Enhanced photovoltaic response of the first polyoxometalate-modified zinc oxide photoanode for solar cell application

Abstract

A photovoltaic electrode consisting of polyoxometalate (SiW12) and zinc oxide (ZnO) was fabricated on indium tin oxide (ITO) glass by one-step electrodeposition. The addition of SiW12 strongly influences the morphology and crystallographic orientation of the ZnO. The photovoltaic properties of the ZnO film and the SiW12–ZnO composite films were investigated via solar cell assembly. Both transient photocurrent and current–voltage curve measurements demonstrate that the photocurrent and power conversion efficiency of the SiW12–ZnO composite film were markedly enhanced in comparison with that of the ZnO film. Based on the results of fluorescence quenching measurements, the enhanced photovoltaic effect should be attributed to the occurrence of the photoinduced electron transfer between polyoxometalate and ZnO, which increases the efficient dissociation of excited electron–hole pairs (excitons).