Luminescent properties and energy transfer mechanism from Tb^(3+) to Eu^(3+) in CaMoO_4:Tb^(3+),Eu^(3+) phosphors

A series of CaMoO_4：Tb^（3＋）,Eu^（3＋） phosphors were prepared by the method of precipitation. The structure and morphology of the phosphors were characterized by the X-ray diffraction（XRD） and field emission scanning electron microscopy（FE-SEM）. The photoluminescence properties of the prepared products were researched, and the energy transfer from Tb^（3＋） to Eu^（3＋） in CaMoO_4 phosphors was studied. By adjusting the doping concentration of Eu^（3＋） ions in CaMoO_4：Tb^（3＋）,Eu^（3＋） phosphors, the emitting color of the phosphors could be easily tuned from green to red. With Tb^（3＋） doped in the phosphors, the red luminescence of Eu^（3＋） by near UV excitation was significantly enhanced. The energy transfer efficiency, rate and average distance between Tb^（3＋） and Eu^（3＋） in CaMoO_4：5%Tb^（3＋）,x%Eu^（3＋）（mole percent） phosphors（x=0.3-10） were calculated. It was found that the interaction type between Tb^（3＋） and Eu^（3＋） was electric dipole-dipole interaction in the phosphors.