Optimization of Three-Terminal Perovskite/Silicon Tandem Solar Cells

We use simulations to optimize perovskite/silicon tandem solar cells in a novel three-terminal configuration, with one terminal at the front and two at the rear. We consider configurations in which the top cell has either the inverted or the same polarity as the bottom cell. Our goal is to minimize the optical losses, to compare the performance of both configurations and to determine the realistically achievable efficiency. Optical simulations show that if the hole-transporting material is in front of the perovskite, it gives rise to parasitic absorption losses. If it is behind the perovskite, these losses are avoided, however, at the cost of increased reflection losses. We systematically minimize these reflection losses. This increases the tandem's total implied photocurrent density from 34.4 to 41.1 mA/cm². To determine the corresponding power conversion efficiency of these three-terminal tandems, electrical circuit simulations are performed based on existing 22.7% efficient perovskite and 24.9% efficient silicon cells. These simulations show that tandem efficiencies up to 32.0% can be obtained.