Plasmonic enhanced upconversion luminescence of β-NaYF4:Yb3+/Er3+ with Ag@SiO2 core–shell nanoparticles

Ag@SiO2 nanoparticles (NPs) are proposed and synthesized to enhance β-NaYF4:Yb3+/Er3+ luminescence by mixing with β-NaYF4:Yb3+/Er3+ in the solution. Luminescence enhancements are found to be dependent on the amount of addition and the silica shell thickness of the Ag@SiO2 NPs. For the same silica shell thickness of Ag@SiO2 NPs, the optimum mass ratio of Ag@SiO2/microcrystals for the enhancement is 1:21500. For different silica shell thickness of Ag@SiO2 NPs, the maximum luminescence enhancement occurs at the silica shell thickness of 8 nm under the condition of optimal mass, an overall enhancement factor of 3.5 fold is obtained.