Optical properties of La₂O₃ and HfO₂ for radiative cooling via multiscale simulations

【摘要】 Radiative cooling materials have gained prominence as a zero-energy solution for mitigating global warming.However,a comprehensive understanding of the atomic-scale optical properties and macroscopic optical performance of radiative cooling materials remains elusive,limiting insight into the underlying physics of their optical response and cooling efficacy.La₂O₃ and HfO₂,which represent rare earth and third/fourth subgroup inorganic oxides,respectively,show promise for radiative cooling applications.In this study,we used multiscale simulations to investigate the optical properties of La₂O₃ and HfO₂ across a broad spectrum.First-principles calculations revealed their dielectric functions and intrinsic refractive indices,and the results indicated that the slightly smaller bandgap of La₂O₃ compared to HfO₂ induces a higher refractive index in the solar band.Additionally,three-phonon scattering was found to provide more accurate infrared optical properties than two-phonon scattering,which enhanced the emissivity in the sky window.Monte Carlo simulations were also used to determine the macroscopic optical properties of La₂O₃ and HfO₂ coatings.Based on the simulated results,we identified that the particle size and particle volume fraction play a dominant role in the optical properties.Our findings underscore the potential of La₂O₃ and HfO₂ nanocomposites for environment-friendly cooling and offer a new approach for high-throughput screening of optical materials through multiscale simulations.更多还原

【Abstract】 Radiative cooling materials have gained prominence as a zero-energy solution for mitigating global warming.However,a comprehensive understanding of the atomic-scale optical properties and macroscopic optical performance of radiative cooling materials remains elusive,limiting insight into the underlying physics of their optical response and cooling efficacy.La₂O₃ and HfO₂,which represent rare earth and third/fourth subgroup inorganic oxides,respectively,show promise for radiative cooling applications.In this study,we used multiscale simulations to investigate the optical properties of La₂O₃ and HfO₂ across a broad spectrum.First-principles calculations revealed their dielectric functions and intrinsic refractive indices,and the results indicated that the slightly smaller bandgap of La₂O₃ compared to HfO₂ induces a higher refractive index in the solar band.Additionally,three-phonon scattering was found to provide more accurate infrared optical properties than two-phonon scattering,which enhanced the emissivity in the sky window.Monte Carlo simulations were also used to determine the macroscopic optical properties of La₂O₃ and HfO₂ coatings.Based on the simulated results,we identified that the particle size and particle volume fraction play a dominant role in the optical properties.Our findings underscore the potential of La₂O₃ and HfO₂ nanocomposites for environment-friendly cooling and offer a new approach for high-throughput screening of optical materials through multiscale simulations.更多还原