Linking On-State Memory
and Distributed Kinetics in Single Nanocrystal Blinking
Amy A. Cordones
Kenneth
L. Knappenberger
Stephen R. Leone
10.1021/jp3041549.s001
https://acs.figshare.com/articles/journal_contribution/Linking_On_State_Memory_and_Distributed_Kinetics_in_Single_Nanocrystal_Blinking/2420644
Memory effects in single nanocrystal fluorescence blinking
are investigated as a function of the on-state kinetics for CdSe/ZnS
quantum dots and CdSe nanorods. The on-state duration probability
distributions for single nanocrystal blinking traces are characterized
by an inverse power law, which crosses over to exponential decay for
long on-state durations. The correlations of subsequent on-state durations
(<i>R</i><sub>log,on</sub>) are found to decrease for nanocrystals
that display earlier crossover times and smaller power law coefficients.
Specifically, <i>R</i><sub>log,on</sub> increases from 0.14
± 0.02 to a saturation value of 0.44 ± 0.01 for nanocrystals
with average crossover times of ∼100 ms to more than 5.0 s,
respectively. The results represent the first link between memory
effects and blinking kinetics and are interpreted in the framework
of two competing charge trapping mechanisms. A slow fluctuation-based
trapping mechanism leads to power-law-distributed on durations and
significant memory effects; however, the additional contribution of
an ionization-induced trapping pathway is found to induce crossover
to exponential decay and decreased memory. Monte Carlo simulations
of nanocrystal blinking based on the two trapping mechanisms reproduce
the experimental results, suggesting that the power law component
and the memory effects correlate with a fluctuation-based mechanism.
This effect is found to be universal, occurring for two nanocrystal
morphologies and in blinking data measured using a wide range of continuous
and pulsed excitation conditions.
2013-04-25 00:00:00
Monte Carlo simulations
power law component
duration
memory effects
nanocrystal
crossover times
Single Nanocrystal BlinkingMemory effects
mechanism
power law coefficients