Crystal Structure and Luminescence Properties of Rare Earth Doped Ba2Bi2/3TeO6 Double Perovskites

Recently there has been an increase in demand for inorganic phosphors as it can be used in many of solid-state lighting devices. A number of perovskite materials especially vanadates, molybdates, and tungstates, can act as host lattices for rare earth ions. These host lattices can efficiently absorb ultraviolet light through the excitation of the charge-transfer state and can transfer the absorbed energy to the activator. In the present study, we investigate the crystal structure and luminescent properties of pure and rare earth doped Ba2Bi2/3TeO6 showing 1:1 rock salt ordering. The compounds were synthesised using solid-state ceramic route. Ba2Bi2/3TeO6 crystallises in Fm (3) over barm symmetry with lattice parameter of 8.48 angstrom. FT Raman and FT IR spectroscopic studies also confirm a cubic perovskite structure for Ba2Bi2/3TeO6 with 1:1 ordering of Bi3+ and Te6+ ions. Optical band gap of Ba2Bi2/3TeO6 double perovskites obtained through using UV-Visible absorption spectroscopy is about 2.8 eV. Photo luminescence properties of Ba2Bi2/3-xRExTeO6 (RE=Eu, Dy, x=0.025, and 0.05) were also investigated. Eu3+ and Dy3+ doped samples show emission in orange-red region of the electromagnetic spectrum. (C) 2017 Elsevier Ltd. All rights reserved.