Flexible Photonic Radiative Cooling Films: Fundamentals, Fabrication and Applications

Photonic structures designed at sub-wavelength scales have emerged as a promising avenue for various energy applications, including cooling devices, water harvesting, photovoltaics, and personal thermal management, which have significantly transformed the global energy landscape. Particularly, flexible photonic radiative cooling films, which facilitate heat dissipation from surfaces by emitting it into outer space via infrared radiation, have achieved great progress in recent years. In this review, the different approaches used to design photonic structures for manipulating solar reflectance and optimizing thermal emittance are summarized. On this basis, this review discusses advancements in flexible radiative cooling films that have been meticulously adhere to these design principles, alongside their cooling effects over recent years. Furthermore, a comprehensive overview of the progress is presented in the photonic integration with new functionality and the fabrication techniques of photonic structures. Lastly, this review highlights the remarkable potential of radiative coolers in various fields. In prospect, the widespread adoption of flexible photonic radiative cooling films holds immense promise for diverse applications.