Dresden 2009 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 14: POSTERS Nanoparticles

CPP 14.11: Poster

Tuesday, March 24, 2009, 14:00–16:30, P3

Optically Detected Cyclic Voltammetry on Single Semiconductor Quantum Dots — •Angel Topalov, Nicole Amecke, and Frank Cichos — Molecular Nanophotonics Group, Institute of Experimental Physics I, University Leipzig, Linnéstraße 5, 04103 Leipzig

An interesting and promising class of materials studied over the last years are semiconductor nanocrystals. Many applications seek to make use of their favorable fluorescence characteristics, like tunable emission wavelength, high quantum yield and photon statistics (antibunching). Additionally they show certain peculiarities like power-law blinking, lifetime-fluctuations and spectral diffusion which can be explained by charges close to or in the dot center leading to Auger processes (non-radiative energy transfer to those charges) and the quantum confined stark effect. Those charges can arise from ejection of electron or hole via tunneling leaving behind the counterpart and additionally changing the matrix charge constellation. One of the main ideas is, thus, the development of an experimental method and setup for controlling those charges on the single particle level, starting with a determination of the specific ionization energy and electron affinity of different sizes of quantum dots. We then use confocal microscopy and cyclic voltammetry (CV) together, which gives us remarkable opportunities for experimental observations on the influences of charges on single crystal fluorescence.