Bismuth in Yttrium Vanadate and Yttrium Europium Vanadate Phosphors

Abstract

Activation of rare earth vanadate by ions other than rare earths is successfully attempted in the present investigation. Bi+3 can be incorporated in the and lattice by solid‐state reaction. The phosphor , excited by cathode rays or uv radiation, shows luminescence with a continuous emission band extending from 4000 to 7000Aå and peaking at 5670Aå. Under 2537Aå excitation, the energy is absorbed essentially by Y‐O components of the matrix and transferred to the emission centers (Bi+3). Under 3650Aå excitation, energy absorbed by charge‐transfer processes involving (V‐O) and (Bi‐O) components of the phosphor is transferred to the emission centers (Bi+3). The transmission of energy from the absorption to the emission centers under 2537 and 3650Aå excitations involved a radiationless process. The phosphor can be modified by incorporating Eu+3 in the lattice. , when excited by short‐or long‐wavelength uv radiation, shows emission spectra with sharp Eu+3 emission peaks. Under cathode‐ray or 3650Aå excitation, the Bi+3 emission is gradually quenched when Eu+3 is incorporated in the lattice with a constant level of Bi+3 concentration; on the other hand, under 3650Aå excitation, the Eu+3 emission is enhanced when Bi+3 is incorporated in the lattice with a constant level of Eu+3 concentration. This indicates a radiationless transfer of energy from Bi+3 to Eu+3 under 3650Aå radiation.