The instability of metal–halide perovskites intrinsically stems from weak hydrogen bonding in their organic–inorganic hybrid structure. Here, we demonstrate that prolonged pressure treatment at ∼1.8 GPa for 12 h induces a permanent lattice modification in (FAPbI3)0.95(MAPbBr3)0.05 polycrystalline films, characterized by strengthened hydrogen bonding between FA cations and iodide. Notably, such pressure-induced H-bond enhancement is preservable after decompression and yields dramatic stability improvements: Light-induced phase segregation is slowed by 12-fold, while resistance to illumination, heat, and moisture improves by four to six times. First-principles calculations reveal that the treatment raises the migration barrier for iodide, explaining the observed suppression of ion migration and phase segregation. These results establish that prolonged pressure treatment can enhance hydrogen bonding and produce substantially more stable perovskite materials and devices without altering their composition.
Yin et al. (Mon,) studied this question.