Highly Uniform Hollow GdF3 Ellipsoids: Controllable Synthesis, Characterization and Up-Conversion Luminescence Properties.

In this paper, the hollow GdF3 ellipsoids were successfully synthesized through a facile hydrothermal approach. The results indicated that the as-obtained GdF3 sample has an orthorhombic structure and the average length and diameter of the hollow ellipsoids are 750 nm and 350 nm, respectively. The possible formation mechanism of the hollow GdF3 ellipsoids has been presented. The upconversion (UC) luminescence properties of the hollow GdF3: Yb3+/Ln3+ (Ln3+ = Er3+, Tm3+, Ho3+) ellipsoids were systematically investigated, which showed green (Er3+, 4S3/2, 2H11/2 → 4I15/2), blue (Tm3+, 1G4 → 3H6), and green (Ho3+, 5S2 → 5I8) luminescence under 980 nm NIR excitation, respectively. Furthermore, the UC white light was successfully obtained in the GdF3: Yb3+/Er3+/Tm3+ sample through adjusting relative doping concentration of Yb3+, Er3+ and Tm3+ ions. These findings may reveal potential applications in the fields of laser, bioanalysis, optoelectronic and nanoscale devices due to multicolor emissions in the visible region.