Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Poster: Nanoparticles and Composite Materials
CPP 8.8: Poster
Montag, 26. März 2012, 17:30–20:00, Poster A
Continuous flow-through synthesis of prismatic silver nanoparticles in micro fluid segment sequences for possible SERS application — •Andrea Knauer1, Andrea Csaki2, Wolfgang Fitzsche2, and Johann Michael Köhler1,2 — 1University of Technology Ilmenau, D-96893, Ilmenau, Germany — 2Institute of Photonic Technology (IPHT) Jena, D- 07745, Jena, Germany
Non-spherical noble metal nanoparticles of gold and silver are of great interest due to their size- and shape-dependent plasmonic absorption in the long wavelength range. The spectral position of the in-plane dipole resonance wavelength can be tuned by the lateral length of the nanoparticles. It was expected that the homogeneity of nucleation and particle growth is influenced by the mixing speed due to the strong effect of reactant concentrations on the nucleation rate. Thus, the particle quality should improve, if high mixing rates under micro continuous-flow conditions and narrow residence time distributions are applied. The segmented flow technique was applied in order to combine a fast mixing by a segment-internal convection and a narrow residence time distribution. From the first synthesis step, homogeneous Ag seeds are obtained. In the second synthesis procedure, silver ions and a reducing agent are dosed into micro droplets containing Ag seeds in order to form silver nanoprisms, which display high size homogeneity. The presented technique can be adapted to synthesize colloidal solutions with tuneable particle sizes. Thus, the long-wavelength absorption can be shifted in a range between 520 and 1000 nm.