Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 41: Nanoparticles and Composite Materials

CPP 41.1: Vortrag

Donnerstag, 3. April 2014, 09:30–09:45, ZEU 222

Ultra-fast in-situ SAXS/WAXS on the nucleation and growth of CdS quantum dots — •Andreas Schiener and Andreas Magerl — Lehrstuhl für Kristallografie und Strukturphysik, Staudtstraße 3, 91058 Erlangen

Quantum dots provide due to their unique electrical and optical properties a high potential for applications in solar cells, photo diodes, as medical tracers, and in numerous other fields. Although many synthesis routes for the controlled fabrication are known and well established, a fundamental understanding of the nucleation and growth process is still missing. In this contribution we present a combined ultra-fast in-situ SAXS and WAXS study, which gives for the first time a direct experimental insight into the evolution of the crystalline and morphological structure of CdS quantum dots in the up to now unexplored time regime between 0.1 ms and 2.5 ms with a time resolution of down to 0.01 ms. The precipitation reaction of CdS takes place along a continuous free liquid jet, which converts the time scale into a length scale to address these short reaction times. A prominent cluster structure with the diameter of about 1 nm was observed both in the SAXS and in the WAXS signal. The formation mechanism of the final quantum dots is dominated by oriented attachment of these primary clusters.