A novel multielectrochromic copolymer based on 1-(4-nitrophenyl)-2,5-di(2-thienyl)-1H-pyrrole and EDOT

Copolymer of 1-(4-nitrophenyl)-2,5-di(2-thienyl)-1H-pyrrole (NTP) with 3,4-ethylene dioxythiophene (EDOT) was electrochemically synthesized and characterized. Resulting copolymer film has distinct electrochromic properties. It has five different colors (light red, red, light grey, green, and blue). At the neutral state lambda(max) x value due to the pi-pi* transition was found to be 550 nm and E-g was calculated as 1.6 eV. Double potential step chronoamperometry experiment shows that copolymer film has good stability, fast switching time (1.2 s) and high optical contrast (42%). Electrochromic device based on P(NTP-co-EDOT) and poly(3,4-ethylenedioxythiophene) was constructed and characterized. Oxidized state of the device shows light red color whereas reduced state blue color. At interval potentials device has good transparency and colors of the device are yellow and grey. Maximum contrast (T%) and switching time of the device were measured as 23% and 1.1 s at 650 nm. Electrochromic devices have good environmental and redox stability. (c) 2007 Elsevier B.V. All rights reserved.