Enhanced electrochromic properties of anatase TiO2 for flexible electrochromic device

Transition metal oxides (TMOs) with switchable optical properties have been attracting huge attention in the scientific community due to their potential application. In this work, we present a new approach to synthesize and stabilize the titanium dioxide (TiO2) using polyol synthesis. The electrochromic properties of anatase TiO2 thin films deposited by dip coating on flexible substrate, from as-synthesized powder, are studied. To enhanced the electrochromic properties of the TiO2, we recently developed a new strategy based on the addition of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT: PSS) leading to TiO2 + PEDOT:PSS hybrid composites film. TiO2 + PEDOT:PSS films exhibit improved electrochromic performance in terms of durability, nice color change between dark-blue and white transparent, fast switching time, and coloration efficiency compared to single-component TiO2. To conclude, an flexible electrochromic device combining two electrochromic composite film–based (TiO2 + PEDOT:PSS), via a lithium-based electrolyte membrane plastified with PMMA, was successfully built. The electrochromic characterizations showed that the flexible hybrid composite device switches reversibly from a dark blue to white transparent in the less than 1 s associated with a high in situ transmittance modulation (∆T = 70%) at 750 nm.