Highly suppressed solar absorption in a daytime radiative cooler designed by genetic algorithm

Abstract Here, we report a selective multilayer emitter for eco-friendly daytime passive radiative cooling. The types of materials and thickness up to 10 layers the structure are optimized by genetic algorithm. cooler is designed mainly target low solar absorption, which allows sub-ambient cooling under direct sunlight. We used custom objective function in region achieve high-performance minimize absorption. minimizes absorption with an average absorptivity 5.0% (0.3–2.5 ?m) while strongly emitting thermal radiation emissivity 86.0% atmospheric transparency window (8–13 ?m). fabricated achieves net flux 84.8 W m ?2 70.6 , respectively, AM 1.5 irradiation (SI) (total heat 892 0.3–2.5 ?m wavelength region). Finally, experimentally demonstrate through 72-hour day-night cycle, showing maximum temperature reduction 3.1 °C 6.0 °C, respectively. Our approach provides additional degrees freedom designing both thereby expected allow