Blinking Statistics and Excitation-Dependent Luminescence Yield in Si and CdSe Nanocrystals

Blinking is a phenomenon observed in single quantum emitters, which reduces their overall light emission. Even though it seems to be a fundamental property of quantum dots (QDs), substantial differences can be found in the blinking statistics of different nanocrystals. This work compares the blinking of numerous single, oxide-capped Si nanocrystals with that of CdSe/ZnS core-shell nanocrystals, measured under the same conditions in the same experimental system and over a broad range of excitation power densities. We find that ONand OFF-times can be described by exponential statistics in Si QDs, as opposed to power-law statistics for the CdSe nanocrystals. The type of blinking (power-law or mono-exponential) does not depend on excitation, but seems to be an intrinsic property of the material system. Upon increasing excitation power, the duty