Preparation of a TiO₂/PEDOT nanorod film with enhanced electrochromic properties

The designed growth of titanium dioxide (TiO₂)/poly(3,4-ethylenedioxythiophene) (PEDOT) nanorod arrays has been achieved by the combination of hydrothermal and electrodeposition methods. Due to the use of one-dimensional (1D) TiO₂ nanorod arrays as the template of the nanocomposites (TiO₂/PEDOT), the surface area of the active materials is enlarged and the diffusion distance of the ions is shortened. The nanorod structure also contributes to increasing the length of PEDOT conjugated chains and facilitates the transfer of electrons in the conjugated chains. Consequently, the TiO₂/PEDOT film delivers a shorter response time (∼0.5 s), higher transmittance contrast (∼55.5%) and long-cycle stability compared to the pure PEDOT film. In addition, the TiO₂/PEDOT electrode is further developed to be a smart bi-functional electrochromic device exhibiting energy storage performance. We expect that this work may lead to new designs for powerful intelligent electrochromic energy storage devices.