The luminescence spectroscopy and thermal stability of red-emitting phosphor Ca9Eu(VO4)7

Eu-based vanadate Ca9Eu(VO4)7 phosphor was synthesized by the solid state reaction method and was characterized by X-ray powder diffraction (XRD). The photoluminescence excitation and emission spectra, fluorescence decay curves and the dependence of luminescence intensity on temperature were investigated. The phosphor can be efficiently excited by near UV light to realize an intense red luminescence (614 nm) corresponding to the electric dipole transition 5D0 → 7F2 of Eu3+ ions. The crystallographic site-occupations of the Eu3+ ions in Ca9Eu(VO4)7 were investigated by the site-selective excitation and emission spectra, and the fluorescence decay curves in the 5D0 → 7F0 region using a pulsed, tunable, narrowband dye laser. The red luminescence together with the thermal stability was discussed on the base of the Eu3+ site-distribution in Ca9Eu(VO4)7 host.