[Synthesis and Fluorescence Properties of Rare Earth Ions Co-Doped CaMoO(4)]

In this paper, a series of CaMoO4 phosphor co-doped rare earth ions were prepared with chemistry co-precipitation method. The concentration of Pr(3+)/Tb(3+) and temperature had obvious influence on the luminescent properties. The crystal structures and spectrum characteristics of the samples were identified with X-ray powder diffraction (XRD) and fluorescence spectrophotometer (PL). According to XRD analysis, the main diffraction peaks of samples are consistent with the standard card (JCPDS 29-0351) of the diffraction peak data. This showed doped rare earth ions did not change matrix lattice structure. The emission spectrum excited by 275 nm exhibit sharp lines peaking at 488, 560, 621 and 560 nm assigned to the (3)P(0)—(3)H(4), (3)P(0)—(3)H(5)，(1)D(2)—(3)H(4) and (3)P(0)—(3)F(2) transitions of the Pr(3+) ions. The intensity of fluorescence reached the strongest when the concentration of the doping amount was 3%. The optimum calcination temperatures of CaMoO(4)∶0.03Pr(3+) and CaMoO(4)∶0.05Tb(3+) were 800 and 600 ℃. Furthermore, the intensity of excitation spectra and emission spectra are dependent on the concentration of the doping amount. The emission spectra intensities of CaMoO(4)∶Pr(3+) phosphors decrease and CaMoO(4)∶Tb(3+) phosphors firstly increase and then decrease because of concentration quenching effect with increasing Pr(3+) and Tb(3+) concentration. In addition, the luminescence properties of Pr(3+) ion in CaMoO(4)∶0.03Pr(3+), yTb(3+) system could be evidently improved with co-doping of Tb(3+) ions which was due to the efficient energy transfer process from Tb(3+) to Pr(3+) ions.