Superatom-in-Superatom Nanoclusters: Synthesis, Structure, and Photoluminescence

We report a new strategy in which a thiolate-protected Ag-25 nanocluster can be doped with open d-shell group 8 (Ru, Os) and 9 (Ir) metals by forming metal hydride (RuH2, OsH2, IrH) superatoms with a closed d-shell. Structural analyses using various experimental and theoretical methods revealed that the Ag-25 nanoclusters were co-doped with the open d-shell metal and hydride species to produce superatom-in-superatom nanoclusters, establishing a novel superatom doping phenomenon for open d-shell metals. The synthesized superatom-in-superatom nanoclusters exhibited dopant-dependent photoluminescence (PL) properties. Comparative PL lifetime studies of the Ag-25 nanoclusters doped with 8-10 group metals revealed that both radiative and nonradiative processes were significantly dependent on the dopant. The former is strongly correlated with the electron affinity of the metal dopant, whereas the latter is governed predominantly by the kernel structure changed upon the doping of the metal hydride(s).

Automated summary

We present a new strategy to dope a thiolate-protected Ag-25 nanocluster with open d-shell group 8 (Ru, Os) and 9 (Ir) metals by forming metal hydride (RuH2, OsH2, IrH) superatoms with a closed d-shell. The synthesized superatom-in-superatom nanoclusters exhibit dopant-dependent photoluminescence properties. Comparative studies reveal that both radiative and nonradiative processes are significantly influenced by the dopant.