Growth and electrochromic properties of poly(3,4-ethylenedioxythiophene) layer on TiO ₂ nanoparticles

The growth of the conductive layer on TiO ₂ nanoparticles was examined. Poly(3,4-ethylenedioxythiophene) (PEDOT) was deposited on the mesoporous TiO ₂ nanoparticle by the chemical polymerization of 3,4-ethylenedioxythiophene (EDOT) under oxidative conditions, to afford PEDOT coated particles having average diameter of -75 nm. The growth of PEDOT on TiO ₂ was confirmed by a field emission-scanning electron microscopy (FE-SEM) and electrochemistry. All-solid-state electrochromic devices were fabricated using the PEDOT-on-TiO ₂ coated electrode and the solid polymer electrolyte as the ion conduction layer. Evaluation of the optical and electrochromic (EC) response was performed by monitoring the intensity of absorbance at the absorption wavelength of 600 nm under different conditions of applied potential. A fast electrochromic response and an efficient EC process with a blue color change was observed from the device constructed with nano-structured PEDOT.