DNA template-regulated intergrowth of a fluorescent silver nanocluster emitter pair

Abstract

We have developed a novel type of intensely fluorescent DNA-templated silver nanoclusters (DNA/AgNCs), which is in the form of the intergrowth of a Ag emitter pair. In a representative mode, the Ag emitter pair with enhanced fluorescence was prepared by a single-stranded DNA template containing emitter-nucleation sequences at its termini and a spacer in the middle. Our work explicitly shows that the spacer length controls the fluorescence intensity of the forming Ag emitter pair, the spacer composition confers the secondary structure of the DNA template to express the optical and morphological properties of the Ag emitter pair, and the combination of the Ag emitter pair plays a significant role in the formation of fluorescent Ag emitter pair intergrowth. Notably, the produced Ag emitter pair exhibits superior luminescent features with a quantum yield of ∼16.3%, high fluorescence enhancement ratio of ∼850 fold, and rapid synthesis within ∼15 min. We have identified two processes of plasmonic resonance and ligand-to-metal–metal charge transfer (LMMCT) which are responsible for the production of the enhanced fluorescence in the Ag emitter pair in the intergrowth state. These findings offer new insight into the experimental and theoretical research of luminescent silver nanomaterials, which in our view render broad applicability of AgNCs for sensing and other applications.