Computational analysis of hybrid perovskite on silicon 2-T tandem solar cells based on a Si tunnel junction

Abstract

In this study, the optoelectronic properties of a monolithically integrated 2 terminals tandem solar cell are simulated with a particular emphasis on the role of a tunnel junction in silicon. Following the large success of low-cost hybrid organic–inorganic perovskites solar cells, the possibility of using perovskites as absorbers in silicon based tandem solar cells is estimated. The top sub-cell consists in methyl ammonium mixed bromide-iodide lead perovskite, CH3NH3PbI3(1−x)Br3x (0 ≤ x ≤ 1), while the bottom sub-cell is made by a single-crystalline silicon bottom sub-cell. A Si-based tunnel junction is used to connect the two sub-cells in series. Numerical simulations are based on a one-dimensional numerical drift–diffusion model. It is shown that a perovskite layer with 20% of bromide and a thickness in the range of 300–400 nm can afford current matching with the silicon bottom cell. Good interconnection between single cells is ensured by standard n and p doping levels beyond 5 × 1019 cm−3 in the tunnel junction. A maximum efficiency of 27% is predicted for the tandem cell, which exceeds the efficiencies of the individual solar cells of silicon (17.3%) and perovskite (17.9%).