Spectrally Selective Daytime Radiative Cooling Coating.

Abstract

Passive daytime radiative cooling offers a carbon‑free route to mitigate urban heat islands and reduce building energy use. Conventional broadband emitters, however, suffer from parasitic absorption of ambient thermal radiation from hot ground and adjacent buildings, severely compromising net cooling in dense urban settings. We present a scalable, spectrally selective radiative cooling coating that overcomes this urban penalty. By combining a phase‑inversion‑derived micro‑nano porous poly (vinyl fluoride) (PVF) layer with a reflective silver substrate, our emitter achieves a record spectral selectivity of 1.37, with 97.5% solar reflectance and 94.4% mid‑infrared emittance strictly confined to the atmospheric window (8_13 µm). In simulated urban canyon tests, the selective emitter stayed 1.9°C cooler than a broadband counterpart, effectively neutralizing heat gain from surrounding infrastructure. The coating also exhibits excellent scalability, adhesion, self‑cleaning ability, and chemical durability. By bridging performance, manufacturability, and resilience, this work offers a viable pathway for adopting radiative cooling in sustainable urban development.