PHOTOELECTROCHEMICAL PROPERTIES OF FILMS BASED ON BISMUTH AND COPPER VANADATES

BiVO4, BiVO4 / WO3 and Cu3VO4 films were obtained by the method of electrochemical synthesis using interferometric control of the film thickness during their deposition; It is shown that films absorb light in the long-wave region of the solar spectrum. The materials obtained also have good adhesion with the optically transparent substrate SnO2. From the analysis of the photocurrent spectra, it was determined that the photoelectrochemical efficiency of BiVO4 crystalline films depends on the thickness of such films. BiVO4 films with a thickness of 80–150 nm showed high values of the quantum yield of the photocurrent as compared with films with a thickness of 0.5–1 μm. From XRD, it was established that after annealing at 500°C, the films BiVO4 and WO3 crystallize into the structure of monoclinic scheelite. It has been established that the WO3 layer in the BiVO4 / WO3 heterostructure increases its overall photoelectrochemical efficiency in the ultraviolet and near visible regions of the spectrum. It was established that, depending on the heat treatment conditions, the band gap of the obtained Cu3VO4 films is from 1.4 to 2.2 eV, which allows them to be used as photoanods for photoelectrochemical converters of solar energy. Due to the narrow width of the bandgap, Cu3VO4 can absorb visible light in almost the entire long-wave region. But the literature data on photoelectrochemical properties of Cu3VO4 and BiVO4 are limited, in this connection there is a need for the development of techniques for the synthesis of photosensitive films based on Cu3VO4 and BiVO4 and their photoelectrochemical characteristics. In this paper we investigate the photoelectrochemical characteristics of copper vapor and vanadium Cu3VO4 and BiVO4 bismuth which can absorb visible light in the long-wave region of the solar spectrum and work in pairs as a photo anode (BiVO4) and a photocathode of Cu3VO4 in a photoelectrochemical cell for the production of hydrogen and oxygen.