Morphology-Preserved Alloying in Anisotropic Gold Nanoparticles Using Atomically Precise Nanoclusters

Noble metal nanoparticles (NPs) exhibit superior plasmonic, catalytic, electronic, and magnetic properties upon alloying with a second metal. However, the synthesis of bimetallic alloy NPs of non-spherical morphologies presents a challenge due to the necessity of concurrently modulating the nucleation and growth kinetics of various metallic constituents. In this study, a simple solution-phase reaction between a phosphine-protected copper nanocluster (NC), namely [Cu₁₈(DPPE)₆H₁₆]²⁺ [DPPE = 1,2-bis(diphenylphosphino)ethane] (abbreviated as Cu₁₈) and gold nanotriangles (AuNTs) is reported as a straightforward strategy to obtain gold-copper alloy nanotriangles (AuCuNTs) while keeping their sizes and sharp edges intact. Extending this protocol to gold nanorods (AuNRs) and nanocubes (AuNCbs) demonstrates its generality for creating anisotropic AuCu alloy NPs. Auger spectroscopic analyses confirm that Cu(0) is the predominant Cu species in the AuCuNTs, indicating that oxidation of Cu in the resulting nanostructures is prevented. A further interaction of AuCuNTs with [Ag₂₅(DMBT)₁₈]− [DMBT = 2,-dimethylbenzenethiol] (abbreviated as Ag₂₅) has yielded AuCuAgNTs, offering a facile synthetic route to trimetallic anisotropic NPs. Thus, the current study corroborates atomically precise metal NCs as versatile precursors for tuning the composition of plasmonic anisotropic NPs to meet diverse technological and industrial needs.