Ion Substitution Strategy toward Spectral Tunability of Environmentally Friendly Rare Earth Sulfide Lattices for Radiative Cooling

Radiation cooling technology can effectively reduce the energy transmission of the sun to the building during the day, thus playing a certain positive role in alleviating the urban heat island effect and reducing energy consumption. In this study, red Nd-doped γ-Ce2S3 and orange La-doped γ-Ce2S3 were prepared by the green synthesis method, and their morphologies and optical properties were systematically studied. The color film produced by mixing the prepared microcrystalline powder with poly(vinylidene fluoride-hexafluoro propylene) at a certain proportion has near-infrared reflectivity and superior environmental resistance, achieving effective cooling of 3–6 °C when applied to the building surface. This study expands ideas for energy-efficient building materials and enriches the path to a carbon neutral sustainable future.