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 environment-dependent 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 an aggregation-induced emission mechanism, and the approach extends to non-precise Au NCs, demonstrating its broad applicability for controlled assembly of metal NCs.