Abstract
BiVO4 films and BiVO4/WO3 heterostructure have been obtained by electrosynthesis method with the use of interferometric control of the thickness of films during their electrodeposition. The electrodeposition of BiVO4 films involves the electrochemical stage of oxidation of VO2+ to H2VO4− and the chemical interaction of BiO+ with H2VO4−. It has been established that the as-deposited film contains up to 25% water by means of two-beam interferometry, DTA and TGA. The films containing BiVO4 and WO3 after annealing at 500 °C are crystallized to a monoclinic scheelite structure. It is found that the photoelectrochemical efficiency of crystalline BiVO4 films depends on their thickness. It is shown that the quantum efficiency (η = 0.30–0.65) at λ = 400–450 nm is observed for BiVO4/WO3 heterostructure with a BiVO4 film thickness of 140 nm and WO3 layer of 500 nm. The WO3 layer makes an additional contribution to photocurrent in the fundamental absorption region and increases the overall photoelectrochemical efficiency in the UV and the near-visible regions.
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