Polyvinyl chloride seal layer for improving the durability of electrochromic switchable mirrors based on Mg–Ni thin film

Electrochromic switchable mirrors consisting of a multilayer of Mg4Ni/Pd/Al/Ta2O5/HXWO3/indium tin oxide on a glass substrate degrade when subjected to changes in humidity and temperature. Polyvinyl chloride was applied as a seal layer to such a device in an attempt to improve its durability. The optical switching properties of the device were investigated through an accelerated degradation test conducted at a constant temperature of 30 °C and a relative humidity of 80%. Although the device with a seal layer was thicker, it showed superior optical switching properties with a transmittance as high as 54% in the transparent state due to interference at the multilayer. Furthermore, the device with a seal layer exhibited higher durability after 35 days in an accelerated degradation environment, as well as higher switching durability.