Probing heterogeneity of NIR induced secondary fluorescence from DNA-stabilized silver nanoclusters at the single molecule level.

In this communication, we investigate optically activated delayed fluorescence (OADF) from DNA-stabilized silver nanoclusters (DNA-AgNCs) at the single molecule level, and we probe the heterogeneity in the primary fluorescence (PF) intensity, NIR induced secondary fluorescence (SF) intensity and SF/PF ratio. Our experiments reveal a heterogeneous distribution in the SF/PF ratio, indicating that engineering of DNA-AgNCs towards a high SF/PF ratio and high OADF signal for background-free imaging might be possible.