Interfacial charge recombination via the triplet state? Mimicry of photoprotection in the photosynthetic process with a dye-sensitized TiO2 solar cell reaction

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 β-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.