Synthesis and characterization of electrochromic films based on 2,5-Bis (2-(3,4-ethylenedioxy)thienyl)pyridine

2,5-bis(2-(3,4-ethylenedioxy)thienyl)pyridine was synthesized by Stille coupling. This monomer having D-A-D structure was successfully electropolymerized by cyclic voltammetry. The electrochemical, optical, electrochromic, nanomechanical properties of the films, as well as their stability and morphology were studied. The polymer films exhibit a multi coloured behaviour, i.e. their colour changed upon oxidation form red (in the neutral state) to purple and sky blue (doped state). In the reduced state are pale blue. Based on the nanomechanical properties, the films synthesized under low number of scans (2 or 5 scans) are well adhered on the ITO electrodes, whereas a higher number of scans (20 scans) results to a thicker, more elastic and more soft film. The poly(2,5-bis(2-(3,4-ethylenedioxy)thienyl)pyridine) films synthesized under few scans are proposed for application in mulicoloured electrochromic devices, since they are well adhered on the ITO, they reversible switch their colour from red to sky blue and they are stable during the potential switch.