Simulations of micro-sphere/shell 2D silica photonic crystals for radiative cooling

Passive daytime radiative cooling has recently become an attractive approach to address the global energy demand associated with modern refrigeration technologies. One technique increase performance is engineer surface of a polar dielectric material enhance its emittance at wavelengths in atmospheric infrared transparency window (8–13 µm) by outcoupling surface-phonon polaritons (SPhPs) into free-space. Here we present theoretical investigation new morphologies based upon self-assembled silica photonic crystals (PCs) using in-house built rigorous coupled-wave analysis (RCWA) code. Simulations predict that micro-sphere PCs can reach up 73 K below ambient temperature, when solar absorption and conductive/convective losses be neglected. Micro-shell structures are studied explore direct SPhP, resulting near-unity between 8 10 µm. Additionally, effect composition explored simulating soda-lime glass micro-shells, which, turn, exhibit temperature reduction 61 temperature. The RCWA code was compared FTIR measurements micro-spheres, on microscope slides.