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Influence of Size and Shape Anisotropy on Optical Properties of CdSe Quantum Dots

We used low-temperature reactions to synthesize different-sized CdSe quantum dots (QDs) capped with fatty-acid and phosphine ligands. From the correlation of high-resolution transmission electron microscopy and X-ray diffraction (XRD) analyses of the synthesized QDs, we observed size-dependent shape...

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Autores principales: Kim, Sung Hun, Man, Minh Tan, Lee, Joong Wook, Park, Kyoung-Duck, Lee, Hong Seok
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7466547/
https://www.ncbi.nlm.nih.gov/pubmed/32806736
http://dx.doi.org/10.3390/nano10081589
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author Kim, Sung Hun
Man, Minh Tan
Lee, Joong Wook
Park, Kyoung-Duck
Lee, Hong Seok
author_facet Kim, Sung Hun
Man, Minh Tan
Lee, Joong Wook
Park, Kyoung-Duck
Lee, Hong Seok
author_sort Kim, Sung Hun
collection PubMed
description We used low-temperature reactions to synthesize different-sized CdSe quantum dots (QDs) capped with fatty-acid and phosphine ligands. From the correlation of high-resolution transmission electron microscopy and X-ray diffraction (XRD) analyses of the synthesized QDs, we observed size-dependent shape anisotropy. In addition, the recorded XRD patterns revealed mixed crystal facets with zinc blende and wurtzite structures in small-sized QDs. Furthermore, from differential absorption (DA) spectra, we extracted the electronic transition energies for different-sized QDs, which were found to be similar to the calculated values of the quantum size levels associated with band mixing of CdSe QDs with a moderate bandgap. We found that the excitonic absorption peaks are increasingly “hidden” with decreasing QD size because of the crystal structure and crystalline quality. The results show good agreement with the obtained diffraction patterns and the estimation errors obtained from the DA spectra.
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spelling pubmed-74665472020-09-14 Influence of Size and Shape Anisotropy on Optical Properties of CdSe Quantum Dots Kim, Sung Hun Man, Minh Tan Lee, Joong Wook Park, Kyoung-Duck Lee, Hong Seok Nanomaterials (Basel) Article We used low-temperature reactions to synthesize different-sized CdSe quantum dots (QDs) capped with fatty-acid and phosphine ligands. From the correlation of high-resolution transmission electron microscopy and X-ray diffraction (XRD) analyses of the synthesized QDs, we observed size-dependent shape anisotropy. In addition, the recorded XRD patterns revealed mixed crystal facets with zinc blende and wurtzite structures in small-sized QDs. Furthermore, from differential absorption (DA) spectra, we extracted the electronic transition energies for different-sized QDs, which were found to be similar to the calculated values of the quantum size levels associated with band mixing of CdSe QDs with a moderate bandgap. We found that the excitonic absorption peaks are increasingly “hidden” with decreasing QD size because of the crystal structure and crystalline quality. The results show good agreement with the obtained diffraction patterns and the estimation errors obtained from the DA spectra. MDPI 2020-08-12 /pmc/articles/PMC7466547/ /pubmed/32806736 http://dx.doi.org/10.3390/nano10081589 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Kim, Sung Hun
Man, Minh Tan
Lee, Joong Wook
Park, Kyoung-Duck
Lee, Hong Seok
Influence of Size and Shape Anisotropy on Optical Properties of CdSe Quantum Dots
title Influence of Size and Shape Anisotropy on Optical Properties of CdSe Quantum Dots
title_full Influence of Size and Shape Anisotropy on Optical Properties of CdSe Quantum Dots
title_fullStr Influence of Size and Shape Anisotropy on Optical Properties of CdSe Quantum Dots
title_full_unstemmed Influence of Size and Shape Anisotropy on Optical Properties of CdSe Quantum Dots
title_short Influence of Size and Shape Anisotropy on Optical Properties of CdSe Quantum Dots
title_sort influence of size and shape anisotropy on optical properties of cdse quantum dots
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7466547/
https://www.ncbi.nlm.nih.gov/pubmed/32806736
http://dx.doi.org/10.3390/nano10081589
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