Preparation and Luminescent Characteristics ofKBaPO4,Tb3+ Phosphor

A green phosphor, KBaPO4:Tb3+, was synthesized by the high temperature solid―state method, using Li2CO3, Na2CO3, K2CO3, BaCO3, NH4H2PO4, NH4Cl, Tb4O7 and CeO2 as starting materials. After these individual materials were blended and grounded thoroughly in an agate mortar, the homogeneous mixture was heat―treated at 950 for 3 h, and the phosphors were obtained. The samples was characterized by powder X―ray diffraction (XRD) (D/max―rA, Cu Ka, 40 kV, 40 mA, λ=0.15406 nm). The spectral characteristics of these phosphors were measured by a SHIMADZU RF―540 fluorescence spectrophotometer. KBaPO4:Tb3+ phosphor shows several emission peaks located at 437, 490, 545, 586 and 622 nm which correspond to the 5D3→7F4 and 5D4→7FJ=6. 5, 4, 3 transition of Tb3+, respectively, and the highest emission peak is 545 nm. Monitored at 545 nm emission, the excitation spectrum consists of several bands, and the highest peak locates at 380 nm. The effects of Tb3+ doping content, the compensators (Li+, Na+, K+ or Cl―), and the sensitize activator Ce3+ on the emission intensity of KBaPO4: Tb3+ phosphor are studied. The results show that the emission intensity can be controlled by the above factors, and the intensity can be enhanced by the selection of the optimal condition. It indicates that KBaPO4:Tb3+ is a promising green phosphor for white light emitting diodes.