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Please use this identifier to cite or link to this item: http://hdl.handle.net/10204/5627

Title: Effects of Ce3+ concentration, beam voltage and current on the cathodoluminescence intensity of SiO2: Pr3+–Ce3+ nanophosphor
Authors: Mhlongo, GH
Ntwaeaborwa, OM
Dhlamini, MS
Swart, HC
Hillie, KT
Keywords: Cathodoluminescence
Energy transfer
Degradation
Issue Date: Feb-2011
Publisher: Elsevier
Citation: Mhlongo, GH, Ntwaeaborwa, OM, Dhlamini, MS, Swart, HC and Hillie, KT. 2011. Effects of Ce3+ concentration, beam voltage and current on the cathodoluminescence intensity of SiO2: Pr3+–Ce3+ nanophosphor. Journal of Alloys and Compounds, vol. 509(6), pp 2986–2992
Series/Report no.: Workflow;7877
Workflow;8120
Abstract: SiO2:Pr3+–Ce3+ phosphor powders were successfully prepared using a sol–gel process. The concentration of Pr3+ was fixed at 0.2 mol% while that of Ce3+ was varied in the range of 0.2–2 mol%. High resolution transmission electron microscopy (HRTEM) clearly showed nanoclusters of Pr and Ce present in the amorphous SiO2 matrix, field emission scanning electron microscopy (FE-SEM) indicated that SiO2 clustered nanoparticles from 20 to 120 nm were obtained. Si–O–Si asymmetric stretching was measured with Fourier transform-IR (FT-IR) spectroscopy and it was also realized that this band increased with incorporation of the activator ions into the SiO2 matrix. The broad blue emission from the Ce3+ ions attributed to the 5d1–4f1 transition was observed from the SiO2:0.2 mol% Pr3+–1 mol% Ce3+ phosphor. This emission was slightly enhanced compared to that of the singly doped SiO2:1 mol%Ce3+ phosphor. Further investigations were conducted where the CL intensity was measured at different beam voltages and currents from 1 to 5 kV and 8.5 to 30 µA, respectively, in order to study their effects on the CL intensity of SiO2:0.2 mol% Pr3+–1 mol% Ce3+. The electron-beam dissociated the SiO2 and as a result an oxygen-deficient surface dead or non-luminescent layer of SiOx, where x < 2 on the surface, was formed.
Description: Copyright: 2011 Elsevier. This is an ABSTRACT ONLY.
URI: http://www.sciencedirect.com/science/article/pii/S0925838810029427
http://hdl.handle.net/10204/5627
ISSN: 0925-8388
Appears in Collections:National Centre for nano-structured materials
Nanotechnology
General science, engineering & technology

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