Localized Electrostatic Interaction Stabilize Perovskite Solar Cells.

Abstract

Metal halide perovskite solar cells (PSCs) have shown great promise for commercialization, yet the weak bonding nature of perovskites renders them vulnerable to external stimuli, undermining the operational longevity of PSCs. Methods aimed at strengthening bonding within perovskite constituents still failed to realize both "high efficiency" and "high stability" in single device. Herein, a localized electrostatic interaction strategy is proposed by employing an unexplored and well-designed organic cation, tetramethyldipropylene-triammonium (IDPA³⁺). IDPA³⁺ features sterically constrained multi-interaction sites that enable strong localized electrostatic interactions with [PbI₆]^4- octahedra, inducing perovskite lattice compression. This compression improves perovskite lattice energy through strengthened chemical bonding within bulk lattice, ultimately reinforcing structural stability while simultaneously suppressing ion migration. Consequently, modified formamidinium lead iodide (FAPbI₃) devices displayed state-of-the-art stability, showing negligible performance loss under continuous operation at 85 °C and damp-heat test. Notably, the p-i-n device achieved a certified power conversion efficiency (PCE) of 25.28% for 1.00 cm², among the highest published certified PCEs. Overall, this work presents localized electrostatic interaction engineering as a promising strategy to intrinsically stabilize perovskite microstructure, bridging the gap between electrostatic regulation and structural stability while highlighting the broader potential of other triply-charged organic molecules for advancing stable PSCs and optoelectronic devices.