Scalable Flexible Hybrid Membranes with Photonic Structures for Daytime Radiative Cooling

TLDR

Passive radiative cooling reduces temperature by simultaneously reflecting solar radiation and emitting infrared heat, yet photonic radiators require nanoscale‑precision fabrication that hampers large‑area, mass‑produced applications. This work aims to provide a simple, inexpensive, and scalable electrospinning approach for producing a high‑performance flexible hybrid membrane radiator. The fabricated FHMR consists of polyvinylidene fluoride/tetraethyl orthosilicate fibers with abundant nanopores and randomly distributed SiO₂ microspheres on its surface. The 300 µm thick FHMR achieves >0.96 infrared emissivity, ≈97 % solar reflectance, excellent flexibility and strength, and delivers an average daytime cooling power of 61 W m⁻², reducing temperature by up to 6 °C under 1000 W m⁻², matching state‑of‑the‑art devices.

Abstract

Abstract Passive radiative cooling technology can cool down an object by reflecting solar light and radiating heat simultaneously. However, photonic radiators generally require stringent and nanoscale‐precision fabrication, which greatly restricts mass production and renders them less attractive for large‐area applications. A simple, inexpensive, and scalable electrospinning method is demonstrated for fabricating a high‐performance flexible hybrid membrane radiator (FHMR) that consists of polyvinylidene fluoride/tetraethyl orthosilicate fibers with numerous nanopores inside and SiO 2 microspheres randomly distributed across its surface. Even without silver back‐coating, a 300 µm thick FHMR has an average infrared emissivity >0.96 and reflects ≈97% of solar irradiance. Moreover, it exhibits great flexibility and superior strength. The daytime cooling performance this device is experimentally demonstrated with an average radiative cooling power of 61 W m −2 and a temperature decrease up to 6 °C under a peak solar intensity of 1000 W m −2 . This performance is comparable to those of state‐of‐the‐art devices.