Acrylic membrane doped with Al2O3 nanoparticle resonators for zero-energy consuming radiative cooling

Abstract Passive daytime radiative cooling plays a significant role in various cooling operations, which helps reducing electricity consumption and decreasing electricity demand. This work presents a new double-layered radiative cooling structure composed of a transparent dipentaerythritol penta-hexa-acrylate (DPHA) top layer, modified using Al2O3 nanoparticles (NPs) as resonators, and a metallic Ag bottom layer (DPHA@Al2O3 NPs/Ag). The DPHA@Al2O3 NPs layer is prepared through a fast photopolymerization process. The prepared DPHA@Al2O3 NPs/Ag system exhibits a solar reflectivity of 0.9465 and long-wave infrared (the so-called atmospheric transparency window) emissivity of 0.9163. The computed radiative cooling power at 27 °C can reach up to 106.43 W m−2. A subambient temperature drop of 10.35 °C is measured from 13:00 to 16:00 p.m. in Seoul, Korea, when using the proposed material as radiative cooler. Since this structure can be applied on flexible substrate, this has far-reaching implications for future applications in wearable devices.