles is comparable to that of the second larger rutile layer.