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Size-Dependent Optical Properties of Colloidal PbS Quantum Dots

Iwan Moreels UGent, KRIS LAMBERT UGent, Dries Smeets, David De Muynck UGent, Tom Nollet UGent, José Martins UGent, Frank Vanhaecke UGent, Andre Vantomme, Christophe Delerue and Guy Allan, et al. (2009) ACS NANO. 3(10). p.3023-3030
abstract
We quantitatively investigate the size-dependent optical properties of colloidal PbS nanocrystals or quantum dots (Qdots) by combining-the Qdot absorbance spectra with detailed elemental analysis of the Qdot suspensions. At high energies, the molar extinction coefficient epsilon increases With the Not volume d(3) and agrees with theoretical calculations using the Maxwell-Garnett effective medium theory and bulk values for the Qdot dielectric function. This demonstrates that quantum confinement has no influence on E in this spectral range, and it provides an accurate method to calculate the Qdot concentration. Around the band gap, epsilon only increases with d(1.3), and values are comparable to the epsilon of PbSe Qdots. The data are related to the oscillator strength f(if) of the band gap transition and results agree well with theoretical tight-binding calculations, predicting a linear dependence of f(if) on d. For both PbS and PbSe Qdots, the exciton lifetime tau is calculated from f(if). We find values ranging between 1 and 3 mu s, in agreement with experimental literature data from time-resolved luminescence spectroscopy. Our results provide a thorough general framework to calculate and understand the optical properties of suspended colloidal quantum dots. Most importantly, it highlights the significance of the local field factor in these systems.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
keyword
MICROCRYSTALS, SEMICONDUCTOR NANOCRYSTALS, ELECTRONIC-STRUCTURE, CDSE, DIELECTRIC CONFINEMENT, EXTINCTION COEFFICIENT, ROUTE, ABSORPTION CROSS-SECTION, GLASSES, SPECTROSCOPY
journal title
ACS NANO
ACS Nano
volume
3
issue
10
pages
8 pages
publisher
AMER CHEMICAL SOC
place of publication
WASHINGTON
Web of Science type
Article
Web of Science id
000271106100020
JCR category
MATERIALS SCIENCE, MULTIDISCIPLINARY
JCR impact factor
7.493 (2009)
JCR rank
10/210 (2009)
JCR quartile
1 (2009)
ISSN
1936-0851
DOI
10.1021/nn900863a
language
English
UGent publication?
yes
classification
A1
id
780823
handle
http://hdl.handle.net/1854/LU-780823
date created
2009-11-15 19:35:55
date last changed
2009-11-24 14:33:48
@article{780823,
  abstract     = {We quantitatively investigate the size-dependent optical properties of colloidal PbS nanocrystals or quantum dots (Qdots) by combining-the Qdot absorbance spectra with detailed elemental analysis of the Qdot suspensions. At high energies, the molar extinction coefficient epsilon increases With the Not volume d(3) and agrees with theoretical calculations using the Maxwell-Garnett effective medium theory and bulk values for the Qdot dielectric function. This demonstrates that quantum confinement has no influence on E in this spectral range, and it provides an accurate method to calculate the Qdot concentration. Around the band gap, epsilon only increases with d(1.3), and values are comparable to the epsilon of PbSe Qdots. The data are related to the oscillator strength f(if) of the band gap transition and results agree well with theoretical tight-binding calculations, predicting a linear dependence of f(if) on d. For both PbS and PbSe Qdots, the exciton lifetime tau is calculated from f(if). We find values ranging between 1 and 3 mu s, in agreement with experimental literature data from time-resolved luminescence spectroscopy. Our results provide a thorough general framework to calculate and understand the optical properties of suspended colloidal quantum dots. Most importantly, it highlights the significance of the local field factor in these systems.},
  author       = {Moreels, Iwan and LAMBERT, KRIS and Smeets, Dries and De Muynck, David and Nollet, Tom and Martins, Jos{\'e} and Vanhaecke, Frank and Vantomme, Andre and Delerue, Christophe and Allan, Guy and Hens, Zeger},
  issn         = {1936-0851},
  journal      = {ACS NANO},
  keyword      = {MICROCRYSTALS,SEMICONDUCTOR NANOCRYSTALS,ELECTRONIC-STRUCTURE,CDSE,DIELECTRIC CONFINEMENT,EXTINCTION COEFFICIENT,ROUTE,ABSORPTION CROSS-SECTION,GLASSES,SPECTROSCOPY},
  language     = {eng},
  number       = {10},
  pages        = {3023--3030},
  publisher    = {AMER CHEMICAL SOC},
  title        = {Size-Dependent Optical Properties of Colloidal PbS Quantum Dots},
  url          = {http://dx.doi.org/10.1021/nn900863a},
  volume       = {3},
  year         = {2009},
}

Chicago
Moreels, Iwan, KRIS LAMBERT, Dries Smeets, David De Muynck, Tom Nollet, José Martins, Frank Vanhaecke, et al. 2009. “Size-Dependent Optical Properties of Colloidal PbS Quantum Dots.” Acs Nano 3 (10): 3023–3030.
APA
Moreels, I., LAMBERT, K., Smeets, D., De Muynck, D., Nollet, T., Martins, J., Vanhaecke, F., et al. (2009). Size-Dependent Optical Properties of Colloidal PbS Quantum Dots. ACS NANO, 3(10), 3023–3030.
Vancouver
1.
Moreels I, LAMBERT K, Smeets D, De Muynck D, Nollet T, Martins J, et al. Size-Dependent Optical Properties of Colloidal PbS Quantum Dots. ACS NANO. WASHINGTON: AMER CHEMICAL SOC; 2009;3(10):3023–30.
MLA
Moreels, Iwan, KRIS LAMBERT, Dries Smeets, et al. “Size-Dependent Optical Properties of Colloidal PbS Quantum Dots.” ACS NANO 3.10 (2009): 3023–3030. Print.