Rational heterostructure stacking enables 23% wide-bandgap perovskite solar cells by side-reaction inhibition

Wide-bandgap (WBG) perovskite solar cells (PSCs) attract intensive attention because of their high tandem compatibility and versatile application scenarios. However, severe interfacial non-radiative recombination of mixed-ion WBG perovskite films was caused by complex defect types and phase impurities, leading to deteriorated device performance and stability. Herein, a rational surface heterostructure design was achieved by precisely constructing a two-dimensional Dion-Jacobson layer atop the 3D WBG layer by inhibiting surface side reactions. A dual-ammonium strategy was screened out to block undesired molecular interactions, refining surface lattice structures and energy landscapes to interfacial defect reduction, charge transport acceleration, and phase stability prolongation. A champion WBG PSC (active area: 0.10 cm²) based on the optimized 1.68 eV perovskite film achieved an impressive efficiency of 23.05% (certified 22.58%) with an open-circuit voltage of 1.25 V, plus a large-area (1.00 cm²) efficiency exceeding 21.25% and a mini-module (7.26 cm²) efficiency of 20.10%.