Modeling the dielectric spectra of silicon dioxide for passive radiative cooling applications

Abstract

Passive radiative cooling (PRC) is a promising strategy for sustainable thermal regulation that relies on materials with tailored infrared emissivity. Silica (SiO₂) is a key component in many PRC applications due to its high transparency in the solar spectrum and strong infrared phonon absorption near 9 µm, aligning with the atmospheric transparency window. However, effective integration of silica into advanced PRC systems – such as photonic coatings, aerogels, and composite networks – requires accurate knowledge of its intrinsic dielectric properties. In this work, the complex dielectric function of silica is derived from atomistic simulations, with an emphasis on infrared-active vibrational modes. We optimize a polarizable force field against available experimental data, including vibrational spectra, elastic moduli, and dielectric constants. The resulting force field provides a robust basis for predictive simulations of silica-based nanostructures relevant to PRC applications.