Characterization of the electronic structure of sputter-deposited Mo-doped BiVO4 thin-film photoanodes

Abstract

Abstract Molybdenum (Mo) doping is a pivotal strategy to enhance the performance of bismuth vanadate (BiVO4) photoanodes in photoelectrochemical (PEC) devices. This research explores the effects of Mo-doping on BiVO4’s electronic properties, uncovering mechanisms behind improved PEC behavior. Mo-doped BiVO4 was produced via single-target RF sputtering, leading to films with increased photocurrent density. Optimal results were achieved with a 3% atomic ratio of Mo and 15% oxygen partial pressure during deposition. Analysis of the local structure revealed Mo6+ substituting V in the BiVO4 host. Mo doping introduced defect states within the VB, partially occupying the d-band of V4+ and creating additional electron states, causing the fermi level to shift from 1.75 to 2.19 eV from the VB edge. This study underscores the adaptability of Mo-doping in shaping BiVO4’s electronic characteristics, opening new pathways in advanced energy conversion technologies.