Synthesis and properties of water-soluble core-shell-shell silica-CdSe/CdS-silica nanoparticles

Yang Wei Lin, Chi Wei Liu, Huan Tsung Chang

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

This paper describes the synthesis of highly water-soluble and fluorescent core-shell-shell silica-CdSe/CdS-silica nanoparticles (CSS silica-QDs-silica NPs). We used cadmium nitrate and 1,1-dimethyl-2-selenourea precursors to synthesize CdSe quantum dots (QDs) in aqueous solution under simultaneous illumination with a diode-pumped solid state green laser and a Xe-Hg lamp. After passivation of the CdSe QDs with CdS, the CdSe/CdS QDs were then conjugated covalently to (3-mercaptopropyl)trimethoxysilane (MRS); we call these nanoparticles "MPS-QDs". We mixed the MPS-QDs with tetraethoxysilane (TEOS), ethanol, and NH 3. By controlling the concentrations of the reagents, the stirring speed, and the reaction time, we synthesized CSS silica-QDs-silica NPs having sizes ranging from 75 to 190 nm. The incubation time for preparing the MPS-QDs and their concentrations are important parameters in determining the morphologies of the CSS silica-QDs-silica NPs. When we mixed 50 nM MPS-QDs, 1.1 mM TEOS, and 78 mM NH 3 and reacted them at a stirring speed of 750 rpm, we obtained 85-nm-diameter CSS silica-QDs-silica NPs having a QD shell thickness of about 20 nm. The CSS silica-QDs-silica NPs provide a strong photolumi-nescence intensity (quantum yield 88%) and exhibit enhanced stability both photochemically and in high-conductivity media (e.g., 1.0 M NaCl).

Original languageEnglish
Pages (from-to)1092-1100
Number of pages9
JournalJournal of Nanoscience and Nanotechnology
Volume6
Issue number4
DOIs
Publication statusPublished - 2006 Apr 1

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics

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