Interstitial Lithium Doping in BiVO₄ Thin Film Photoanode for Enhanced Solar Water Splitting Activity

As one of the most promising candidates of photoanode material, bismuth vanadate (BiVO 4 ) has been paid wide attention and achieved remarkable progress. However, the full exploitation of solar-energy-conversion potential of bismuth vanadate (BiVO 4 ) is still limited by poor charge transport. Introducing dopants into BiVO 4 has been proved to be a feasible method to improve the photoelectrochemical water splitting performance. In this work, lithium is introduced as an interstitial dopant to crystalline BiVO 4 thin film photoanode, with the aid of pulsed laser deposition (PLD). Solid-state transport characterization demonstrates increased carrier density and electron conductivity in BiVO 4 bulk due to interstitial lithium doping, which also increased the photocurrent and photon-to-current conversion efficiency both by up to 20% for solar water splitting. Computational results based on density functional theory determine the effect of lithium doping on the electronic and atomic structures of BiVO 4 and verify the role of lithium dopant as a shallow donor that improves the conductivity of BiVO 4 .