Browsing by Author "Popovici, EJ"

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    Luminescence study of some yttrium tantalate-based phosphors
    Karsu, EC; Popovici, EJ; Ege, A; Morar, M; Indrea, E; Karali, T; Can, N
    Yttrium tantalate (YTaO4), yttrium niobium-tantalate (YTaNbO4), yttrium niobate (YNbO4), europium and terbium activated yttrium tantalate (YTaO4:Eu, YTaO4:Tb) and europium activated yttrium niobate (YNbO4:Eu) phosphors were prepared by solid-state reaction, from a homogeneous mixture consisting of Y2O3, Eu2O3, Tb4O7, Ta2O5, Nb2O5 and Na2SO4 as flux. Photoluminescence (PL), thermally stimulated luminescence (TSL), X-ray diffraction (XRD) and scanning electron microscopy (SEM) of yttrium tantalate based phosphors are reported. In the present study TSL characteristics of these phosphors were first investigated and reported after exposure to beta, UV (311 nm) and X-ray radiations. (C) 2011 Elsevier B.V. All rights reserved.
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    Radioluminescence study of rare earth doped some yttrium based phosphors
    Ayvacikli, M; Ege, A; Ekdal, E; Popovici, EJ; Can, N
    This paper reports the luminescence emission spectra of Y(Ta,Nb)04 activated by rare earth ions such as Eu3+ and Tb3+. The influence of these rare earth ions on the radioluminescence (RL) of yttrium niobate and tantalate phosphors was investigated. The luminescent properties were studied under X-ray and preliminary RL measurements to further evaluate prepared materials. The emission centers of the rare earth activators (Eu3+, Tb3+) were found to contribute efficiently to the total luminescence. With their various luminescence chromaticities, these rare earth activated phosphors are promising materials for solid-state lighting applications as well as for X-ray intensifying screens in medical diagnosis, providing the broad band variation of visible RL from blue to red. (c) 2012 Elsevier B.V. All rights reserved.