Enhancing up-conversion luminescence of Er3+ with copper sulfide nanostructures

Highlights: • A ternary composite structure containing hotspots was prepared for up-conversion luminescence. • The enhancement of up-conversion luminescence in the composites was realized. • The maximum enhancement factor can reach to 16.2 times. • The fluorescence enhancement mechanism in the composites was systematically studied. A ternary composite structure containing hotspots (a small area with strong electromagnetic field) was obtained by Er₂O₃@SiO₂ particles and copper sulfide nanoparticles for up-conversion luminescence, and the enhancement mechanism of up-conversion luminescence in the above-mentioned composites have been systematically studied. By adjusting the optical field in the vicinity of the binary composite structure and the ternary composite structure via hotspots, the enhancement of up-conversion luminescence in the composites were realized, and the maximum enhancement factor can reach to 16.2 times. The results showed that under the synergistic effect of the absorption of incident photons by the copper sulfide film, the scattering of incident photons by Er₂O₃@SiO₂ particles, and the strong absorption of incident photons by copper sulfide nanoparticles, the up-conversion luminous intensity of the ternary composite structure was greatly improved.