Top-Down Dual-Interface Carrier Management for Highly Efficient and Stable Perovskite/Silicon Tandem Solar Cells

• An innovated top-down dual-interface carrier management strategy is developed to effectively improve both interfaces of the wide-bandgap perovskite using a multi-functionalized piperazinium chloride post-treatment. • The 1.68 eV unencapsulated single-junction perovskite solar cells exhibit a champion PCE of 22.3%, with a record VOC × FF product (84.4% relative to the Shockley–Queisser limit). • An impressive PCE of 31.5% for the 1.04 cm2 monolithic perovskite/silicon tandem solar cell based on silicon heterojunction bottom cell is demonstrated. • The device retains 91.3% of its initial efficiency after 1200 h of maximum power point tracking without encapsulation, and the tandem cell shows excellent long-term operational stability (T80 = 755 h) without encapsulation in ambient air.