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Thursday, December 31, 2009

Synthesis, characterization, and evaluation of lubrication properties of composites of ordered mesoporous carbons and luminescent CePO4:Tb nanocrystals

Synthesis, characterization, and evaluation of lubrication properties of composites of ordered mesoporous carbons and luminescent CePO4:Tb nanocrystals: "

Abstract  Having new potential applications in forging processes in mind, composites of an ordered mesoporous carbon and luminescent
metal phosphate nanocrystals were synthesized for the first time. Three kinds of CMK-3/CePO4:Tb nanocomposites were prepared by treating a mesoporous CMK-3 host with different lanthanide phosphate precursor solutions.
Characterization of the obtained nanocomposites by small-angle X-ray scattering, wide-angle X-ray diffraction, transmission
electron microscopy, thermogravimetry, and nitrogen physisorption analysis showed that in two cases, the nanocrystals (ca.
2–3 nm in size) were located inside the mesopores, whereas in the third case the nanocystals (ca. 6 nm in size) merely adhered
to the outer surfaces of the carbon particles. The CMK-3 and the two nanocomposites had ordered hexagonal structures (space
group p6mm); all the materials possessed amorphous carbon walls. After combustion of the nanocomposites, the residues upon excitation
with UV light exhibited the typical green luminescence of Tb3+. A preliminary evaluation of the lubrication properties of the CMK-3 and one nanocomposite material was performed. The friction
factors determined by means of ring upsetting tests revealed that the carbon materials were able to lower frictional forces
although they were 3–4 times less efficient than a commercial graphite-based reference lubricant.


  • Content Type Journal Article
  • DOI 10.1007/s10853-009-4130-3
  • Authors

    • Falk Heinroth, Leibniz Universität Hannover Institut für Anorganische Chemie Callinstr. 9 30167 Hannover Germany
    • Dominic Gruss, Institut für Integrierte Produktion gGmbH Holleritallee 6 30419 Hannover Germany
    • Sven Müller, Institut für Integrierte Produktion gGmbH Holleritallee 6 30419 Hannover Germany
    • Florian Waltz, Leibniz Universität Hannover Institut für Anorganische Chemie Callinstr. 9 30167 Hannover Germany
    • Julia Martynczuk, Leibniz Universität Hannover Institut für Physikalische Chemie und Elektrochemie Callinstr. 3A 30167 Hannover Germany
    • Armin Feldhoff, Leibniz Universität Hannover Institut für Physikalische Chemie und Elektrochemie Callinstr. 3A 30167 Hannover Germany
    • Peter Behrens, Leibniz Universität Hannover Institut für Anorganische Chemie Callinstr. 9 30167 Hannover Germany
    • Michael Wiebcke, Leibniz Universität Hannover Institut für Anorganische Chemie Callinstr. 9 30167 Hannover Germany


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Luminescence properties of double-perovskite Sr2Ca1−2xEuxNaxMoO6 red-emitting phosphors prepared by the citric acid-assisted sol–gel method

Luminescence properties of double-perovskite Sr2Ca1−2xEuxNaxMoO6 red-emitting phosphors prepared by the citric acid-assisted sol–gel method: "

Abstract  Double-perovskite Sr2Ca1−2x
Eu
x
Na
x
MoO6 red-emitting phosphors were prepared by the citric acid-assisted sol–gel method, and their luminescence properties were investigated
as a function of sintering temperature and Eu3+-doping concentration. B-site substituted Sr2Ca0.8Eu0.1Na0.1MoO6 phosphor, in which Na+ ions act as charge compensators, was selected to study the thermal behavior, phase structure, microstructure, and photoluminescence
property under different sintering temperatures. The photoluminescence studies on Sr2Ca1−2x
Eu
x
Na
x
MoO6 (x = 0.02, 0.05, 0.10, 0.15, 0.2) show that a dominant red emission line at around 594 nm, which is due to the Eu3+ magnetic dipole transition of 5D07F1, is observed under different Eu3+ excitations (396 and 412 nm). Further, Eu3+ dopant content dependent emission spectra investigations of Sr2Ca1−2x
Eu
x
Na
x
MoO6 phosphors indicates that, when the Eu3+ concentrations x = 0.05, there are minimum differences between the emission intensity of 5D07F1 transition at 594 nm and that of 5D07F2 transition at 615 nm. With increasing Eu3+ concentration, the variation of the emission intensities between the two transitions keep nearly invariable and Sr2Ca0.8Eu0.1Na0.1MoO6 phosphor has the strongest red emission in this series.


  • Content Type Journal Article
  • DOI 10.1007/s10853-009-4123-2
  • Authors

    • Zhiguo Xia, China University of Geosciences School of Materials Sciences and Technology Beijing 100083 China
    • Jianfeng Sun, Beijing Technology and Business University College of Chemistry and Environmental Engineering Beijing 100048 China
    • Haiyan Du, Beijing Technology and Business University College of Chemistry and Environmental Engineering Beijing 100048 China
    • Daimei Chen, China University of Geosciences School of Materials Sciences and Technology Beijing 100083 China
    • Jiayue Sun, Beijing Technology and Business University College of Chemistry and Environmental Engineering Beijing 100048 China


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Ligand-Controlled Polytypism of Thick-Shell CdSe/CdS Nanocrystals

Ligand-Controlled Polytypism of Thick-Shell CdSe/CdS Nanocrystals: "Journal of the American Chemical Society, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable)."

A Hybrid Nanosensor for TNT Vapor Detection

A Hybrid Nanosensor for TNT Vapor Detection: "Nano Letters, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable)."

