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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 41: Nanoparticles and Composite Materials II

CPP 41.2: Vortrag

Donnerstag, 25. März 2010, 14:15–14:30, H48

Excitation Dynamics in Polymer-Coated Semiconductor Quantum Dots with Integrated Dye Molecules: The Role of Reabsorption and Radiationless Transfer — •Tobias Niebling, Sebastian Friede, Feng Zhang, Zulquarnain Ali, Wolfram Heimbrodt, and Wolfgang J. Parak — Department of Physics and Material Sciences Center (WZMW), Philipps University Marburg, Renthof 5, D-35032 Marburg, Germany

Colloidal quantum dots can provide a basis for applications in biolabelling and bioanalytics. Inorganic CdSe/ZnS core-shell quantum dots (QDs) were coated with amphiphilic polymers in order to transfer them to aqueous solutions. The polymer shell allows a functionalization of the nanoparticles. In this work ATTO-dye molecules were linked to the QDs. The excitation dynamics within this system have been investigated by steady state and time-resolved optical spectroscopy. (I) Reabsorption of QD emission by the dye molecules and (II) Förster resonant energy transfer (FRET) from the donor QD to the accepting dye molecules dominate the photoluminescence properties. The spectral overlap between the QD emission and the dye absorption and thereby the transfer efficiency can be tuned by the size of the QDs. Our description of the emission behaviour yields a kinetic model that considers the dynamics of the excited QD and dye molecules with respect to the different transfer mechanisms and reveals the respective contributions of reabsorption and radiationless transfer.