Luminescence of (La,Dy)F3: Effect of solvent ratio (water/ethylene glycol) and Ce3+ co-doping

Luminescent LaF3:Dy3+ and LaF3:Dy3+ co-doped with Ce3+ have been successfully synthesized separately via co-precipitation method. Different ratios of ethylene glycol(EG)/water have been used for the synthesis of LaF3:Dy3+ whereas LaF3:Dy3+ co-doped with Ce3+ have been prepared only in ethylene glycol(EG) medium. The synthesized products have been characterized using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infra‐red (FT-IR) and photoluminescence spectroscopy. XRD results show all the samples prepared to be well crystallized in a pure hexagonal structure with no impurity phases. Photoluminescence, lifetime decay and energy transfer efficiency studies indicate the existence of an energy transfer between the Ce3+ and Dy3+ ions, which increases with increase of Dy3+ ions concentration. LaF3:Dy3+ nanophosphor prepared in EG:water mixture(1:1) showed the highest luminescence intensity when compared with those prepared in EG or water alone. This enhancement in luminescence (when using EG-water mixture) might be related to the increase in crystallinity/particle size as well as to the decrease in agglomeration of particles in the corresponding solvent mixture medium.