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