摘要：

New organic dyes that contain variable lengths of conjugation, featuring oligothiophene and arylamines at the 2- and 3-position, have been synthesized. These compounds are characterized by photophysical, electrochemical, and theoretical computational methods. Nanocrystalline TiO-based dye-sensitized solar cells were fabricated using these molecules as light-harvesting sensitizers. The overall efficiencies of the sensitized cells range from 4.11 to 6.15%, compared to a -di(thiocyanato)-bis(2,2′-bipyridyl)-4,4′-dicarboxylate ruthenium(II)-sensitized device (7.86%) fabricated and measured under similar conditions. The devices made from these compounds have higher open-circuit voltage () compared to oligothiophene congeners with arylamines at the 2-position only. The hydrophobic segment at the 3-position appears to help retarding the charge transfer from the conduction band of TiOto the electrolyte, I. Supplementary studies of the transient photovoltage and electrochemical impedance are in support of retarded charge transfer of TiO(e) with both oxidized sensitizer and I. Computation on a pair of compounds with and without arylamines at 3-position indicates that the former has larger charge transfer efficiency at the electronically excited state.

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