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

Abstract

In this work, the tungsten trioxide (WO3) 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 WO3 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 WO3 films exhibited amorphous structure and the WO3 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 WO3 films was investigated for colored and bleached states with their optical transmission. It was found that WO3 nanorod structure prepared by OAD exhibited good electrochromic property due to very large effective surface area and more ion insertion in WO3 nanorod films. In addition, WO3 nanorod film prepared by OAD at 80° exhibited an optimum electrochromic property with optical contrast of 62%.