Molecular engineering of polythiophene-based polymers consisting of anthraquinone moiety for electrochromism and energy storage

In this work, three new D-A type conjugated polymers ( PAQT-Th , PAQT-EDOT, , PAQT-DTh) ) were prepared by electrochemical polymerization of three monomers ( AQT-Th , AQT-EDOT, , AQT-DTh) ) consisting of anthraquinone and thiophene-based moieties, and directly deposited on ITO substrates as electrodes for electrochromic energy storage devices. All these three polymers showed efficient electrochromic performance involving short response time among 0.3-1.4 s, large optical contrast up to 42 %, high coloration efficiency over 146.8 cm2/C 2 /C (the highest CE value was 263.3 cm2/C 2 /C for PAQT-Th), ), and good cycling stability. Moreover, the present electrochemical redox active polymer thin films exhibited charge/discharge properties with area capacitance over 2.8 mF/cm2 2 at the current density of 0.02 mA/cm2. 2 . Electrochromic energy storage devices based on these three polymer thin films were fabricated and showed obvious color change during the charge/discharge process, which suggested their potential applications in energy saving smart windows.