A multielectrochromic copolymer based on pyrrole and thiophene derivatives

Copolymer films consisting of (R)-(-)-3-(1-pyrrolyl)propyl-N-(3,5-dinitrobenzoyl)-α-phenylglycinate (DNBP) and 3,4-(ethylenedioxy)thiophene (EDOT) were electrochemically deposited onto ITO electrodes and their electrochromic properties were investigated. Besides high absorption in the near infrared region, these films presented multielectrochromism with three different colors, being brown in the reduced state, green in the neutral state, and blue in the oxidized state. Spectrochronoamperometry data revealed that the copolymer films have fast switching time, high chromatic contrast, and high stability to redox cycling. The films also displayed lower band gap and better electrochromic properties as compared to the homopolymer PDNBP.