Preparation and characterization of nanocrystalline tungsten oxide thin films for electrochromic devices: Effect of deposition parameters

Abstract

Abstract In the present work, we have reported on deposition of tungsten oxide thin films by DC magnetron sputtering for the fabrication of electrochromic device and the effect of deposition parameters like oxygen partial pressure and substrate temperature on optical, structural, morphological and electrochromic properties of the films. The films were deposited on to Silicon, Quartz and ITO coated glass plates to characterize the properties of the films. The thickness of the films was measured from stylus profilometry and it is 350 nm and the optical transmittance of the films was in the range of 53–75% in the visible region, measured from UV–Visible spectrometer. The films are nanocrystalline in nature and crystallinity improved by increasing the substrate temperature analyzed from X-Ray diffraction. The morphology and composition of the films was determined from SEM, AFM and EDS and the films are nanocrystalline in nature of the size 38 nm and stoichiometric. The phase composition and bonding in the films were investigated from FTIR and Micro-Raman studies. The diffusion coefficient and coloration efficiency of the films were measured from cyclicvoltammetry studies and the values are 3.61 × 10−18 cm2/s and 34.35 cm2/C at 550 nm.