Photoelectrochemical cells with tungsten trioxide/Mo-doped BiVO4 bilayers

Mo-doped BiVO4 nanocrystals with low bandgap energy were embedded into the surface of WO3 film, resulting in WO3/BiV0.95Mo0.05O4 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.