Fabrication of all-solid organic electrochromic devices on absorptive paper substrates utilizing a simplified lateral architecture

Poly(3,4-ethylenedioxythiophene) doped with the polymer anion poly(styrenesulfonate), PEDOT:PSS, is a common electrochromic material used in the preparation of electrochromic devices (ECDs). In this paper, the PEDOT:PSS doped with a solvent was used both as the electrode and the electrochromic functional layer for fabrication of ECDs on absorptive paper surfaces. The doped PEDOT:PSS dispersion was assessed for the film-forming evenness, sheet resistance and conductivity, and the performance of prepared ECDs for their color contrast and switching dynamics. The ECD performance is discussed in relation to the absorptive characteristics of the substrates. The results indicate that it is feasible to prepare ECDs onto absorptive substrates, despite the partial polymer material imbibition into them. The extent of polymer absorption influences the ECD performance: an increased absorption reduces the color contrast but speeds up the color switching. The electrochemical properties of the used solid electrolyte were found to be crucial for functioning of the ECDs. Insufficient ion transport and associated high resistance led to failure of the devices.