Dielectric Aggregation‐Mediated Dual‐Band Robust Optical Performance for Low‐Cost Radiative Cooling

Radiative cooling belongs to passively enhanced heat dissipation that reflects sunlight and emits infrared radiation. However, conflicting reflectivity and emissivity across the two bands present challenges to reach 95% performance simultaneously, while a few available photonic reports have shortcomings in terms of scalability and environmental stability. The decoupling optimization of scattering and absorption is demonstrated by modulating the aggregation state of merely 4 vol% dielectrics in the porous skeleton. It allows Mie scattering and resonant absorption to function in their respective bands, resulting in a double 95% optical performance. Such a broad spectral response enables high-throughput heat dissipation of 8 °C and supports subambient cooling of 5 °C outdoors. This one-step strategy extends to the manufacture of a range of metamaterials as required for strength, heat resistance, and degradation, combined with robust environmental stability, including resistance to fouling and peeling.