Fluorescence intermittency, or blinking, is the phenomenon of random switching between ON (bright) and OFF (dark) states of the emitter under its continuous excitation.
It is a common property of the nanoscale emitters (molecular fluorophores, colloidal quantum dots) related to the competition between the radiative and non-radiative relaxation pathways.
[1][2] The peculiar feature of such blinking in most cases is the power-law (in contrast to exponential) statistics of the ON and OFF time distributions,[2] meaning that the measurements of the time-averaged intensity of a single emitter is not reproducible in different experiments and implying a complex dynamics of the involved process.
For CdSe-ZnS core-shell nanocrystals, "charge trapping" is the dominant theory explaining observed power-law blinking kinetics.
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