Monodisperse hollow microspherical YPO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+) with diameters of around 2.5 µm have been successfully synthesised by combining a convenient homogeneous precipitation method, an ion exchange method, and a calcination process for the first time. X-ray diffraction, Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and photoluminescence spectra were used to characterise the samples. Upon ultraviolet excitation, Eu 3+-and Tb 3+-doped microspherical YPO 4 showed typical red and green emission, respectively, which provide potential applications in bioanalysis, future colour displays, lightemitting devices, and so on.

Structure-based rational design of photocatalysts to enable combination of nanocomponents of radically different properties for enhanced solar energy utilization is a very challenging task.

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.