The study of electrochromic thin films, which are transparent in the visible range, is significantly important in producing smart doors production and saving energy. This paper reports the results of preparing WO3 thin films on glass substrates and ITO substrates by thermal vacuum evaporation method. | Journal of Science and Technology 54 (1A) (2016) 112-119 SYNTHESIS AND INVESTIGATION SOME PROPERTIES OF WO3 ELECTROCHROMIC THIN FILMS Nguyen Duy Thien*, Vu Dang Tuan, Nguyen Quang Hoa, Sai Cong Doanh, Le Van Vu Centre for Materials Science, Faculty of Physics, VNU - Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam * Email: duythien_303@ Received: 28 August 2015; Accepted for publication: 28 October 2015 ABSTRACT The study of electrochromic thin films, which are transparent in the visible range, is significantly important in producing smart doors production and saving energy. This paper reports the results of preparing WO3 thin films on glass substrates and ITO substrates by thermal vacuum evaporation method. The influence of annealing temperature on the properties of thin films was investigated by X-ray diffraction, Raman scattering spectroscopy, X-ray energy dispersive spectroscopy, Atomic force microscopy and absorption and transmittance UV–vis spectroscopy. The results show that WO3 thin films have a high transmittance of about 90% in the visible wavelength from 400 to 900 nm, good substrate adhesion. The WO3 thin films were crystallized at 400 oC and the crystallization of thin films on the ITO substrate better than glass substrate. Electrochromic characteristics of WO3 thin films were investigated by Autolab electrochemical system. The results show the transmittance of WO3 thin film was reduced to around 12 % in visible region when increasing the applied voltage from - V to - V. The transmittance of the film was completely recovered by using an applied voltage of 2 V. Keywords: electro-chromic property, electrochemical, WO3, thin film, thermal evaporation. 1. INTRODUCTION WO3 is a typical materials of the transition metal oxide family, which has been studied quite early [1, 2] because of many interesting physical properties, such as opto-chromic properties [3], electro-chromic properties [4, 5, 6], gas-chromic .
