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Heafey E, Laferrière M, Scaiano JC. Comparative study of the quenching of core and core-shell CdSe quantum dots by binding and non-binding nitroxides. Photochem Photobiol Sci. 2007;6(5):580-4doi: 10.1039/b616616d.
Heafey, E., Laferrière, M., & Scaiano, J. C. (2007). Comparative study of the quenching of core and core-shell CdSe quantum dots by binding and non-binding nitroxides. Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology, 6(5), 580-4. https://doi.org/10.1039/b616616d
Heafey, Eve, et al. "Comparative study of the quenching of core and core-shell CdSe quantum dots by binding and non-binding nitroxides." Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology vol. 6,5 (2007): 580-4. doi: https://doi.org/10.1039/b616616d
Heafey E, Laferrière M, Scaiano JC. Comparative study of the quenching of core and core-shell CdSe quantum dots by binding and non-binding nitroxides. Photochem Photobiol Sci. 2007 May;6(5):580-4. doi: 10.1039/b616616d. Epub 2007 Feb 13. PMID: 17487312.
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Photochem Photobiol Sci. 2007 May;6(5):580-4. doi: 10.1039/b616616d. Epub 2007 Feb 13.

Comparative study of the quenching of core and core-shell CdSe quantum dots by binding and non-binding nitroxides.

Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology

Eve Heafey, Marie Laferrière, J C Scaiano

Affiliations

  1. Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.

PMID: 17487312 DOI: 10.1039/b616616d

Abstract

The quenching of core and core-shell CdSe quantum dots by TEMPO and 4-amino-TEMPO has been examined using steady state fluorescence spectroscopy. The efficiency of quenching is strongly dependent on the nanoparticle size, the binding properties of the nitroxide, and the presence or not of a protective shell, ZnS in our systems. The shell reduces the quenching efficiency significantly only in the case of binding nitroxides, such as 4-amino-TEMPO. Downward quenching plots revealing bimodal quenching characterize the Stern-Volmer plots obtained for 4-amino-TEMPO. The slope characteristic of the low concentrations regime depends strongly on the presence of a shell. For example, for particles with a 2.4 nm core, emitting at 525 nm the concentrations of 4-amino-TEMPO required to reduce the emission to one half are 0.65 microM and 0.08 mM for core and core-shell nanoparticles, respectively. Surprisingly, in the high concentration regime, a single Stern-Volmer slope of about 4000 M-1 seems to accommodate all systems. We speculate that this value is characteristic of the exchange of TOPO ligands by 4-amino-TEMPO.

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