Dresden 2011 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 48: Nanoparticles and Composite Materials II

CPP 48.6: Vortrag

Freitag, 18. März 2011, 11:45–12:00, ZEU 114

New Approach to Photoluminescence Intermittency: Luminescence Intensity-resolved Investigation of CdSe/ZnS Quantum Dots — •Robert Schmidt, Cornelius Krasselt, and Christian von Borczyskowski — Institute of Physics and nanoMA (Center for nanostructured Materials and Analytics), Chemnitz University of Technology, 09107 Chemnitz, Germany

The photoluminescence of single emitters like semiconductor quantum dots (QDs) shows intermittency, called blinking, which divides the intensity time traces into bright “on”-, dark “off”- and “gray” intermediate states, where the distribution of on- and off-times follow a power-law [1]. While these states can be well described by a charge separation model, the physical background of the blinking dynamics, especially of the “on”-states, is less evident. Here we investigate the fluorescence of single CdSe/ZnS-QD by single photon counting techniques and use the “change-point analysis” [2] to analyze their fluorescence time traces with respect to photoluminescence intensities. This allows us to gain new information about the “on”-state-dynamics and further insights into the fundamental physical background of QD blinking.

[1] F. Cichos, C. von Borczyskowski & M. Orrit, Current Opinion in Colloid & Interface Science 12, 272-284 (2007).

[2] L.P. Watkins & H. Yang, J. Phys. Chem. B 109, 617-628 (2005).