COLL 253 |
| Although most applications of CdSe quantum dots (QDs) have exploited their intense, tunable luminescence, recent studies in our group have focused on the quenching of this luminescence by stable free radical species and their potential as fluorescent probes in radical reactions. In the process of further investigating the quenching mechanism, several disulfide biradicals were synthesized. Through fluorescence spectroscopy and electron paramagnetic resonance (EPR), we have been able to study the nature of disulfide binding to the QD surface and the dynamics of the process. We show evidence that adsorption occurs slowly but irreversibly, while the efficiency of fluorescence quenching is sensitive to the distance from the QD surface to the radical moiety. Understanding the electron interaction mechanism from an excited QD to an adsorbed molecule has important implications in QD-based photochemistry. In addition, using a disulfide as an irreversible binding agent to CdSe surfaces may allow for more reliable attachment of ligands to QD surfaces. |
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Fundamental Research in Colloid and Surface Chemistry
6:00 PM-8:00 PM, Monday, August 20, 2007 BCEC -- East Registration, Poster
Division of Colloid & Surface Chemistry |