Optical characterization and electrochemical behavior of electrochromic windows using magnetron sputter deposition Tungsten Oxide and (1-x) WO 3 xTiO 2 thin films

Abstract

Since Deb's experiment in 1973 on the electrochromic effect, transmissive electrochromic devices (ECDs) exhibit outstanding potential as energy efficient window controls which allow dynamic control of the solar energy transmission^[1]. These devices with non-volatile memory, once in the coloured state, remain in the same state even after removal of the field. The optical and electrochemical properties of electrochromic windows using magnetron sputter deposition tungsten oxide thin films and titanium oxide doped tungsten oxide thin films are investigated. From the UV region of the transmittance spectra, the band gap energy from the fundamental absorption edge can be determined. And the impedance of these thin films in 1 mol LiClO₄ propylene carbonate electrolyte (LIPC) are measured and analysed. Equivalent circuit of thin film impedances, and correlative resistances and constant phase angle element are gained. SEM and XRD of the tungsten oxide thin films and (1-x) WO₃xTiO₂ thin films are studied. These performance characteristics make tungsten oxide thin films and titanium oxide doped tungsten oxide thin films materials suitable for electrochromic windows applications.