Enhancing the performance of poly(3-methylthiophene)-based electrochromic devices via insertion of a TiO2 buffer layer

► We spin-coat TiO2 on ITO glass to fabricate TiO2 films annealing at 450 °C/30 min. ► Electropolymerization of 3-Methylthiophene on TiO2 film forms a composite electrode. ► P3MT/TiO2 composite electrode retains 84% relative to 56% ΔT of ITO electrode. ► An introduction of TiO2 layer in electrochromic devices enhances the stability.