Highly enhanced upconversion luminescence in lanthanide-doped active-core/luminescent-shell/active-shell nanoarchitectures

Abstract

We reported a new strategy to remarkably improve upconversion luminescence of Ln³⁺-doped nanoparticles via an active-core/luminescent-shell/active-shell engineering technique. By optimization of the structure of a NaGdF₄:Yb@NaYF₄:Yb/Er@NaGdF₄:Yb sandwich-like nanoarchitecture, a significant enhancement of upconversion emission intensity was realized with the help of the synergistic actions of the suppression of Er-defect energy transfer and the efficient energy transfer from Yb³⁺ in both active-core and active-shell to Er³⁺ in the luminescent-shell layer.