Highly Stable, Luminescent Gold Nanocluster Assemblies Driven by Depletion and Covalent Linker Interactions

Abstract

Supramolecular assembly of ultra-small, metal nanoclusters (NCs) offers a versatile platform to modulate their environmentdependent physicochemical properties; however, achieving structural control together with high thermodynamic stability remains challenging due to weak and dynamic noncovalent interactions. Herein, we present a straightforward strategy to construct highly stable assemblies of atomically precise, Au22(SG)18 NCs by coupling depletion attraction forces with a tetrathiol-containing small-molecule crosslinker, which imparts covalent linkage and thermodynamic robustness against harsh environments such as pH, solvent, probe sonication, and high temperature. The resulting assemblies also exhibit enhanced photoluminescence via aggregation-induced emission mechanism, and the approach extends to non-precise Au NCs, demonstrating its broad applicability for controlled assembly of metal NCs.