Unraveling the Effect of Single Atom Doping on the Carrier Relaxation Dynamics of MAg 24 n - Nanoclusters.

Precisely doped metal nanoclusters (NCs) are currently emerging nanomaterials for their unique photophysical properties. Here, we report the influence of single atom doping on the excited state relaxation dynamics of a series of MAg 24 (2,4-Me 2 PhS) 18 n - NCs where M is Ag, Au, Pd, and Pt. The NCs with a group 11 metal (Ag and Au) as central atoms exhibit dual emission at NIR and visible range, whereas it shows only NIR emission for group 10 metal (Pd and Pt) doped NCs. Global target analyses of transient absorption (TA) data reveal the three-state relaxation, i.e., initially excited state (S n ), ligand-centered charge transfer (CT) state (S L ), and metal-centered lowest excited state (S 1 ). Apart from the HOMO-LUMO (H-L) energy gap, the electron affinity of the central metal atom and rigidity of the NC structural framework influence the relaxation processes of the NCs. The extensive study into the relaxation dynamics will bestow the single atomic level modulation of photophysical properties.