State-of-the-art neutral tint multichromophoric polymers for high-contrast see-through electrochromic devices

Two new multichromophoric electrochromic polymers featuring a conjugated EDOT/ProDOT copolymer backbone (PXDOT) and a reversible Weitz-type redox active small molecule electrochrome (WTE) tethered to the conjugated chain are reported here. The careful design of the WTEs provides a highly reversible redox behavior with a colorless red switching that complements the colorless blue switching of the conjugated backbone. Subtractive color mixing successfully provides high performing solution processable polymeric layers with colorless neutral tint switchable limiting states for application in see-through electrochromic devices. Design, synthesis, comprehensive chemical and spectroelectrochemical characterization as well as the preparation of a proof-of-concept device are discussed.