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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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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).
