Pattern-free, Thermally Stable, Broadband ZrN/GZO Metasurface Solar Absorber for High Temperature Applications

This work presents a wideband, thermally stable, and high-emissivity solar absorber to operate under the high-temperature conditions. The periodic nanostructure of the device comprises square-shaped stacking layers made of high-temperature materials GZO and ZrN deposited on a SiO2 substrate backed with a tungsten (W) reflecting layer. The developed device exhibits a total emissivity of greater than 90% across the wavelength range of 400 to 2400 nm and thermal radiation efficiency of 94% at 1500°C. The proposed structure has demonstrated exceptional performance at high-temperature operating conditions as a thermal emitter. Besides that, the proposed device shows excellent solar energy capturing ability, exhibits its solar spectra, and shows a nearly perfect match with the standard solar AM 1.5 model that makes it potentially useful for solar cell-based applications. Furthermore, the physics behind the high percentage of solar energy absorption in the structure was analyzed in terms of the surface electric field at selective wavelengths. Additionally, the proposed structure is insensitive to the polarization of the light due to its symmetric structure. Furthermore, it shows wide angular stability, which makes the proposed emitter useful for industrial applications such as seawater distillation, water distillation in remote areas, energy storage, and thermal applications, including solar photovoltaic-thermal (SPVT) systems.