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Prof. Colin D. Heyes, University of Arkansas
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Prof. Colin D. Heyes, University of Arkansas
Tuning Organic-Inorganic and Inorganic-Inorganic Interfaces of Quantum Dots for Ensemble and Single Molecule Fluorescence Applications
Physical Chemistry Seminar Series
Due to the high surface-to-volume ratio of nanoparticles, the fluorescence properties of colloidal quantum dots (QDs) are strongly affected by the various interfaces present. Simple core-only QDs have an inorganic-organic surface-ligand interface, while core-shell (or core-multishell) quantum dots have, in addition, inorganic-inorganic core-shell interfaces. We have systematically tuned the interfaces of cadmium-chalcogenide or copper-indium-chalcogenide cores and upon adding cadmium- and zinc-chalcogenide shells. The optical and structural properties at the ensemble and single particle level are analyzed by a combination of time-resolved fluorescence spectroscopy, single-particle fluorescence microscopy, quantitative FT-IR absorption spectroscopy, X-ray photoelectron (XPS) spectroscopy and high-resolution TEM/HAADF-STEM/EELS microscopy. In particular, we explore connections between the structural details of the interfaces and the quantum yield, radiative and non-radiative excited state decay rates, ligand binding, fluorescence blinking and the formation of a dark fraction. We also evaluate the response of these properties to external environments will be discussed to help devise strategies to tailor QDs for various applications. To illustrate these connections, I will present several applications utilizing bandgap and lifetime engineering of quantum dots – in particular for ultrasensitive biophysical and biomedical imaging.
For more information contact Prof. Angelo Bongiorno (404-385-5169).
Status
- Workflow Status:Published
- Created By:Shirley Tomes
- Created:11/12/2012
- Modified By:Fletcher Moore
- Modified:10/07/2016
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