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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

Twenty years of the constitution of South Africa – cause for celebration and reflection
2016-05-11

Description: Judge Azar Cachalia Tags: Judge Azar Cachalia

Judge Azar Cachalia

The University of the Free State’s Centre for Human Rights and the Faculty of Law held the celebration of the twentieth anniversary of the adoption of the South African Constitution on 11 May 2016 on the Bloemfontein Campus.  Students and faculty members celebrated and reflected on not only the achievements of the constitution but also on perspectives regarding its relevance in modern society, and to what extent it has upheld the human rights of all citizens of South Africa.

The panel discussion started with a presentation on the pre-1996 perspective by Judge Azar Cachalia of the Supreme Court of Appeal.  Judge Cachalia reflected on his role in the realisation and upholding of the constitution, from his days as a student activist, then as an attorney representing detainees during political turmoil, and currently as a judge: “My role as an attorney was to defend people arrested for public violence. My role as a judge today is to uphold the constitution.”  He stressed the importance of the constitution today, and the responsibility institutions such as the police service have in upholding human rights.  Judge Cachalia played a significant role in drafting the new Police Act around 1990, an Act which was to ensure that the offences perpetrated by the police during apartheid did not continue in the current democratic era. Further, he pointed out that societal turmoil has the potential to make society forget about the hard work that was put into structures upholding human rights. “Constitutions are drafted in moments of calm.  It is a living document, and we hope it is not torn up when we go through social conflict, such as we are experiencing at present.”

Thobeka Dywili, a Law student at the UFS, presented her views from the new generation’s perspective.  She relayed her experience as a student teaching human rights at schools in disadvantaged communities. She realised that, although the youth are quite aware of their basic human rights, after so many years of democracy, “women and children are still seen as previously disadvantaged when they should be equal”. She pointed out that, with the changing times, the constitution needs to be looked at with a new set of eyes, suggesting more robust youth engagement on topics that affect them, using technology to facilitate discussions. She said with the help of social media, it is possible for a simple discussion to become a revolution; #feesmustfall was a case in point.

Critical perspectives on the constitution were presented by Tsepo Madlingozi of University of Pretoria and University of London. In his view, the constitution has not affected policy to the extent that it should, with great disparities in our society and glaring issues, such as lack of housing for the majority of the poor.  “Celebration of the constitution should be muted, as the constitution is based on a decolonisation approach, and does not directly address the needs of the poor. The Constitutional Court is not pro-poor.”  He posed the question of whether twenty years on, the present government has crafted a new society successfully.  “We have moved from apartheid to neo-apartheid, as black elites assimilate into the white world, and the two worlds that exist have not been able to stand together as a reflection of what the constitution stands for.”

Prof Caroline Nicholson, Dean of the Faculty of Law, encouraged more open discussions, saying such dialogues are exactly what was intended by the Centre for Human Rights. She emphasised the importance of exchanging ideas, of allowing people to speak freely, and of sharing perspectives on important issues such as the constitution and human rights.

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