Plasmonic influence on the up-conversion luminescence in NaYF_4:Er~(3+)/Yb~(3+) nanocrystals

摘要

We study the fluorescence properties of up-converting α-NaYF_4:Er~(3+)/Yb~(3+) nanocrystals (NCs) in the presence of spherical Au nanoparticles. The effects of plasmon excitations in the Au nanoparticles were studied using scanning confocal fluorescence microscope. The results show that the ~4S_(3/2)→ ~4I(15/2) transition in erbium ions, which appears at 540 nm, resonant with the plasmon band of the Au nanoparticles, is efficiently quenched. In contrast, in the case of ~4F_(9/2)→ ~4I_(15/2) transition, which appears at 650 nm, we find the increase of emission intensity. Complementary measurement of fluorescence lifetimes of individual NaYF_4:Er~(3+)/Yb~(3+) nanocrystals reveals that plasmonic excitations in Au nanoparticles influence the dynamics of both emission band in erbium ions.