Metasurface-Based Selective Emitter for Passive Radiative Cooling

Abstract

Recently developed passive radiative cooling structures are capable for daytime cooling. However, their emission spectra hardly cover strongly and selectively only the atmospheric window region. Here, we propose metasurface-based radiative cooler, in which high emissivity is achieved over the full range of main transparency window. The structure cools down the temperature near 13ºC under ambient air even with ultra-thin layer of 3 μm. This study opens up the possibility of many applications not only for sub ambient cooling but also ultra-thin thin flexible devices and IR absorption spectroscopy.