9-13 July 2012
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=11&confId=14"><font color=#ff0000>SAIP2012 PROCEEDINGS AVAILABLE</font></a>

Luminescent dynamics of GdTaO<sub>4</sub>:Pr<sup>3+</sup>

10 Jul 2012, 12:00
Oral Presentation Track A - Division for Condensed Matter Physics and Materials DCMPM1


Mr Luyanda Lunga Noto (University of Free State (Student))

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Abstract content <br> &nbsp; (Max 300 words)

Rare earth tantalates (MTaO4) 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 (Pr3+) 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 Pr3+ in GdTaO4:Pr3+ is reported. X-ray diffraction (XRD) spectra indicated that GdTaO4:Pr3+ phosphor material is successfully prepared at 1200 °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 TaO4 group to either Gd3+ states in the GdTaO4:Pr3+ system is presented. Afterglow measurements were carried out after UV irradiation at room temperature. The phosphorescence lifetime (τ) observed for GdTaO4:Pr3+ 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

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Main supervisor (name and email)<br>and his / her institution

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

Primary author

Mr Luyanda Lunga Noto (University of Free State (Student))


Prof. HC Swart (University of Free State) Prof. JJ Terblans (University of Free State) Dr Marek Gusowski (University of Free State) Prof. OM Ntwaeaborwa (University of Free State) Dr Shreyas Pitale (University of Free State)

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