Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 44: Quantum dots: Preparation and characterization

HL 44.13: Talk

Wednesday, March 18, 2015, 12:45–13:00, EW 203

In situ Raman monitoring of silica shell formation on colloidal CdSe/CdSe quantum dots — •Philipp Baumeister¹, Amelie Biermann¹, Tangi Aubert², Zeger Hens², Janina Maultzsch¹, and Axel Hoffmann¹ — ¹Institut für Festkörperphysik, Technische Universität Berlin, Germany — ²Physics and Chemistry of Nanostructures, Ghent University, Ghent, Belgium

Colloidal CdSe/CdS quantum dots offer possibilities for a variety of applications, in particular for biological imaging. Due to their high luminescence yield, discrete spectrum and stability, quantum dots used as biological markers are in many cases superior to regular dyes. The toxicity of CdSe and CdS remains a problem for biological uses. Furthermore, for those applications the quantum dots need to be modified for water solubility and acid resistance. One approach to solve these problems is the coating the quantum dots with a silica shell.
In this talk we discuss the influence of the silica shell synthesis on the encapsulated CdSe/CdS quantum dots utilizing in situ Raman spectroscopy. This made it possible to monitor the formation of the silica shell in real time. We were able to measure an increasing strain in the CdS-shell during the first hours of the synthesis, despite the silica shell being an amorphous material.