Direct measurement of off-state trapping rate fluctuations in single quantum dot fluorescence.

Fluorescence decay times measured during the off-state of single CdSe/ZnS quantum dot blinking are found to decrease with increasing off-state duration, contradicting the charging model widely considered to explain the blinking phenomenon. The change in the nonradiative process of a short off-state duration compared to a long one is investigated here through simultaneous measurement of fluorescence decay and blinking behavior. The results are investigated in the framework of two models based on fluctuating trapping rates.