Synthesis and characterization of Ln,Yb:BaGdF5 (Ln = Er,Ho) nanocrystals by hydrothermal method

The Er,Yb: BaGdF₅ and Ho,Yb: BaGdF₅ nanocrystal materials with the narrow particle size distribution was synthesized by a hydrothermal method at 180°C for 24 h. The phase structure and fluorescence properties were investigated by X-ray diffraction, scanning electron microscopy and up-conversion spectroscopy, respectively. The phase composition does not change with increasing the pH value, leading to the formation of a pure phase BaGdF₅, while the solution was turbid state. The products show a good crystallinity, dispersion and uniform particle size distribution. Under the LD excitation at 980 nm, Er,Yb: BaGdF₅ and Ho,Yb: BaGdF₅ nanocrystal materials were researched in the visible range of the fluorescence spectrum. Er,Yb: BaGdF₅ nanocrystals were achieved the launch of green, blue, and red. Ho,Yb: BaGdF₅ nanocrystal with green and red light output were realized. The light-emitting belong to the two-photon transition process. And the possible mechanism for the corresponding up-conversion luminescence was also discussed. The Er,Yb: BaGdF₅ and Ho,Yb: BaYbF₅ nanocrystals with the narrow particle size distribution have potential applications in biological field as luminescence probes.