2021/01/14 by Tong Wang, Yi Wu, Lan Shi +3 · 3 citations
Engineering · Physics and Astronomy · #Thermal Radiation and Cooling Technologies #Quantum Electrodynamics and Casimir Effect #Optical properties and cooling technologies in crystalline materials
paper · pdf · doi:10.1038/s41467-020-20646-7
openalex publication_date 2021/01/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract All-day passive radiative cooling has recently attracted tremendous interest by reflecting sunlight and radiating heat to the ultracold outer space. While some progress has been made, it still remains big challenge in fabricating highly efficient and low-cost radiative coolers for all-day and all-climates. Herein, we report a hierarchically structured polymethyl methacrylate (PMMA) film with a micropore array combined with random nanopores for highly efficient day- and nighttime passive radiative cooling. This hierarchically porous array PMMA film exhibits sufficiently high solar reflectance (0.95) and superior longwave infrared thermal emittance (0.98) and realizes subambient cooling of ~8.2 °C during the night and ~6.0 °C to ~8.9 °C during midday with an average cooling power of ~85 W/m 2 under solar intensity of ~900 W/m 2 , and promisingly ~5.5 °C even under solar intensity of ~930 W/m 2 and relative humidity of ~64% in hot and moist climate. The micropores and nanopores in the polymer film play crucial roles in enhancing the solar reflectance and thermal emittance.