Synthesis, Morphology Control and Luminescent Properties of Rare Earth Ion-Doped CaWO₄ Microstructures

Abstract

Rare earth ions (Tb 3+ , Eu 3+ ) doped CaWO 4 microstructures were synthesized by a facile hydrothermal route without using any templates and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectrum. The results indicate that the asprepared samples are well crystallized with scheelite structure of CaWO 4 , and the average diameter of the microstructures is 2∼4 μ m. The morphology of CaWO 4 :Eu 3+ microstructures can be controllably changed from microspheres to microflowers through altering the doping concentration of Eu 3+ from 3% to 35%, and the microflowers are constructed by a number of CaWO 4 :Eu 3+ nanoflakes. Under the excitation of UV light, the emission spectrum of CaWO 4 :Eu 3+ is composed of the characteristics emission of Eu 3+ 5 D 0 -7 F J ( J = 1, 2, 3, 4) transitions, and that of CaWO 4 :Tb 3+ is composed of Tb 3+ 5 D 4 -7 F J ( J = 6, 5, 4, 3) transitions. Both of the optimal doping concentrations of Tb 3+ and Eu 3+ in CaWO 4 microstructures are about 5%.