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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

UFS professor addresses genetically modified food in South Africa in inaugural lecture
2016-09-23

Description: Chris Viljoen inaugural lecture Tags: Chris Viljoen inaugural lecture

At the inaugural lecture were, from the left front,
Prof Lis Lange, Vice Rector: Academic;
Prof Chris Viljoen; Prof Gert van Zyl,
Dean: Faculty of Health Sciences; back: Prof Marius Coetzee,
Head of Department of Haematology and Cell Biology;
and Dr Lynette van der Merwe, Undergraduate
Programme Director.
Photo: Stephen Collett

The first genetically modified (GM) crops in South Africa were planted in 1998. Eighteen years later, the country is one of the largest producers of GM food in the world. Those in support of genetically modified crops say this process is the only way to feed a rapidly growing world population. But those who criticise GM food describe it as a threat to the environment and safety of the population. Who is right? According to Prof Chris Viljoen of the Department of Haematology and Cell Biology at the University of the Free State, neither position is well-founded.

GM crops play a vital role in food security

While GM crops have an important role to play in increasing food production, the technology is only part of the solution to providing sufficient food for a growing world population. The major genetically modified crops produced in the world include soybean, cotton, maize and canola. However, the authenticity of food labelling and the long-term safety of GM food are issues that consumers are concerned about.

Safety and labelling of GM food important in South Africa
In his inaugural lecture on the subject “Are you really going to eat that?” Prof Viljoen addressed the importance of the safety and labelling of GM food in the country. “In order for food to be sustainable, production needs to be economically and environmentally sustainable. On the other hand, food integrity, including food quality, authenticity and safety need to be ensured,” Prof Viljoen said. 

Labelling of food products for genetic modification was mandatory in South Africa, he went on to say. “It allows consumers the right of choice whether to eat genetically modified foods or not.” The Consumer Protection Act of 2008 requires food ingredients containing more than 5% of GM content to be labelled. 

GMO Testing Facility world leader in food diagnostic testing
In 1999, Prof Viljoen spearheaded research in developing a GM diagnostic testing platform, and in 2003, a commercial diagnostic platform for GM status certification, called the GMO Testing Facility, was founded. The facility is a licensed Eurofins GeneScan laboratory   a world leader in food diagnostic testing   and provides diagnostic detection and quantification of genetically modified organisms (GMOs) in grain and processed foods for the local and international market.

Molecular diagnostic technology the future of food integrity, authenticity and safety
With GM labelling now well-established in South Africa, the next challenge is to establish the use of molecular diagnostic technology to ensure that food integrity, including food authenticity and safety is maintained, said Prof Viljoen.

“To the question ‘Are you really going to eat that?’ the answer is ‘yes’, but let’s continue doing research to make sure that what we eat is safe and authentic.”

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