Low-cost and scalable sub-ambient radiative cooling porous films

Abstract. Passive radiative cooling is an environmentally friendly and energy-free cooling method, but the practical application of radiative cooling materials is still limited by high costs and cumbersome preparation processes. Here, low-cost and chemically stable polyvinylidene fluoride (PVDF) was selected as the raw material and porous P-PVDF films for daytime radiative cooling were prepared by a simple phase separation method. A solar reflectivity of 95.6% and an atmospheric window emissivity of 99.1% were obtained, resulting in high-performance radiative cooling without a metal reflective layer. A cooling power of 69.43  W  ·  m  −  2 was achieved in direct sunlight, achieving sub-ambient cooling of 4.2°C. This work provides a unique solution for radiative cooling materials, which is expected to be implemented in practical applications of passive radiative cooling.