• Alkaline earth cations are successfully incorporated into perovskite lattice with the aid of sulfonic acid anions, while alkaline earth metal halides lack doping capacity.
• Sulfonic acid anions effectively regulate crystallization and passivate metallic Pb0 defect states, improving power conversion efficiency to 24.95%.
• By comparing FACF3SO3 and Ca(CF3SO3)2-doped films, the suppression of halide migration with an activation energy of 1.246 eV is attributed to Ca2+ cations, providing a methodology for decoupling cation and anion effects.
• The study presents an effective method to decouple cation and anion effects, enabling the fabrication of efficient and stable perovskite solar cells.