Enhanced upconversion luminescence in Cu1.8S@NaYF4: Yb@ NaYF4: Yb, Er core-shell nanoparticles.

Effective coupling between upconversion nanoparticles (UCNPs) and localized surface plasmon resonance (LSPR) nanostructures have been successfully used to improve the upconversion luminescence (UCL) of lanthanide ions. Here, to explore a more effective coupling method between Cu 1.8 S and UCNPs, Cu 1.8 S@NaYF 4 : X%Yb3+@NaYF 4 : Yb3+, Er3+ nanoparticles were synthesized. In comparison to NaYF 4 @NaYF 4 : Yb3+, Er3+ nanoparticles, the UCL intensity of the green and red emissions of Cu 1.8 S@NaYF 4 : 30%Yb3+@NaYF 4 : Yb3+, Er3+ nanoparticles were conspicuously increased by ~28-fold and ~101-fold, respectively. The significant enhancement of UCL in Cu 1.8 S@NaYF 4 : 30%Yb3+@NaYF 4 : Yb3+, Er3+ nanoparticles comes from the synergistic contribution of two aspects: LSPR light scattering of the Cu 1.8 S core and the increased near-infrared absorption from the appropriate amount of Yb3+ ions in the intermediate layer. The present work is important for possible applications of such core-shell nanoparticles to photocatalysis, bioluminescent labeling, and perovskite solar cells. [ABSTRACT FROM AUTHOR]