Revealing Energy Loss and Nonradiative Recombination Pathway in Mixed-Ion Perovskite Solar Cells

Multiple-cation lead mixed-halide perovskites (MLMPs) with tunable band gaps have been demonstrated as ideal candidates to achieve perovskite solar cells with high efficiencies. It is well-known that a large open-circuit voltage (VOC) loss caused by nonradiative recombination still limits the approach to the Shockley–Queisser limit. However, there are few comprehensive contributions regarding the origin and pathway of nonradiative recombination in n-i-p structured MLMPs. Here, we compare the performance of MLMPs containing different halides and analyze the energy loss and interface trap-assisted nonradiative recombination characterizations. It is found that Br-containing devices with a lower interface trap density of 3.2 × 1013 cm–2 obtain a high VOC of 1.12 V, a small energy loss of 0.02 eV, radiative recombination current density of 8.05 × 10–21 A m–2, and total recombination current density of 22.16 mA cm–2. This work provides an opportunity to understand the device physics and reveals the nature of nonradiative recombination based on experiment and simulation.