New Donor–Acceptor–Donor Conjugated Polymer with Twisted Donor–Acceptor Configuration for High-Capacitance Electrochromic Supercapacitor Application

Abstract

A new donor–acceptor–donor monomer chalcogena-diazolobenzotriazole (CDB)–3,4-ethylenedioxythiophene (EDOT) is designed and synthesized with a torsion angle of 39° between the donor EDOT and acceptor CDB due to the existence of large steric hindrance between the EDOT and planar CDB structures. The corresponding conjugated polymer film pCDB–EDOT is prepared via electrochemical deposition on indium tin oxide-coated glass, and their electrochromic and capacitive properties are characterized. The polymer film displays a reversible switch from the green of the neutral state to the transparent gray of the oxidation state. Besides, the polymer pCDB–EDOT shows excellent capacitance, with an area specific capacitance of up to 4.65 mF cm–2 at 0.05 mA cm–1. This is one of the highest area specific capacitance in D–A–D type conjugated materials reported so far. Moreover, the polymer film maintains excellent rate capability and high capacitive stability. The assembled electrochromic supercapacitor device can change the appearance color from dark green (no power) to blue (fully charged), accompanied by outstanding energy storage ability and good cycle stability, which could run a single yellow LED (1.8 V, 0.04 W) for more than 60 s. These results indicate the great potential of polymer pCDB–EDOT in the applications of energy-sustainable intelligent devices.