Deposition of CdS, CdS/ZnSe and CdS/ZnSe/ZnS shells around CdSeTe alloyed core quantum dots: effects on optical properties

Oluwasesan Adegoke, Tebello Nyokong, Patricia B. C. Forbes (Lead / Corresponding author)

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

In this work, we synthesized water-soluble L-cysteine-capped alloyed CdSeTe core quantum dots (QDs) and investigated the structural and optical properties of deposition of each of CdS, CdS/ZnSe and CdS/ZnSe/ZnS shell layers. Photophysical results showed that the overcoating of a CdS shell around the alloyed CdSeTe core [quantum yield (QY) = 8.4%] resulted in effective confinement of the radiative exciton with an improved QY value of 93.5%. Subsequent deposition of a ZnSe shell around the CdSeTe/CdS surface decreased the QY value to 24.7%, but an increase in the QY value of up to 49.5% was observed when a ZnS shell was overcoated around the CdSeTe/CdS/ZnSe surface. QDs with shell layers showed improved stability relative to the core. Data obtained from time-resolved fluorescence measurements provided useful insight into variations in the photophysical properties of the QDs upon the formation of each shell layer. Our study suggests that the formation of CdSeTe/CdS core/shell QDs meets the requirements of quality QDs in terms of high photoluminescence QY and stability, hence further deposition of additional shells are not necessary in improving the optical properties of the core/shell QDs.

Original languageEnglish
Pages (from-to)694-703
Number of pages10
JournalLuminescence
Volume31
Issue number3
Early online date2 Sep 2015
DOIs
Publication statusPublished - May 2016

Keywords

  • Cadmium Compounds/chemistry
  • Fluorescence
  • Optical Phenomena
  • Quantum Dots
  • Selenium Compounds/chemistry
  • Solubility
  • Sulfides/chemistry
  • Tellurium/chemistry
  • Water/chemistry
  • Zinc Compounds/chemistry

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