Electrochromic Properties of Acid Dye Doped Poly(3,4-ethylenedioxythiophene) by Electropolymerization

The electrochromic properties of an electrochemical polymerized composite consisted of poly(3,4-ethylenedioxythiophene) doped with acid red G (PEDOT-ARG) are reported. The structures of PEDOT-ARG were characterized via cycle voltammograms, spectroelectrochemistry and colorimetric analysis. Film of the PEDOT-ARG composites switches from aubergine in the reduction state to light blue in the oxidized state, which is different from the pure PEDOT of dark blue (-0.8 V) and light blue (1.0 V). Because of the big molecule of acid red G as the dopant, the response time reaching 90% of the full optical contrast of PEDOT-ARG was 5.7 s for the oxidation process and 5.4 s for the reverse reduction process, which is a little slower than the pure PEDOT. Additionally, the colorimetric analysis results show that components of red in PEDOT-ARG films become stronger than the pure PEDOT films at the whole electrochromic process. It is shown that acid dye doping is an effective method to broaden the color change range of the electrochromic materials.