Solid State-Synthesized Lanthanum Orthovanadate (LaVO4) Co-doped with Eu as Efficient Photoluminescent Material

Abstract The compositional and structural properties of nanocrystalline lanthanum orthovanadate (LaVO4), obtained through solid-state synthesis and co-doped with Eu3+ were investigated. Lanthanum and vanadium oxides were used as only starting reagents to synthesize LaVO4-Eu3+ nanocrystalline powders using a high-energy ball-milling (HEBM) process followed by air heating in temperatures between 600 to 1200°C. The La2O3 powder, which served as the precursor for the HEBM synthesis, had a residual europium impurity which was found to be the effective Eu3+ ions source in the production of Eu:LaVO4. The powders were characterized using X-ray powder diffraction (XRD), Raman spectroscopy, X-ray photoelectron (XPS), Fourier-transform infrared (FTIR) absorption spectroscopy, emission spectroscopy (PL - photoluminescence and excitation spectra, UV-Vis DRS method), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The mean size of crystallites of LaVO4 were in the range of 53 nm to 84 nm for annealing temperatures in the range of 600°C to 1200°C, respectively. Due to a very low content of Eu3+ ions (less than 0.1 wt. %) in the synthesized powders, the luminescence behavior of lanthanum orthovanadate with the monoclinic structure could be observed. The correlation between the structural, morphological and photoluminescent properties of LaVO4 was examined for the first time in this work.