Thermally Conductive Radiative Cooling Polymer Composite for Outdoor Thermal Management

Abstract

Passive radiative cooling, which dissipates heat to deeper space without any energy consumption or greenhouse gas emissions, has garnered considerable attention. The key to achieving daytime radiative cooling is effectively reflecting solar irradiance because the absorbance of just a few percent exceeds the cooling power and efficiently heats the objects. Recently proposed photonic structures exhibit high solar reflectance, which is promising for daytime radiative cooling. However, they either require stringent fabrication or sacrifice many practical properties (e.g., heat dissipation and mechanical properties, etc.) that present a significant challenge in their large area fabricating and limit their applications to subambient cooling, although above-ambient cooling is more demanding in realworld applications. Here, we present a simulation-aided design scalable composite film consisting of a visibly transparent polymer encapsulation 2D dielectric nanoplates. The simulation results prove that the 2D shape endows the nanoplates with higher backscattering efficiency than previously reported spheric scatterers. Combing with their high refractive index and wide bandgap, they may be the best choice to reject solar irradiance. The nanoplates substantially improve the advantageous properties of composite film, which endow it with a high solar reflectance (97%) and an unprecedented heat dissipation ability.