Dual‐Site‐Binding Ligand‐Driven (100) Orientation for Efficient and Stable Perovskite Solar Cells

ABSTRACT Regulating crystal orientation is a powerful strategy for enhancing the optoelectronic performance of perovskite solar cells (PSCs). However, most existing approaches rely on single‐site ligand binding, which not only forms insulating layers that hinder charge transport but also involves weak coordination that limits orientation control. Here, we report a holistic strategy based on a dual‐site‐binding ligand, dithiopyr, that simultaneously modulates nucleation kinetics, crystal orientation, defect passivation, and charge transport in perovskite films. By coordinating its dual thioester functionalities with adjacent Pb 2+ defect sites, dithiopyr effectively relieves lattice strain and promotes a preferential (100) orientation, thereby facilitating efficient charge transport. As a result, the inverted PSCs achieve power conversion efficiencies of 26.90% (certified 26.14%) (1.55 eV), 22.02% (1.25 eV), and 23.11% (1.68 eV), respectively. Notably, large‐area modules (30 × 30 cm 2 ) deliver an efficiency of 21.28%, which is among the highest values reported for inverted perovskite solar cells. Unencapsulated devices retain 93.1% of their initial efficiency after 3600 h under ambient conditions and maintain over 95% of their initial performance after 1100 h of maximum power point tracking. This work establishes dithiopyr as a versatile and robust platform for precise crystal orientation control toward high‐performance perovskite photovoltaics.