Photoelectrochemical cells with tungsten trioxide/Mo-doped BiVO4 bilayers

Abstract

Mo-doped BiVO₄ nanocrystals with low bandgap energy were embedded into the surface of WO₃ film, resulting in WO₃/BiV_0.95Mo_0.05O₄ photoanodes, which were tested in photoelectrochemical cells for water splitting. Bilayer photoelectrochemical cells showed enhanced photocurrent density: three times that shown by a cell with a pure WO₃ photoanode and 1.5 times that of a cell with a WO₃/BiVO₄ bilayer photoanode. BiVO₄ showed poor charge carrier mobility; the performance of photoelectrochemical cells can be improved only when BiVO₄ is combined with a WO₃ bottom layer, even after Mo doping and tailoring its transition energies by atomic doping.