Improved durability of electrochromic switchable mirror with surface coating in environment

Abstract

Electrochromic switchable mirrors can be reversibly changed between a reflective state and a transparent state by applying a voltage. In our previous work, the properties of the device were significantly affected by environmental factors such as temperature and relative humidity. In that work, the effects on the device properties were investigated through an accelerated degradation test in a thermostat/humidistat bath at a constant temperature of 40 °C and a relative humidity of 80%. The switching speed between the reflective state and transparent state increased as the duration of the simulated environmental exposure increased. The device stored for 7 days under the simulated environmental conditions showed a around 45-fold slower switching speed than that of the as-prepared device. In this work, a high-durability surface coating material constructed from a cyclo olefin polymer sheet and ultraviolet resin was developed to protect the device from environmental degradation. The device with surface coating kept under the simulated environmental conditions for 7 days showed almost the same switching speed as the as-prepared device with the surface coating.