Pancake-Like Surface Halide-Fluorothiolate-Enriched Au₁₂Ag₃₀ Nanoclusters for Defect Passivation and Moisture...

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 [Au₁₂Ag₃₀(SPh^3,5-(CF₃)₂)₁₀Br₂₀]^6- (Au₁₂Ag₃₀) NC, and its use to boost the power conversion efficiency (PCE) and durability of perovskite solar cells. Single-crystal x-ray diffraction of Au₁₂Ag₃₀ revealed an Au₁₂ icosahedron wrapped by a six-layer Ag₃₀ shell, the (100) facets of which are capped by 20 Br^- ligands, with 10 -CF₃-bearing thiolates forming a hydrophobic equatorial belt. Introducing 0.5 mg/mL of this cluster into ((FA_0.95Cs_0.05)PbI₃)_0.975(MAPbBr₃)_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. Au₁₂Ag₃₀ 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.