A Trilayer Structure with Surface Binary Microsphere Array for Radiative Cooling and Heating Regulation

Passive daytime radiative cooling is of tremendous interest but would overcool during cold nights or winter days, exacerbating the heating cost, especially in high-latitude areas. Integrating the heating and cooling in one photothermal system can avoid cooling penalties and potential barriers for wide practical scenarios. Herein, we demonstrate a trilayer structure with visible and infrared spectral engineering for all-season radiative cooling and heating. The cooling mode with a solar reflectivity of 0.95 and a mid-infrared emissivity of 0.98 endows a comparable daytime subambient cooling of 9.8 °C with a theoretically net cooling power of 76.6 W/m2. Meanwhile, the heating mode with a solar absorptivity of 0.88 and a mid-infrared emissivity of 0.28 yields a daytime above-ambient heating of 16.3 °C with a theoretical net heating power of 667.8 W/m2. Promisingly, the surface binary microsphere array further enhances the mid-infrared emissivity, superhydrophobicity, and environmental durability, making the trilayer structure a viable pathway for thermal management with great potential in electricity savings and CO2 emission reduction. This work offers new possibilities for designing next-generation radiative cooling materials, greatly widening the scope of use.