Unlocking 27.3% perovskite photovoltaics by interface-locked dual-molecule contact

Inverted perovskite solar cells (PSCs) remain constrained by nickel ion (Ni³⁺)-triggered interfacial redox chemistry and buried-interface defect landscapes that drive nonradiative loss and undermine operational stability. We report an interface-locked dual-molecule contact by coassembling [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) with 9H-carbazol-2-yl trifluoromethanesulfonate (CzOTf), in which π-π-stabilized cofacial packing rigidifies molecular orientation and strengthens interfacial electronic coupling for efficient hole extraction, whereas the sulfonate terminus offers broader lead (Pb)-related defect coordination and relieves interfacial tensile stress, collectively promoting higher-quality crystallization and a chemically stabilized buried interface. Enabled by this synergistic regulation, vacuum-flash-evaporated 1.53-electron volt PSCs deliver certified efficiencies up to 27.31%. The strategy also translates to perovskite/HJT-Si (silicon heterojunction) tandems with an efficiency of 32.84%. Furthermore, the corresponding 766-square centimeter large-area module achieved a power conversion efficiency of 21.54%. The CzOTf-modulated PSCs retain 92% of their initial efficiency after 2000 hours of continuous light soaking (ISOS-L-1). The CzOTf-modulated large-area module operated stably outdoors for 35 days without degradation.