Aqueous synthesis of glutathione-capped CdTe/CdS/ZnS and CdTe/CdSe/ZnS core/shell/shell nanocrystal heterostructures

Anirban Samanta, Zhengtao Deng, Yan Liu

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

Here we demonstrate the aqueous synthesis of colloidal nanocrystal heterostructures consisting of the CdTe core encapsulated by CdS/ZnS or CdSe/ZnS shells using glutathione (GSH), a tripeptide, as the capping ligand. The inner CdTe/CdS and CdTe/CdSe heterostructures have type-I, quasi-type-II, or type-II band offsets depending on the core size and shell thickness, and the outer CdS/ZnS and CdSe/ZnS structures have type-I band offsets. The emission maxima of the assembled heterostructures were found to be dependent on the CdTe core size, with a wider range of spectral tunability observed for the smaller cores. Because of encapsulation effects, the formation of successive shells resulted in a considerable increase in the photoluminescence quantum yield; however, identifying optimal shell thicknesses was required to achieve the maximum quantum yield. Photoluminescence lifetime measurements revealed that the decrease in the quantum yield of thick-shell nanocrystals was caused by a substantial decrease in the radiative rate constant. By tuning the diameter of the core and the thickness of each shell, a broad range of high quantum yield (up to 45%) nanocrystal heterostructures with emission ranging from visible to NIR wavelengths (500-730 nm) were obtained. This versatile route to engineering the optical properties of nanocrystal heterostructures will provide new opportunities for applications in bioimaging and biolabeling.

Original languageEnglish
Pages (from-to)8205-8215
Number of pages11
JournalLangmuir
Volume28
Issue number21
DOIs
Publication statusPublished - May 29 2012

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glutathione
Nanocrystals
Glutathione
Heterojunctions
Quantum yield
nanocrystals
synthesis
Photoluminescence
photoluminescence
Encapsulation
Rate constants
Optical properties
Tuning
Ligands
tuning
routes
engineering
optical properties
life (durability)
Wavelength

ASJC Scopus subject areas

  • Electrochemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Materials Science(all)
  • Spectroscopy

Cite this

Aqueous synthesis of glutathione-capped CdTe/CdS/ZnS and CdTe/CdSe/ZnS core/shell/shell nanocrystal heterostructures. / Samanta, Anirban; Deng, Zhengtao; Liu, Yan.

In: Langmuir, Vol. 28, No. 21, 29.05.2012, p. 8205-8215.

Research output: Contribution to journalArticle

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