Ionic Charge Imbalance in Perovskite Solar Cells

Ion migration in perovskite solar cells is usually analyzed and understood in terms of charge neutrality condition. However, several recent reports indicate possibility of ionic imbalance in the active layer due to external ion migration and/or chemical reactions. In this context, here we explore the influence of ionic charge neutrality on the performance of perovskite solar cells. Our results indicate that ionic imbalance leads to an asymmetry in the device electrostatics, which have interesting implications on the impact of material/interface degradation, hysteresis, and finally on the long-term stability and influence of optimal device architecture (NIP vs. PIN).