Toward Purple-to-Green-to-Transmissive-to-Black Color Switching in Polymeric Electrochrome

A novel 3,4-ethylenedioxythiophene (EDOT)-based donor–acceptor electroactive monomer (HCQE) bearing carbazole subunit is synthesized, and then the corresponding polymer, poly­(HCQE), is directly deposited onto ITO/glass surface via electrochemical process. Spectroelectrochemical studies demonstrate that poly­(HCQE) is capable of showing both n- and p-doping processes. Hence, this low band polymer serves the multielectrochromic feature at three separate states (−0.4 to −2.0 V, −0.4 to 1.2 V, and 1.2 to 2.0 V) with a highly unique near colorless and colored states, fast switching times, redox switching stability, and exceptional transmittance change. To the best of our knowledge, this is the first report of a neutral state green multielectrochromic polymer exhibiting successive switching of colored-to-bleached-to-colored in three distinct regimes.