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

Mg 4 Ta 2 O 9 :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∼458 nm depending on the doping ion and its concentration. XEL spectra and decay time data indicate that Mg 4 Ta 2 O 9 :1 at % Hf4+ has excellent X-ray excited scintillation performance typically with light yield of 13469 ph/MeV and decay time of 5.28 μs. Thus, it has potential application in optical conversion devices and security inspection. Mg 4 Ta 2 O 9 :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 SEM images of MTO: Hf4+ with the corresponding elemental EDX analysis indicate that the powder shape is irregular and the elements of Mg, Ta, O and Hf disperse homogeneously on the particles. The VUV light excited and X-ray excited luminescence performance indicate it has potential application in optical conversion devices and security inspection. [Display omitted] • Mg 4 Ta 2 O 9 : x at% M (M = Hf4+, Zr4+, W6+, Mo6+; x = 0, 1, 2, 3, 4, 5) powders were synthesized. • The photoluminescence, X-ray excited radio-luminescence and decay times are characterized. • MTO doped by 2 at % Hf4+ / Zr4+ and 1 at % W6+ / Mo6+ have the decay time of 5.28 μs, 5.60 μs, 3.70 μs, 4.16 μs, respectively. • The main excitation peak of photoluminescence is at 160 nm instead of about 220 nm reported. • Mg 4 Ta 2 O 9 :1 at % Hf4+ has excellent X-ray excited scintillation performance typically with light yield 13469 ph/MeV. [ABSTRACT FROM AUTHOR]