Doping of Silver Atom Enhances the Fluorescence Intensity in Glutathione Functionalized Gold Nanoclusters

Glutathione (GSH) is a widely used surface ligand for stabilizing metal nanoclusters owing to its biocompatibility, strong metal-chelating ability, antioxidant properties, and minimal affinity for endogenous cellular proteins. However, the low quantum yield of GSH-protected gold nanoclusters (GSH-Au NCs) limits its practical applications. In the present study, silver (Ag) doping is employed in GSH-Au NCs to significantly enhance the photoluminescence intensity as well as lifetime, while preserving the microenvironment and the surface reactivity essential for subsequent functionalization. The doped nanoclusters exhibit a remarkable sixfold increase in luminescence. This is attributed to the modulation of metal(I)-thiolate motifs and the amplification of aurophillic interactions, leading to more rigid structure which help to reduce non-radiative deexcitation pathways.