6‑Trifluoromethylnicotinamide\nBilaterally Anchored\nAll Cations Implementing Efficient and Humidity-Stable Perovskite\nSolar Cells

For organic–inorganic hybrid perovskite solar\ncells (PSCs),\nthe volatilization of organic components and the presence of undercoordinated\nPb<sup>2+</sup> ions are the primary causes of device stability imbalance.\nThese factors also serve as significant determinants that restrict\nthe commercialization scale of PSCs. Here, 6-trifluoromethylnicotinamide\n(TNA) molecules, featuring amide and trifluoromethyl groups at both\nends, were introduced as Lewis additives into the precursor solution\nof perovskite to anchor all cation defect sites and optimize the crystallization\nprocess of perovskite. Theoretical calculations confirmed that the\n−NH<sub>2</sub> and CO groups within the amide group\non one side of the TNA molecule synergistically passivated the undercoordinated\nPb<sup>2+</sup> ions, whereas the trifluoromethyl group on the other\nside formed hydrogen bonds with the organic components of perovskite.\nThe scorpion-like bilateral all-cation anchoring ability of TNA molecules\nwas further substantiated through experimental characterization. Upon\noptimization of the TNA treatment concentration, a perovskite film\ncharacterized by large grains and a reduced defect density of states\nwas achieved. The photovoltaic performance of PSCs incorporating TNA\nexhibited significant enhancement with an increase in efficiency from\n22.42% (Control) to 24.15%. Under a harsh high-humidity environment,\nthe comprehensive cation passivation effect of TNA significantly hindered\nthe decomposition and phase transition of perovskite films, thereby\nensuring excellent humidity stability for the PSCs.