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Fluorescence behavior of cysteine-mediated Ag@CdS nanocolloids.
Thakur, Priya; Joshi, Satyawati S; Kapoor, Sudhir; Mukherjee, Tulsi.
Afiliação
  • Thakur P; Department of Chemistry, University of Pune, Pune 411007, India.
Langmuir ; 25(11): 6377-84, 2009 Jun 02.
Article em En | MEDLINE | ID: mdl-19469470
ABSTRACT
Ag@CdS quantum dots were synthesized by a colloidal method. CdS nanoparticles stabilized by L-cysteine were doped with varying silver concentrations. Ag@CdS nanoparticles were characterized by UV-visible spectroscopy, steady-state and time-resolved fluorescence, X-ray diffraction, Fourier transform infrared resonance (FTIR), and transmission electron microscopy. The effect of dopant concentration and effect of aging of Ag@CdS colloids were studied. At low silver content, emission was found to enhance, while at high silver content, emission quenching was observed after aging. Ag-CdS nanocolloids exhibited multiexponential decay with tau2 being a long-lived component. X-ray diffraction spectra of as prepared samples indicated that silver occupies an interstitial position, while for annealed samples, Ag+ ions get oxidized to Ag2+ and substituted for Cd2+ in the CdS lattice. FTIR studies have shown that cysteine acts as a monodentate ligand for cadmium and silver for as-prepared sample, whereas it acts as a tridentate ligand for annealed samples toward silver. Transmission electron microscopy of as-prepared samples showed spherical-shaped composites with a uniform layer of capping molecules.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Teoria Quântica / Prata / Sulfetos / Coloides / Compostos de Cádmio / Cisteína / Nanopartículas Idioma: En Revista: Langmuir Assunto da revista: QUIMICA Ano de publicação: 2009 Tipo de documento: Article País de afiliação: Índia

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Teoria Quântica / Prata / Sulfetos / Coloides / Compostos de Cádmio / Cisteína / Nanopartículas Idioma: En Revista: Langmuir Assunto da revista: QUIMICA Ano de publicação: 2009 Tipo de documento: Article País de afiliação: Índia