Tailored Arylboronic Acid Derivatives Stabilize Perovskite Octahedron in Inverted Perovskite Solar Cells

The absence of halide ions in perovskite at the buried interface remains a critical factor restricting the stability in efficient inverted perovskite solar cells (PSCs), mainly due to the metastable perovskite lattice. Herein, through a systematic investigation of the bonding mechanisms between arylboronic acid derivatives and perovskite, designing 5-fluoro-6-hydroxypyridin-3-ylboronic acid (FO-PyBA) anchors robustly on the perovskite surface vacancies to reinforce the perovskite octahedron to stabilize the buried interface. The -B(OH)₂ and C ═ O groups in FO-PyBA promote the concurrent formation of C ═ O─Pb and B─O─Pb coordination bonds alongside N─H···I and O─H···I hydrogen bonds, which establish a robust coplanar multidentate anchoring with perovskite to reinforce the octahedral framework. Crucially, this more stable multidentate anchoring is enabled by precisely tailoring the interatomic distances of anchoring sites in derivatives to match the defect sites of perovskite. The FO-PyBA effectively suppresses Pb/I vacancy defects and iodine ions migration to reduce interfacial nonradiative recombination. Consequently, it enabled inverted PSCs achieving a champion efficiency of 26.85% (certificated 26.70%) and maintained 94% of its initial efficiencies after 1000 h of operating under one-sun illumination in N₂.