Luminescent properties and energy transfer mechanism from Tb3+ to Eu3+ in CaMoO4:Tb3+,Eu3+ phosphors

A series of CaMoO4:Tb3+,Eu3+ 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 Tb3+ to Eu3+ in CaMoO4 phosphors was studied. By adjusting the doping concentration of Eu3+ ions in CaMoO4:Tb3+,Eu3+ phosphors, the emitting color of the phosphors could be easily tuned from green to red. With Tb3+ doped in the phosphors, the red luminescence of Eu3+ by near UV excitation was significantly enhanced. The energy transfer efficiency, rate and average distance between Tb3+ and Eu3+ in CaMoO4:5%Tb3+,x%Eu3+ (mole percent) phosphors (x=0.3–10) were calculated. It was found that the interaction type between Tb3+ and Eu3+ was electric dipole-dipole interaction in the phosphors.