Polyvinylpyrrolidone (PVP)-assisted hydrothermal synthesis of luminescent YVO4:Eu3+ microspheres

Spherical YVO4:Eu3+ microstructures were hydrothermally synthesized by the reaction of NH4VO3, Y2O3, and Eu2O3 at 180 °C for 24 h with the assistance of polyvinylpyrrolidone (PVP) as a surfactant. The resulting products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. The experimental results showed that ball-like YVO4:Eu3+ microspheres with a diameter of about 4–5 μm, corresponding to the SEM observations, formed at 180 °C for 24 h using 0.2 g PVP with the molecular weight of 20,000 g mol−1. The amount of PVP and the reaction time of hydrothermal processing were found to play a key role in the formation of YVO4:Eu3+ microspheres. It has been observed that the relative luminescence intensities of the as-synthesized samples increased with increasing hydrothermal reaction times due mainly to the increase of crystallinity.