Activated Reactive Evaporated Nano Crystalline WO3 Thin Films for Electrochromic Windows

摘要

Tungsten trioxide thin films were deposited by using home built activated reactive evaporation (ARE) technique on ITO coated substrates at an optimized conditions. The microstructural, optical and electrochromic properties of the as deposited WO3 films were investigated. The X-ray diffraction pattern of the film displayed characteristic triplet of (200), (020) and (002) Bragg reflections, in which (200) orientation is predominant and attributed to the monoclinic structure. The films were found to be smooth, uniform and composed with roughly spherically shaped nano grains of size in the range 60–70 nm. The as deposited WO3 films exhibited 85% of optical transmittance with evaluated optical band gap of 3.46 eV. The electrochromic studies were carried out for these WO3 films and observed to be 69% of optical modulation with colouration efficiency of 120 mC/cm2 at the wavelength of 550 nm.