Characterization of flexible switchable mirror film prepared by DC magnetron sputtering

An electrochromic switchable mirror on a flexible plastic sheet was developed taking into consideration practical use, low cost and high adaptability. The mirror has a multilayer of Mg4Ni/Pd/Al/Ta2O5/WO3, which was fabricated by DC magnetron sputtering on an ITO-coated PET sheet. In the previous research, when the mirror was exposed to air for a long period of time, its optical switching properties disappeared. This work focused on the mechanism of degradation of the mirror in different environments. When the mirror was stored in a desiccator for 50 days as a means of preservation, its switching speed was seven times higher as compared with the mirror exposed to air. It is also well known that oxygen and moisture in air easily penetrate PET sheets. The features of the PET sheet strongly affected the durability of the optical switching layer. When the state of the optical switching layer was changed to nonmetallic due to the formation of oxide and hydroxide, the optical switching properties almost disappeared.