Porous cobalt oxide thin films from low temperature solution phase synthesis for electrochromic electrode

Electrochromic Co3O4 electrodes have been synthesized through soft solution chemistry on ITO-coated glass substrates followed by heat treatment. X-ray diffraction result reveals that the crystalline Co3O4 phase is formed over the treated temperatures from 100 to 500 °C and its crystallinity becomes stronger as the temperature increases. Among the tested electrodes, the best electrochromic performance is obtained for the electrode treated at 100 °C by showing ca. 15% of optical change, relatively fast response times and high coloration efficiency of ca. 32.5 cm2 C− 1. This low temperature synthesis process allows the electrochromic active Co3O4 film to be formed on flexible polymer substrates.