Photoelectrochemical properties of undoped and Ti-doped WO3

Undoped and Ti-doped WO3 (up to 0.65 at% Ti) polycrystalline specimens were investigated. The flat band potential was determined based on the photocurrent experiments; the effect of Ti concentration on solar energy conversion efficiency was discussed. It was found that incorporation of titanium ions into WO3 lattice leads to the decrease of the recombination process and shifts the flat band potential towards positive values. The incident photon-to-current efficiency (IPCE) assumes highest values for WO3+0.4 at% Ti. The maximum solar energy conversion efficiency has been observed at voltage bias 0.45-0.65 V.