Pulsed Electric Field-Induced NH3 Post-Treatment Strategy for Perovskite Solar Cells
Surface and interface defects in perovskite films induce non-radiative recombination losses that limit device performance. Conventional solution-phase passivation methods often cause disordered surface composition. This study introduces a pulsed electric field (PEF)-induced NH3 post-treatment strategy for perovskite films. Under PEF, nitrogen atoms in NH3 interact with coordinatively unsaturated Pb2+ in the [PbI6]4− octahedral framework, stabilizing Pb2+ defects, while hydrogen atoms strengthen interactions with I− ions, suppressing iodine migration and reducing iodine vacancies. The PEF-induced NH3 modification yields a more uniform surface potential distribution, enhancing carrier transport. The average power conversion efficiency (PCE) increases from 23.32% to 24.79%. Unencapsulated devices retain 84% of initial PCE after 1000 h in air, compared to 75% for control devices. This approach synergistically regulates passivation and defect healing, reducing non-radiative recombination and improving charge transport and long-term stability.