The activation process through a bimodal transmittance state for improving electrochromic performance of nickel oxide thin film

In this study, we investigated the potential of using nickel oxide (NiO)-lithium phosphorous oxynitride (LiPON) composite as an anode electrode in electrochromic devices and evaluated the effect of Li+ insertion (or extraction) kinetics and diffusion of Li+. NiO–LiPON composite thin films were fabricated using the RF magnetron co-sputtering method. Here, we observed, for the first time, the bimodal colored states of the NiO–LiPON composite. This was caused by reacting both Ni metal and LiO under extremely cathodic condition, which enhanced the electrochromic properties – electrochromic response time and optical modulations – of the device. We also found that the NiO–LiPON composite thin films displayed long term stability.