Abstract

• Tungsten trioxide (WO3) thin films were coated onto fluorine tin oxide (FTO) coated glass substrates by spray pyrolysis technique and annealing at different temperatures (300oC, 400oC and 500oC). The presented work studied the effect of annealing temperature on the surface morphology, optical and electrochemical properties of WO3 films by using scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-vis spectroscopy and cyclic voltammetry (CV). Optical study showed that the decreased optical transmission and band gap was observed in WO3 film at higher annealing temperature (400oC and 500oC). The electrochemical study revealed that anodic peak current density was higher in WO3 film annealed at 400oC in KI electrolytic solution. Upon modulating the annealing temperature, change in optical and electrochemical properties of WO3 films was correlated to surface morphology change in WO3 films.