Synthesis and characterization of LiLuF4:Er3+ and LiLuF4:Yb3+,Er3+ exhibiting upconversion fluorescence pumped by a 1560 nm laser

Abstract

Er³⁺ (10%) and Yb³⁺/Er³⁺ (10%/10%) doped tetragonal LiLuF₄ microcrystals were synthesized via a hydrothermal method. The upconversion (UC) luminescence of LiLuF₄:Yb³⁺,Er³⁺ and LiLuF₄:Er³⁺ microcrystals is studied under 1560 nm pulsed laser excitation. The UC luminescence spectra indicated that LiLuF₄ with doped rare earth ions achieved emissions that come from 2–4 photon UC processes. In the Yb³⁺/Er³⁺ doped LiLuF₄, the UC fluorescence shows enhanced emission of Er³⁺ ions in the infrared range of about 1 μm under 1560 nm laser excitation. The UC population processes of Er³⁺ and the energy transfer (ET) mechanism between Er³⁺ and Yb³⁺ played important roles in the as-prepared samples.