Dye-sensitization on the Photocurrent at Zinc Oxide Electrode in Aqueous Electrolyte Solution

The dye-sensitized photocurrents generated from the electrochemical systems <zinc oxide|aq solution|platinum> have been studied. The action spectra for the photocurrent, its dependence on the concentration of the dye solution and other experimental results have revealed that the photocurrent is caused by the dye adsorbed on the electrode, not from that dissolved in the liquid phase. From the analysis of the decay of the photocurrent with the time of illumination, the quantum yield for the electron injection from the excited dye has been determined. Rose Bengal showed the quantum yield of 22%. The influence of halide ions on the photocurrent has also been studied.