Transmission attenuation and chromic contrast characterization of R.F. sputtered WO3 thin films for electrochromic device applications

WO3 thin films were deposited on indium doped tin oxide (ITO) substrates by R.F. sputtering and investigated for their electrochromic properties. Iono-optical studies were performed in a three-electrode electrochemical cell to deduce information about the intercalation kinetics. Addition of acetonitrile (AN) to the non-aqueous electrolyte is found to modify the electrolyte properties and increase the diffusion coefficient by almost two orders. The device shows a coloration efficiency (C.E.) of 46.45cm2C−1 and reversibility of 98%. The variation in color with applied potential has been plotted on xy-chromaticity diagram and chromic contrast of the device has been calculated using L*a*b* values.