Luminescence properties of Mg4Ta2O9:M (M= Hf4+, Zr4+, W6+, Mo6+) with vacuum ultraviolet light and X-ray excitation

Mg4Ta2O9:x at % M (M = Hf4+, Zr4+, W6+, Mo6+; x = 0, 1, 2, 3, 4, 5) with single phase were synthesized via the conventional solid-state reactions in air. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), vacuum ultraviolet (VUV) light excited spectra and X-rays excited luminescence (XEL). Structural characterization and Rietveld refinement show that more than 60% of 5 at % Hf4+, Zr4+, W6+ and Mo6+ doped ions enter into the Ta sites and less than 40% ions into the Mg(1) and Mg(2) sites. They can be excited efficiently by VUV light at 160 nm, and emit wide UV-A or blue light at 355 similar to 458 nm depending on the doping ion and its concentration. XEL spectra and decay time data indicate that Mg4Ta2O9:1 at % Hf4+ has excellent X-ray excited scintillation performance typically with light yield of 13469 ph/MeV and decay time of 5.28 mu s. Thus, it has potential application in optical conversion devices and security inspection.