Luminescence and energy transfer in CaAl4O7 : Tb3+, Ce3+

Samples of CaAl4O7 doped with Tb3+, Ce3+, and Tb3+ and Ce3+, respectively are prepared by sintering. Microstructures are analyzed by X-ray diffraction and high-resolution transmission electron microscope experiments. The samples show single monoclinic phase. The blue Ce3+ emission at 440 nm is efficiently quenched in the sample of CaAl4O7 : Tb3+, Ce3+, in which the dominant emission is in the green at 545 nm, originating from the transition of 5D4 to 7F5. Excitation spectrum of the CaAl4O7 : Tb3+, Ce3+, monitoring at 545 nm of the green emission, consists of both contributions from Ce3+ and Tb3+. 95% of total energy of Tb3+ green emission is transferred from Ce3+.