Ion-Induced Field Screening as a Dominant Factor in Perovskite Solar Cell Operational Stability

The presence of mobile ions in metal halide perovskites negatively impacts the intrinsic stability of perovskite solar cells (PSCs). However, the extent of their contribution to degradation, compared to other factors like trap-assisted recombination, is not well understood. This study reveals that mobile ion-induced internal field screening plays a dominant role in PSC degradation under operational conditions. The increased field screening leads to a significant drop in steady-state efficiency, primarily due to a reduction in current density. The bulk and interface quality remain stable with aging, but the open-circuit voltage decreases due to rising mobile ion density.