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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

SA cannot sustain momentum - Boesak
2010-09-02

Photo: Stephen Collett

South Africa finds it increasingly difficult to live up to the challenges facing it as a nation because of its failure to meet its democratic ideals and possibilities, peace and lack of self-belief.

This was according to renowned cleric and former political activist, Dr Allan Boesak, who recently delivered the CR Swart Memorial Lecture, the oldest memorial lecture at the University of the Free State (UFS). His lecture was on the topic Creating moments, sustaining momentum.

He said South Africa had plenty of opportunities to show the whole world what was possible if all the people of this country joined hands and worked together to build a truly united society. However, he said, the country somehow invariably contrived to find its way out of these wonderful possibilities.

He cited events of historical significance like Codesa, the inauguration of Nelson Mandela as the first democratic president of South Africa, the assassination of South African Communist Party leader, Chris Hani; and the rugby and soccer world cups.
To drive his point home about this dismal failure of the country to “sustain momentum”, he alluded to the current public servants’ strike that is gradually crippling public service.

“The public servants’ strike was neither unexpected nor is it completely unjustifiable. Most of us have understanding for the frustration of teachers and health workers. Their demands resonate with most of us, and I think that it is scandalous of SACP fat cats to tell workers to “stop crying like babies,” he said.

He also added to the criticism of the much-maligned decision of the government to spend billions of taxpayers’ money to purchase weapons when there was “no discernible military threat” to the country. He said the greatest threat to the security of the country was poverty, inequality and social cohesion.

“As for the argument that arms sales bring in foreign exchange – how can we be instrumental in killing the poor elsewhere with the intention of feeding our poor, and then our ill-gained profits feed only the already well-fed?” he asked.
“Can we see the hopeless contradiction, the total impossibility of being both the apostle of peace and a merchant of death?”

He also lambasted the Black Economic Empowerment (BEE) policy of the government which he said benefited only those connected to the political aristocracy.

“It couples with the unashamed, in-your-face display of wealth by the privileged elite in this country, the crass materialism of the so-called “bling generation”, and the casual carelessness with which promises to the poor are given and treated. It is only the public symptom of the deep-seated scorn our political elites feel for the poor,” he said.

He said the government’s disdain to the poor was “setting fire to our future”.

“The anger of people on the ground can no longer be denied or ignored, and little by little, the leadership articulating and directing this anger is being estranged from politically elected leadership, and even more disturbing, from our democratic processes,” he said.

He concluded that the country’s difficulty in dealing with race and racism was putting the reconciliation process kick-started by Mandela just over a decade ago, under a threat.
 

 

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