Journal of Alloys and Compounds 497 (2010) 201–209 Contents lists available at ScienceDirect Journal of Alloys and Compounds journal homepage: www.elsevier.com/locate/jallcom Synthesis and characterisation of terbium activated yttrium tantalate phosphor Elisabeth-Jeanne Popovici a,∗ , Mihail Nazarov b , Laura Muresan a , Do Young Noh b , Lucian Barbu Tudoran c , Ecaterina Bica a , Emil Indrea d a Raluca Ripan Institute for Research in Chemistry, Babes Bolyai University, 30 Fantanele, 400294 Cluj-Napoca, Romania b Centre for Extreme Light Applications, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, Republic of Korea c Electronic Microscopy Centre, “Babes-Bolyai” University, 5-7 Clinicilor, 400006 Cluj-Napoca, Romania d National Institute for R&D of Isotopic and Molecular Technologies, 30 Donath, 400295 Cluj-Napoca, Romania article info Article history: Received 4 October 2009 Received in revised form 28 February 2010 Accepted 1 March 2010 Available online 7 March 2010 Keywords: Phosphors Yttrium tantalate Luminescence X-ray diffraction abstract Terbium activated yttrium tantalate (YTaO 4 :Tb) samples were prepared by solid-state reaction from homogeneous mixtures of Y 2 O 3 and Ta 2 O 5 for host-lattice formation, Tb 4 O 7 or Tb(NO 3 ) 3 ·5H 2 O as activator source and Li 2 SO 4 , Na 2 SO 4 , CsF, Na 4 P 2 O 7 or Na 2 B 4 O 7 as flux. Photoluminescence (PL) measurements, FT-IR spectroscopy, X-ray diffraction and scanning electron microscopy revealed that PL properties are influenced by the degree of crystalline order and particle morphology and sizes regulated during the thermal synthesis. The effect of flux and terbium concentration on the morpho-structural characteristics and PL properties of YTaO 4 :Tb powder is reported. © 2010 Elsevier B.V. All rights reserved. 1. Introduction The development of luminescent materials has been the subject of extensive research in the past years. Particular interest has been focused on inorganic luminescent materials, which have practical applications in almost all devices involving the artificial production of light [1]. More recently, the development of flat electrolumines- cence, plasma, and field emission displays, as well as scintillators in X-ray and positron emission tomography has increased the demand for materials with better characteristics in terms of stability, bright- ness, and industrial processing ability [2]. Terbium ions are widely used as efficient emission centres in many oxide-based compounds, having relatively high transitions probabilities originating from the 4f electron configuration. The strong green emission with high glow purity and stability make terbium doped phosphors to be suitable for many technological applications e.g. cathode ray tubes, fluorescence lamps, X-ray imaging devices, scintillators, light emitting diodes, field emission displays, etc. [3]. Due to these potential technological applications, terbium is a valuable activator and the understanding of its role and optical properties is of great importance. A large number of studies have been lately dedicated to terbium ions doped oxide-based ∗ Corresponding author. Tel.: +40 364 405975; fax: +40 264 420441. E-mail addresses: jennypopovici@yahoo.com, epopovici@chem.ubbcluj.ro (E.-J. Popovici). matrices such as yttrium/gadolinium aluminate [4–7], gadolinium tungstate [8] or lutetium tantalate [9]. Yttrium tantalate YTaO 4 -based phosphors are luminescent materials, the performances of which correlate with the crystalline structure and particle morphology or dimensions and determine their utilization in X-ray medical imaging [10]. The ultraviolet-blue light emission of phosphors is associated with TaO 4 groups from the host crystalline lattice [11,12]. When rare earth ions (RE) such as Eu 3+ and/or Tb 3+ are used to partially replace the yttrium ions, additional luminescence centres are created and emission is shifted toward longer wavelength [13,14]. Rare earth doped YTaO 4 -based phosphors possess superior X- ray absorption characteristics and luminescence efficiency and therefore, they are perspective materials as ceramic scintilla- tors for applications in high-energy physics or X-ray computed tomography for industrial and medical imaging. In the last years, many papers have been devoted to the investigation of rare earth activated yttrium tantalate based phosphors [15–18]. The present study continues our previous works related to the synthesis and properties of YTaO 4 -based phosphors with or with- out rare earth doping ions [19–21]. The preparation of YTaO 4 -based phosphors is achieved by solid-state reaction route, from synthe- sis mixtures containing appropriate metallic oxides. The thermal synthesis is flux-assisted by alkaline salts in order to improve the crystalline structure of the YTaO 4 host lattice as well as the forma- tion of the emission centres. 0925-8388/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jallcom.2010.03.010