DNA Stabilizes Eight-Electron Superatom Silver Nanoclusters with Broadband Downconversion and Microsecond-Lived Luminescence.

ABSTRACT

DNA oligomers are known to serve as stabilizing ligands for silver nanoclusters (AgN-DNAs) with rod-like nanocluster geometries and nanosecond-lived fluorescence. Here, we report two AgN-DNAs that possess distinctly different structural properties and are the first to exhibit only microsecond-lived luminescence. These emitters are characterized by significant broadband downconversion from the ultraviolet/visible to the near-infrared region. Circular dichroism spectroscopy shows that the structures of these two AgN-DNAs differ significantly from previously reported AgN-DNAs. We find that these nanoclusters contain eight valence electrons, making them the first reported DNA-stabilized luminescent quasi-spherical superatoms. This work demonstrates the important role that nanocluster composition and geometry play in dictating luminescence properties of AgN-DNAs and significantly expands the space of structure-property relations that can be achieved for AgN-DNAs.