Influence on optical properties and switching durability by introducing Ta intermediate layer in Mg–Y switchable mirrors

Improving the optical properties of switchable mirrors based on Mg–Y alloy using antireflection coatings

“…2. As a result of the simulation, it was indicated that a switchable mirror covered with AR layer with then value of $ 2.1 and thickness of $ 60 nm would improve T vis to over 70%, while the switchable mirror without AR had T vis of 45% which is consistent with the previous experimental result [5]. Thus, it was concluded that an AR layer is effective to improve T vis in the transparent state.…”

“…Thin Ta intermediate layers were then inserted between the Mg-Y alloy and Pd layers to prevent Pd from diffusing into the Mg-Y layer. Such Ta inserted switchable mirrors covered with thin Pd of 3 nm improved the optical properties without degradation in switching durability [5]. Because for south facing windows in Japan the amount of solar radiation through the windows in the winter is much larger than that in the summer due to the difference in incident angle of the sunlight.…”

“…For the calculation we assumed the following conditions: (1) For the AR layer, the refractive index n was constant and the extinction coefficient κ was zero in the visible range; (2) the thicknesses of the Mg 0.4 Y 0.6 H x , Ta, and PdH 1 À δ layers were 50, 2, and 3 nm, respectively; (3) the complex optical indices of Mg 0.4 Y 0.6 H x and PdH 1 À δ layers were the evaluated values from the previous study[5] and those of Ta were the reference values[6]; (4) the refractive index n and the thickness of the substrate were 1.5 and 1 mm. The layer structure to calculate T vis values of AR coated switchable mirrors in the transparent state.…”

Metal Hydride Switchable Mirrors (Review)

“…This layer allows reducing the palladium layer thickness. Tantalum has the best properties of the wide range of metals (Ti, Nb, V, and Ta) [25]. It has the least attenuation of visible light and the highest density compared to other metals.…”

“…The modulation of light transmission Δτ vis ~ 35% at cyclic switching of a mirror with a Ta buffer layer more than twice exceeds the similar characteristic Δτ vis ~ 15% of a mirror without such a layer. It is interesting to note that the exper- iment with a cyclic mirror switching in the amount of 10 thousand cycles has continued without interruption for about six months [25].…”