Bifunctional Interface Synergy for High‐Performance Wide‐Bandgap and Tandem Perovskite Solar Cells

further enhances charge extraction through dipole-induced band offset. This synergistic modification enables inverted 1.77 eV perovskite solar cells with a champion efficiency of 20.27%, and reduced open-circuit voltage loss (0.42 V). Unencapsulated devices retain 94% of their initial efficiency after 800 hours, demonstrating excellent stability. Crucially, an all-perovskite tandem solar cell based on this top cell achieves a remarkable efficiency of 28.14%. This bifunctional strategy offers an effective approach to minimizing interfacial loss issues, providing a critical foundation to the development of perovskite tandem photovoltaics.