Advanced passive daytime radiative cooling: from material selection and structural design to application towards multifunctional integration

Passive daytime radiative cooling (PDRC) can scatter sunlight and radiate Earth’s heat into outer space through the atmospheric window to achieve cooling without additional energy consumption. The PDRC is considered a novel strategy that has the potential to address both energy shortages and global warming simultaneously. Despite significant progresses in the field of PDRC devices, there are still challenges from PDRC materials, manufacturing techniques, testing methods, and technical standards. Most of the reported results are far from practical applications. At present, there is still a lack of comprehensive review covering the material selection and structural design for efficient PDRC, multifunctional integration, and their related applications, which is the purpose of this review. In this review, we introduced the basic principles and design guidelines of PDRC aiming to maximize the cooling power. Then, the research progress of various PDRC devices based on material selection and structural design is highlighted, especially focusing on multifunctionality and related integrated technologies. Additionally, we summarized the development and potential applications of PDRC devices in energy-saving buildings, personal thermal management, electronic device cooling, energy harvesting, and water collection. Finally, existing challenges and future developments for PDRC devices are discussed and proposed.