In Situ Formation of SiO₂ Nanospheres on Common Fabrics for Broadband Radiative Cooling

Radiative cooling materials are attracting more and more attention because of their intrinsic advantages in energy saving and environmental protection, especially radiative cooling fabrics. In this paper, we used tetraethyl orthosilicate (TEOS) as the silicon source and prepared radiative cooling fabrics by in situ synthesizing SiO2 microspheres on polyester cloth. The in situ formation of SiO2 microspheres results in strong bonding with polyester fibers, solving the problem of powder peeling. The fabrics we prepared have a high emissivity of more than 95% in the midinfrared band and a relatively high reflectivity of ∼70% in the visible–near infrared band and can realize effective radiative cooling. The cooling effect would vary with the amount of TEOS added, and the sample with the optimal performance could achieve a maximal temperature drop of 11.2 °C under direct sunlight (10:00 a.m. to 16:00 p.m.) when compared with the surrounding environment. Such cooling fabrics can be made from commonly used fabrics on a large area, suggesting their potential use in fields such as outdoor cooling clothing and refrigerated shipments and thus opened up a way for the preparation and application of radiative cooling fabrics.