Blinking suppression on millisecond-to-minutes time scales in giant nanocrystal quantum dots

Fluorescence intermittency (blinking) is an intrinsic feature of molecular-like fluorophores, including nanocrystal quantum dots (NQDs). The effect complicates applications of NQDs in areas such as quantum informatics, bio-imaging, and real-time tracking. Previously we developed ``giant'' NQDs in which a small emitting core is overcoated with a thick shell of a wider-gap material and observed strong blinking suppression on a time scale of 100s ms and longer. In this work, we employ time-tagged correlated single photon counting to detect photoluminescence (PL) traces from individual ``giant'' CdSe/CdS NQDs with resolution better than 1 ms. We observe a strong dependence of the fluorescence on/off times on shell thickness and almost complete blinking suppression on all measured time scales for NQDs coated with more than $\sim $10 monolayers of CdS. Further systematic analysis of our PL traces reveal a photon statistics that differs significantly from a power-law distribution of on/off times typically observed for ``regular'' NQDs.