Influence of oxygen flow rate on electrochromic property of WO3 nanorods prepared by glancing reactive magnetron sputtering

Abstract

Tungsten oxide (WO3) is widely applied as an electrochromic layer for several smart window applications. The objective of this research is to develop the nanostructure of WO3 films with high electrochromic response. The one dimensional nanostructure of WO3 films was prepared by glancing-angle deposition (GLAD) technique; the tungsten oxide nanorods (WO3 NRs) were deposited onto indium tin oxide substrate by DC reactive magnetron sputtering. The effect of oxygen flow rate on the properties of WO3 NRs films was investigated by varying the oxygen flow rate from 12 - 30 sccm, during the deposition of the films. Then, the electrochromic property, the coloring-bleaching and the morphological of the films were characterized by cyclic voltammetry (CV), spectrophotometry and field-emission scanning electron microscopy (FESEM), respectively. We study the effect of ion insertion into the WO3 NRs by varying the doping ions - H+, Na+ and Li+ - and measuring the property by CV. The results showed that the insertion of H+ into the WO3 NRs films is faster than that of the others. Moreover, the CV peak and the film transmittance different between coloring and bleaching periods indicated that the electrochromic response increased as the oxygen flow rates were increased. In addition, the nanorods of the WO3 films were confirmed by FESEM. The influence of oxygen flow rate on morphology and electrochromic property has been discussed. © 2017 Elsevier Ltd. All rights reserved.