Review on electrochromic property for WO3 thin films using different deposition techniques

Thin film technology plays an important role in technological development and recent research in engineering. Recent developments in the synthesis of transition metal oxides in the form of porous thin films have opened up opportunities in the construction of electrochromic devices with enhanced properties. The general applications of thin films are in the field of optoelectronics, microelectronics, etc. There are numbers of different techniques used for the deposition of stable thin films of oxide materials. The transition metal oxides like WO3 and MoO3 have good electrochromic properties and these oxides can also change their optical properties when the voltage pulse applied. These electrochromic materials are used for displays, rear-view mirrors and smart windows for energy saving and gas sensors. Tungsten Oxide (WO3) is the best suited material for energy conservation applications due to its better coloration efficiency. Thin films of WO3 are deposited by various techniques like physical vapour deposition, chemical vapour deposition, sol-gel method, magnetron sputtering methods. Out of this some methods like magnetron sputtering method offers good flexibility for deposition and allow to fabricate required topographical, physical, crystallographic, desired geometrical and metallurgical structures. This paper is aimed to summarize applications of WO3 thin films as electrochromic material and the effect of various deposition techniques on electrochromic and optical properties of WO3 thin films.