Progress in radiative cooling materials for urban skin: Achievements in scalability, durability, color modulation, and intelligent thermal regulation

Passive Daytime Radiative Cooling (PDRC) materials have the potential to achieve zero-energy cooling in buildings and are extensively studied to mitigate the urban heat island effect. However, existing research primarily focuses on improving cooling performance through spectrum modulation, overlooking the necessity for multifunctional materials in buildings. To guide researchers in developing more reliable PDRC materials for urban skin, this review addresses current challenges in four key categories: scalability, durability, color modulation, and intelligent thermal regulation. The review commences by presenting the fundamentals of PDRC, emphasizing scalability as a crucial prerequisite for building applications. Subsequently, it delves into various issues, with each area discussed in dedicated sections. These sections explore fundamental design principles, showcase representative examples, evaluate their efficiency, and highlight future challenges and opportunities in the PDRC domain. By comparing and elaborating on these aspects, this state-of-the-art review offers design concepts for multifunctional PDRC materials, aiming to facilitate their real-world applications.