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 TiO 2 /WO 3 films were prepared by an electrochemical deposition method with the purpose of adding WO 3 nanoparticles to porous nanocrystalline doctor‐blade TiO 2 (nc‐TiO 2 ) films. The results of the characterization of electrochromic properties in 1 M LiClO 4 + propylene carbonate (LiClO 4 + PC) of both the nc‐TiO2/F‐doped tin oxide (FTO) and WO 3 /TiO 2 /FTO configurations showed the reversible coloration and bleaching of the ECDs. The response time of the ECD coloration of WO 3 /TiO 2 /FTO was found to be as small as 2 sec, and its coloration efficiency (CE) as high as 35.7 cm 2 × C −1 . By inserting WO 3 nanoparticles into the porous TiO 2 structures, WO 3 /TiO 2 heterojunctions 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 WO 3 /TiO 2 can 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.