Crystal structure and luminescence properties of LiYP4O12:Ce3+ phosphor

LiYP4O12 polyphosphate doped with Ce3+ ions was prepared by the melt solution technique. The crystal structure, interatomic distances, and atom coordination numbers were determined using x-ray powder diffraction. A study of the spectral-kinetic luminescent properties was performed employing excitation with pulsed radiation from a synchrotron (UV-VUV range) and a laboratory x-ray source. The characteristics of Ce3+ luminescence, namely the emission doublet maxima at 3.97 and 3.72 eV and the 4f-5d excitation maxima at 4.20, 5.11, 5.40, 5.65 and 6.55 eV, are discussed in terms of crystal field splitting in a low-symmetry site of the LiYP4O12 host lattice. The location of the Ce3+ energy levels with respect to the valence and conduction bands of the LiYP4O12 host is estimated from the temperature dependence of the decay time measured for Ce3+ 5d-4f luminescence.