Manipulating ion migration for enhanced performance and durability of perovskite photovoltaics

The ability to harness ion migration in metal halide perovskites offers a promising avenue for enhancing both the efficiency and stability of perovskite-based devices, thereby accelerating their commercial viability. Herein, we report a spatial alternating poling strategy to annihilate complementary pair of defects (e.g. halide vacancy-interstitial pair) along their migration pathways. Perovskite solar cells (PSCs) subjected to this treatment exhibited notable improvements in open-circuit voltage (Voc) and fill factor (FF) as a direct consequence of reduced defect densities as substantiated by comprehensive material and device characterizations. Statistical analysis of 100 individual devices revealed an average enhancement of 7.4% in power conversion efficiency (PCE), underscoring the effectiveness of this post-processing approach. Furthermore, we innovated a reverse poling protocol to counteract performance decay during operation by reversing the migration direction of mobile ions under the built-in electric field. Our strategy effectively mitigated device degradation, resulting in prolonged operational stability and enhanced energy output. These findings highlight the practical utility of ion migration engineering as a versatile tool for simultaneously improving the performance and durability of perovskite photovoltaics.