Enhancement of electrochromic contrast of poly(3,4-ethylenedioxythiophene) by incorporating a pendent viologen

A 3,4-ethylenedioxythiophene derivative bearing a viologen unit has been synthesized and electropolymerized to form the corresponding polymer (see Figure). Electrochemical and spectroelectrochemical studies showed that the polymer has the characteristics of both PEDOT and viologen, and possesses high electrochromic contrast due to the cooperative electrochromic action of PEDOT and viologen.