Luminescence of Phosphors Based on Host Lattices ABO4 (A is Sc, In; B is P, V, Nb)

Abstract

The luminescence of the unactivated and Bi3+- and Eu3+-activated compounds ABO4 (A is Sc, In; B is P, V, Nb) is reported and compared with the luminescence of the corresponding rare-earth and yttrium compounds. The ScNbO4 shows a weak, blue emission, ScVO4 a blue-green, and InVO4 a green emission. The other host lattices show no or only a very weak emission at room temperature. The color of the vanadate emission depends strongly on the choice of A. This was studied by replacing part of the A ions by other ions or a combination of ions. The shift of the vanadate emission is ascribed to two effects, viz., metal–metal interaction (e.g., Bi3+–VO4) and the effect of the size of the metal ions at the A sites (e.g., Sc3+). The Eu3+-activated phosphors show some interesting features. The intensity of the forced electric dipole emission from the Eu3+ ion seems to depend strongly on the position of the lowest strong absorption band. In the zircon structure the D50−7F2 emission is hypersensitive to the surroundings, although no linear crystal-field component can be present. Both (In, Eu) PO4 and (In, Eu) VO4 show an orange (D50−7F1) emission due to the presence of inversion symmetry at the In3+ site.