Luminescence of Ce~(3+),Tb~(3+) ,Gd~(3+) and Energy Transfers among Them in Yttrium Borophosphate

Green emitting phosphors of yttrium borophosphate doped with Ce 3+ ,Tb 3+ and Gd 3+ have been prepared by reaction of BPO 4 with rare earth oxides for the first time.The spectroscopic properties of Ce 3+ ,Tb 3+ and Gd 3+ and interaction among them have been also studied.There exist energy transfers of Ce 3+ →Tb 3+ and Gd 3+ →Tb 3+ ,and competitive absorption and individual emission between Ce 3+ and Gd 3+ .Ce 3+ emission and 5D 4→ 7F J and 5D 3→ 7F J emissions in Tb 3+ are enhanced with addition of Gd 3+ to yttrium borophosphate doped with Ce 3+ ,Tb 3+ ,but the intensity of Ce 3+ emission inceases more than that of Tb 3+ emission.In words,Gd 3+ prevents energy transfer from Ce 3+ to Tb 3+ .When yttrium in the substrate is replaced wholly by gadolinium,luminescence of phosphor is enhanced greatly and luminescence purity of the phosphor is relatively good,however,x value of chromatic coordinates lowers slightly.