ITO/Cu multilayer electrodes for high-brightness electrochromic displays

Fabry–Perot (F–P) nanocavity-type electrochromic devices with multicolor tunability have attracted significant interest in the past two years for their potential uses in a wide variety of applications, such as electronic display, military camouflage, and dynamic decoration. However, challenges such as insufficient brightness, lengthy switching times, and poor cycling stability have yet to be overcome. Herein, we demonstrate electrochromic electrodes based on ITO/Cu as both the current collector and the reflective layer, with WO3 as the electrochromic material, forming a unique three-layered structure. The constituted WO3/ITO/Cu films present a high brightness value of about 84% before coloration, and a decent brightness value of 48% after coloration at −0.8 ​V. Moreover, a fast switching time between different coloration states (tc ​= ​2.2 ​s; tb ​= ​1 ​s) is recorded, attributed to the extremely low sheet resistivity of the ITO/Cu current collector. The films also reveal excellent electrochemical cycling stability across 2000 cycles.