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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

Researcher uses NRF funding for studies to conserve plant and animal life
2017-04-18

Description: Butterfly Tags: Butterfly

It is difficult to survey all different types of
plants and animals and is therefore necessary to
choose one representative group. Butterflies are
relatively cheap and easy to sample. They are
known to be linked to specific habitats and to
respond to human pressures, such as farming.
Photo: Dr Falko Buschke


Earth is the only planet we know of that contains life. The variety of different plants and animals is remarkable: from the giant whales that swim our oceans, to the tiny mosses that grow on the shaded sides of rocks.  Many of these plants and animals are important to humans. For example, trees provide us with oxygen to breathe, bees pollinate our crops and owls control pests. More importantly though, we can tell a lot about society from the way it cares for nature. Humans are the custodians of the planet and the way we care for nature reflects the way we value life.

Dr Falko Buschke, Lecturer at the Centre for Environmental Management at the University of the Free State, is interested in understanding how the distribution of biodiversity [the variety of living things in nature] in time and space influences the way we should conserve and manage nature.

Earth is losing biodiversity faster than at any time in human history

The planet is losing biodiversity faster than at any time in human history. “There is an urgency to conserve plants and animals before they are lost forever. Nature is complex, so the way we study it should embrace this complexity. We should not rely on limited data on one type of species from one place and assume that it will also apply elsewhere. Instead, it is important that biodiversity research is comprehensive in the types of plants and animals while also considering that ecological and evolutionary processes vary through time and across geographic space,” he said.

To conduct his research, Dr Buschke uses a variety of research tools, including biological data surveyed directly from nature, spatial data from satellite remote sensing and geographic information systems databases, and data generated though custom-built computer simulations.

"There is an urgency to conserve
plants and animals before they
are lost forever."

Field work in the eastern Free State
Although parts of the eastern Free State are considered a global priority for biodiversity conservation, it is mainly privately owned commercial farmland. This means that it is important that plants and animals can survive despite living side by side with agricultural production.

“My project investigates whether the sandstone outcrops, known as inselbergs (island-mountains), are safe havens for plants and animals. Because it is difficult to survey all the different types of plants and animals, it is necessary to choose one representative group. That is where butterflies come in. Butterflies are relatively cheap and easy to sample. They are known to be linked to specific habitats and to respond to human pressures, such as farming,” he said. “Once this butterfly data is collected, it can be linked to satellite information on plant growth patterns. This will provide a clearer picture of whether plants and animals can persist side-by-side with commercial agriculture”.

Dr Buschke has just begun surveys that will carry on until the end of this year. “This 12-month project is funded under the Foundational Biodiversity Information Programme through the South African National Biodiversity Institute (SANBI) and the National Research Foundation (NRF).

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