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Perovskite solar cells (PSCs) have attracted considerable attention as a prominent photovoltaic technology, yet the state-of-the-art PSCs still contain thermally unstable methylammonium (MA) cations and use laboratory-level assembly methods, making the device’s stability and scalability challenging. Herein, we demonstrate a generic zwitterion-assisted strategy to improve the efficiency and stability of formamidinium (FA)-based PSCs made by a scalable blade-coating technique. The zwitterion, 3-(1-pyridinio)-1-propanesulfonate (PPS), plays dual roles in effectively suppressing the formation of undesirable δ-phase and passivating the trap states of FA-based perovskite films. As a consequence, uniform FA-based perovskite films with an area as large as 16 cm2 were successfully obtained, and the small-area (0.1 cm2) device incorporating PPS achieved a champion efficiency up to 18.9%, as well as enabled a best efficiency of 16.2% for a large-area (1 cm2) device. More importantly, unencapsulated devices with PPS also exhibited superior thermal and moisture stability, remaining at 88% of initial efficiency after aging in air for 1000 h. This methodology provides a low-cost and facile pathway to realize the synergistic effect of crystallization modulation and defect passivation for large-scale perovskite devices with excellent optoelectronic performance and stability.

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To regulate the optical and electrical properties of the crystals and films of the intrinsic methylammonium lead iodide (CH 3 NH 3 PbI 3 ), we dope them with sodium (Na) by selecting sodium iodide (NaI) as a dopant source. The highly conductive p-type sodium-doped CH 3 NH 3 PbI 3 (MAPbI 3 : Na) perovskite single crystals and thin films are successfully grown using the inverse temperature crystallization (ITC) method and antisolvent spin-coating (ASC) method, respectively. With the increase of Na + doping concentration, the grain size of the film increases, the surface becomes smoother, and the crystallinity improves. Hall effect results demonstrate that both the MAPbI 3 : Na thin films and single crystals change their quasi-insulating intrinsic conductivity to a highly conductive p-type conductivity. The room-temperature photoluminescence (PL) peaks of doped MAPbI 3 films slightly blue shift, while the photocarriers' lifetime becomes longer. The optical fingerprints of the doped levels in MAPbI 3 : Na perovskites can be identified by temperature-dependent PL. Obvious fingerprints of Na-related acceptor (A 0 X) levels in the doped MAPbI 3 : Na were observed at 10 K. These results suggest that sodium doping is an effective way to grow highly conductive p-type MAPbI 3 perovskites.