Decoration of upconversion nanoparticles@mSiO2 core–shell nanostructures with CdS nanocrystals for excellent infrared light triggered photocatalysis

Abstract

In this work, we demonstrate a facile process to synthesize upconversion nanoparticles (UCNPs)@mesoporous SiO₂ (mSiO₂) core–shell nanoparticles decorated with CdS nanoparticles. The size and morphology of the as-prepared products have been investigated carefully; which show that the UCNPs and CdS nanoparticles are ca. 50 and 5 nm in diameter, respectively, and the mesoporous silica layer is 10 nm in thickness. The fluorescence spectra of the as-prepared UCNPs@mSiO₂/CdS nanoparticles show that the fluorescence emissions (380, 451 and 470 nm) have been greatly quenched via energy transitions from the UCNPs nanoparticles (donors) to the CdS nanoparticles (acceptors). CdS nanoparticles were activated by the UCNPs to produce photo-generated ˙OH radicals under irradiation of infrared (IR) light. Photodegradation towards RhB dyes was studied to demonstrate the photocatalytic properties for the as-prepared UCNPs@mSiO₂/CdS nanoparticles under irradiation of near infrared light. The as-designed nanostructures of UCNPs@mSiO₂/CdS nanoparticles show excellent photocatalytic performance on photodegradation towards RhB under irradiation of infrared light. This kind of nanostructure may find potential applications in photodynamic therapy of cancer cells, for use as nanotransducers, in dyed sensitized solar cells etc.