Boosting daytime radiative cooling performance with nanoporous polyethylene film

Radiative cooling without energy consumption and environmental pollution holds great promise as the next-generation cooling technology. To date, daytime radiative cooling performance is still slightly low, especially in humid areas. In this work, we demonstrated that nanoporous polyethylene (Nano PE) film can improve solar reflectivity from 96% to 99%, thus boosting radiative cooling performance. Moreover, the experimental results in humid areas indicate that Nano PE films can improve radiative cooling performance by ∼76% in a clear day and 120% in a day with few clouds. Additionally, compared with ordinary PE films, thin Nano PE films have significantly higher weather fastness and mechanical strength. More importantly, nano PE films can scatter part of visible light, thus suppressing the generation of light pollution in practical applications. Lastly, the modeling results reveal that with Nano PE films, more than 95% of China's areas can achieve daytime cooling performance. Our work can boost the development of radiative cooling technology with a very low cost. © 2021