Eu(III)-doped barium tellurooxyphosphate phosphor with orange-red emission

Eu^3+ photoluminescence (PL) is studied in the tellurooxyphosphate, Ba_2TeO (PO_4)_2 , host. A series of phosphor compositions with varying concentrations of Eu^3+ dopant in Ba_2TeO (PO_4)_2 are synthesized by high temperature solid-state reaction and the PL spectra are recorded. Under 395 nm wavelength excitation, the emission spectrum shows a single peak corresponding to the non-degenerate transition, ^5D_0→^7F_0 indicating that Eu^3+ preferentially occupies a single crystallographic site. The peak due to the degenerate hypersensitive ^5D_0→^7F_2 electric dipole transition of Eu^3+ in the emission spectrum indicates that the site occupied by Eu^3+ in the tellurooxyphosphate host lattice is non-centrosymmetric. The CIE coordinate values are x = 0.61 and y = 0.34 and are found to be close to the values of the reference phosphor Y_2O_3:Eu^3+ .