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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

State-of-the-art physics equipment and investment in students result in academic success
2017-09-26

Description: State-of-the-art physics equipment 1 Tags: State-of-the-art physics equipment 1 

At the recent nanotechnology facility tour at the UFS,
were, from the left, Dr Mthuthuzeli Zamxaka, SAASTA;
Prof Hendrik Swart, Sarchi Chair in the Department of Physics;
and Xolani Makhoba, Department of Science and Technology.
Photo: Leonie Bolleurs

Nanoscience, which is revealing new properties of very small arrangements of atoms, called nanoparticles, is opening a new world of possibilities. The Department of Physics at the University of the Free State is undertaking fundamental research with potential commercial applications. Its equipment and expertise is giving solid state physics research the edge in South Africa.

The UFS team of researchers and students are passionate about studying planets and atoms, all under one roof. Recently, the department, in collaboration with the South African Agency for Science and Technology Advancement (SAASTA), hosted a nanotechnology facility tour to give the public, learners and the media the opportunity to familiarise themselves with the science of nanotechnology, its origins, potential applications and risks.

Successes of the department
According to Prof Hendrik Swart, Senior Professor in the Department of Physics, the increase in resources since 2008 is playing a big role in the success rate of its research outputs. The Sarchi Chair awarded to Prof Swart in 2012 (bringing with it funding for equipment and bursaries) also contributed to the successes in the department.

The UFS Directorate Research Development also availed funding that was used for bursaries. These bursaries made it possible for the department to appoint 10 post-doctoral fellows, not one of them originally from South Africa.

The investment in people and equipment resulted in researchers and students publishing some 80 articles in 2016. Their work was also cited more than 900 times by other researchers in that year.

Another highlight in terms of the department’s growth in the past 10 years is the new wing of the Physics Building. Physics at the UFS is the only place in sub-Saharan Africa where state-of-the art equipment is found under one roof.

Description: State-of-the-art physics equipment 2  Tags: State-of-the-art physics equipment 2  

Antonie Fourie, Junior Lecturer in the UFS Department of
Physics, explained to a group of delegates and
members of the media the workings of an electron beam
evaporation system.
Photo: Leonie Bolleurs

Application of research
The department is a unique research facility with equipment that includes the X-ray Photoelectron Spectrometer (for the study of atoms), the Scanning Auger Microscope, as well as the Ion Time-of-Flight Secondary Ion Mass Spectrometer (revealing the chemical bonds in a sample, and drawing maps of the positions of atoms).

One of the areas on which the department is focusing its research, is phosphors. Researchers are exploring light emitting diodes (LEDs) which use less energy, are brighter and provide a wider viewing field. They are also looking into LED displays (LCDs) which are used in flat screens – the phosphors create the different colours and backlighting.

The research on solar cells reveals that phosphors can increase their efficiency by increasing the range of light frequencies which can be converted into electricity. Glow-in-the-dark coatings absorb light in the day and emit it later so cells can charge at night. As glow-in-the-dark phosphors become cheaper and more effective, they can be used as a lighting substitute on the walls of houses, street numbers and stop signs.

Video production of the Department of Physics research and equipment

 

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