Nuclear magnetic resonance spectroscopy demonstrating dynamic stabilization of CdSe quantum dots by alkylamines

A. Hassinen; I. Moreels; C. de Mello Donega; J.C. Martins; Z. Hens

doi:10.1021/jz100781h

Nuclear magnetic resonance spectroscopy demonstrating dynamic stabilization of CdSe quantum dots by alkylamines

A. Hassinen, I. Moreels, C. de Mello Donega, J.C. Martins, Z. Hens

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Abstract

The exchange kinetics of octylamine between a free state and a state bound to the surface of CdSe quantum dots is analyzed using nuclear magnetic resonance (NMR) spectroscopy in solution. On the basis of 1D 1H and DOSY and NOESY spectroscopy, we find that all octylamine molecules present interact with the CdSe quantum dot surface, although the octylamine resonances and diffusion coefficient resemble those of free octylamine. This indicates that these NMR observables are a weighted average of a free and a bound state, implying that the overall octylamine exchange rate is fast as compared to the intrinsic NMR time scale. A lower limit on the first-order desorption rate constant of 50 s−1 follows from DOSY measurements as a function of the diffusion delay. This result is compared with literature data based on the quenching of the CdSe photoluminescence upon alkylamine desorption.

Original language	English
Pages (from-to)	2577-2581
Number of pages	5
Journal	Journal of Physical Chemistry Letters
Volume	1
Issue number	17
DOIs	https://doi.org/10.1021/jz100781h
Publication status	Published - 2 Sept 2010

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2010 - Hassinen - jz100781h[1]
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title = "Nuclear magnetic resonance spectroscopy demonstrating dynamic stabilization of CdSe quantum dots by alkylamines",

abstract = "The exchange kinetics of octylamine between a free state and a state bound to the surface of CdSe quantum dots is analyzed using nuclear magnetic resonance (NMR) spectroscopy in solution. On the basis of 1D 1H and DOSY and NOESY spectroscopy, we find that all octylamine molecules present interact with the CdSe quantum dot surface, although the octylamine resonances and diffusion coefficient resemble those of free octylamine. This indicates that these NMR observables are a weighted average of a free and a bound state, implying that the overall octylamine exchange rate is fast as compared to the intrinsic NMR time scale. A lower limit on the first-order desorption rate constant of 50 s−1 follows from DOSY measurements as a function of the diffusion delay. This result is compared with literature data based on the quenching of the CdSe photoluminescence upon alkylamine desorption.",

author = "A. Hassinen and I. Moreels and {de Mello Donega}, C. and J.C. Martins and Z. Hens",

year = "2010",

month = sep,

day = "2",

doi = "10.1021/jz100781h",

language = "English",

volume = "1",

pages = "2577--2581",

journal = "Journal of Physical Chemistry Letters",

issn = "1948-7185",

publisher = "American Chemical Society",

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TY - JOUR

T1 - Nuclear magnetic resonance spectroscopy demonstrating dynamic stabilization of CdSe quantum dots by alkylamines

AU - Hassinen, A.

AU - Moreels, I.

AU - de Mello Donega, C.

AU - Martins, J.C.

AU - Hens, Z.

PY - 2010/9/2

Y1 - 2010/9/2

N2 - The exchange kinetics of octylamine between a free state and a state bound to the surface of CdSe quantum dots is analyzed using nuclear magnetic resonance (NMR) spectroscopy in solution. On the basis of 1D 1H and DOSY and NOESY spectroscopy, we find that all octylamine molecules present interact with the CdSe quantum dot surface, although the octylamine resonances and diffusion coefficient resemble those of free octylamine. This indicates that these NMR observables are a weighted average of a free and a bound state, implying that the overall octylamine exchange rate is fast as compared to the intrinsic NMR time scale. A lower limit on the first-order desorption rate constant of 50 s−1 follows from DOSY measurements as a function of the diffusion delay. This result is compared with literature data based on the quenching of the CdSe photoluminescence upon alkylamine desorption.

AB - The exchange kinetics of octylamine between a free state and a state bound to the surface of CdSe quantum dots is analyzed using nuclear magnetic resonance (NMR) spectroscopy in solution. On the basis of 1D 1H and DOSY and NOESY spectroscopy, we find that all octylamine molecules present interact with the CdSe quantum dot surface, although the octylamine resonances and diffusion coefficient resemble those of free octylamine. This indicates that these NMR observables are a weighted average of a free and a bound state, implying that the overall octylamine exchange rate is fast as compared to the intrinsic NMR time scale. A lower limit on the first-order desorption rate constant of 50 s−1 follows from DOSY measurements as a function of the diffusion delay. This result is compared with literature data based on the quenching of the CdSe photoluminescence upon alkylamine desorption.

U2 - 10.1021/jz100781h

DO - 10.1021/jz100781h

M3 - Article

SN - 1948-7185

VL - 1

SP - 2577

EP - 2581

JO - Journal of Physical Chemistry Letters

JF - Journal of Physical Chemistry Letters

IS - 17

ER -

Nuclear magnetic resonance spectroscopy demonstrating dynamic stabilization of CdSe quantum dots by alkylamines

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