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.

Electrochromism of DC magnetron sputtered TiO2 thin films: Role of deposition parameters

“…In particular, the work by Yoshimura et al [26] pointed at the importance of conducting the sputtering at unusually high pressures (that are known to promote nanocrystallinity [107], analogously to the case of gas evaporation [108]). Furthermore, our observed coloration efficiencies are consistent with those in some studies on films prepared by sol-gel deposition [38], chemical bath deposition [41,43], and doctor blade technique [54,55]. Our earlier work on sputter deposition in the presence of CF 4 in order to make titanium oxyfluoride films is yet the one that produced the highest coloration efficiency (cf.…”

“…Thus a doctor blade technique has been employed recently by Dinh et al [54,55] and has given TiO 2 films with η ≈ 34 cm 2 /C.…”

Electrochromism in sputter-deposited W–Ti oxide films: Durability enhancement due to Ti

“…Other, supporting studies on the electrochromism in W-Ti oxide have been reported for films prepared by sputtering [16][17][18][19], chemical technology involving spraying [20][21][22] dipping [16,23] or spinning [24][25][26], electrodeposition [27,28] and anodization [29]. The enhanced stability has been investigated in depth in recent work on W-Ti oxide films made by sputtering [30,31] and chemical techniques [26].…”

Honey-Comb Structured WO3/TiO2Thin Films with Improved Electrochromic Properties

“…Since these drawbacks have proven difficult to overcome in a pure WO 3 system there have been a number of attempts to solve them by doping or mixing with other electrochromic materials, usually another transition metal oxide. [9][10][11][12][13][14][15][16] In 2005, Patil et al…”

“…Since these drawbacks have proven difficult to overcome in a pure WO 3 system there have been a number of attempts to solve them by doping or mixing with other electrochromic materials, usually another transition metal oxide. [9][10][11][12][13][14][15][16] In 2005, Patil et al 17 investigated the effect of TiO 2 additions on the electrochromic properties of tungsten trioxide films prepared through spray pyrolysis, finding improved electrochromic reversibility, but not any real enhancement of the coloration efficiency. 17 One possible way to improve electrochromic efficiency is to tailor the morphology of the oxide to have spacious channels that can aid charge/ion injection into and transport within the film.…”