Boosting the Photoluminescence of Au@Cu 12 Nanoclusters via Strategic Fluorine‐Atom Ligand‐Shell Engineering

ABSTRACT Atomically precise metal nanoclusters (NCs) provide a unique platform for exploring structure–property correlations; however, achieving high photoluminescence quantum yields (PLQYs) in solution remains a significant challenge. While core‐doping with heavy atoms, such as gold, is a proven strategy to enhance emission via the “heavy atom effect, ” the role of peripheral ligand shell engineering in modulating inter‐cluster interactions and structural dynamics is less explored. Herein, we report a strategic ligand‐engineering approach to improve the photoluminescence of gold‐centered, copper‐rich nanoclusters (Au@Cu 12). Incorporating a single fluorine atom at the para position of the aromatic alkynyl ligands, we synthesized two structural isomers: AuCu 12 S 2 P (O i Pr) 2 6 (CCPhF) 4 + (1 F) and AuCu 12 S 2 P (O n Pr) 2 6 (CCPhF) 4 + (2 F). Structural characterization, including high‐precision single‐crystal neutron diffraction, reveals that the strategic fluorine “anchor” introduces a network of hydrogen bonding interactions that effectively restrict surface conformational motion. 2 F achieves an exceptional PLQY of 79% in solution, significantly surpassing its non‐fluorinated predecessor (55%). Our findings demonstrate that subtle surface modifications can lead to significant improvements in optical performance.