Energy-saving ZnSe/Ag/ZnSe multilayers for solar-control glazing

This study introduced ZnSe/Ag/ZnSe transparent heat mirrors as a high-performance alternative to conventional oxide-based dielectric/metal/dielectric (D/M/D) coatings. Multilayer films were fabricated by thermal evaporation, with the silver layer systematically varied from 6 to 22 nm to investigate its influence on optical and thermal performance. Structural and chemical analysis confirmed improved Ag crystallinity, lower roughness, and sharper interfaces with increasing Ag thickness. The optimal performance was obtained for the structure with a 22 nm Ag layer, where the multilayer achieved a peak visible transmittance of 73%, an integrated visible transmittance of 66%, a maximum NIR reflectance of approximately 80%, an integrated NIR reflectance of 57%, a visible-to-solar transmittance ratio of 1.43, and a figure of merit of 2.87. The calculated NIR emissivity indicator and solar heat gain coefficient decreased with increasing Ag thickness, reaching values of 0.18 and 0.42, respectively, at an Ag thickness of 22 nm. Thermal shielding tests under broadband irradiation demonstrated a heat-shielding efficiency of 44%. These results establish ZnSe as a viable dielectric layer for spectrally selective solar-control coatings.