Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 8: Poster: Nanoparticles and Composite Materials

CPP 8.16: Poster

Monday, March 26, 2012, 17:30–20:00, Poster A

Blinking of single CdSe/ZnS nanoparticles on an Al covered silicon substrate — •Andreas Mölleken, Daniel Braam, Günther M. Prinz, Martin Geller, and Axel Lorke — Fakultät für Physik and CeNIDE, University of Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany

Semiconductor nanoparticles have attracted great interest as tunable light emitters. They can be easily fabricated without a solid state matrix and therefore placed into different environments and coupled to other nanostructures and metal surfaces. However, a drawback (and a phenomenon that is not yet understood in detail) remains: the blinking and spectral diffusion mechanism in the luminescence behaviour of single nanoparticles [1]. Previous studies have shown that the blinking behaviour is changed if the nanoparticles are close to a metal surface. In this study, we investigate the coupling between single nanoparticles and an Al metal surface. We fabricate a solution consisting of CdSe/ZnS core/shell nanoparticles dispersed in toluene with 1% PMMA and spin-coat this dispersion on top of an aluminium covered silicon substrate. For the measurements we use a µ-PL setup with two different excitation sources (405nm/532nm) in wide-field illumination. The setup enables us to study simultaneously many single nanoparticles and their luminescence behaviour. Our measurements show a blinking behaviour of the emission of single nanoparticles, which we can evaluate in terms of their characteristic on- and off-time statistics. Additionally we observe a slow blue shift in the emission energy over long time periods.

[1] Frantsuzov et al., Nature Phys. 4, 519 (2008)