Switchable and Tunable Radiative Cooling: Mechanisms, Applications, and Perspectives

The cost of annual energy consumption in buildings in the United States exceeds 430 billion dollars ( <i>Science</i> 2019, 364 (6442), 760-763), of which about 48% is used for space thermal management (https://www.iea.org/reports/global-status-report-for-buildings-and-construction-2019), revealing the urgent need for efficient thermal management of buildings and dwellings. Radiative cooling technologies, combined with the booming photonic and microfabrication technologies ( <i>Nature</i> 2014, 515 (7528), 540-544), enable energy-free cooling by radiative heat transfer to outer space through the atmospheric transparent window ( <i>Nat. Commun.</i> 2024, 15 (1), 815). To pursue all-season energy savings in climates with large temperature variations, switchable and tunable radiative coolers (STRC) have emerged in recent years and quickly gained broad attention. This Perspective introduces the existing STRC technologies and analyzes their benefits and challenges in future large-scale applications, suggesting ways for the development of future STRCs.