Evidence for the photoinduced charge recombination to the excited-triplet state has been observed in chemical solar cell reaction consisting of dye-sensitized TiO2 colloidal ethanol solution, which mimicks the photoprotection function in the photosynthetic units. The dye is all-trans-retinoic acid. a structural analog of beta-carotenoid. Two channels of charge recombination. i.e., through triplet and ground states were observed by nano-second flash photolysis. The possibility of applying the function of photoprotection to the synthetic solar cell is discussed. which provides a potential entry of molecular engineering of the dye to improve the long term stability of the synthetic solar cell. (C) 2002 Elsevier Science B.V. All rights reserved.