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Unformatted text preview: 1 Encapsulating of Single Quantum Dots into Polymer Particles Y AN G AO A , S ABRINA R EISCHMANN A , J OHANNES H UBER A , T OBIAS H ANKE B , R UDOLF B RATSCHITSCH B , A LFRED L EITENSTORFER B AND S TEFAN M ECKING A * a Chair of Chemical Materials Science, Department of Chemistry, University of Konstanz, Germany b Chair of Modern Optics and Quantum Electronics, Department of Physics, University of Konstanz, Germany * Corresponding author: Tel: +49(0)7531 88-2593, Fax +49 (0) 7531 88-5152; E-mail: firstname.lastname@example.org. ABSTRACT Single semiconductor quantum dots were embedded into polymer particles with diameters below 0.1 μ m by an emulsion polymerization procedure or via a secondary dispersion approach. The photoluminescence properties of the nanocrystals are retained upon encapsulation, as demonstrated by fluorescence confocal microscopy. Keywords: quantum dots, emulsion polymerization, hybrid particles, polymerization, fluorescence Abbrevations: Quantum dots (QDs), Sodium dodecyl sulfate (SDS), methyl methacrylate (MMA) and 2,2-azobisisobutyronitrile (AIBN), Dynamic light scattering (DLS), atomic force microscopy (AFM) The identical original publication in Colloid and Polymer Science is available at www.springerlink.com . Please cite this article as: Y. Gao, S. Reischmann, J. Huber, T. Hanke, R. Bratschitsch, A. Leitenstorfer, S. Mecking, Coll. Polym. Sci. 2008 , 286 , 1329 - 1334. Introduction Hybrid organic-inorganic particles are of widespread interest. 1 The incorporation of inorganic nanoparticles in larger polymer micro- or nanoparticles will provide them with the colloidal properties of the latter, e.g. dispersability in a given medium and adsorption behaviour towards a surface. The inorganic nanoparticles can be protected from their environment and from damage incurred upon mechanical manipulation. Manipulation may also be facilitated by the “size enlargement” occurring by the incorporation in the larger polymer particles. Among various methods for the preparation of nanocomposite particles, heterophase polymerization has proven particularly versatile. 2-6 In order to provide compatibility with an organic phase (e.g. solvent, monomer or polymer), inorganic nanoparticles with a bound or physisorbed organic shell are employed. Due to a limited miscibility of polymers with this organic shell, aggregation of the inorganic nanoparticles frequently occurs upon polymer 2 formation. 6,7 The preparation of composite particles with non-aggregated inorganic nanoparticles is challenging. Inorganic semiconductor quantum dots (QDs) possess unique optical properties, namely size-dependent tunable emission, photostability, broad absorption spectra and narrow emission spectra....
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