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

Abstract

Non-radiative recombination has a negative impact on the device performance of perovskite solar cells (PSCs), and defect passivation can suppress the non-radiative recombination sufficiently. Herein, an innovative and effective synergistic passivation strategy is reported by introducing three kinds of maleic anhydride derivatives serving as Lewis base additives to the PbI2 precursor solution to obtain modified perovskite films and systematically investigating the synergistic effect of functional group passivation defects. Studies found that the electronic effect of the maleic anhydride derivatives would affect their interaction with defects. For example, the electrostatic interaction between the −CH3 positively charged by the conjugation effect and iodine(I) in 2,3-dimethylmaleic anhydride (M-MAH) enhances the coordination strength of the C═O bond with antisite lead (Pb) defects. Such synergetic passivation of M-MAH improves crystallinity and orientation and reduces defect state density. This modification also causes the edge of the perovskite band to bend upward, facilitating hole extraction and transport. These advantages enable the M-MAH-modified PSCs a champion power conversion efficiency (PCE) of 21.61% and significant environmental stability. Our findings not only provide new insights into the synergistic passivation associated with electrostatic interaction but also propose a simple strategy for fabricating high-performance perovskite optoelectronic devices.