Preparation, structure and luminescence properties of the Ln_1-xCa_xVO₄, Ln = La, Eu (0 ≤ x ≤ 0.2) phases

Chem. Met. Alloys 9 (2016) 119-122

https://doi.org/10.30970/cma9.0340

Alina A. SLEPETS, Tetiana A. VOITENKO, Sergiy A. NEDILKO, Sergiy G. NEDILKO, Oksana V. CHUKOVA

Ln_1-xCa_xVO₄, 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_0.9Ca_0.1VO₄ sample. Single-phase samples of the investigated compounds formed at 630°C. According to X-ray diffraction data, a monoclinic phase of Ca²⁺-doped LaVO₄ and a tetragonal phase of Ca²⁺-doped EuVO₄ 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 Ln³⁺ ions.

Flow-chart for the preparation of orthovanadates by the sol-gel method.

Keywords

Ca²⁺-doped RVO₄ / Nanoparticles / Sol-gel process / Thermal analysis / Scanning electron microscopy SEM