Characterization of WO3 Thin Films Prepared at Different Deposition Currents on CTO Substrates

The phenomenon of electrochromism has attracted interest due to its widespread exciting applications, including antidazzle rearview mirrors, high contrast displays superior to liquid crystals and smart windows for energy‐saving applications. Most of these applications make use of WO3 films as active electrodes. Recently much effort has been made to understand the electrochromic process occurring in WO3 which is highly dependent on its optical, structural and morphological nature. In this paper the electrochromic behaviour of the electrodeposited WO3 thin film with respect to the various deposition currents is studied. Optical gaps of electrodeposited tungsten trioxide films are studied by focusing attention on the deposition current. The optical band gap, the refractive index and extinction coefficient of the films prepared under various deposition current is also discussed. Film composition and surface morphological studies are also carried out using EDAX and SEM respectively. O‐H stretching and W‐O stretching is obtained using FT‐IR spectrum. The electrodeposition parameters like pH, bath temperature, concentration, deposition time are optimized. The powder X‐ray diffraction studies show triclinic structure. The surface compositional analysis was studied by EDAX and the surface morphology was studied by SEM. Optical absorption, transmittance and reflectance spectra were recorded to study the optical band gap and optical constant changes with the deposition current density. The variation of FT‐IR spectra with the deposition current densities (0.50, 0.65, 0.75 mA/cm2) are also discussed for the electrodeposited WO3 thin films.