Effects of oblique angle deposition on optical and morphological properties of WO3 nanorod films for electrochromic application

Abstract In this work, the tungsten trioxide (WO 3 ) films were prepared on ITO glass by reactive dc magnetron sputtering. The effects of oblique angle deposition (OAD) between 0 – 85° were investigated for optical and morphological properties of WO 3 films and its electrochromic application. The crystal structure, morphologies and optical properties were characterized by grazing – incidence X-ray diffraction, field emission scanning electron microscopy and spectrophotometer, respectively. All WO 3 films exhibited amorphous structure and the WO 3 nanorod morphologies were demonstrated when the OAD more than 60°. It is owing to the shadowing effect and limits adatom diffusion. The electrochromic property of WO 3 films was investigated for colored and bleached states with their optical transmission. It was found that WO 3 nanorod structure prepared by OAD exhibited good electrochromic property due to very large effective surface area and more ion insertion in WO 3 nanorod films. In addition, WO 3 nanorod film prepared by OAD at 80° exhibited an optimum electrochromic property with optical contrast of 62%.