Monday, December 28, 2009

Uniform YF3:Yb,Er up-conversion nanophosphors of various morphologies synthesized in polyol media through an ionic liquid

Uniform YF3:Yb,Er up-conversion nanophosphors of various morphologies synthesized in polyol media through an ionic liquid: "

Abstract  We describe a facile procedure for the synthesis at low temperature (120 °C) of water-dispersible uniform YF3:Yb,Er up-conversion nanophosphors of various morphologies (rhombic and spheroidal) by homogeneous precipitation in polyol
solutions containing different lanthanide salts and an ionic liquid (1-butyl, 2-methylimidazolium tetrafluoroborate) as fluoride
source. It is shown that the shape of the obtained nanoparticles is mainly determined by the nature of both, the polyol and
the lanthanide precursors, which also affects to their colloidal stability in water suspensions. These morphological differences
are explained on the basis of a different mechanism of particle formation. The efficiency of the up-conversion processes in
the synthesized rhombic and spheroidal nanoparticles is also comparatively analyzed and the observed differences are justified
on the basis of the different impurities incorporated to the nanophosphors during their synthesis process.


  • Content Type Journal Article
  • Category Research Paper
  • DOI 10.1007/s11051-009-9824-6
  • Authors

    • Nuria O. Nuñez, CSIC-US Instituto de Ciencia de Materiales de Sevilla Americo Vespucio 49 41092 Isla de la Cartuja, Sevilla Spain
    • Marta Quintanilla, C-IV, Universidad Autónoma de Madrid Depto. Física de Materiales Madrid Spain
    • Eugenio Cantelar, C-IV, Universidad Autónoma de Madrid Depto. Física de Materiales Madrid Spain
    • Fernando Cussó, C-IV, Universidad Autónoma de Madrid Depto. Física de Materiales Madrid Spain
    • Manuel Ocaña, CSIC-US Instituto de Ciencia de Materiales de Sevilla Americo Vespucio 49 41092 Isla de la Cartuja, Sevilla Spain


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Upconversion for White Light Generation by a Single Compound

Upconversion for White Light Generation by a Single Compound: "Journal of the American Chemical Society, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable)."

Powder Synthesis of Y-α-SiAlON and Its Potential as a Phosphor Host

Powder Synthesis of Y-α-SiAlON and Its Potential as a Phosphor Host: "The Journal of Physical Chemistry C, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable)."

Surfactant-free Synthesis of Ultrasmall Gold Nanoclusters

Surfactant-free Synthesis of Ultrasmall Gold Nanoclusters: "The Journal of Physical Chemistry C, Volume 0, Issue 0, Articles ASAP (As Soon As Publishable)."

Efficient and Switchable Manganese Luminescence in MnF2:Ce Nanocrystals

Efficient and Switchable Manganese Luminescence in MnF2:Ce Nanocrystals: "The Journal of Physical Chemistry C, Volume 113, Issue 47, Page 20271-20274, November 26, 2009."

Electron Transfer-Induced Blinking in Ag Nanodot Fluorescence

Electron Transfer-Induced Blinking in Ag Nanodot Fluorescence: "The Journal of Physical Chemistry C, Volume 113, Issue 47, Page 20264-20270, November 26, 2009."

Triplet Sensitized Red-to-Blue Photon Upconversion

Triplet Sensitized Red-to-Blue Photon Upconversion: "The Journal of Physical Chemistry Letters, Volume 0, Issue 0, Page 195-200, Articles ASAP (As Soon As Publishable)."

The first solid-phase route to fabricate and size-tune gold nanoparticles at room temperature

The first solid-phase route to fabricate and size-tune gold nanoparticles at room temperature: "


Dipen Debnath, Sung H. Kim, Kurt E. Geckeler

(Paper from J. Mater. Chem.)

Dipen Debnath, J. Mater. Chem., 2009, DOI: 10.1039/b905260g

To cite this article before page numbers are assigned, use the DOI form of citation above.


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Luminescence properties and electronic structure of Sm3+-doped YAl3B4O12

Luminescence properties and electronic structure of Sm3+-doped YAl3B4O12: "

Abstract  The luminescence properties of Sm3+ ions in YAl3B4O12 were studied upon synchrotron excitation in the 3.8–11 eV region. In addition to the 4f → 4f excitation bands, the excitation spectra of the Sm3+ emission contain broad bands at 6.1 and ~7.0 eV. These bands are attributed to charge transfer transition in Sm3+–O2− complexes and 4f → 5d transition of Sm3+ ions, respectively. The optical absorption edge of YAl3B4O12 was determined at 7.3 eV. A comparison with the results of electronic structure calculations on YAl3B4O12 is also made.


  • Content Type Journal Article
  • DOI 10.1007/s10853-009-4104-5
  • Authors

    • V. P. Dotsenko, Physico-Chemical Institute, Ukrainian Academy of Sciences 86 Lustdorfskaya doroga 65080 Odessa Ukraine
    • I. V. Berezovskaya, Physico-Chemical Institute, Ukrainian Academy of Sciences 86 Lustdorfskaya doroga 65080 Odessa Ukraine
    • N. P. Efryushina, Physico-Chemical Institute, Ukrainian Academy of Sciences 86 Lustdorfskaya doroga 65080 Odessa Ukraine
    • A. S. Voloshinovskii, Ivan Franko National University of Lviv 8 Kyryla i Mefodiya str. 79005 Lviv Ukraine
    • G. B. Stryganyuk, Ivan Franko National University of Lviv 8 Kyryla i Mefodiya str. 79005 Lviv Ukraine


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