Optoelectrochemical properties of the copolymer of 2,5-di(4-methylthiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole monomer with 3,4-ethylenedioxythiophene

Abstract

Copolymer of 2,5-di(4-methylthiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole (MTNP) with 3,4-ethylene dioxythiophene (EDOT) was electrochemically synthesized and characterized via cyclic voltammetry, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy, conductivity measurements. Spectroelectrochemical investigations showed that resulting copolymer film has distinct electrochromic properties. It has five different colors (dark purple, red, light grey, green, blue). At the neutral state λ max due to the π-π ⁎ transition was found to be 500 nm and E g was calculated as 1.71 eV. Double potential step chronoamperometry experiment shows that copolymer film has good stability, fast switching time (1.1 s) and high optical contrast (30%). Electrochromic device based on P(MTNP-co-EDOT) and PEDOT was constructed and characterized. Oxidized state of the device shows dark purple color with a blue color reduced state. At interval potentials device has good transparency and colors of the device are yellow and grey. Maximum contrast and switching time of the device were measured as 23% and 1.1 s at 650 nm.