Luminescence and energy transfer of a color tunable phosphor Tb3+, Eu3+ co-doped KCaY(PO4)2

A series of color-tunable Tb3+, Eu3+ co-doped KCaY(PO4)2 phosphors were synthesized by solid-state reaction for the first time. The luminescent properties and energy transfer process were investigated. Cross relaxation was proved to be responsible for Tb3+→Eu3+ energy transfer. The emitting color of phosphors can be tuned from green through yellow and finally to red with increasing Eu3+/Tb3+ ratio. The results indicate that KCaY(PO4)2:Tb3+, Eu3+ might be served as an UV-convertible color-tunable phosphor.