12-15 July 2011
Saint George Hotel
Africa/Johannesburg timezone
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Synthesis and photoluminescence studies of (Ba1-xSrx)Al2O4:Eu2+;Nd3+ prepared by combustion method

Presented by Ms. Mantwa Annah LEPHOTO on 13 Jul 2011 from 17:00 to 19:00
Type: Poster Presentation
Session: Poster1
Track: Track A - Condensed Matter Physics and Material Science

Content

<p>Barium-substituted phosphor powders 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> composition were prepared by combustion method at an initiating temperature of 500<sup>0</sup>C, using urea as reducer. The powders were then annealed at higher temperatures of 800<sup>0</sup>C and 1000<sup>0</sup>C for 3 hours. Their crystallinity and phase were characterized by x-ray diffraction (XRD). The x-ray diffraction shows that the crystallinity 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> at (x=0) greatly improved after annealing at the higher temperature of 1000<sup>0</sup>C and shows the hexagonal structure that closely correspond with the JCPDS data (PDF#17-0306). The morphology of the (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> 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 (BaAl<sub>2</sub>O<sub>4</sub>:Eu<sup>2+</sup>;Nd<sup>3+</sup>showed a much higher intensity compared to both the sample with x=1 (SrAl<sub>2</sub>O<sub>4</sub>:Eu<sup>2+</sup>;Nd<sup>3+</sup>and the mixed composition of the two. (BaAl<sub>2</sub>O<sub>4</sub>:Eu<sup>2+</sup>;Nd<sup>3+</sup>(x=0) and SrAl<sub>2</sub>O<sub>4</sub>:Eu<sup>2+</sup>;Nd<sup>3+</sup> (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 4f<sup>6</sup>5d<sup>1</sup>-4f <sup>7</sup> transitions of Eu<sup>2+</sup> were obtained. Their phosphorescence was investigated by using the fluorescence Cary eclipse spectrophotometer coupled with a xenon lamp. Phosphorescence show higher luminescence for (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>at (x=0).

Level (Hons, MSc, PhD, other)?

MSc

Consider for a student award (Yes / No)?

Yes

Short Paper

Yes

Place

Location:
Room: Asteria


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