Electrochromic, optical and binding-energy performances of Tantalum Pentoxide and Zirconium dioxide films deposited with RF magnetron sputtering and cathodic arc plasma

Abstract

This research investigated the electrochromic, optical and binding-energy performances of Tantalum Pentoxide (Ta2O5) and Zirconium Dioxide (ZrO2) films as the ion conduction layer for an all-solid-state electrochromic device (ECD). The Ta2O5 film was commonly prepared by radio frequency (RF) magnetron sputtering with different oxygen/argon (O2/Ar) ratio, while the ZrO2 film was prepared by a cathodic arc with different deposition pressure because the ZrO2 film deposited with RF magnetron sputtering achieved poor electrochromic efficiency. The results exhibited that the Ta2O5 film deposited with O2/Ar ratio of 0.1 had the maximum colored/bleached variation (ΔT) of 52.9%@550 nm, color efficiency (CE) of 21.1 cm2/C, ionic conducting rate of 3 × 10−7 S/cm, and the lowest resistance of 14.3 kΩ. On the other hand, the ZrO2 film deposited with deposition pressure of 45 mTorr had the maximum ΔT of 55.43%@550 nm, CE of 35 cm2/C, ion conducting rate of 3.44 × 10−6 S/cm, and the lowest resistance of 19.37 kΩ. The colored/bleached variation of ZrO2 film was better than that of the Ta2O5 film, as proved by the location shifting of the binding-energy of Zr3d deposited by cathodic arc being larger than that of the Ta4f deposited by RF sputtering. However, the economic ZrO2 film has the potential to replace the traditional Ta2O5 film for an all-solid-state ECD.