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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 research could light up South African homes
2016-01-21

Reitumetse Maloa, postgraduate student and researcher at the UFS Department of Microbial, Biochemical and Food Biotechnology, is using her research to provide solutions to the energy crises in South Africa.

A young researcher at the university is searching for the solution to South Africa’s energy and electricity problems from a rather unlikely source: cow dung.

“Cow dung could help us power South Africa,” explains Reitumetse Maloa, postgraduate student and researcher at the UFS Department of Microbial, Biochemical and Food Biotechnology.

Reitumetse’s research is trying to understand how the bacteria works that is responsible for producing biogas.

“Biogas can be used for cooking, heating, lighting and powering generators and turbines to make electricity. The remaining liquid effluent can fertilise crops, as it is high in nitrogen, phosphorus and potassium.”

By using cow dung and food waste to produce biogas, we will be able to lower greenhouse gases.

Biogas is produced in a digester - an oxygen-free space in which bacteria break down or digest organic material fed into the system. This process naturally produces biogas, which is mainly a mixture of methane and carbon dioxide.

“Many countries, such as Germany and the United States, have begun generating electricity from cow dung and food waste, through a process known as biogas production. In South Africa, a number of industries, including waste-water treatment facilities and farms, have caught on to this technology, using it to generate heat and to power machines.”

Until recently the world has relied heavily on electricity derived from fossil fuels such as coal, natural gas and oil. Once these fuels have been extracted from underground reservoirs, they are treated or cleaned, transported to power plants and transformed into the electricity that will reach your house. Fossil fuels are considered a ‘dirty’ energy source which gives off greenhouse gases when burned. Those gases are the major contributing factor to climate change.

“We know very little about the interaction of the bacteria inside the biogas digester. To use biogas as a sustainable fuel source, we need to understand and describe the bacteria population and growth dynamics inside the digester to produce biogas optimally. Currently we are testing a variety of feedstock, including bran, maize and molasses, for biogas production potential, as well as optimising the conditions leading to maximum biogas production. We are also exploring the potential to use the effluent as fertiliser on local farms. The ultimate goal is to have biogas systems that will supply our university with clean energy.”


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