Structure and luminescence properties of Eu3+-doped trigonal double-perovskite Ba2Lu0.667WO6

Eu3+-doped tungstate Ba2Lu0.667WO6 was synthesized by the sol-gel method. The X-ray diffraction (XRD) patterns and structural refinement indicate that the matrix Ba2Lu0.667WO6 is trigonal double-perovskite structure. The phosphors were characterized by the scanning electron microscope (SEM), diffuse reflection, photoluminescence spectra and decay curves. It was found that the undoped host shows blue emission. The optimal doping concentration of Ba2Lu0.667WO6:Eu3+ is about 12 mol%. This phosphor can be efficiently excited by near-ultraviolet and blue light to realize the stronger orange-red luminescence. The phosphor presents the dominated 5D0→7F1 transition at a low doping level, and the 5D0→7F2 transition increases its intensity in the Eu3+-heavily doped samples. The host has the ability to converse UV light to blue, orange-red color. The thermal stability of the red-emission was investigated. The high activation energy of Ba2Lu0.667WO6:Eu3+ phosphor is very valuable for the application in W-LED devices. The different luminescence features were discussed on the base of the crystal structure.