Stability has become the main obstacle for the commercialization of perovskite solar cells (PSCs) despite the impressive power conversion efficiency (PCE). Poor crystallization and ion migration of perovskite are the major origins of its degradation under working condition. Here, high‐performance PSCs incorporated with pyridine‐2‐carboxylic lead salt (PbPyA2) are fabricated. The pyridine and carboxyl groups on PbPyA2 can not only control crystallization but also passivate grain boundaries (GBs), which result in the high‐quality perovskite film with larger grains and fewer defects. In addition, the strong interaction among the hydrophobic PbPyA2 molecules and perovskite GBs acts as barriers to ion migration and component volatilization when exposed to external stresses. Consequently, superior optoelectronic perovskite films with improved thermal and moisture stability are obtained. The resulting device shows a champion efficiency of 19.96% with negligible hysteresis. Furthermore, thermal (90 °C) and moisture (RH 40–60%) stability are improved threefold, maintaining 80% of initial efficiency after aging for 480 h. More importantly, the doped device exhibits extraordinary improvement of operational stability and remains 93% of initial efficiency under maximum power point (MPP) tracking for 540 h.

Large opening circuit voltage (V oc) loss and poor moisture stability have significantly hindered the progress of inorganic perovskite solar cells (IPSCs). Here, we report a dual-protection strategy via incorporating monomer trimethylolpropane triacrylate (TMTA) into CsPbI2Br perovskite bulk and capping the surface with 2-thiophenemethylammonium iodide (Th−NI) to ameliorate the above issues. Benefiting from growth control and effective suppression of both bulk and surface recombination, the resulting devices show a great improved efficiency from 12.17 to 15.58% with a champion V oc of 1.286 V. Also, the dual-protection strategy endows films with promoted moisture tolerance, and the nonencapsulated device retains 83.4% of its initial efficiency after aging at 25% relative humidity for 1540 h. More importantly, the target device shows good operational stability and reveals the unfallen efficiency after maximum power point tracking for 350 h at 45 °C. Our work offers a feasible method to fabricate efficient and stable CsPbI2Br IPSCs for future commercialization.