Enhanced Colouration Efficiency of Pulsed DC Magnetron Sputtered WO 3 Films Cycled in H 2 SO 4 Electrolyte Solution

Abstract

In the present investigation, we report on DC power and pulsing frequency induced changes in electrochromic properties of pulsed DC magnetron sputtered WO 3 films by intercalating/deintercalating H + ions from 0.1 M H 2 SO 4 electrolyte solution. The observed efficient colouration ↔ bleaching mechanism of WO 3 films confirms the effective electrochromic nature of the films associated with the electrochemical intercalation/deintercalation of H + ions and electrons into WO 3 lattice. The higher optical modulation was observed in the visible region of the optical transmittance spectra of colored and bleached WO 3 films. The maximum coloration efficiency of 79 cm 2 /C was observed the first time for the film deposited at a DC power of 150 W and a pulsing frequency of 25 kHz.