Enhanced Photocatalytic Performance Depending on Morphology of Bismuth Vanadate Thin Film Synthesized by Pulsed Laser Deposition

We have fabricated high quality bismuth vanadate (BiVO₄) polycrystalline thin films as photoanodes by pulsed laser deposition (PLD) without a postannealing process. The structure of the grown films is the photocatalytically active phase of scheelite-monoclinic BiVO₄ which was obtained by X-ray diffraction (XRD) analysis. The change of surface morphology for the BIVO₄ thin films depending on growth temperature during synthesis has been observed by scanning electron microscopy (SEM), and its influence on water splitting performance was investigated. The current density of the BiVO₄ film grown on a glass substrate covered with fluorine-doped tin oxide (FTO) at 230 °C was as high as 3.0 mA/cm² at 1.23 V versus the potential of the reversible hydrogen electrode (V_RHE) under AM 1.5G illumination, which is the highest value so far in previously reported BiVO₄ films grown by physical vapor deposition (PVD) methods. We expect that doping of transition metal or decoration of oxygen evolution catalyst (OEC) in our BiVO₄ film might further enhance the performance.