Optoelectrochemical characterization of electrochromic devices with starch based solid electrolytes

This paper describes the manufacturing and spectroelectrochemical characterization of all solid electrochromic devices (ECD). Both electrochromic (WO3) and storage ion (CeO2-TiO2) thin films were obtained by sol-gel method and deposited by dip-coating technique. The electrolytes were obtained by plasticization of starch with glycerol and addition of LiClO4 salt. The spectroelectrochemical measurements were performed with the complete devices as a function of the applied potential. The obtained results revealed that the color/bleaching process was reversible and the inserted/extracted charge was about 4.6 mC/cm(2) for the applied potential of -2.0 V and increased up to 5.3 mC/cm(2) for -2.3 V. This value was stable up to -2.5 V applied. The transmittance change at 630 nm was about 30% for 2.3 V applied and the optical density was about 0.25. The memory tests showed that the colored device bleached completely in open circuit in about 500 min. All the obtained results show that the presented devices are very good candidates to be tested as smart windows for architectural applications.