Fabrication of an all solid-state electrochromic device using zirconium dioxide as an ion-conducting layer

Zirconium dioxide (ZrO2) thin films were deposited onto glass substrates, indium tin oxide (ITO) coated glass substrates and nickel oxide (NiO) / ITO / glass structures by reactive radio frequency (RF) magnetron sputtering using a zirconium target at room temperature. The deposition power was held at 75 W and the influence of deposition pressure and film thickness on the properties of the ZrO2 films were investigated. Optical, electrochemical and electrochemical impedance spectroscopy measurements of the ZrO2 films were performed and the electrochromic behavior of a half-cell structure of ZrO2 / NiO / ITO / glass was investigated in a wide spectral range. The amount of inserted/extracted charges into/from each film during bleaching/coloring process were investigated in detail. The highest coloration efficiency (24.3 cm2/C) and optical modulation (42.8%) at a wavelength of 550 nm were found for a ZrO2 / NiO / ITO / glass structure having a ZrO2 film with a thickness of 100 nm, deposited at 4.00 Pa. Finally, a unique design of an all solid-state electrochromic device with a configuration of ITO / NiO / wet lithiated ZrO2 / dry lithiated tungsten oxide (WO3) / ITO / glass was fabricated. The optical modulation of the device was 53% at 550 nm for the applied potentials of ±3 V.