Advanced Passive Radiative Cooling Emitter with Ultrahigh Sub-ambient Cooling Performance

Abstract

Passive radiative cooling technologies are vital for energy conservation and emissions reduction, yet their development faces significant challenges. Herein, we fabricate an advanced passive radiative cooling emitter by coating BaSO4@SiP/H-SiO2@PAN on an aluminum substrate, which achieves a remarkable average temperature reduction of 20.1°C and ultrahigh cooling power of 121.0 W·m-2 under strong solar radiation, demonstrating the outstanding sub-ambient cooling performance. Through meticulous design optimization, it exhibits an efficient reflectance of 95.5% in the visible spectrum and superior mid-infrared emissivity of 97.9%. Additionally, the emitter's superhydrophobic surface, with a water contact angle (WCA) of 155°, ensures the excellent self-cleaning property. Furthermore, the performances remain stable even after its prolonged UV exposure, exhibiting the outstanding durability. This innovative emitter provides a critical solution for energy-efficient cooling in buildings and outdoor equipment, significantly contributing to reduced energy consumption and carbon emissions.