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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

More grey areas than just black and white in history?
2017-12-15


Description: Abraham Mlombo readmore Tags: Historic, historian, International Studies Group, ISG  

Dr Abraham Mlombo: As a historian, he draws energy
from the people surrounding him.
Photo: Charl Devenish


 

Very few people understand that their actions and views within a territory stem from their roots or history. To enlighten the reading man on the composition of his base and the intricacies of the powers that are at play, is the work of historians.

Dr Abraham Mlombo is one of these historians, stationed within the International Studies Group at the University of the Free State (UFS).

This research group consists of postgraduate researchers, postdoctoral fellows, and academic staff that focus on African history, although they depart from more traditional study methods  a more global perspective. To date, Dr Mlombo's research examined the historical relations between South Africa and Southern Rhodesia. It was a broad study of the political, economic, social, and cultural relations from 1923 to 1953. He plans to continue by truly exploring the connections between South Africa and the region, and how they shaped one another. Dr Mlombo's interests in cross-border history and politics were inspired by his master’s degree in Political Science at Stellenbosch University. He researched his PhD at the UFS.

He draws energy for his work from the people surrounding him, and likes to be part of new experiences with people from different backgrounds. He feels such environments shape the way one works, as well as one’s world view. Dr Mlombo hints that sometimes, and specifically in South Africa, people focus very narrowly on their history and forget that many international links are at play. He sees his work as a historian to help open people's horizons.

Dr Mlombo suggests that future research should include a more critical analysis of how things unfolded during the second half of the 20th century. Writings should include more social- and people-oriented history, because he thinks there are more grey areas than just black and white. Many more interrogations must also follow into the assumptions of historical events and the individuals who played the greatest roles in Southern Africa.

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