Pancake‐Like Surface Halide‐Fluorothiolate‐Enriched Au 12 Ag 30 Nanoclusters for Defect Passivation and Moisture Shielding in Perovskite Solar Cells

ABSTRACT There are few examples of the function‐oriented synthesis of atomically precise metal nanoclusters (NCs) whose ligand composition and geometry readily translate into device‐level performance. Here, we report the design and synthesis of the pancake‐like [Au 12 Ag 30 (SPh 3,5− (CF 3 ) 2 ) 10 Br 20 ] 6− (Au 12 Ag 30 ) NC, and its use to boost the power conversion efficiency (PCE) and durability of perovskite solar cells. Single‐crystal x‐ray diffraction of Au 12 Ag 30 revealed an Au 12 icosahedron wrapped by a six‐layer Ag 30 shell, the (100) facets of which are capped by 20 Br − ligands, with 10 ‐CF 3 ‐bearing thiolates forming a hydrophobic equatorial belt. Introducing 0.5 mg/mL of this cluster into ((FA 0.95 Cs 0.05 )PbI 3 ) 0.975 (MAPbBr 3 ) 0.025 perovskite films boosted the device PCE from 23.55% to 25.53% and enables 94.8% retention after 1142 h of continuous one‐sun illumination. Au 12 Ag 30 is also distinguished by its −6 superatomic charge, and 66.7% surface halogen coverage—the highest ever reported. These findings establish anisotropic halide/thiolate‐protected NCs as potent additives for simultaneous defect passivation and environmental protection in high‐efficiency optoelectronics.