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

The lanthanide-doped GdF
₃
nanoparticles have been produced by a simply hydrothermal synthesis procedure. The excitation and emission spectra of the Eu
³⁺
-doped GdF
₃
nanoparticles showed that the excitation energy of Gd
³⁺
is efficiently transferred to Eu
³⁺
in the Eu
³⁺
-doped GdF
₃
nanoparticles. Due to very low phonon energies of GdF
₃
matrix, the
⁵
D
₁
emission of Eu
³⁺
ions in the Eu
³⁺
-doped GdF
₃
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 Eu
³⁺
-doped GdF
₃
nanoparticles increased with increasing concentration of Eu
³⁺
ions and reached a maximum at approximately 15 mol%. The Er
³⁺
-doped GdF
₃
nanoparticles exhibit the typical emission spectra of Er
³⁺
in the near-infrared region. The upconversion emission of the Er
³⁺
/Yb
³⁺
codoped GdF
₃
nanoparticles can also be observed. However, the upconversion emission intensity of the Er
³⁺
/Yb
³⁺
-codoped GdF
₃
nanoparticles was much weaker than that of the Er
³⁺
/Yb
³⁺
-codoped GdF
₃
bulk crystal