Design and Optimization of Inorganic Multilayer Films for Transparent Radiative Cooling Coatings

This optimization study was conducted to develop transparent radiative cooling coatings exhibiting high reflectance across the solar spectrum and strong thermal emission through the mid-infrared atmospheric window. In radiative cooling applications, polymeric based materials (e.g., PDMS) are commonly preferred; however, challenges such as long-term durability and yellowing create a need for the development of stable and inorganic coatings. In this project, an inorganic multilayer thin-film design has been developed by conducting computational optimization study via Transfer Matrix Method and Tree-Structured Parzen Estimator. The 6-layer configuration demonstrates balanced performance with weighted reflectance of 0.63, emissivity of 0.44, and transmittance of 0.71 compared to 4,5,8,10 and 12-layer stacks. The findings reveal the potential of passive daytime radiative cooling coatings that use stable and inorganic materials for transparent radiative cooling applications.