Ligand-Driven Structural Modulation and Enhanced Photoluminescence in High-Nuclearity Ag₅₆ Nanoclusters

Abstract

Atomically precise silver nanoclusters (AgNCs) offer unique opportunities to correlate structure and photophysical properties, yet enhancing their photoluminescence emission remains challenging due to dominance of non-radiative decay pathways. Here, we report a ligand-engineering strategy to modulate the optical properties of high-nuclearity Ag₅₆ NCs. The synthesized two NCs, Ag₅₆S₁₂(^tBuS)₂₀(CF₃CO₂)₁₂(MeCN)₃ (NC-I) and Ag₅₆S₁₂(^tBuS)₂₀(ⁿBuSO₃)₁₂ (NC-II), possess a similar hexagonal-close-packed Ag₁₄ kernel, which is encapsulated by a similar icosahedral S₁₂ middle-shell and an outer Ag₄₂ shell, but differ in overall symmetry and outer Ag-ligand shell connectivity. Replacement of bidentate CF₃CO₂⁻ with tridentate ⁿBuSO₃⁻ ligands increases overall Ag─X (X = O, S, and Ag) bonding interactions, resulting in not only a more rigid and compact outer Ag₄₂ shell structure but also contraction of cationic Ag₁₄ core and anionic icosahedral S₁₂ middle-shell. These structural modifications enhance radiative decay and suppress non-radiative pathways, leading to a 17-fold increase in photoluminescence quantum yield and extended average emission lifetime. Computational analysis confirms that ligand-induced geometric stabilization and electronic delocalization govern the excited-state dynamics. This work demonstrates that rational ligand design can synergistically tune cluster geometry, rigidity, and electronic structure, providing a general strategy to improve the photophysical performance of high-nuclearity AgNCs.

Keywords

emission / DFT / nanocluster / silver

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2026 The Author(s). Aggregate published by SCUT, AIEI, and John Wiley & Sons Australia, Ltd.