Optical design and optimization of BP/c-Si tandem solar cells

Black phosphorus (BP), widely studied in nanophotonics, has shown great potential applications in the field of thin film solar cells due to the wide absorption wavelength range and the tunable band-gap. Here, a tandem solar cell with BP and crystalline silicon (c-Si) as top and bottom active layer are proposed. Two types of optical design strategies such as one dimensional photonic crystal interlayers and top nanopyramid antireflective layer are employed to optimize the BP/c-Si tandem cell device structure to enhance the light absorption. Simulation results show that the one dimensional photonic crystal interlayers significantly enhance the light absorption in the tandem solar cell while nanopyramid antireflective layer hardly works. With optimized structure parameters, a maximum short-circuit current of 18.50 mA/cm2 for BP/c-Si tandem solar cell with one dimensional photonic crystal interlayers has been achieved which is enhanced by 19.4% compare to that of the counterpart without interlayers.