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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 36: Poster: Nanoparticles and Composite Materials

CPP 36.16: Poster

Mittwoch, 16. März 2011, 17:00–19:00, P2

The accurate estimation of power law exponents in terms of binned data — •André Heber, Nicole Amecke, and Frank Cichos — Molecular Nanophotonics, University of Leipzig, Leipzig, Germany

Since the first observations of single quantum dots, is has been known that they show random intensity switches between a photon-emitting state, called on-state, and an off-state, where no photons are emitted. The durations of the states are described as cut-off power laws or pure power laws, respectively. It is estimated that the power laws stretch from the fluorescence lifetime of a quantum dot to hours. However, due to experimental limitation, in intensity time traces only on- and off- states longer than 1 ms can be measured. In this poster we argue that it is difficult to conclude from the measurement of binned data to the microscopic mechanisms of the blinking behavior. We compare different analysis methods including least square fits and maximum likelihood estimators of simulated blinking traces. As a result we show that linear least square fits to log-log histograms are better suited to determine the power law from binned data than maximum likelihood estimators.