Study On High-throughput Preparation And Modification Of Nickel-oxide-based Electrochromic Films

Electrochromic(EC)refers to the phenomenon that the optical properties of materials or devices,change reversibly under specific external electric fields.Since the first discovery in 1961,hundreds of EC materials have been discovered thanks to decades of development.Among them,nickel oxide(NiO),a representative inorganic cathode EC material,attracts great attention due to its low driving voltage,bistable states,and low energy consumption.It has been commercialized in the fields of electrochromic smart windows,electrochromic passenger aircraft portholes,smart dimming glasses,anti-glare rearview mirrors,and so on.However,the display application of NiO thin films is limited due to its low optical contrast,long boot time,long response time,and poor cycle stability.This work aims at the above-mentioned issues,an In-line magnetron sputtering highthroughput preparation technology is introduced to study the influence annealing temperatures and Al doping effect on the EC performances of NiO film,such as optical contrast,boot time,and response time.A sample with 20% Al doping content undert400 °C annealing temperature is screened and outperforms the rest high-throughput samples.The screened sample with optimized EC performances is then applied as electrochromic layer to assemble EC devices.This work shows that the increasing of annealing temperature is conducive to enhance the crystallinity,reduce the surface roughness,increase the maximum optical contrast,improve the working cycle stability,and shorten the colored/bleached response time of the NiO film.However,high annealing temperature will hamper the EC activity of NiO and prolong the boot time.A proper amount of Al doping will increase the surface roughness,improve the electrical conductivity,increase the maximum optical contrast(up to 80%),and shorten the "colored/bleached time".However,the Al doping content is negatively correlated to the working cycle stability.Future works may aim at study of binary doping systems based on Al and group VI element in order to not only maintain the optical performances and colored/bleached response time,but also improve the working cycle stability of NiO thin film.