First-principles Study of CeO2/BiVO4 Interfaces

Using density functional theory calculations, we investigate the structural, energetic, and electronic properties of CeO2/BiVO4 interfaces. We find that, despite a 5\% mismatch, thin CeO2 layers (with thicknesses of up to three monolayers) can be epitaxially grown on BiVO4(010) substrates. At these epitaxial interfaces, all the atoms are fully coordinated. Thus, no localized interface state appears in the band gap. More importantly, the surface states of BiVO4, which serve as recombination centers for excited charges, are eliminated by the CeO2 coating layers. These findings explain the significant decrease of charge recombination observed in experiments.