On transient absorption and dual emission of the atomically precise, DNA-stabilized silver nanocluster Ag16Cl2

Abstract

DNA-stabilized silver nanoclusters with 10 to 30 silver atoms are interesting biocompatible nanomaterials with intriguing fluorescence properties. However, they are not well understood, since atom-scale high level theoretical calculations have not been possible due to a lack of firm experimental structural information. Here, by using density functional theory (DFT), we study the recently atomically resolved (DNA)₂–Ag₁₆Cl₂ nanocluster in solvent under the lowest-lying singlet (S₁) and triplet (T₁) excited states, estimate the relative emission maxima for the allowed (S₁ → S₀) and dark (T₁ → S₀) transitions, and evaluate the transient absorption spectra. Our results offer a potential interpretation of the recently reported transient absorption and dual emission of similar DNA-stabilized silver nanoclusters, providing a mechanistic view on their photophysical properties that are attractive for applications in biomedical imaging and biophotonics.