22-30 July 2021
North-West University
Africa/Johannesburg timezone
More Information Coming Soon

Effect of annealing time on the structure, morphology and optical properties of mixed phases of barium and strontium aluminates doped with 0.1% Tb3+ prepared by citrate sol-gel method

29 Jul 2021, 12:15
15m
Potchefstroom Campus (North-West University)

Potchefstroom Campus

North-West University

Oral Presentation Track A - Physics of Condensed Matter and Materials Physics of Condensed Matter and Materials

Speaker

Mr Mpho Maluleka (Sefako Makgatho Health Sciences University)

Description

Citrate sol-gel method was used to successfully prepare mixed phases of strontium and barium aluminate powders doped with 0.1% Tb3+. All powders were annealed at 1000 oC while varying the annealing time (AT) from 0.5 – 4 hours (h). The X-ray powder diffraction (XRD) results revealed that the prepared powders is the mixture of phases consisting of cubic (Sr3Al2O6, Ba3Al2H12O12), monoclinic (SrAl2O4, SrAl4O7), hexagonal (Ba0.6Sr0.4Al2O4, SrO, BaAl2O4) and orthorhombic (BaH4O3) crystal structures. Tb3+ did not influence the structure of mixed phases of BaAl2O4/BaH4O3/Ba3Al2H12O12/Ba0.6Sr0.4Al2O4/SrAl2O4,SrAl4O7/ Sr3Al2O6/SrO (BBBBSSSS). The energy dispersive X-ray spectroscopy (EDS) mapping showed homogeneous distribution of elements on the surface. The scanning electron microscopy (SEM) images showed that as the AT increases the particle becomes more agglomerated and smoother. Transition electron microscopy (TEM) images suggested that the particle sizes were not influenced by the AT. Ultraviolet–visible (UV–vis) diffuse reflection spectroscopy confirmed that AT influenced the energy band gap (Eg) of the prepared nanophosphor. The Eg can be tuned between 5.1 and 5.7 eV. Photoluminescence (PL) results showed four emission peaks located around 489, 546, 589 and 618 nm which are attributed to 5D4 →7F6, 5D4 →7F5, 5D4 →7F4, and 5D4 →7F3 transitions of Tb3+ ions, respectively.

Apply to be considered for a student ; award (Yes / No)?

Yes

Level for award;(Hons, MSc, PhD, N/A)?

MSc

Primary authors

Mr Mpho Maluleka (Sefako Makgatho Health Sciences University) Setumo Victor Motloung (SMU) Prof. Lehlohonolo Fortune Koao (University of Free State (Qwaqwa)) Prof. Tshwafo Elias Motaung (University of South Africa) Dr Motlalepula Rebecca Mhlongo (Sefako Makgatho Health Sciences University)

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