Defect Suppression in Triple-Cation Perovskites via Zwitterionic Choline Bitartrate for Scalable High-Efficiency Photovoltaics

To overcome the instability and scalability challenges of perovskite solar cells, we engineer zwitterionic choline bitartrate as a dual-functional additive. Its tartrate anions passivate undercoordinated Pb2+ defects through multidentate coordination, while choline cations suppress halide vacancy migration. This synergistic mechanism enables CsFAMA-based devices to achieve 24.92% efficiency (0.05 cm2) with exceptional scalability of 24.12% (1 cm2) and 21.37% (36 cm2 modules), while suppressing PbI2 impurities, enlarging grains, and retaining >95% of the initial power conversion efficiency after 600 h at 85 °C, establishing a new paradigm for stable, high-performance perovskite photovoltaics.