Photoelectrochemical cells with tungsten trioxide/Mo-doped BiVO4 bilayers.

Mo-doped BiVO(4) nanocrystals with low bandgap energy were embedded into the surface of WO(3) film, resulting in WO(3)/BiV(0.95)Mo(0.05)O(4) 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 WO(3) photoanode and 1.5 times that of a cell with a WO(3)/BiVO(4) bilayer photoanode. BiVO(4) showed poor charge carrier mobility; the performance of photoelectrochemical cells can be improved only when BiVO(4) is combined with a WO(3) bottom layer, even after Mo doping and tailoring its transition energies by atomic doping.