Improved electrochromic performance in sprayed WO3 thin films upon Sb doping

• As-deposited films possess monoclinic structure of WO3.
• Crystallite size of WO3 film decreases upon Sb doping.
• Upon Sb doping, the charge storage capacity of WO3 films improves.
• 20 at% Sb-doped WO3 film exhibits the best electrchromic performance.

We report for the first time improved electrochromic properties of tungsten oxide (WO3) nanocrystalline thin films upon Sb doping. The Sb-doped WO3 films were deposited by cost effective spray pyrolysis technique. The structural and morphological studies of the as-deposited films have been carried out by grazing incidence X-ray diffraction (GIXRD) and field emission scanning electron microscopy (FESEM). XRD analyses reveal polycrystalline monoclinic nature of the as-deposited films. The electrochromic behaviours of the films have been studied in an electrochemical analyzer using a three-electrode electrochemical cell, and 0.01 M H2SO4 solution (aqueous) as electrolyte. The charge storage capacity, electrochemical stability and reversibility of the films as well as H+ ion diffusion coefficient in the films during coloration/decoloration process improve upon Sb doping and are optimal for 20 at% Sb dopant concentration.