Optical properties of water-soluble L-cysteine-capped alloyed CdSeS quantum dot passivated with ZnSeTe and ZnSeTe/ZnS shells

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dc.contributor.author Adegoke, Oluwasesan
dc.contributor.author Nyokong, Tebello
dc.contributor.author Forbes, Patricia B.C.
dc.date.accessioned 2017-02-14T07:53:28Z
dc.date.available 2017-02-14T07:53:28Z
dc.date.issued 2015-08
dc.description.abstract Alloyed quantum dots (QDs) passivated with shell materials have valuable optical characteristics suitable for a wide array of applications. In this work, alloyed ternary CdSeS QDs passivated with ZnSeTe and ZnSeTe/ZnS shells have been synthesized via a hot-injection method and a ligand exchange reaction employing L-cysteine as a thiol ligand has been used to obtain these water-soluble nanocrystals for the first time. The photoluminescence (PL) quantum yield (QY) of alloyed L-cysteine-capped CdSeS was 71.2% but decreased significantly to 5.2% upon passivation with a ZnSeTe shell. The red shift in PL emission of the CdSeS/ZnSeTe QDs was attributed to be strain-induced whilst a lattice-induced process likely created defect states in the core/shell interface hence contributing to the decline in the PL QY. Nonetheless, the fluorescence stability of CdSeS/ZnSeTe QDs in aqueous solution was unperturbed. Further passivation with a ZnS shell (CdSeS/ZnSeTe/ZnS) improved the PL QY to a value of 58.7% and thus indicates that the defect state in the QDs core/shell/shell structure was reduced. PL lifetime exciton measurements indicated that the rates of decay of the QDs influenced their photophysical properties en_ZA
dc.description.department Chemistry en_ZA
dc.description.librarian hb2017 en_ZA
dc.description.sponsorship A postdoctoral fellowship offered by the University of Pretoria is gratefully appreciated by O. Adegoke. This work is based on research supported in part by the National Research Foundation of South Africa, Grant Numbers: 92584, 90720 and 93394 (P. Forbes). en_ZA
dc.description.uri http:// www.elsevier.com/locate/optmat en_ZA
dc.identifier.citation Adegoke, O, Nyokong, T & Forbes, PBC 2015, 'Optical properties of water-soluble L-cysteine-capped alloyed CdSeS quantum dot passivated with ZnSeTe and ZnSeTe/ZnS shells', Optical Materials, vol. 46, pp. 548-554. en_ZA
dc.identifier.issn 0925-3467 (print)
dc.identifier.issn 1873-1252 (online)
dc.identifier.other 10.1016/j.optmat.2015.05.024
dc.identifier.uri http://hdl.handle.net/2263/59013
dc.language.iso en en_ZA
dc.publisher Elsevier en_ZA
dc.rights © 2015 Elsevier B.V. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Optical Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in Optical Materials, vol. 46, pp. 548-554, 2015. doi : 10.1016/j.optmat.2015.05.024. en_ZA
dc.subject Core/shell en_ZA
dc.subject Photoluminescence en_ZA
dc.subject Quantum yield en_ZA
dc.subject Alloy en_ZA
dc.subject Hot-injection en_ZA
dc.subject Quantum dots (QDs) en_ZA
dc.title Optical properties of water-soluble L-cysteine-capped alloyed CdSeS quantum dot passivated with ZnSeTe and ZnSeTe/ZnS shells en_ZA
dc.type Postprint Article en_ZA


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