Photo-to-electric conversion of a nanostructured TiO~2 electrode cosensitized with dye pairs of ZnTSPP-H~2TSPP and ZnTSPP-GaTSPc was investigated. Doping of ZnTSPP reduces self-aggregation of H~2TSPP and GaTSPc in the surface of the electrode. Cosensitization markedly enhances the photoelectric response of Q band and in the meantime greatly decreases that of Soret band under monochromatic illumination. But this decrease in Soret band is off-set by the enhancement of Q band. As a result, cosensitization improves the total photo-to-electric conversion in the whole wavelength range and creates the mixed effect in short-circuit photocurrent. The photoelectric behaviors of the cosensitized electrode is attributed to the presence of a low-lying charge-transfer state originating from the formation of heteroaggregates in dye pairs of ZnTSPP-H~2TSPP and ZnTSPP-GaTSPc.

Key words: PORPHYRIN, PHTHALOCYANIN (=PHTHALOCYANINE), TITANIUM DIOXIDE, NANOPHASE MATERIALS, ELECTRODE, ZINC COMPLEX, GALLIUM COMPLEX, PHOTOELECTRICAL CONVERSION, CHARGE TRANSFER