Radiative cooling, what’s next?

Radiative coatings make use of omnipresent surface thermal radiation for passive cooling of objects without consuming energy or emitting greenhouse gases, and are a promising energy-saving strategy at scale to address the climate change problem. In the last decade, thanks to advances in photonics and micro/nano-fabrication technologies, we have witnessed the emergence of high-performance radiative coatings with hundreds of different designs. In this work, the development timeline of radiative coatings is summarized and potential research directions in this field are analyzed. Existing challenges and opportunities, especially for passively switchable radiative coatings, are discussed. We hope this short review promotes radiative coating materials and products for serving the sustainability of our society in various markets such as buildings, vehicles, and space objects.