  Co-doped with calcium, europium and erbium ions lanthanum vanadate
crystalline nanoparticles are synthesized and investigated with a goal to
clarify the mechanisms of calcium and erbium impurities effects on europium
ions luminescence and to find compositions with enhanced luminescence
intensity. The XRD analysis reveals dependence of crystal structure on dopants
concentration: monoclinic crystal phase is observed for low dopant
concentrations and content of tetragonal crystal phase increases with dopant
concentrations increase. The SEM investigation reveals formation of
nanoparticles with two types of shapes. Photoluminescence spectra consist of
lines caused by inner transitions in the erbium and europium ions. It has been
shown that dependence of the europium ions luminescence intensity on the
calcium and erbium concentrations is caused by cumulative effects of dopants on
crystal lattice structure, on defects in the first coordination sphere of the
europium ions and on efficiency of excitation energy transfer.
