Synthesis of w-CdS quantum dots and discovery of intense sub band emission owing to longitudinal optical phonons

Mohammed A. Gondal*, Abdulaziz A. Bagabas, Mohamed A. Dastageer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Cadmium sulfide (CdS) quantum dots (QDs), capped with cetyltrimethylammonium bromide (CTAB), and was synthesized as stable, aqueous, colloidal nanofluid. A series of nine intense, well-resolved emission lines between 400 and 750 nm were observed for the first time when exciting the CdS QDs nanofluid with a 355-nm high energy pulsed Nd:YAG laser radiation. The energy separation between any two successive emission lines equals to the characteristic overtone energy of 295 cm-1 of the longitudinal optical phonon of CdS QDs. In addition, recording the PL spectrum by using a xenon broad band light source resulted in the observation of this characteristic overtone energy of 295 cm-1. In agreement with this photoluminescence characteristic, Raman spectrum exhibited four prominent Stokes lines with Raman shift equal to and multiple of 295 cm-1. Transmission electron microscopy investigation showed that the CdS QDs were spherical with hexagonal wurtzite structure and had a size in the range of 5-10 nm.

Original languageEnglish
Pages (from-to)3835-3842
Number of pages8
JournalJournal of Nanoparticle Research
Volume13
Issue number9
DOIs
StatePublished - Sep 2011

Keywords

  • Laser-induced photoluminescence
  • Nano material synthesis
  • Optical characterization
  • Optical phonons
  • Quantum dots

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics
  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • General Materials Science
  • Modeling and Simulation

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