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Passive radiative cooling is a method to dissipate excess heat from a material by the spontaneous emission of infrared thermal radiation. For a solar cell, the challenge is to enhance PRC while retaining transparency for sunlight above the bandgap. Here, we design a hexagonal array of cylinders etched into the top surface of silica solar module glass to enhance passive radiative cooling. Multipolar Mie-like resonances in the cylinders are shown to cause antireflection effects in the infrared, which results in enhanced infrared emissivity. Using Fourier transform infrared spectrometry we measure the hemispherical reflectance of the fabricated structures and find the emissivity of the silica cylinder array in good correspondence with the simulated results. The microcylinder array increases the average emissivity between λ = 7.5–16 μm from 84.3% to 97.7%, without reducing visible light transmission.

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The luminescent solar concentrator (LSC) offers a potential pathway for achieving low-cost, fixed-tilt light concentration. Despite decades of research, conversion efficiency for LSC modules has fallen far short of that achievable by geometric concentrators. However, recent advances in anisotropically emitting nanophotonic structures could enable a significant step forward in efficiency. Here, we employ Monte Carlo ray-trace modeling to evaluate the conversion efficiency for anisotropic luminophore emission as a function of photoluminescence quantum yield, waveguide concentration, and geometric gain. By spanning the full LSC parameter space, we define a roadmap toward high conversion efficiency. An analytical function is derived for the dark radiative current of an LSC to calculate the conversion efficiency from the ray-tracing results. We show that luminescent concentrator conversion efficiency can be increased from the current record value of 7.1–9.6% by incorporating anisotropy. We provide design parameters for optimized luminescent solar concentrators with practical geometrical gains of 10. Using luminophores with strongly anisotropic emission and high (99%) quantum yield, we conclude that conversion efficiencies beyond 28% are achievable. This analysis reveals that for high LSC performance, waveguide losses are as important as the luminophore quantum yield.