Pyramidal nanotexture optimization for light trapping in perovskite-silicon tandem solar cells

Perovskite-silicon tandem solar cells yield promising power conversion efficiencies, significantly higher than those for single-junctions. Light management in tandem solar cells is important to reduce optical losses. Nanotextured interfaces can enhance the light trapping and coupling in the tandem while reducing reflectance and increasing the generation rate of carriers. Here, optical numerical simulations allow for the optimization of the texture of the top cell of a full tandem layer stack, while ensuring feasible conformal deposition of the perovskite layer onto the bottom silicon cell. The optimum nanopyramid height and width were found to be 400 nm and 500 nm, respectively, yielding a significant reduction of the reflectance. We show that the nanopyramids are resonant structures, creating hotspots of generated carriers that can enhance the efficiency of the cell.