Enhancement of red emission by co-dopant Ln3＋ ions in Eu3＋：LaOF nanoparticles

Fluoride nanoparticles of Ln3＋（Ln3＋=Pr3＋, Nd3＋, Sm3＋, Cod3＋,Tb3＋ Dy3＋, I-I03＋, Er3＋, Tm3＋, yb3＋）/Eu3＋：LaOF and Eu3＋：LaOF with rhombohedral crystal structure were prepared by a hydrothermal-sintering method. The red fluorescence emission of Eu3＋ ions was found to be enhanced with most of the co-dopant Ln3. ions. Compared with strong fluorescence emission at 610 nm of Eu3＋：LaOF nanoparticles, the enhancement factors was up to ten times in Ln3~ （Ln3＋=Gd3＋, Dy3＋, Tm3＋）FEu3＋：LaOF co-doped nanoparticles. The results show that the asymmetry of the local environment of Eu3＋ ion was reduced by co-doping Ln3＋ ion into the nanoparticles, and that energy transfer might occur between Eu3_ and codopant Ln3＋ ions, which is suggested as the source of the observed fluorescence enhancement.