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TRPL data from semiconductor nanocrystals on semi-logarithmic (left column) and logarithmic (right column) axes. The three rows correspond to the different nanocrystal structures: (a) bare CdSe (sample A), (b) core shell (sample B), and (c) triple layer structure (sample C). All data sets are from single nanocrystals except for the uppermost one in each window, which is from an ensemble. The black scatter plots are raw data, the gray scatter plots are results of our MC simulation, and the solid red lines are analytical biexponential fits. In all cases, corresponds to the peak of the TRPL signal.
TCSPC and blinking data histograms on common logarithmic axes for 14 different single nanocrystals. The increments on both axes of the figure correspond to factors of 10. (Inset) Three level system used to simulate the tails of the TRPL data. Level 0 represents the nanocrystal ground state; level 1 the quantum confined exciton; and level 2 the charged fluorescence off state. is the radiative lifetime that corresponds to the slower decay in the original biexponential fit. The two additional fitting parameters are the lifetimes for escape from the exciton state to the fluorescence off state, labeled as , and the power law coefficient .
Fitting parameters , , and for the best fits to the data shown in Fig. 1 and for the average values from the blinking data in Fig. 2. The numbers in parentheses represent estimated error bars for the values stated.
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