Mixed Nanostructured Ti-W Oxides Films for Efficient Electrochromic Windows

Abstract

With the aim to enhance the electrochromic (EC) efficiency and electrochemical stability of electrochromic devices (ECD), mixed nanostructured TiO2/WO3films were prepared by an electrochemical deposition method with the purpose of adding WO3nanoparticles to porous nanocrystalline doctor-blade TiO2(nc-TiO2) films. The results of the characterization of electrochromic properties in 1 M LiClO4+ propylene carbonate (LiClO4+ PC) of both the nc-TiO2/F-doped tin oxide (FTO) and WO3/TiO2/FTO configurations showed the reversible coloration and bleaching of the ECDs. The response time of the ECD coloration of WO3/TiO2/FTO was found to be as small as 2 sec, and its coloration efficiency (CE) as high as 35.7 cm2× C−1. By inserting WO3nanoparticles into the porous TiO2structures, WO3/TiO2heterojunctions were formed in the films, consequently enabling both the CE and electrochemical stability of the working electrodes to be considerably enhanced. Since a large-area WO3/TiO2can be prepared by the doctor-blade technique followed by the electrochemical deposition process, mixed nanostructured Ti-W oxides electrodes constitute a good candidate for smart window applications, taking advantage of the excellent coloration and stability properties as well as the simple and economical fabrication process involved.