Properties of all-thin-film glass/ITO/WO3:H/Ta2O5/NiOx/ITO electrochromic devices prepared by magnetron sputtering

Thin films of WO3:H (~450 nm) were prepared on indium tin oxide (ITO) coated glass by reactive direct current magnetron sputtering at room temperature. The visible transmittance of the original state, and the X-ray photoelectron spectroscopy analysis of WO3:H films prove that H+ ions have been introduced into the structure of WO3. Based on the optimized parameters of WO3:H thin film, the Glass/ITO/WO3:H/Ta2O5/NiOx/ITO electrochromic devices (ECDs) are prepared monolithically by magnetron sputtering. Different applied voltages of 1.0, 2.0 and 3.0 V were applied to the ECD for investigating its influence on the ECD's optical contrast and cycle life. Though the ECD can get a higher contrast about 42% at 550 nm under 3.0 V voltage, however, it will be destructed quickly. When the operating voltage is 2.0 V, the ECD has a stable cycle performance with the optical contrast of >30%.