Upconversion luminescence of Eu3+ and Sm3+ single-doped NaYF4 and NaY(MoO4)2

Abstract

In this paper, the upconversion luminescent phosphors of NaYF4:Eu3+, NaY(MoO4)2:Eu3+, NaYF4:Sm3+ and NaY(MoO4)2:Sm3+ were synthesized by hydrothermal method. The crystal structure, morphology, upconversion luminescent relative intensity (asymmetry ratio) and luminescent chromaticity were investigated in details. The results indicate that the asymmetry ratiors of the same rare earth ions are different in different matrices. The asymmetry of the Eu3+ and Sm3+ ions occupying the lattice sites is higher in NaY(MoO4)2 matrix than in NaYF4 matrix, which leads to different asymmetry ratiors and different luminescent chromaticity: orange-red light and red light were emitted by preparative phosphors under excitation near 800 nm. More pure red light can be emitted by phosphors of NaY(MoO4)2 as the matrix; even higher purity red light can be produced by NaY(MoO4)2:Eu3+. The upconversion luminescence mechanisms of Eu3+ and Sm3+ ions were analyzed by magnetic dipole transition and electric dipole transition under excitation near 800 nm.