Spray deposition process of polycrystalline thin films of CuWO4 and study on its photovoltaic electrochemical properties

The preparation of copper tungstate (CuWO4) thin film for the first time by Spray Pyrolysis (SP) process using its ammonical solution as precursor is presented here. The growth of the film takes place by pyrolytic decomposition of the spraying precursor solution onto the preheated glass substrates. X-ray diffraction (XRD) study confirms the polycrystalline, single-phase nature of the sintered films. Scanning electron microscope (SEM) images clearly show the uniform aggregate of crystallites of dimensions 1–2 μm. The study of optical absorption spectrum in the wavelength range 350–850 nm shows direct as well as indirect optical transitions in both the materials. The films are semiconducting in nature and highly resistive at room temperature as evident from their d.c. electrical conductivity measurements obtained by the Two Point Probe method in the temperature range 310–600 K. The thin films deposited on fluorine doped tin oxide (FTO) coated conducting glass substrates are then used as photoanode in photovoltaic electrochemical (PVEC) cell. The PVEC cell configuration is: CuWO4 |Ce4+, Ce3+| Pt; 0.1 M in 0.1 N H2SO4. The PVEC characterization reveals the fill factor and power conversion efficiency to be 0.33 and 0.64%, respectively. The flat band potential is found to be − 0.14 V (SCE).