High performance electrochromic devices based on WO₃–TiO₂ nanoparticles synthesized by flame spray pyrolysis

We demonstrate high performance WO₃–TiO₂ nanoparticles synthesized by flame spray pyrolysis for the applications in electrochromic devices (ECDs). It is shown that the post-annealing process significantly improves the crystallinity of WO₃–TiO₂ nanoparticles. The WO₃–TiO₂ nanoparticles exhibit a much higher transmittance compared to the conventional TiO₂ nanoparticles. The optimized WO₃–TiO₂ nanoparticles are successfully adopted to the electrochromic devices. The WO₃–TiO₂-based ECDs show a higher transmittance than the TiO₂-based ECDs due to the high transmittance of WO₃–TiO₂. In addition, the electrochromic response of the WO₃–TiO₂-based ECDs is much faster than that of the TiO₂-based ECDs. The WO₃–TiO₂-based ECDs show a much higher reflective property compared to the TiO₂-based ECDs at the mirror state. These results indicate that the high performance WO₃–TiO₂ nanoparticles synthesized by a simple one-step flame spray pyrolysis process can be a promising material for highly efficient ECDs.