[Synthesis and fluorescence properties of SrZn(WO4)2:Tb3+, Ce3+ phosphors]

SrZn(1-x) (WO4)2:xTb3+, yCe3+ green fluorescent phosphors for near ultraviolet excitation were prepared using chemical co-precipitation. The phases of different doping ratio samples were characterized by the X-ray diffraction (XRD). The emission spectrum and excitation spectrum of samples were characterized by fluorescence spectroscopy (PL). The luminescence properties of the rare-earth Tb3+ ion doped and Ce3+ and Tb3+ ion codoped samples were discussed. XRD analysis shows that the main diffraction peaks of samples were consistent with the standard card (JCPDS 08-0490 and the JCPDS 15-0774) of the diffraction peak data. This showed that the doping rare earth ions did not change matrix lattice structure. The excitation spectrum showed that the excitation spectrum peaks at 223 nm which is assigned to the 7F-7D absorption transitions of Tb3+. The emission spectrum excited by 223 nm exhibits sharp lines peaking at 543 nm which was assigned to the 5D4-7F5 transitions of the Tb3+ ions. With Tb3+ and Ce3+ co-doping, the spectrum didn't change much. The intensity of fluorescence reached the strongest when the concentration of Tb3+:Ce3+ arrived at 0.06:0.02 which may means that there was energy transfer between the ions of Ce3+ and Tb3+.