LaVO4, LaPO4 and LaBO3: synthesis, Rietveld refinement, and comparison of optical properties

Rare earth metals luminescent materials have been practically applied in almost all devices from cathode ray tubes to coating materials. Lanthanum containing samples of orthovanadate, orthophosphate and orthoborate (LaVO4, LaPO4 and LaBO3) compounds have been successfully prepared by microwave-assisted solid state synthesis (MASSS) method. Characterizations were done by powder X-ray diffraction (XRD), Rietveld refinement method, fourier transform infrared (FTIR) spectroscopy, photoluminescence spectroscopy (PL) and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). The Rietveld refinement analyses by using XRD data reveal that LaVO4 and LaPO4 powders are crystallized in monoclinic system; LaBO3 is in orthorhombic. The morphological results confirm the particle sizes are in the range micron to nano-scale. While LaPO4 and LaBO3 powders exhibit green phosphor, LaVO4 seems yellow under visible range.