Preparation and luminescent properties of Eu3+ and Tb3+ ions in the host of CaMoO4

The samples of CaMoO4:Eu3+,Tb3+ have been synthesized via the Pechini method, and their luminescent properties were investigated. Both under UV and X-ray excitation, Eu3+ and Tb3+ ions show high luminescent efficiency in emitting red and green light in single doped samples, and the energy transfer from MoO4 tetrahedron unit to Eu3+ and Th3+ ions occurred. When co-doped the Eu3+ and Tb3+ ions into the CaMoO4 matrix, it modified the luminescence spectra. At low concentration (<= 1.5%), there is only the energy transfer transition from MoO4 unit to the activators. While at high concentration (>1.5%), there is not only the energy transfer from the host to the activators, but also the interaction between these activators: Tb3+ ion serves as the donor and Eu3+ ion serves as the acceptor. The energy transfer from Th3+ to Eu3+ was studied via time-resolved fluorescence spectrum. By controlling the doping concentration, the luminescent color could be modified within the whole visible spectrum. From the standpoints of modified color and luminescent efficiency, they are attractive candidates in the manufacture of fluorescent lamps for advertising signs or other color raster displays. (C) 2007 Elsevier B.V. All rights reserved.