Recent advances in spectrally selective structural designs for radiative cooling

Radiative cooling technology passively dissipates surface heat to outer space through the atmospheric window (8–13 μm), providing an innovative pathway for continuous cooling with zero energy consumption and zero carbon emissions. The core challenge for high-performance daytime radiative cooling lies in strict spectral selectivity: A solar reflectance exceeding 90% in the solar spectrum band (0.3–2.5 μm) is required to minimize solar heating, while an infrared emissivity higher than 90% must be maintained within the atmospheric window to maximize radiative heat dissipation. This review systematically provides the latest advances in radiative cooling materials and structures in recent years, centered on the core driving force of “spectral selective structural design”. According to the optical modulation hierarchy of structural design ranging from random to precise, existing research is categorized into two major technical pathways: (1) Random scattering structures based on intrinsic material properties, including polymer films and functional coatings. Their infrared emission relies on molecular bond vibrations or lattice phonon resonances, while micro/nano pores or fibrous structures enhance solar light reflection via multiple scattering. (2) Precise micro/nano structures based on photonic engineering, including multilayer films, photonic crystals, and metamaterials, achieve finer spectral modulation through mechanisms, such as photonic band gaps, Mie scattering and surface polaritons. This paper further summarizes the application progress of this technology in building energy conservation, personal thermal management, heat dissipation of electronic devices, atmospheric water collection and other fields, and emphatically analyzes the key design trade-offs faced in the transition from laboratory research to large-scale applications, including cost control, environmental durability, climate adaptability, as well as the synergy and constraint between color aesthetics and cooling efficiency. Finally, this paper puts forward a prospective outlook on the future development of intelligent, responsive, and multi-functionally integrated radiative cooling materials. This review aims to provide a systematic reference framework centered on structural design for researchers in the radiative cooling community, and promote the evolution of this technology towards high efficiency, practicality, and sustainability.