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Journal of Nanotechnology
Volume 2012 (2012), Article ID 435205, 6 pages
http://dx.doi.org/10.1155/2012/435205
Research Article

Preparation of SiO2-Capped Sr2MgSi2O7:Eu,Dy Nanoparticles with Laser Ablation in Liquid

1Departiment of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502, Japan
2Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan

Received 7 March 2012; Accepted 29 May 2012

Academic Editor: Wei Qian

Copyright © 2012 Mika Ishizaki et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The effect of SiO2 capping on the optical properties of nanoparticles was investigated. The photoluminescence (PL) intensity was successfully improved by SiO2-capping. Sr2MgSi2O7:Eu,Dy nanoparticles were prepared by laser ablation in liquid. The SiO2 capping was performed using the Stöber method with ultrasonication. The TEM images indicated that the Sr2MgSi2O7:Eu,Dy nanocrystal was capped with amorphous SiO2, and the shape of the completely capped nanoparticle was an elliptical nanorod, which aggregated after a long SiO2 capping reaction time. The peak wavelength and the shape of the PL spectra were not changed by the pelletization and the laser ablation in liquid. The PL intensity of SiO2 capped nanoparticles was significantly increased. Nonradiative relaxation via surface defects and energy transfer to water molecules decrease the PL intensity. These phenomena accelerate in the case of nanoparticles. SiO2 capping would prevent these phenomena and improve the optical properties of nanoparticles. The combination of laser ablation in liquid and the chemical reaction is important to expand the applications of this method in various research fields.