12-15 July 2011
Saint George Hotel
Africa/Johannesburg timezone

Synthesis and photoluminescence studies of (Ba<sub>1-x</sub>Sr<sub>x</sub>)Al<sub>2</sub>O<sub>4</sub>:Eu<sup>2+</sup>;Nd<sup>3+</sup> prepared by combustion method

13 Jul 2011, 17:00


Poster Presentation Track A - Condensed Matter Physics and Material Science Poster1


Ms Mantwa Annah Lephoto (University of The Free State)


Barium-substituted phosphor powders of (Ba1-xSrx)Al2O4:Eu2+ ;Nd3+ composition were prepared by combustion method at an initiating temperature of 5000C, using urea as reducer. The powders were then annealed at higher temperatures of 8000C and 10000C for 3 hours. Their crystallinity and phase were characterized by x-ray diffraction (XRD). The x-ray diffraction shows that the crystallinity of (Ba1-xSrx)Al2O4:Eu2+;Nd3+ at (x=0) greatly improved after annealing at the higher temperature of 10000C and shows the hexagonal structure that closely correspond with the JCPDS data (PDF#17-0306). The morphology of the (Ba1-xSrx)Al2O4:Eu2+;Nd3+ composition were investigated using Scanning Electron Microscopy (SEM). The effect of varying the Ba/Sr concentration on the thermoluminescence (TL) glow curves was investigated using the Thermoluminescence Reader (Integral-Pc Based) Nucleonix TL 1009I. Photoluminescence (PL) properties of all phosphor samples were investigated by measuring their emission spectra using a 325nm He-Cd laser. For the as-prepared phosphor samples, the sample with x=0 (BaAl2O4:Eu2+;Nd3+showed a much higher intensity compared to both the sample with x=1 (SrAl2O4:Eu2+;Nd3+and the mixed composition of the two. (BaAl2O4:Eu2+;Nd3+(x=0) and SrAl2O4:Eu2+;Nd3+ (x=1)showed a broad emission at 505nm and 522nm respectively while the mixed composition showed two peaks at 447nm and 517nm. The broad emission peaks attributed to 4f65d1-4f 7 transitions of Eu2+ were obtained. Their phosphorescence was investigated by using the fluorescence Cary eclipse spectrophotometer coupled with a xenon lamp. Phosphorescence show higher luminescence for (Ba1-xSrx)Al2O4:Eu2+;Nd3+at (x=0).

Consider for a student <br> &nbsp; award (Yes / No)? Yes
Level (Hons, MSc, <br> &nbsp; PhD, other)? MSc
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)? Yes

Primary author

Ms Mantwa Annah Lephoto (University of The Free State)


Dr Bakang Moses Mothudi (UNISA) Dr Daniel Barasa Bem (University of The Free State) Prof. Hendrik Swart (University of The Free State) Prof. Odireleng Martin Ntwaeaborwa (University of The Free State)

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