Efficient Daytime Radiative Cooling Cover Sheet with Dual-Modal Optical Properties

摘要

Daytime radiative cooling is an eco-friendly cooling technique that does notconsume additional fuel and is a promising technology now being developedusing various materials and methods. Existing radiative cooling emitters aretypically in the form of multilayered or mixed thin films and photonic structures,which are difficult to apply in industrial fields. Moreover, the complicatedprocesses and materials used increase the cost. Herein, a dual-modalradiative cooling emitter in the form of a cover sheet developed by electrospinningpolyacrylonitrile (PAN) with alumina (Al_2O_3) and silica (SiO_2) nanoparticlesis reported; it is an easily accessible and highly practical architecturethat can be applied and used in daily life. Additionally, this radiative coolingcover sheet exhibits dual selective- and broadband-like optical properties inthe IR region depending on the substrate characteristics for efficient cooling.The cooling power is numerically proven to be 89.51 W m~(?2), and experimentally,a temperature drop of 9.67℃ could be measured on a daily car model.