Long-Range Correlated Fluorescence Blinking in CdSe/ZnS Quantum Dots

We studied fluorescence intermittency (blinking) in pairs of colloidally grown nanocrystal quantum dots (NQDs) and found that the fluorescence trajectories of dots separated by up to similar to 1 mu m are correlated. Blinking rate enhancement was observed when nearby NQDs were in opposite emitting states. Models of fluorescence blinking in colloidal quantum dots typically invoke particle charging to explain bright and dark periods in the fluorescence trajectory. Likewise, the phenomenon of fluorescence blinking correlation observed in this study is explained by an interdot Coulomb. interaction established by ejection of one or more photoinduced charges. Our results suggest that blinking can be controlled, ultimately leading to switchable nanoscale emitters.