Synthesis and up-conversion luminescence of NaGdF_4:Yb~(3+), Tm~(3+)

摘要

NaGdF_4 is regarded as an ideal UC host material for Ln~(3+) activators because of its unique crystal structure, high Ln~(3+) solubility, low phonon energy and high photochemical stability. Ln~(3+)-doped NaGdF_4 UC nanoparticles have been widely investigated as bio-imaging and magnetic resonance imaging agents recently. NaGdF_4:Yb~(3+), Tm~(3+) nanoparticles are synthesized by high temperature thermal decomposition method. The phase, luminescence, particle morphology and size are characterized. The synthesized NaGdF_4:Yb~(3+), Tm~(3+) nanoparticles change from cubic phase to hexagonal phase when the reaction temperature increases from 300 to 340 ℃. But the increasing reaction temperatures have no obvious influence on the particle size and morphology. The phase and doping concentration of Yb~(3+) have obvious influence on the UC emission intensity of NaGdF_4:Yb~(3+), Tm~(3+) nanoparticles.