Universal Approach for Managing Iodine Migration in Inverted Single‐Junction and Tandem Perovskite Solar Cells

. Consequently, the synergistic effect of BT2F-2B effectively suppresses the decomposition of perovskite and the defect density of the iodide vacancies. This approach delivers a PCE over 26% for inverted single-junction PSCs, with exceptional operational stability. According to the ISOS-L-3 testing protocol (maximum power point tracking at 85 °C and 50% relative humidity), treated PSCs retain 85% of their original PCE after 1000 h of aging. When the BT2F-2B is applied to a wide-bandgap (1.77 eV) perovskite system, the PCE of all-perovskite tandem solar cells reaches 27.8%, confirming the universality of the proposed strategy.