All-solid-state switchable mirror on flexible sheet

The all-solid-state switchable mirror based on magnesium–nickel thin film was fabricated on the flexible sheet of polyethylene terephthalate (PET) to reduce process cost and make handling easy for practical application of smart window. The device has the multilayer of Mg4Ni/Pd/Al/Ta2O5/HXWO3/indium tin oxide (ITO) on PET sheet. Each material of the Mg4Ni, Pd, Al, Ta2O5, HXWO3 and ITO layers in the device work as an optical switching layer, a proton injector, a buffer layer, a solid electrolyte, an ion storage layer and a transparent conductor, respectively. The effect of the sheet resistance of ITO on the optical switching property of the device was investigated. The optical switching speed of the device on the PET sheet became fast decreasing with the sheet resistance of ITO. The device on the PET sheet with the lower sheet resistance of 35 Ω/sq of ITO showed faster switching speed of 10 s from the reflective state to the transparent one and higher durability than those of the device with other sheet resistances. We expect that the device with lower sheet resistance of ITO made better switching property in the view point of low power consumption operation.