Polymer-free Multilayer Visibly Transparent Radiative Cooler via Spectrally Selective Inverse Design

Radiative cooling is a promising approach for sustainable thermal management that does not consume energy.We developed a polymer-free, multilayer, visibly transparent radiative cooler (PF-MTRC) structure.We designed this structure using a spectrally selective inverse design method based on particle swarm, and we evaluated the performance of the structure through numerical simulations.The visible light transparency, near-infrared reflectance, and midinfrared absorptivity of a single six-layer PF-MTRC structure were 58.7%, 74.7%, and of 84%, respectively.The solar reflectance and the mid-infrared emissivity of the PF-MTRC were higher than and comparable to those of the conventional polymer-based emitter layer, respectively, demonstrating higher spectral selectivity within a single multilayer design.Additionally, the PF-MTRC was highly stable in the tolerance to thickness variations during fabrication.PF-MTRC shows the potential to overcome the durability issues of conventional polymer-based structures for applications in transparent passive cooling devices.