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Study of Structural and Optical Properties of Undoped and Rare Earth Doped TiO2 Nanostructures

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dc.contributor.advisor Dhlamini, M. S.
dc.contributor.advisor Mothudi, B. M.
dc.contributor.advisor Mhlongo, G. H. Talane, Tsholo Ernest 2018-10-10T10:28:32Z 2018-10-10T10:28:32Z 2017
dc.identifier.citation Talane, Tsholo Ernest (2017) Study of Structural and Optical Properties of Undoped and Rare Earth Doped TiO2 Nanostructures, University of South Africa, Pretoria, <>
dc.description.abstract Un-doped, Er3+ doped (TiO2:Er3+) as well as Er3+/Yb3+ co-doped (TiO2:Er3+/Yb3+) nanocrystals with different concentrations of RE3+ (Er3+, Yb3+) were successfully synthesized using the sol-gel method. The powder X-ray diffraction (XRD) spectra revealed that all undoped and doped samples remained in anatase after annealing at 400°C. The presence of RE3+ ions in the TiO2 host lattice was confirmed by conducting elemental mapping on the samples using Scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometer (EDX), which was in agreement with X-ray photoelectron spectroscopy (XPS) results. Transmission electron microscope (TEM) images approximated particle sizes of the samples to be between 1.5 – 3.5 nm in diameter and this compares well with XRD analyses. Phonon quantification in TiO2 was achieved using Fourier transform infrared (FT-IR) spectroscopy. Optical bandgap from Ultraviolet/Visible/Near-Infrared was extrapolated from Kubelka-Munk relation and the narrowing of the bandgap for the doped samples as compared to the undoped sample was observed. The photoluminescence PL study of the samples revealed two emission peaks attributed to direct band-gap and defect-related emissions. A laser beam with 980 nm wavelength was used to irradiate the samples, and the displayed emission lines of the TiO2: Er3+ in the visible region of the electromagnetic spectrum confirmed up-conversion luminescence. Enhancement of up-conversion luminescence intensity due to Yb3+ co-doping was observed, indicating an efficient energy transfer process from the sensitizer Yb3+ to the activator Er3+. en
dc.format.extent 1 online resource (vii, 94 leaves) : illustrations (chiefly color) en
dc.language.iso en en
dc.subject Sol-gel en
dc.subject Annealing en
dc.subject TiO2 nanopowders en
dc.subject Optical band-gap en
dc.subject Up-conversion luminescence en
dc.subject Rare earth en
dc.subject Erbium en
dc.subject Ytterbium en
dc.subject.ddc 543.62
dc.subject.lcsh Nanoscience en
dc.subject.lcsh Nanostructured materials en
dc.subject.lcsh Fourier transform infrared spectroscopy en
dc.subject.lcsh Nanotechnology. en
dc.subject.lcsh X-ray photoelectron spectroscopy en
dc.title Study of Structural and Optical Properties of Undoped and Rare Earth Doped TiO2 Nanostructures en
dc.type Dissertation en
dc.description.department Physics en M. Sc. (Physics) en

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