Orange to green switching anthraquinone-based electrochromic material

An easily accessible anthraquinone-benzodithiophene-based high bandgap polymer (PTAq) was synthesized by Stille coupling reactions in remarkably high yield (96.5%). The highest occupied molecular orbital energy level of the polymer was estimated from the onset of oxidation in a cyclic voltammetry study to be −5.7 eV. PTAq showed an orange-to-green color switching with the application of a 1.0-V external potential to the polymer film, which was visible to the naked eye. The optical behavior change was also monitored using ultraviolet–visible absorption spectroscopy and revealed a respectable 75% transmittance change when the polymer film was subjected to a 1.0-V external potential. The high color contrast observed makes PTAq one of the most promising materials for electrochromic device applications.