Regensburg 2007 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 28: Polymer Physics V

CPP 28.2: Talk

Thursday, March 29, 2007, 17:30–17:45, H40

Low temperature mobility of Frenkel excitons on amphi-PIPE J-Aggregates — •Christian Spitz, Antonio Saghati, and Ralf Menzel — Universität Potsdam

The mobility of optically excited excitons on J-aggregates can be demonstrated by the phenomena of exciton exciton annihilation. In this intensity dependent process the collision of two excitons results in their annihilation and hence in a shortening of the mean excitation lifetime. By measuring the intensity dependent fluorescent lifetime in contrast to the predicted immobilization of the excitons at low temperature we could prove the excellent mobility of the excitons on the ampi-PIPE J-aggregates of the octyl derivate of 5,5,6,6-tetrachloro-1,1-diethyl-3-3 bis(4-sulpho-n-butyl) benzimidacarbocyanine (TDBC) at a temperature (4 K), which is far below their expected freezing point. The high mobility is further approved by fluorescence depolarisation at low temperatures.