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27 July 2021 | Story Leonie Bolleurs | Photo UFS Photo Archive
Prof Hendrik Swart played a key role in the Department of Physics acquiring the PHI Quantes XPS system, the first in Africa and one of only 20 in the world.

The state-of-the-art equipment in the Department of Physics at the University of the Free State (UFS) differentiates this department from its competitors. Availability of the equipment makes it possible for researchers as well as students to deliver work that receives national and international recognition. 

Recently, the department acquired a PHI Quantes XPS system, the first in Africa and one of only 20 in the world. 

Creating better phosphor 

“The Quantes XPS system uses X-rays to determine the chemical composition of molecules on the surface of a sample. The system is unique in the sense that it also has an extra X-ray source that can determine the chemical state below the surface, which was not possible in the past.  This will help us to dictate the position of defects in our phosphor materials that will consequently enable us to create better phosphor for solid state lighting as well as solar cell applications,” explains Prof Hendrik Swart, Senior Professor in the Department of Physics, who also holds the SARChI Chair in Solid State Luminescent and Advanced Materials.

After he had the opportunity to observe the system in the factory in Chigasaki, Kanagawa, Japan, where he attended a conference, Prof Swart was very impressed by its performance. He discussed it with Prof Koos Terblans, Head of the department, and other colleagues, and started making plans to buy the system. 

When the department first bought the X-ray photoelectron spectroscopy (XPS) system in 2007/2008, it became the national facility on XPS measurements. Not only is this an upgrade of the XPS system bought 14 years ago, but the new system will enable the department to do more measurements. “The number of samples that we have to handle has just become too much for one system. The new system’s increased capacity for making measurements addresses this challenge and it also gives UFS scientists and postgraduate students more time to spend on fundamental measurements to develop research of a higher level,” says Prof Swart.

(The Quantes XPS system. Photo:Supplied)

Explaining about the measurements, Prof Swart says: “This advanced X-ray photoelectron spectroscopy (XPS) instrument has the capability to analyse the very small area that the user is interested in and a large area of the uniform sample surface. The two different types of X-ray sources – the hard X-ray source and the more conventional soft X-ray source – can be switched automatically, allowing users to analyse the same area and/or points of a sample. The PHI Quantes XPS system ensures the availability of superior features such as automatic analysis, automatic sample transfer, turnkey charge neutralisation, and advanced data processing.”

“This XPS instrument is designed to pioneer new methods and applications transcending conventional ideas of what is possible.”

Optimising efficiency of materials

Prof Swart says the Department of Physics, especially the Research Chair in Advanced and Luminescent Materials, is developing new high-technology materials on a daily basis. “It is very important to know the chemical composition and defect distribution of the materials in order to add value to the fabrication of these materials,” he adds.

“The distribution of these defects is vital for the efficiency of the phosphor materials. If we know where these defects are located, we can determine the mechanisms of the light output coming from these phosphors,” describes Prof Swart.

Research conducted as part of the Research Chair in Solid State Luminescent and Advanced Materials will benefit significantly from this new system.

(Prof Koos Terblans, Head of the Department of Physics next to the Quantes XPS system. Photo:Supplied) 

“We are currently concentrating on phosphors as sensors (temperature), light-emitting diodes (LEDs), and solar cells, where we optimise the efficiency and durability of these materials. Any new knowledge, which I believe the PHI Quantes XPS system will provide us, will help us to reach our goal much quicker,” he says. 

Apart from the positive impact on research, the PHI Quantes XPS system will also be a benefit to society in the long term. Improved LEDs can be used to save electricity, and better solar cells can help to generate electricity, to mention but two examples. 

News Archive

NRF researcher addresses racial debates in classrooms
2017-03-24

Description: Dr Marthinus Conradie Tags: Dr Marthinus Conradie

Dr Marthinus Conradie, senior lecturer in the
Department of English, is one of 31 newly-rated National
Research Foundation researchers at the University of
the Free State.
Photo: Rulanzen Martin

Exploring numerous norms and assumptions that impede the investigation of racism and racial inequalities in university classrooms, was central to the scope of the research conducted by Dr Marthinus Conradie, a newly Y-rated National Research Foundation (NRF) researcher.

Support from various colleagues
He is one of 31 newly-rated researchers at the University of the Free State (UFS) and joins the 150 plus researchers at the university who have been rated by the NRF. Dr Conradie specialises in sociolinguistics and cultural studies in the UFS Department of English. “Most of the publications that earned the NRF rating are aimed to contributing a critical race theoretic angle to longstanding debates about how questions surrounding race and racism are raised in classroom contexts,” he said.

Dr Conradie says he is grateful for the support from his colleagues in the Department of English, as well as other members of the Faculty of the Humanities. “Although the NRF rating is assigned to a single person, it is undoubtedly the result of support from a wide range of colleagues, including co-authors Dr Susan Brokensha, Prof Angelique van Niekerk, and Dr Mariza Brooks, as well as our Head of Department, Prof Helene Strauss,” he said.

Should debate be free of emotion?
His ongoing research has not been assigned a title yet, as he and his co-author does not assign titles prior to drafting the final manuscript. “Most, but not all, of the publications included in my application to the NRF draw from discourse analysis of a Foucauldian branch, including discursive psychology,” Dr Conradie says. His research aims to suggest directions and methods for exploring issues about race, racism, and racial equality relating to classroom debates. One thread of this body of work deals with the assumption that classroom debates must exclude emotions. Squandering opportunities to investigate the nature and sources of the emotions provoked by critical literature, might obstruct the discussion of personal histories and experiences of discrimination. “Equally, the demand that educators should control conversations to avoid discomfort might prevent in-depth treatment of broader, structural inequalities that go beyond individual prejudice,” Dr Conradie said. A second stream of research speaks to media representations and cultural capital in advertising discourse. A key example examines the way art from European and American origins are used to imbue commercial brands with connotations of excellence and exclusivity, while references to Africa serve to invoke colonial images of unspoiled landscapes.

A hope to inspire further research
Dr Conradie is hopeful that fellow academics will refine and/or alter the methods he employed, and that they will expand, reinterpret, and challenge his findings with increasing relevance to contemporary concerns, such as the drive towards decolonisation. “When I initially launched the research project (with significant aid from highly accomplished co-authors), the catalogue of existing scholarly works lacked investigations along the particular avenues I aimed to address.”

Dr Conradie said that his future research projects will be shaped by the scholarly and wider social influences he looks to as signposts and from which he hopes to gain guidelines about specific issues in the South African society to which he can make a fruitful contribution.

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