Hydrothermal synthesis and luminescence behavior of lanthanide-doped GdF/sub 3/ nanoparticles

The lanthanide-doped GdF₃ nanoparticles have been produced by a simply hydrothermal synthesis procedure. The excitation and emission spectra of the Eu³⁺-doped GdF₃ nanoparticles showed that the excitation energy of Gd³⁺ is efficiently transferred to Eu³⁺ in the Eu³⁺-doped GdF₃ nanoparticles. Due to very low phonon energies of GdF ₃ matrix, the ⁵D₁ emission of Eu³⁺ ions in the Eu³⁺-doped GdF₃ nanoparticles can be observed at room temperature when the doping concentration of Eu ³⁺ ions is lower than 15 mol%. The luminescence intensity of the Eu³⁺-doped GdF₃ nanoparticles increased with increasing concentration of Eu³⁺ ions and reached a maximum at approximately 15 mol%. The Er³⁺-doped GdF₃ nanoparticles exhibit the typical emission spectra of Er³⁺ in the near-infrared region. The upconversion emission of the Er³⁺ /Yb³⁺ codoped GdF₃ nanoparticles can also be observed. However, the upconversion emission intensity of the Er³⁺ /Yb³⁺-codoped GdF₃ nanoparticles was much weaker than that of the Er³⁺/Yb³⁺-codoped GdF₃ bulk crystal