Dresden 2003 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 22: POSTER C

CPP 22.4: Poster

Donnerstag, 27. März 2003, 12:00–14:00, ZEU/250

Blinking of single dye molecules with power law distributions — •Jörg Schuster, Frank Cichos, and Christian von Borczyskowski — Institut für Physik 122501, TU Chemnitz, 09107 Chemnitz

We studied the blinking dynamics of different dye molecules (Terrylene, Rhodamine 6G and diI) on bare silica surfaces by means of single molecule widefield imaging. In contrast to what is found in the literature we observe power law distributions for both on- and off-times in a time range from 0.02 to 10 s. Furthermore we studied the influence of oxygen on the blinking dynamics by flushing the samples with nitrogen. Compared to ambient air we observe significant changes in the on- and off-time distributions. In the case of Terrylene and Rhodamine 6G the on times decrease in the presence of nitrogen while the off-times increase. For diI no change in the on-times is observed but the off times also decrease when flushing with nitrogen. It is obvious, that power law distributions for on and off-times cannot be caused by a single, energetically well defined i.e. triplet state but may rather be the result of a distribution of dark states (or trap states) as it was stated for the blinking dynamics of single semiconductor quantum dots. We suppose that the observed effects are due to the interaction of the dyes with the silica surface, rather than to be a property of the molecule itself.