Synergistic Passivation via Lewis Coordination and Electrostatic Interaction for Efficient Perovskite Solar Cells

Non-radiative recombination has anegative impact on the deviceperformance of perovskite solar cells (PSCs), and defect passivationcan suppress the non-radiative recombination sufficiently. Herein,an innovative and effective synergistic passivation strategy is reportedby introducing three kinds of maleic anhydride derivatives servingas Lewis base additives to the PbI2 precursor solutionto obtain modified perovskite films and systematically investigatingthe synergistic effect of functional group passivation defects. Studiesfound that the electronic effect of the maleic anhydride derivativeswould affect their interaction with defects. For example, the electrostaticinteraction between the -CH3 positively chargedby the conjugation effect and iodine(I) in 2,3-dimethylmaleic anhydride(M-MAH) enhances the coordination strength of the C UO bondwith antisite lead (Pb) defects. Such synergetic passivation of M-MAHimproves crystallinity and orientation and reduces defect state density.This modification also causes the edge of the perovskite band to bendupward, facilitating hole extraction and transport. These advantagesenable the M-MAH-modified PSCs a champion power conversion efficiency(PCE) of 21.61% and significant environmental stability. Our findingsnot only provide new insights into the synergistic passivation associatedwith electrostatic interaction but also propose a simple strategyfor fabricating high-performance perovskite optoelectronic devices.