LAUSR

Abstract A series of Ca2-1.5xEux(MoO4)2 (0 ≤ x ≤ 4/3) phosphors have been fabricated by a traditional solid-state reaction. The correlations between the crystal structure, luminescent properties and surface morphologies with the chemical composition of the as-fabricated Ca2-1.5xEux(MoO4)2 crystals have been investigated in detail. The results show that the Ca2-1.5xEux(MoO4)2 (0 ≤ x ≤ 1.3) phosphors possess tetragonal phase, whereas the obtained Ca2-1.5xEux(MoO4)2 (x = 4/3) (i.e. Eu2(MoO4)3) phosphor exhibits monoclinic phase. The morphologies of crystals change gradually from quasi sphericity to tetragonal bipyramid owing to the preferential growth along c-axis induced by Eu3+ ions. The photoluminescence spectra reveal that the intensities of the characteristic emission and excitation peaks initially increase and then decrease with increasing x, given the maximum at x = 1/3. Our results indicate that the difference in the charge, electronegativity, as well as ionic radius between Ca2+ ions and Eu3+ ions lead to the variation of crystal symmetry, crystal phase, surface morphologies and luminescence of the final Ca2-1.5xEux(MoO4)2 crystals.