Omnidirectional Multi‐Type Defect Passivation Enables Efficient and Stable Perovskite Solar Cells via Dual Organic Potassium Salts

Despite significant advancements in perovskite solar cells, their defect states remain a critical bottleneck limiting further breakthroughs in efficiency and stability. Herein, an omnidirectional multi-type defect passivation strategy is judiciously proposed, which achieves comprehensive defect passivation within the bulk, at surfaces, and throughout interfaces by introducing two organic potassium salts, potassium 4-formylphenyltrifluoroborate and potassium propylxanthate, into the perovskite precursor and interfacial layer, respectively. The highly electronegative functional groups from the organic anion moiety can not only form hydrogen bonds with positively charged FA⁺, but also act as typical Lewis bases to stabilize uncoordinated Pb²⁺ defects. Meanwhile, the free K⁺ can suppress internal ion migration by binding with iodide ions, thereby comprehensively eliminating various defects that are responsible for non-radiative recombination in the device. Ultimately, the device achieves a remarkable PCE power conversion efficiency (PCE) of 25.78% with a negligible hysteresis and an open-circuit voltage loss of ≈349 mV. Impressively, benefiting from the hydrophobic interface protection and throughout defect elimination, the resultant devices exhibit admirable stabilities, with retaining 88.7% of its initial PCE after 1100 h of continuous thermal stress at 85 °C and 86.8% after 1400 h of aging under 40 ± 5% relative humidity, respectively.