Fluorescence quenching of CdS quantum dots by 4-azetidinyl-7-nitrobenz-2-Oxa- 1,3-diazole: a mechanistic study

Santhosh, Kotni ; Patra, Satyajit ; Soumya, S. ; Khara, Dinesh Chandra ; Samanta, Anunay (2011) Fluorescence quenching of CdS quantum dots by 4-azetidinyl-7-nitrobenz-2-Oxa- 1,3-diazole: a mechanistic study ChemPhysChem, 12 (15). pp. 2735-2741. ISSN 1439-4235

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/cphc.20...

Related URL: http://dx.doi.org/10.1002/cphc.201100515

Abstract

Fluorescence quenching of CdS quantum dots (QDs) by 4-azetidinyl-7-nitrobenz-2-oxa-1,3-diazole (NBD), where the two quenching partners satisfy the spectral overlap criterion necessary for Forster resonance energy transfer (FRET), is studied by steady-state and time-resolved fluorescence techniques. The fluorescence quenching of the QDs is accompanied by an enhancement of the acceptor fluorescence and a reduction of the average fluorescence lifetime of the donor. Even though these observations are suggestive of a dynamic energy transfer process, it is shown that the quenching actually proceeds through a static interaction between the quenching partners and is probably mediated by charge-transfer interactions. The bimolecular quenching rate constant estimated from the Stern-Volmer plot of the fluorescence intensities, is found to be exceptionally high and unrealistic for the dynamic quenching process. Hence, a kinetic model is employed for the estimation of actual quencher/QD ratio dependent exciton quenching rate constants of the fluorescence quenching of CdS by NBD. The present results point to the need for a deeper analysis of the experimental quenching data to avoid erroneous conclusions.

Item Type:Article
Source:Copyright of this article belongs to John Wiley and Sons.
Keywords:Quantum Dots; Charge Transfer; Energy Transfer; Fluorescence; Static and Dynamic Quenching
ID Code:86704
Deposited On:12 Mar 2012 16:08
Last Modified:12 Mar 2012 16:08

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