Afterglow Properties of Silica-Capped Sr2MgSi2O7:Eu,Dy Nanoparticles Prepared by Laser Ablation in Ethanol

The effect of silica-capping on the afterglow property of Sr2MgSi2O7:Eu,Dy nanoparticles was investigated. Sr2MgSi2O7:Eu,Dy nanoparticles were prepared by laser ablation in liquid. Afterglow nanoparticles were capped with silica using Stöber method. A dense silica capping layer was achieved after 4 hours of reaction. Silica-capping of the afterglow nanoparticles improved the particles’ afterglow property, which was degraded by nanosizing. Decay curves indicated that initial values of afterglow intensity were increased with silica-capping capacity. Moreover, silica-capping decreased the decay curve constant γ, which was related to trap parameters. The decrease in the value of γ resulted in the reduction in the slope of decay curve, and thus the improvement of the afterglow property. We concluded that capping nanoparticles with silica improved the particles’ afterglow property by the passivation of surface defects and the prevention of energy transfer to water molecules.