Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties

HL 91.17: Poster

Thursday, March 14, 2013, 16:00–20:00, Poster A

Time-resolved optical spectroscopy of colloidal quantum dots and gold nanoparticles with dye molecules — •Robert Malinowski, Uwe Kaiser, Mikko Wilhelm, Wolfram Heimbrodt, Faheem Amin, Dorleta Jimenez de Aberasturi, and Wolfgang Parak — Experimental physics of Philipps-University Marburg

We report about the opportunity to do multiplexed detection of different ionic species via ion-sensitive fluorophores. Multiplexed measurements can be made possible by coupling ion-sensitive fluorophores to different types of nanoparticles for biological sensor applications. These nanoparticles exhibit different radiative lifetimes and will act as donor for energy transfer to the ion-sensitive fluorophores as acceptors. As result the ion-sensitive fluorophores will obtain different effective lifetimes and can be read out in parallel via time-resolved detection of fluorescence. We investigate inorganic CdSe/ZnS core-shell quantum dots (QD) and gold nanoparticles (Au-NP) which are coated with amphiphilic polymers and functionalized by dye molecules. Main tasks are time resolved photoluminescence measurements of QD-dye and Au-dye mixtures in different concentrations. Using a laser (355nm) with pulse durations of a few nanoseconds, it is possible to characterize the time behavior of the photoluminescence decay of the dye molecules. By variation of the QD-dye to Au-dye ratio, the decay of the dye photoluminescence shows different behavior. The experimental results can be described and analyzed in the framework of a kinetic model. This opens up the possibility to determine the proportion of QD-dye and Au-dye for unknown mixing ratios by lifetime measurements.