%0 Journal Article
%T Structural, Optical, and Electrochromic Properties of Pure and Mo-Doped WO3 Films by RF Magnetron Sputtering
%A Vempuluri Madhavi
%A Paruchuri Kondaiah
%A Obili Mahammad Hussain
%A Suda Uthanna
%J Conference Papers in Science
%D 2013
%R 10.1155/2013/104047
%X Pure and Mo-doped WO3 films were formed on ITO-coated glass substrate held at 473£¿K by RF magnetron sputtering technique. The structural, morphological, and optical properties of pure and Mo-doped WO3 thin films have been systematically studied. The structural properties revealed that the pure WO3 films exhibited a (020) reflection related to the orthorhombic phase of WO3, whereas Mo-doped films showed (200) reflection. The surface morphology revealed that pure WO3 films showed the dense surface and Mo-doped films contained agglomerated grains which were uniformly distributed on the surface of the substrate. The optical transmittance decreased from 85% to 75% for pure and Mo-doped WO3 films, respectively. The electrochromic properties of the films were measured by cyclic voltametry in 1£¿M Li2SO4 electrolyte solution. The optical modulation of pure WO3 films at near IR was 50%, and the calculated color efficiency was 33.8£¿cm2/C, while in Mo-doped WO3 the efficiency improved to 42.5£¿cm2/C. 1. Introduction Tungsten oxide (WO3) is the most widely used electrochromic material because of easiness in synthesis and favorable electrical and optical properties. The application of electrochromic materials for smart windows, displays, and antiglare mirrors and several applications have been developed such as control of incoming daylight into buildings, smart windows, rearview mirrors, and aphotochromic and electrochromic devices [1¨C3]. Tungsten oxide is the extensively studied electrochromic material [4, 5]. Doping of vanadium, niobium, nitrogen, titanium, or nickel to WO3 enhances in the electrochromic properties. Muthu Karuppasamy and Subramanyam [6] reported that the color efficiency decreased from 121 to 13£¿cm2/C with increase of vanadium doping of 9 at. % in tungsten oxide films deposited by DC magnetron sputtering. Bathe and Patil [7] studied the electrochromic properties of niobium-doped WO3 films, and the coloration efficiency decreased with the increase of niobium doping. Sun et al. [8] studied the nitrogen-doped WO3 films formed by reactive DC pulsed sputtering and the color efficiency achieved to 45£¿cm2/C at 5 at. % nitrogen doped films. Karuppasamy and Subrahmanyam [9] studied the electrochromic properties of titanium doped tungsten oxide films and realized the improvement in the electrochromic properties with the increase of titanium doping. Gesheva et al. [10] studied MoO3-WO3 films formed by chemical vapour deposition method and showed the color efficiency of 141£¿cm2/C when compared to 84£¿cm2/C for WO3 and 39£¿cm2/C for MoO3 films. Valyukh et al. [11]
%U http://www.hindawi.com/journals/cpis/2013/104047/