Thin Solid Films, Vol.519, No.3, 1087-1092, 2010
Probing mechanism of dye double layer formation from dye-cocktail solution for dye-sensitized solar cells
Absorption of photon in wide wavelength region is an important requirement for the enhancement of photoconversion efficiency of dye-sensitized solar cells (DSSC). Lack of photon absorption from visible to NIR wavelength region by a single dye requires the use of plural dyes for the panchromatic sensitization of nanoporous TiO(2). To our incredible surprise, when a dye cocktail of organic dye NK3705 and inorganic ruthenium based dye Z907 was implied for the dye adsorption, it led to the formation of dye double layer in spite of random arrangement of two dyes as evidenced from confocal laser microscopic investigations. Investigation pertaining to the evaluation of rate of dye adsorption and dye desorption for different organic and inorganic sensitizing dyes suggests that a combination of one dye with faster diffusion along with weak binding on TiO(2) surface and another dye with slow diffusion along with strong binding leads to the formation of dye double layer from a dye mixture by a simple dipping process. (C) 2010 Elsevier B.V. All rights reserved.
Keywords:Dye-sensitized solar cells;Nanocrystalline TiO(2);Dye cocktail;Dye double layer;Rate of adsorption/desorption