Plasmon-enhanced upconversion luminescence in (mCu2-xS, NaYF4:Er/Yb)@ porous silica composites

Abstract

The design of core–shell structures is significant for the applications of upconversion luminescent materials. Herein, a novel core–shell hybrid structure of (mCu2-xS, NaYF4:Er/Yb)@ porous silica composites was constructed using Cu2-xS nanoparticles and hexagonal NaYF4:Er/Yb particles for upconversion luminescence (UCL). Owing to the localized surface plasmon resonance (LSPR) coupling between Cu2-xS nanoparticles, the internal optical field of the composites was amplified, which induced more photons to participate in the upconversion process of (mCu2-xS, NaYF4:Er/Yb)@ porous silica composites. Furthermore, the UCL intensity of (mCu2-xS, NaYF4:Er/Yb)@ porous silica composites in the emission band of green was 45 times higher than that of NaYF4:Er/Yb@SiO2, and the quantum yield of the composites was 1.32%. The UCL enhancement mechanism of the composites was also investigated.