The detailed balance limit of perovskite/silicon and perovskite/CdTe tandem solar cells

Here, the detailed balance limit of the light to electric power conversion efficiency η of the tandem solar cells with a solution processible perovskite top cell is presented, investigating a bandgap range from 1.4 to 2.6 eV for the top cell. As the bottom cell, Si and CdTe are considered. On the one hand, Si is attractive due to its ability to convert photons down to the near infrared into excited charger carriers. On the other hand, it is shown that CdTe is a more suitable bottom cell for wide band perovskite top cells, when both cells are connected in series. Here, a four terminal (4T) tandem device is compared to several two terminal (2T) tandem configurations: (i) a tandem cell that is optimized for maximum efficiency under current matching conditions; (ii) a tandem where emitted photons from the top cell are reabsorbed in the bottom cell (photon recycling); and (iii) a tandem cell with current matching over a broad spectral range due to an incomplete light absorption in the top cell.