Mechanism of Electrochemical Dye Sensitization: Effects of Semiconductor Doping Level and Reducing Agent on the Photocurrent Quantum Yield

The electrochemical spectral Sensitization of SnO 2 and ZnO electrodes with rhodamine B and rose bengal has been studied in acetonitrile. The photocurrent quantum yield was shown to depend remarkably on the doping level of the semiconductor electrodes. The quantum yield approached unity under the most preferable conditions. The effect of hydroquinone on the Sensitization process (supersensitization) also depended on the semiconductor doping level. These results, together with the fluorescence quenching behaviors of the dyes adsorbed on the semiconductors, are taken into account to elucidate the mechanism of electrochemical spectral sensitization and supersensitization.