Synthesis, characterization, and self-organization of dendrimer- encapsulated HgTe quantum dots

Amiya Priyam, Daniel E. Blumling, Kenneth Knappenberger

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Mercury telluride (HgTe) quantum dots (QDs) were synthesized in methanol at 5 °C using generation 5 (G5) and 7 (G7) polyamidoamine (PAMAM) dendrimers, which function both as nucleation sites and as nanoparticle stabilizers. Transmission electron microscopy (TEM) data indicate these particles were slightly oblate, with an average aspect ratio of 1.3 ± 0.1 and a minor axis of 2.6 ± 0.3 nm. The crystal phase was determined to be coloradoite (cubic system) by analysis of the electron diffraction pattern. Absorption maxima for HgTe QDs ranged from 950 to 970 nm, depending on the dendrimer generation and concentration. QD size distribution was optimized by careful variation of the Hg2+:dendrimer surface group molar ratio for both G5 and G7 dendrimers. An increase in molar ratio from 1:0.5 to 1:4 resulted in a decrease in the half-width at half-maximum (HWHM) of the HgTe bandgap absorption from 68 ± 3 to 52 ± 2 nm, indicating a size distribution focusing of 23 ± 4%. Second-derivative analysis of HgTe QD FTIR absorption spectra suggested that the quantum dots were fully encapsulated by a single G7 dendrimer, whereas multiple G5 dendrimers were necessary to stabilize a single nanoparticle. TEM and FTIR data revealed that the HgTe QDs form two-dimensional necklace-type arrays through a self-organization process, which proceeds through interpenetration of dendritic arms. TEM data further indicated that the average nanonecklace contained 10-15 QDs with an average inter-QD separation of 1.3 ± 0.7 nm and a total chain length of 46 ± 6 nm.

Original languageEnglish (US)
Pages (from-to)10636-10644
Number of pages9
JournalLangmuir
Volume26
Issue number13
DOIs
StatePublished - Jul 6 2010

Fingerprint

Dendrimers
dendrimers
Semiconductor quantum dots
quantum dots
synthesis
Transmission electron microscopy
transmission electron microscopy
mercury tellurides
Nanoparticles
nanoparticles
Mercury
Chain length
Electron diffraction
Diffraction patterns
Methanol
aspect ratio
Aspect ratio
Absorption spectra
Energy gap
Nucleation

All Science Journal Classification (ASJC) codes

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

Cite this

Priyam, Amiya ; Blumling, Daniel E. ; Knappenberger, Kenneth. / Synthesis, characterization, and self-organization of dendrimer- encapsulated HgTe quantum dots. In: Langmuir. 2010 ; Vol. 26, No. 13. pp. 10636-10644.
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Synthesis, characterization, and self-organization of dendrimer- encapsulated HgTe quantum dots. / Priyam, Amiya; Blumling, Daniel E.; Knappenberger, Kenneth.

In: Langmuir, Vol. 26, No. 13, 06.07.2010, p. 10636-10644.

Research output: Contribution to journalArticle

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