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Tehrān, Iran

Ghahari M.,Iranian Materials and Energy Research Center | Ghahari M.,Institute of Colorants | Aghababazadeh R.,Institute of Colorants | Aghababazadeh R.,Iran University of Science and Technology | And 6 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2011

The effect of surfactant on the luminescent intensity of SiO 2@Y 2O 3:Eu 3+ particles with a core shell structure is described. Core-shell particles are used in phosphor materials and employing spherical particles with a narrow size distribution is vital for the enhancement of luminescent properties. Three kinds of different surfactants were used to synthesis SiO 2 nano particles via a sol gel process. The results demonstrated that comb polycarboxylic acid surfactant had a significant influence on the morphology and particle size distribution. Somehow, particles with 100 nm size and narrow size distribution were produced. These particles had relatively uniform packing, unlike particles produced with other surfactants or without surfactant which had irregular assembly. The photoluminescence intensity of SiO 2@Y 2O 3:Eu 3+ particles that was synthesized by comb polycarboxylic acid surfactant was higher than those which were produced without surfactant. Copyright © 2011 American Scientific Publishers. Source

Fabbri P.,University of Modena and Reggio Emilia | Ghahari M.,Iranian Materials and Energy Research Center | Ghahari M.,Institute of Colorants | Pilati F.,University of Modena and Reggio Emilia | And 4 more authors.
Materials Letters | Year: 2010

In this work a new approach has been developed for the synthesis of SiO2@Y2O3 particles with core-shell structure. The method is based on the synthesis of a covalently bonded sacrificial polymer shell grown onto silica particles. It is suitable to promote and stabilize the adsorption of different ions, namely Yttrium from its nitrate solution. After calcination and consequent elimination of the sacrificial polymer shell, the SiO2@Y2O3 core-shell particles are obtained. Results reveal that the shell thickness of these core-shell particles is higher and more uniform than that of particles prepared without sacrificial polymer shell. © 2010 Elsevier B.V. All rights reserved. Source

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