Atomic Layer Deposition of Bismuth Vanadates for Solar Energy Materials

The fabrication of porous nanocomposites is key to the advancement of energy conversion and storage devices that interface with electrolytes. Bismuth vanadate, BiVO 4 , is a promising oxide for solar water splitting where the controlled fabrication of BiVO 4 layers within porous, conducting scaffolds has remained a challenge. Here, the atomic layer deposition of bismuth vanadates is reported from BiPh 3 , vanadium(V) oxytriisopropoxide, and water. The resulting films have tunable stoichiometry and may be crystallized to form the photoactive scheelite structure of BiVO 4 . A selective etching process was used with vanadium‐rich depositions to enable the synthesis of phase‐pure BiVO 4 after spinodal decomposition. BiVO 4 thin films were measured for photoelectrochemical performance under AM 1.5 illumination. The average photocurrents were 1.17 mA cm −2 at 1.23 V versus the reversible hydrogen electrode using a hole‐scavenging sulfite electrolyte. The capability to deposit conformal bismuth vanadates will enable a new generation of nanocomposite architectures for solar water splitting.