Surface Analysis of Electrochromic Switchable Mirror Glass Based on Magnesium-Nickel Thin Film in Accelerated Degradation Test

With the capability to change between reflective and transparent states, electrochromic switchable mirrors are expected to have numerous applications in optical devices, electronics devices and new energy-saving windows. If conventional windows can be adapted to incorporate switchable mirror technology, the solar radiation coming into a room could be effectively controlled, owing to features of the reflective state. Conventional windows are often subjected to environmental conditions such as high temperature and humidity. Considering practical use, we investigated the effects of the environment on the optical switching properties of the device in accelerated degradation tests using a thermostat/ humidistat bath at a constant temperature of 313 K and constant relative humidity of 80%. When the device was kept in the bath for 950.4 ks, it lost its optical switching properties. This result was associated with the degradation of the surface layer of the Mg4Ni thin film, which became rougher with increasing bath duration. We confirmed that the layer contained species in non-metallic states of oxide and hydroxide. Furthermore, the degradation mechanism to form the mixture state depended on the holding time in the bath. [doi:10.2320/matertrans.MBW201010]