Manganese Doping Stabilizes Perovskite Light-Emitting Diodes by Reducing Ion Migration
Lead-halide perovskite light-emitting diodes have recently emerged as high-performance devices. However, they degrade rapidly. This degradation has been attributed to the mixed ionic–electronic nature of these perovskites. Manganese doping increases the stability of perovskite light-emitting diodes, but the effects of manganese doping on ion migration are not well understood. We use impedance spectroscopy and transient ion-drift measurements to study the effect of manganese doping on ion migration in PEABr0.2Cs0.4MA0.6PbBr3 quasi-bulk two-/three-dimensional perovskite light-emitting diodes. We find that manganese doping enhances the activation energy for ion migration twofold and reduces the diffusion coefficient. These changes in the behavior of mobile ions help us to explain the improved stability in perovskite light-emitting diodes upon manganese doping and lead to a better understanding of the influence of passivating agents on ion migration and thus on the stability of the devices.