Influence of Perovskite Interface Morphology on the Photon Management in Perovskite/Silicon Tandem Solar Cells.

Perovskite/silicon tandem solar cells are considered as one of the cost-effective solutions for determining high energy conversion efficiencies. Efficient photon management allows improving light incoupling in the solar cells by reducing optical losses. The optics relies upon the interface morphology, consequently, the growth mechanism of the top cell on the bottom cell is crucial for the implementation of efficient perovskite/silicon tandem solar cells. To describe the interface morphologies of perovskite/silicon tandem solar cells, a three-dimensional surface algorithm is used that allows investigating the perovskite solar cells deposited on the textured crystalline silicon solar cells. We distinguish between two extreme cases in which the film grows only in the direction of the substrate normal or in the direction of the local surface normal. The growth mode has a significant influence on the film roughness, the effective thickness of the film, the optics of the solar cell, and the photovoltaic parameters. The optics is investigated by finite-different time-domain simulations. The influence of the interface morphology on the photovoltaic parameters is discussed and guidelines are provided to reach high short-circuit current density and energy conversion efficiency.