Isomerizing Passivators in Perovskite Solar Cells:\nThe Impact of Molecular Spatial Configuration

Defect\npassivation, relying on the interaction between passivators\nand the perovskite lattice, effectively improves the photoelectric\nperformance of perovskite solar cells. Nevertheless, the principles\nfor designing passivators, such as tuning molecular configuration\nand electrostatic potential, can sometimes be invalid even with those\nwidely reported functional atoms and groups, showing an uncovered\nmissing factor in current passivating mechanisms. Herein, by carefully\ncomparing the isomerism of passivators, we unearth that the spatial\nposition of functional atoms on the passivators plays a key role in\ndetermining their passivating capabilities. We find that the passivation\nbecomes stronger when the spacing of functional atoms matches that\nof lead ions in between the neighboring lattice. Interestingly, by\nutilizing such a strategy, we achieve strong passivation from a passivator\neven with weak electrostatic potential. Eventually, we stepwise increase\nthe device performance from a baseline of 22.74% to 23.30%/23.88%/24.60%\nwith improved device stability, showcasing the advantage of optimizing\nmolecular spatial configuration for passivators.