Tungsten Oxide-Modified ITO Electrode for Electrochromic Window Based on Reversible Metal Electrodeposition

Abstract

Reversible metal electrodeposition (RME) windows are a promising material for electrochromic windows and electronic display applications. However, the lifetime of RME devices is a major drawback in the preparation of commercial and practical devices. In this study, we propose a new strategy to prolong the stability and improve the efficiency of RME devices. By using tungsten oxide, a well-known electrochromic material, to modify the surface of a transparent conductive electrode, superior, stable, and highly effective devices were prepared successfully. By applying a low potential of -0.8 V to 0.5 V, the RME device can quickly switch between a bleached state and colored state with different colors changing from transparent to black and deep blue. The performance improvement of the RME device can be explained by the simultaneous reduction of tungsten oxide and metal ion deposition in the conductive substrate under an applied potential. Furthermore, the lifetime of the device increased significantly (over 1500 cycles) owing to the shielding role of tungsten oxide film in the acid medium, which is an indispensable component of reversible electrochromic devices.