Flexible electrochromic devices prepared on ultra-thin ITO glass

Abstract

Electrochromic devices (ECDs) containing iron-based metallo-supramolecular polymers (Fe-MEPE) and Prussian blue (PB) as active electrode materials, a polymer electrolyte and flexible ultra-thin indium tin oxide (ITO) glass as transparent conductive substrate are demonstrated here. The electrochromic Fe-MEPE and PB thin films were deposited on ultra-thin ITO glass by means of dip coating and electrodeposition, respectively, and characterized optically and (spectro-)electrochemically. By applying a low voltage of 2.5 V/−0.5 V, the Fe-MEPE/PB ECDs can be reversibly switched from a blue-colored dark state to a nearly colorless bright state with a visible light transmittance (τ_v) change from 8% to 58%. The devices exhibit a fast response for decoloration/coloration and good cycling stability tested over 250 switching cycles without any substantial loss of optical contrast. Thus, these ECDs based on ultra-thin glass are very attractive for flexible, lightweight, and low-power electrochromic applications, e.g., in architectural or automotive glazing, aircraft, marine, home appliances, and displays.