Preparation and luminescent properties of Eu 3+ and Tb 3+ ions in the host of CaMoO 4

Abstract

The samples of CaMoO 4:Eu 3+,Tb 3+ have been synthesized via the Pechini method, and their luminescent properties were investigated. Both under UV and X-ray excitation, Eu 3+ and Tb 3+ ions show high luminescent efficiency in emitting red and green light in single doped samples, and the energy transfer from MoO 4 tetrahedron unit to Eu 3+ and Tb 3+ ions occurred. When co-doped the Eu 3+ and Tb 3+ ions into the CaMoO 4 matrix, it modified the luminescence spectra. At low concentration (≤1.5%), there is only the energy transfer transition from MoO 4 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: Tb 3+ ion serves as the donor and Eu 3+ ion serves as the acceptor. The energy transfer from Tb 3+ to Eu 3+ 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.