Effect of Surface Modification to Photoanodes in Alkoxysilyl Dye-Sensitized Solar Cells on the Photovoltaic Performance

Abstract

The effect of surface modification to dye-adsorbed TiO2 electrodes in alkoxysilyl dye-sensitized solar cells on the photovoltaic performance was investigated with using alkylcarboxylic acids with different alkyl-chain lengths as surface modifiers. More effective suppression of a back-electron-transfer reaction was observed with the increment of the amount of the adsorbed modifier on the dye-adsorbed TiO2 electrode and with lengthening the alkyl chain of the alkylcarboxylic acid. The photovoltaic performance of the cells was confirmed to be improved by the surface modifications of the dye-adsorbed TiO2 electrodes using alkylcarboxylic acids, and the necessities of tuning the surface-modification degree and the selection of the alkyl-chain length with regarding the molecular size of the sensitizing dye were exhibited for the efficient improvement of the photovoltaic performance of the cell.