Preparation, structure and luminescence properties of the Ln1-xCaxVO4, Ln = La, Eu (0 ≤ x ≤ 0.2) phases

Abstract

Ln 1-x Ca x VO 4 , Ln = La, Eu (0 ≤ x ≤ 0.2) samples were prepared by the aqueous nitrate-citrate sol-gel route using citric acid as complexing agent. Thermal analysis was used to explain the thermal decomposition behavior and crystallization process of the Eu 0.9 Ca 0.1 VO 4 sample. Single-phase samples of the investigated compounds formed at 630°C. According to X-ray diffraction data, a monoclinic phase of Ca 2+-doped LaVO 4 and a tetragonal phase of Ca 2+-doped EuVO 4 nanoparticles were obtained. Scanning electron microscopy images showed particles of different shapes with diameters from 100 to 500 nm, the crystallite surface being loose and porous. The photoluminescence spectra contain wide bands of matrix emission and narrow lines due to f-f transitions in the Ln 3+ ions. Ca 2+-doped RVO 4 / Nanoparticles / Sol-gel process / Thermal analysis / Scanning electron microscopy SEM