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dc.contributor.author
Ludescher, Lukas
dc.contributor.author
Dirin, Dmitry
dc.contributor.author
Kovalenko, Maksym V.
dc.contributor.author
Sztucki, Michael
dc.contributor.author
Boesecke, Peter
dc.contributor.author
Lechner, Rainer T.
dc.date.accessioned
2019-02-12T15:34:56Z
dc.date.available
2019-01-30T03:18:28Z
dc.date.available
2019-02-12T15:34:56Z
dc.date.issued
2019
dc.identifier.issn
2296-2646
dc.identifier.other
10.3389/fchem.2018.00672
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/321153
dc.identifier.doi
10.3929/ethz-b-000321153
dc.description.abstract
To study the influence of the chemical and crystalline composition of core/shell NCs on their photoluminescence (PL) the mean structural profile of a large ensemble of NCs has to be retrieved in atomic resolution. This can be achieved by retrieving the chemical profile of core/shell NCs using anomalous small angle x-ray scattering (ASAXS) in combination with the analysis of powder diffraction data recorded by wide angle x-ray scattering (WAXS). In the current synchrotron based study, we investigate CdSe/CdS core/shell NCs with different core dimensions by recording simultaneously ASAXS and WAXS spectra. The CdS shells are grown epitaxial on nominal spherical CdSe cores with core diameters from around 3.5–5.5 nm. Three different CdSe shell thicknesses are realized by depositing around 4, 6, and 8 monolayers (MLs) of CdSe. We reveal that the epitaxial core/shell structure depicts a chemical sharp interface, even after a post growth annealing step. With increasing NC diameter, however, the CdSe/CdS NCs deviate significantly from a spherical shape. Instead an elliptical particle shape with pronounced surface facets for the larger core/shell NCs is found. In combination with the powder diffraction data we could relate this anisotropic shape to a mixture of crystal phases within the CdSe core. The smallest CdSe cores exhibit a pure hexagonal wurtzite crystal structure, whereas the larger ones also possess a cubic zincblende phase fraction. This mixed crystal phase fractions lead to a non-spherical shell growth with different thicknesses along specific crystallographic directions: The long axes are terminated by basal crystal faces parallel either to the a- or c-axis, the short axes by “tilted” pyramidal planes. By combining these structural data with the measured PL quantum yield values, we can clearly connect the optical output of the NCs to their shape and to their shell thickness. Above 6 ML CdS shell-thickness no further increase of the PL can be observed, but for large aspect ratio values the PL is significantly decreased. The gained understanding of the internal crystal structure on CdSe/CdS NCs is general applicable for a precise tuning of the optical properties of crystalline core/shell NCs.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Frontiers Media
dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
dc.subject
core/shell nanocrystals
en_US
dc.subject
CdSe/CdS
en_US
dc.subject
photoluminescence
en_US
dc.subject
SAXS
en_US
dc.subject
WAXS
en_US
dc.title
Impact of Crystal Structure and Particles Shape on the Photoluminescence Intensity of CdSe/CdS Core/Shell Nanocrystals
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution 4.0 International
ethz.journal.title
Frontiers in Chemistry
ethz.journal.volume
6
en_US
ethz.pages.start
672
en_US
ethz.size
11 p.
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.grant
Chemically Engineered Nanocrystal Solids
en_US
ethz.grant
All-Inorganic Quantum Dot Films for Photovoltaic Applications
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Lausanne
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02020 - Dep. Chemie und Angewandte Biowiss. / Dep. of Chemistry and Applied Biosc.::02513 - Laboratorium für Anorganische Chemie / Laboratory of Inorganic Chemistry::03934 - Kovalenko, Maksym / Kovalenko, Maksym
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02020 - Dep. Chemie und Angewandte Biowiss. / Dep. of Chemistry and Applied Biosc.::02513 - Laboratorium für Anorganische Chemie / Laboratory of Inorganic Chemistry::03934 - Kovalenko, Maksym / Kovalenko, Maksym
en_US
ethz.grant.agreementno
306733
ethz.grant.agreementno
330524
ethz.grant.fundername
EC
ethz.grant.fundername
EC
ethz.grant.funderDoi
10.13039/501100000780
ethz.grant.funderDoi
10.13039/501100000780
ethz.grant.program
FP7
ethz.grant.program
FP7
ethz.date.deposited
2019-01-30T03:18:29Z
ethz.source
WOS
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2019-02-12T15:35:16Z
ethz.rosetta.lastUpdated
2024-02-02T07:08:57Z
ethz.rosetta.versionExported
true
ethz.COinS
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