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ABSTRACT: Water-soluble, monodispersed, and bluish green-emitting Au(10) nanoclusters were synthesized through a simple reaction, in which histidine served as both a reducing agent and a protecting ligand. UV-visible absorption, photoluminescence, electrospray ionization (ESI) mass spectrometry, and X-ray photoelectron spectroscopy (XPS) were carried out to demonstrate the chemical composition and optical properties of the Au(10) clusters. The mechanism of this proposed reaction was explored and the reducing ability of histidine was proved from its imidazole group. Finally, the fluorescence of Au NCs at different reaction times, pH value, and temperature was measured in situ. Then a synthetic strategy was proposed for gold nanoclusters with a defined chemical composition, and the resulting Au(10) clusters stabilized by histidine are biocompatible with bioorganisms, showing a great potential for applications such as biological labeling and biosensors.
Nanoscale 06/2011; 3(6):2596-601. · 5.91 Impact Factor
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ABSTRACT: Multi-walled carbon nanotubes (MWCNTs) were supramolecularly functionalized by pyrene-derivatized hydrolyzed poly(styrene-co-maleic anhydride) (pyrene-HSMA) in aqueous solution. The MWCNTs/pyrene-HSMA conjugates were found to exhibit a solvent-dependent fluorescence property by photoluminescence measurements. The fluorescence intensity of the MWCNTs/pyrene-HSMA conjugate was used as a probe to estimate the interaction between polymer and MWCNTs in solvents. The polymer conformation around the MWCNTs was demonstrated by atomic force microscopy. We suggested that pyrene-HSMA functionalized MWCNTs in a non-wrapping mode, and that the conformation change of the polymer around the MWCNTs resulted in the solvent-dependent fluorescence property. The dispersion state of the MWCNTs/pyrene-HSMA conjugate in various solvents was also investigated by transmission electron microscopy. The fluorescence responses of the MWCNTs/pyrene-HSMA conjugate to pH value and temperature were studied as well.
Nanotechnology 05/2009; 20(13):135705. · 3.98 Impact Factor
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ABSTRACT: Atomically monodispersed gold clusters were synthesized by etching gold nanocrystals (particles and rods) with the assistance of biomolecules (amino acids, peptides, proteins, and DNA) under sonication in water. The resulting gold clusters were exclusively composed of eight atoms, as demonstrated by photoluminescence, optical absorption, electrospray ionization mass spectrometry, and transmission electron microscopy measurements. The gold clusters exhibited solvent-dependent photoluminescence properties when exposed to organic solvents, such as chloroform, tetrahydrofuran, or N,N-dimethylformamide, which was attributed to the rich surface properties of the clusters. This strategy, based on top-down etching, offers an approach to create metal clusters from nanomaterials, which show great potential applications in biological labeling/imaging and sensors that utilize photoluminescence properties as the response.
Chemistry 04/2009; 15(19):4944-51. · 5.93 Impact Factor
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ABSTRACT: Well-defined hexangularly faced CdS nanorod arrays were fabricated via a facile one-step and nontemplate hydrothermal approach in large scale by using biomolecules of glutathione as capping agents. Structural and morphological evolutions of CdS nanorod arrays were studied by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. A formation mechanism of CdS nanorod arrays via this one-step synthesis was tentatively studied by investigating the effects of synthesis parameters on the nanorod arrays. The growth process of CdS nanorod arrays was discussed further from the absorption spectra of CdS nanorod arrays obtained at different reaction times.
08/2008;
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ABSTRACT: Large-scale three-dimensional (3D) CdS nanocrystals with a flowerlike morphology were synthesized by a facile hydrothermal treatment from Cd(NO3)2, thiourea, and hexamethylenetetramine [(CH2)6N4, HMT], where HMT acted as a capping agent. The reaction conditions influencing the synthesis of these 3D CdS nanocrystals such as initial precursor ratios, reaction time, reaction temperatures, and capping agents were studied and optimized. The morphology, structure, and phase composition of CdS nanostructures were examined by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and high-resolution TEM. The formation mechanism of the 3D CdS nanocrystals with flowerlike structure was proposed based on the results, which may pave the way to shape-controlled synthesis of inorganic nanocrystals with 3D complex structures. The room-temperature photoluminescence (PL) of the obtained CdS nanocrystals was also studied.
01/2008;
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ABSTRACT: Synthesis of nanoscale inorganic crystals with controlled size, shape, and hierarchy has attracted intensive research interest, since they are potential building blocks for advanced materials and optoelectronic devices. As an important group II-IV semiconductor with extensive applications in optical and electronic nanodevices, complex three-dimensional nanocrystals CdS with well-defined structures have just received great attentions since they offer new opportunities as building blocks to fabricate or assemble into advanced materials for further generation of optoelectronic devices, we report for the first time to large-scale synthesize an interesting 3D structured CdS nanocrystals by a facile hydrothermal method. The photoluminescence results of the 3D CdS nanocrystal indicated they have the potential applications for the building blocks on optoelectronic devices.
Optical Fiber Communication and Optoelectronics Conference, 2007 Asia; 11/2007
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ABSTRACT: Highly-fluorescent, water-soluble and ambient-stable nanohybrids based on multi-walled carbon nanotubes and gold nanoparticles (Au@MWNTs) with high-density and well-distributed Au nanoparticles were obtained assisted by organic optoelectronic active molecules as an interlinker and stabilizer via a facile in-situ fabrication method in aqueous solution, and were confirmed by TEM, SEM, EDX, UV-Vis measurements. The Au nanoparticle diameters of the hybrids can be controlled and decreased to a limited small range with high stability via this in-situ fabrication approach. The optical properties of the hybrids were studied, and it was found that the hybrid exhibited strong visible luminescence under the UV lamp irradiation, which might extend its potential application on light emitting sources, biological labeling etc.
Optical Fiber Communication and Optoelectronics Conference, 2007 Asia; 11/2007
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ABSTRACT: Water-soluble hybrids of multi-walled carbon nanotubes (MWNTs) and gold nanoparticles (Au@MWNTs) were fabricated via the in situ solution method and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). An optoelectronic-active compound of N,N'-bi(2-mercaptoethyl)-perylene-3,4,9,10-tetracarboxylic diimide (MEPTCDI) was employed as interlinker and stabilizer for the formation of the Au@MWNTs hybrids. The size of Au nanoparticles in the hybrids can be controlled and decreased to a limited small range with high stability via this in situ fabrication approach. The hybrid formation mechanism was proposed by making comparison with other hybrids, employing various organic or organic groups as interlinkers, and was further demonstrated by TEM, ultraviolet–visible (UV–vis), and atomic absorption measurements. The optical properties of the Au@MWNTs hybrids were studied, and it was found that the hybrid exhibited strong visible luminescence under UV lamp irradiation, which might extend its potential applications to biological labeling, etc.
Nanotechnology 10/2007; 18(48):485603. · 3.98 Impact Factor
