Engineering luminescent Au(0)@Au(I)-thiolate core-shell nanoclusters by HCl-etching of Au(I)-thiolate complexes

Abstract Metal nanoclusters (NCs) with aggregation-induced emission (AIE) characteristics have garnered substantial interest due to their intense photoluminescence and extensive potential applications. Elucidating the mechanisms underlying their high-efficiency luminescence is critical for advancing high-performance luminescent metal NCs materials. In recent years, Au(0)@Au(I)-thiolate NCs featuring core-shell architectures have demonstrated exceptional luminescent properties, offering an attractive strategy for engineering highly emissive Au NCs. This study presents a facile method for synthesizing novel green-emitting homocysteine stabilized Au NCs (Hcy-Au NCs) with core-shell structure. The critical mechanistic feature involves precisely controlled HCl etching of Au(I)-thiolate complexes, driving their decomposition to generate the Au(0) cores essential for the core-shell structures, thereby enabling the formation of luminescent Hcy-Au NCs. This convenient one-pot methodology demonstrates remarkable versatility, having been successfully extended beyond the preparation of luminescent Hcy-Au NCs and glutathione stabilized Au NCs (GSH-Au NCs) to include the synthesis of luminescent cysteine stabilized Au NCs (Cys-Au NCs) and D-Penicillamine stabilized Au NCs (DPA-Au NCs). Our work provides valuable insights for developing novel highly luminescent metal NCs.