title: Synthesis and characterization of the water-soluble silica-coated ZnS:Mn nanoparticles as fluorescent sensor for Cu(2+) ions.
abstract: Silica-coated ZnS:Mn nanoparticles were synthesized by coating hydrophobic ZnS:Mn nanoparticles with silica shell through microemulsion. The core-shell structural nanoparticles were confirmed by X-ray diffraction (XRD) patterns, high-resolution transmission electron microscope (HRTEM) images and energy dispersive spectroscopy (EDS) measurements. Results show that each core-shell nanoparticle contains single ZnS:Mn nanoparticle within monodisperse silica nanospheres (40nm). Photoluminescence (PL) spectroscopy and UV-vis spectrum were used to investigate the optical properties of the nanoparticles. Compared to uncoated ZnS:Mn nanoparticles, the silica-coated ZnS:Mn nanoparticles have the improved PL intensity as well as good photostability. The obtained silica-coated ZnS:Mn nanoparticles are water-soluble and have fluorescence sensitivity to Cu(2+) ions. Quenching of fluorescence intensity of the silica-coated nanoparticles allows the detection of Cu(2+) concentrations as low as 7.3x10(-9)molL(-1), thus affording a very sensitive detection system for this chemical species. The possible quenching mechanism is discussed.
authors.affiliation: Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100, PR China.
authors.forename: Bohua
authors.initials: B
authors.lastname: Dong
authors.forename: Lixin
authors.initials: L
authors.lastname: Cao
authors.forename: Ge
authors.initials: G
authors.lastname: Su
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Hua
authors.initials: H
authors.lastname: Qu
authors.forename: Daixun
authors.initials: D
authors.lastname: Jiang