A Stochastic Model for Energy Transfer from CdS Quantum Dots/Rods (Donors) to Nile Red Dye (Acceptors)

Sadhu, Suparna; Tachiya, M.; Patra, Amitava

doi:10.1021/jp906160z

Cited by 107 publications

(188 citation statements)

References 19 publications

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“…The second assumption considers that when a micelle contains n solubilized molecules, the rate constant for exit of a solubilized molecule from the micelle is n times as fast as when it contains one solubilized molecule. In recent past the model has been successfully used to understand the drug binding to polymer degradation [37], nanoparticle quenching [38] etc. The above model is well relevant in our experimental framework.…”

Section: Tachiya Kinetic Modelmentioning

confidence: 99%

“…In this context, we have applied a kinetic model developed by Tachiya [44] for the quenching of luminescent probes undergoing non-radiative energy transfer in restricted environments. In contemporary literature, the kinetic model finds its relevance in various aspects including drug binding [45], nanoparticles quenching [38]. The model provides a clear understanding about the number of possible binding sites of the host molecules.…”

Section: Structural Studiesmentioning

confidence: 99%

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Ultrafast interfacial solvation dynamics in specific protein DNA recognition

et al. 2013

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Section: Tachiya Kinetic Modelmentioning

confidence: 99%

Section: Structural Studiesmentioning

confidence: 99%

Ultrafast interfacial solvation dynamics in specific protein DNA recognition

et al. 2013

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“…Some groups have characterized the number of ligands bound indirectly using optical methods. (10,16,(26)(27)(28) In most of these previous studies, fitting based on a binding model that differentiates bound and free states is used to indirectly infer N. NMR, though difficult to measure due to the high concentration required for its measurement, allows one to directly differentiate between bound versus free ligands due to their different signatures in the NMR spectrum. In this paper, we examine the transfer of photoexcited holes from quasi-type-II symmetric (nearly spherical) CdSe-core CdS-shell to a quantified number of molecular acceptors on the QD surface, to clarify the limitations and efficiencies of such a system.…”

Section: Introductionmentioning

confidence: 99%

Efficiency of Hole Transfer from Photoexcited Quantum Dots to Covalently Linked Molecular Species

Ding

Olshansky

Leone³

et al. 2015

J. Am. Chem. Soc.

131

172

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Hole transfer from high photoluminescence quantum yield (PLQY) CdSe-core CdS-shell semiconductor nanocrystal quantum dots (QDs) to covalently linked molecular hole acceptors is investigated. 1H NMR is used to independently calibrate the average number of hole acceptor molecules per QD, N, allowing us to measure PLQY as a function of N, and to extract the hole transfer rate constant per acceptor, k ht. This value allows for reliable comparisons between nine different donor–acceptor systems with variant shell thicknesses and acceptor ligands, with k ht spanning over 4 orders of magnitude, from single acceptor time constants as fast as 16 ns to as slow as 0.13 ms. The PLQY variation with acceptor coverage for all k ht follows a universal equation, and the shape of this curve depends critically on the ratio of the total hole transfer rate to the sum of the native recombination rates in the QD. The dependence of k ht on the CdS thickness and the chain length of the acceptor is investigated, with damping coefficients β measured to be (0.24 ± 0.025) Å–1 and (0.85 ± 0.1) Å–1 for CdS and the alkyl chain, respectively. We observe that QDs with high intrinsic PLQYs (>79%) can donate holes to surface-bound molecular acceptors with efficiencies up to 99% and total hole transfer time constants as fast as 170 ps. We demonstrate the merits of a system where ill-defined nonradiative channels are suppressed and well-defined nonradiative channels are engineered and quantified. These results show the potential of QD systems to drive desirable oxidative chemistry without undergoing oxidative photodegradation.

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“…[17,[26][27][28][29][30] The literature suggests that fluorescence quenching of the QDs by organic molecules is most often attributed to the energy transfer mechanism on the basis of the spectral overlap criterion and decrease in average lifetime. [31][32][33][34][35] Exciton dissociation of QDs by Fçrster resonance energy transfer (FRET) is a dynamic quenching process, whereas the quenching of QD emission by charge transfer (electron and/or hole) can proceed through either dynamic or static quenching mechanisms. [28,29,36] There are some cases where both dynamic and static quenching mechanisms contribute to QD exciton quenching.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence Quenching of CdS Quantum Dots by 4‐Azetidinyl‐7‐Nitrobenz‐2‐Oxa‐1,3‐Diazole: A Mechanistic Study

Santhosh¹,

Patra²,

Soumya³

et al. 2011

ChemPhysChem

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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 Förster 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.

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A Stochastic Model for Energy Transfer from CdS Quantum Dots/Rods (Donors) to Nile Red Dye (Acceptors)

Cited by 107 publications

References 19 publications

Ultrafast interfacial solvation dynamics in specific protein DNA recognition

Ultrafast interfacial solvation dynamics in specific protein DNA recognition

Efficiency of Hole Transfer from Photoexcited Quantum Dots to Covalently Linked Molecular Species

Fluorescence Quenching of CdS Quantum Dots by 4‐Azetidinyl‐7‐Nitrobenz‐2‐Oxa‐1,3‐Diazole: A Mechanistic Study

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