2021/08/13 by K. Araki, Araki, Ken, Richard Z. Zhang +1
Engineering · Materials Science · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Metamaterials and Metasurfaces Applications #Optics (physics.optics) #Thermal Radiation and Cooling Technologies #Transition Metal Oxide Nanomaterials
paper · pdf · doi:10.48550/arxiv.2108.06013
openalex publication_date 2021/08/13 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
High performance metasurfaces for thermal radiative cooling applications can be identified using computational optimization methods. This work has identified an easy-to-fabricate temperature phase transition VO2 nanowire array laid atop dielectric BaF2 Fabry-Perot cavity-on-metal with total coating thickness of 2 um. This optimized structure has ability to self-adaptively switch between high reflectance at low temperature to high emissivity at high temperature in the broad thermal infrared spectrum. This design demonstrates exceptional turn-down figure-of-merit compared to previously realized configurations utilizing VO2 metasurfaces and multilayers. The mechanism is achieved with a sub-wavelength nanowire array effective medium that switches between anti-reflecting gradient coating and Fabry-Perot interference. This thin metasurface coating could impact self-cooling of the solar cells, batteries, and electrical devices where risk presents at high temperatures.