Comprehensive photonic approach for diurnal photovoltaic and nocturnal radiative cooling

A novel photovoltaic/radiative cooling (PV/RC) hybrid system based on a selective plate is proposed. This system can generate electricity via diurnal PV conversion and obtain cooling energy by radiative cooling. We introduce a comprehensive photonic approach to simultaneously reduce impractical solar radiation absorption of the selective plate and enhance its thermal radiation for the hybrid system. Initially, we design a photonic structure made of 1D multilayer stack and 2D photonic crystal, which can selectively reflect solar radiation and actively radiate heat to the outer space while maintaining its solar transmission in PV conversion band (0.3-1.1 mu m). Then, we demonstrate that applying the photonic structure to a monocrystalline silicon solar cell can obtain a diurnal electricity output of 99.2 W m(-2) and generate a nocturnal RC power by 128.5 W m(-2), indicating 6.9% and 30.5% higher than those of a bare cell. In addition, the potential cooling energy obtained is far more in this structure than in existing RC emitters, including daytime RC emitter reported in a recent research. Results indicate that a comprehensive photonic approach can be used to design spectral selective structures for advancing the applications of exploiting solar energy harvesting and radiative cooling utilization.