Universality of the Fluorescence
Intermittency in
Nanoscale Systems: Experiment and Theory
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Abstract
A variety of optically active nanoscale objects show
extremely
long correlations in the fluctuations of fluorescence intensity (blinking).
Here we performed a systematic study to quantitatively estimate the
power spectral density (PSD) of the fluorescence trajectories of colloidal
and self-assembled quantum dots (QDs), nanorods (NRs), nanowires (NWs),
and organic molecules. We report for the first time a statistically
correct method of PSD estimation suitable for these systems. Our method
includes a detailed analysis of the confidence intervals. The striking
similarity in the spectra of these nanoscale systems, including even
a “nonblinking” quantum dot investigated by Wang and
collaborators (<i>Nature</i> <b>2009</b>, <i>459</i>, 685–689), is powerful evidence for the existence
of a universal physical mechanism underlying the blinking phenomenon
in all of these fluorophores (Frantsuzov et al. <i>Nat. Phys.</i> <b>2008</b>, <i>4</i>, 519–522). In this
paper we show that the features of this universal mechanism can be
captured phenomenologically by the multiple recombination center model
(MRC) we suggested recently for explaining single colloidal QD intermittency.
Within the framework of the MRCs we qualitatively explain all of the
important features of fluorescence intensity fluctuations for a broad
spectrum of nanoscale emitters