9-13 July 2012
Africa/Johannesburg timezone
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Luminescent dynamics of GdTaO4:Pr3+

Presented by Mr. Luyanda Lunga NOTO on 10 Jul 2012 from 12:00 to 12:20
Type: Oral Presentation
Session: DCMPM1
Track: Track A - Division for Condensed Matter Physics and Materials

Abstract

Rare earth tantalates (MTaO<sub>4</sub>) with M = Gd, Y, La, are being extensively studied for possible applications in X-ray imaging systems and mercury free fluorescent lamps, and field emission display (FED) devices due to their high luminescence efficiency, physical and chemical stability, strong irradiation hardness and good X-ray absorption.1,2 In recent years, trivalent praseodymium (Pr<sup>3+</sup>) doped materials displaying red persistent luminescence are of considerable interest in the development of long persistent materials.3 In addition, the energy distribution of the defect levels within the forbidden region of these compounds is determined using thermoluminescence (TL) spectroscopy. Luminescent dynamics including fluorescence, phosphorescence, and thermoluminescence of Pr<sup>3+</sup> in GdTaO<sub>4</sub>:Pr<sup>3+</sup> is reported. X-ray diffraction (XRD) spectra indicated that GdTaO<sub>4</sub>:Pr<sup>3+</sup> phosphor material is successfully prepared at 1200 &deg;C using the solid state reaction method. Red and blue-green emissions were observed upon probing the materials with energetic photons using the DESY synchrotron radiation. A simplified energy transfer scheme explaining energy transfer from the TaO<sub>4</sub> group to either Gd<sup>3+</sup> states in the GdTaO<sub>4</sub>:Pr<sup>3+</sup> system is presented. Afterglow measurements were carried out after UV irradiation at room temperature. The phosphorescence lifetime (τ) observed for GdTaO<sub>4</sub>:Pr<sup>3+</sup> compound as a result of traps was 620 s. The depth of the trap levels was investigated from the TL data. (1) Brixner, L. H.; Chen, H. Y. Chemical Etching Characteristics 1983, 130, 2435. (2) Bo, L.; Kun, H.; Liu, X.; Gua, M.; Huanga, S.; Chen, N.; Qib, Z.; Zhang, G. Solid. Stat. Comm. 2007, 144, 484. (3) Noto, L. L.; Pitale, S. S.; Terblans, J. J. Ntwaeaborwa O.M.; H.C. Swart, H.C. Physica B 2012, 407, 1517

Award

yes

Level

MSc

Supervisor

Hendrik C. Swart, SwartHC@ufs.ac.za, University of Free State

Paper

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