Preparation of SiO 2 -Capped Sr 2 MgSi 2O 7:Eu,Dy nanoparticles with laser ablation in liquid

Abstract

The effect of SiO 2 capping on the optical properties of nanoparticles was investigated. The photoluminescence (PL) intensity was successfully improved by SiO 2-capping. Sr 2MgSi 2O7:Eu,Dy nanoparticles were prepared by laser ablation in liquid. The SiO 2 capping was performed using the Stber method with ultrasonication. The TEM images indicated that the Sr 2MgSi 2O 7:Eu,Dy nanocrystal was capped with amorphous SiO 2, and the shape of the completely capped nanoparticle was an elliptical nanorod, which aggregated after a long SiO 2 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 SiO 2 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. SiO 2 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. Copyright © 2012 Mika Ishizaki et al.