Metal oxide materials could offer earth-abundant, non-toxic alternatives to existing light-absorber materials in thin-film photovoltaic and photoelectrochemical cells. However, efficiency of these devices based on existing metal oxides is typically low due to poor material properties. In this research, novel Sb: SnO2 nanowire electron collector has been synthesized, investigated and was used to improve the photo-conversion efficiency of top-performing BiVO4 photoelectrochemical cell. The performance of Sb: SnO2/BiVO4 achieved a new record for the product of light absorption and charge separation efficiencies (ηabs × ηsep) of ~ 54.3% and 56.3% under front- and back-side illumination at 0.6 VRHE. In addition, a new promising metal oxide material (BiCuW2O8) has been synthesized and investigated to make photovoltaic cell which has potential to achieve over 30% solar power conversion efficiency.