Doctoral Degrees (Physics)
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Recent Submissions
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Effect of host anion or cation substitution on the luminescence and stability of lanthanum oxide based phosphors doped with bismuth
(University of the Free State, 2022-01)LaOCl:Bi3+ phosphor powders were successfully prepared via the solid-state reaction method and compared to LaOBr:Bi3+. Photoluminescence measurements revealed that the phosphors displayed ultraviolet emission around 344 ... -
An image guided adaptive radiotherapy strategy for cervix cancer treatment based on equivalent uniform dose
(University of the Free State, 2021-11)Aim: This study aims to develop an image-guided adaptive strategy to compensate for temporal effects of tumour shrinkage and organ motion in cervix cancer treatment based on the equivalent uniform dose (EUD). The strategy ... -
Luminescence properties of Gd2O3:Bi3+ co-doped Ln3+ as powder and thin films phosphor for solar cell application
(University of the Free State, 2021-11)The main aim of this project is to study the luminescence properties of Gd2O3:Bi3+ co-doped Ln3+(Yb3+ and Er3+) phosphor powder and thin films to improve the energy conversion efficiency of photovoltaics (PV) by using the ... -
Material Properties of RE- Doped Ln (Ln= Y, La) oxides and oxysulfides phosphors for red-emitting devices
(University of the Free State, 2015-11)Structural and optical properties of Eu3+-doped Ln (Ln=Y, La) oxide and oxysulfide nano crystals synthesized by sol-combustion method were analysed as a function of host to fuel ratio. Structural characterization shows ... -
Study on luminescence and structural properties of vanadates phosphors
(University of the Free State, 2016-01)A self-activated yellow emitting zinc vanadate (Zn2 Y20 1) was synthesized by combustion method. The influence of the processing parameters such as synthesis temperature and dopants concentration on the structure, ... -
Theoretical and experimental investigation on surface segregation of Cu-Ni(S) bulk and thin film alloys
(University of the Free State, 2017-07)In this study, the surface segregation in a Ni-Cu alloywasinvestigated by modeling the segregation process theoreticallyand also measuring it experimentally. This was performedfor abulkcrystaland thin films. In addition ... -
Origin of pulsar timing noise: possible correlations between pulsar spin-down rates and magnetospheric processes
(University of the Free State, 2017-03)English: Pulsars are extremely accurate clocks that allow us to explore certain unanswered questions in the elds of exotic compact forms of matter and gravitational wave as- trophysics. Pulsars that form part of a timing ... -
Upconversion of infrared to visible light in rare-earths doped phosphate phosphors for photodynamic therapy application
(University of the Free State, 2017-06)Phosphate phosphors have emerged as an important family of luminescent material due to their low sintering temperature, broad band gaps, high thermal and chemical stability, and moderate phonon energies. Their structure ... -
Theoretical and experimental study of core-shell structured ZnO/ZnS and growth mechanism of un-doped and doped ZnO nanomaterials
(University of the Free State (Qwaqwa Campus), 2017-12)There is currently widespread interest among researchers in ZnO-ZnS coreshell nanorods as electrodes in prototype solar cells. ZnS has been proposed as a suit- able inorganic sensitizer to ZnO because ZnO and ZnS when in ... -
A combined ab initio and experimental study of lanthanides and/or transition metal doped oxides
(University of the Free State (Qwaqwa Campus), 2017-01)Ab initio modelling techniques have produced a notable contribution in analysing semiconductor metal oxides properties by use of first principles. These techniques have transformed to a high level of accuracy, owing to the ... -
Structural and luminescence properties of re doped fluoride and silicate phosphors
(University of the Free State (Qwaqwa Campus), 2017-04)This work covers several aspects of rare earth activated silicate and fluoride commercial phosphor powders and thin films. All the films were synthesized by pulsed laser deposition technique using Nd- YAG laser and ... -
A molecular dynamics study of segregation and diffusion in FCC nanocrystals using the sutton-chen potential
(University of the Free State, 2017-02)English: English: Nanotechnology research has expanded notably, with a wide range of applications from catalysis in fuels, to optics. A key factor in manufacturing these particles is understanding diffusion and segregation ... -
Surface segregation of Sn and Sb in the low index planes of Cu
(University of the Free State, 2005-05)In this study, the segregation parameters for Sn and Sb in Cu were determined for the first time using novel experimental procedures. Sn was first evaporated onto the three low index planes of Cu(111), Cu(110) and Cu(100) ... -
'n ISS studie van die (110), (111) en (100)-enkel-kristalvlakke van NiAI
(University of the Free State, 2000-11)English: In this study the [110]-, the [111]- and the [1OO]-single crystal surfaces of Ni Al were investigated. The aim was to firstly harmonize the existing knowledge of these surfaces and secondly to create a clear and ... -
Sol-gel synthesis and characterization of MAl2O4 (M = Zn or Mg) spinels doped, co-doped and triply doped nano-phosphors
(University of the Free State (Qwaqwa Campus), 2014-12)The luminescent and structural properties of the MAl2O4 (M = Zn, Mg) (which are thereafter referred as hosts) phosphors prepared by sol-gel methods at a relatively low temperature (~80 °C) are discussed. Zinc, magnesium ... -
Luminescence enhancement of phosphors by doping with silver
(University of the Free State, 2015-10)Phosphor materials doped with noble metals have attracted considerable attention for the past fifty years due to their possible applications in lighting and solar cells with improved efficiency, biology, lasers and novel ... -
Luminescence properties of Y2O3:Bi3+ as powder and thin film phosphor for solar cell application
(University of the Free State, 2015-07)The luminescent properties of the bismuth doped yttrium oxide (Y2-xO3:Bix) phosphor material was investigated as a powder and as thin films for possible application as a down-conversion material for solar cells. The goal ... -
Effect of broadband excitation ions in the luminescence of Ln.³+ doped SrF₂ nanophosphor for solar cell application
(University of the Free State, 2015-06)SrF2:Pr3+-Yb3+ phosphor powder was previously investigated for down-conversion application in solar cells. The rst surface, structural and optical characterization results indicated that the Pr3+-Yb3+ couple requires a ... -
Luminescence investigations of CaS:Eu2+ powder and pulsed laser deposited thin films for application in light emitting diodes
(University of the Free State, 2015-06)The main objective of this thesis was to investigate the luminescent properties of commercial CaS:Eu2+ powder and pulsed laser deposited thin films for application in light emitting diodes. X-ray diffraction (XRD), X-ray ... -
The role of MHD instabilities in the magnetospheric propeller outflow and emission in the nova-like variable star AE Aquarii
(University of the Free State, 2007-02)English: AE Aquarii is a close binary consisting of a white dwarf primary star and a K4-5 red dwarf, the secondary. Mass is transferred from the Roche lobe filling secondary to the Roche lobe of the white dwarf. The white ...
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