Amino Pyridine Iodine as an Additive for Defect-Passivated Perovskite Solar Cells

Defect passivation of the perovskite surface and grain boundary (GBs) has become a widely adopted approach to reduce charge recombination. Research has demonstrated that functional groups with Lewis acid or base properties can successfully neutralize trap states and limit nonradiative recombination. Unlike traditional Lewis acid-base organic molecules that only bind to a single anionic or cationic defect, zwitterions can passivate both anionic and cationic defects simultaneously. In this work, zwitterions organic halide salt 1-amino pyridine iodine (AmPyI) is used as a perovskite for defect passivation. It is found that a pair of amino lone electrons in AmPyI can passivate defects surface and GBs through hydrogen bonding with perovskite, and the introduced I- can bind to uncoordinated Pb2+ while also controlling the surface morphology of the film and improving the crystallinity. In the presence of the AmPyI additive, we obtained about 1.24 mu m of amplified perovskite grains and achieved an efficiency of 23.80% with minimal hysteresis.

Automated summary

This research demonstrates that using zwitterionic organic halide salt 1-amino pyridine iodine (AmPyI) as a defect passivation agent for perovskite can effectively modify both the surface and grain boundary defects. The introduction of AmPyI improves the film crystallinity and enhances the binding between cations and perovskite. This approach leads to enhanced perovskite grain size and a high efficiency of 23.80% with minimal hysteresis.