Harit Keawmuang, Junkyeong Park, Heon Lee, Seokju Choi, Sunae So, Changhyeon Lim, Trevon Badloe, Chang Ju Hyeon, Minseo Jeong, Dasol Lee, Ya Huang, Siming Zhao, Rufan Zhang, Juhoon Baek, Minkyung Kim, Fei Xie, Longnan Li, Wei Li, Xuzhe Zhao, Jiachen Li, Kaichen Dong, Saichao Dang, Qiaoqiang Gan, Shaowen Cao, Yi Long, Hyunkyu Kwak, Do Hyeon Kim, Young Min Song, Jung Bin Yang, Dong Rip Kim, Yansu Hou, Jia Zhu, Bin Zhu, Shengxi Bai, Kaixin Lin, Chi Yan Tso, Seonggon Kim, Yong Tae Kang, Qingsong Fan, Qizhang Li, Po-Chun Hsu, Junsuk Rho
Radiative cooling (RC) is a sustainable technology that passively lowers the temperature of terrestrial objects through thermal radiation, dissipating heat into outer space via the atmospheric window, unlike conventional cooling systems that require electricity and release waste heat to the environment. In recent years, RC technologies have advanced rapidly, moving steadily toward practical implementation and commercialization. Here, this mega-review offers a comprehensive overview of RC, encompassing its fundamental background, the underlying photonic and thermal principles, and fabrication approaches for constructing efficient cooling devices. We discuss a variety of RC structures along with their design strategies and explore the diverse functionalities that adapt RC toward particular requirements. We further review emerging applications of RC, highlighting practical implementations. Finally, we outline the key challenges and future directions, offering perspectives and insights to guide continued progress in this rapidly advancing field.