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01 March 2024 | Story Leonie Bolleurs | Photo SUPPLIED
Dr Lucas Erasmus
Dr Lucas Erasmus, Junior Researcher in the Department of Physics, has just returned from Belgium where he had his public defence of a joint PhD with Ghent University, titled: Luminescent solar concentrators – where Sm2+ doped phosphors shine.

“I like taking what I have learned from literature and going to the laboratory to test it. Sometimes the results surprise me, leading to additional experiments or refining. This process could continue for several months and even years, with me slowly building the puzzle. And finally, one day, all the pieces come together, and everything becomes very clear to me as a physicist. And if I am lucky, I will have the privilege of knowing a secret about nature that nobody else has known up to this point. However, as an innovator, I am tasked with using this new knowledge to develop ways to manipulate nature to deliver a helpful device.”

These are the thoughts of Dr Lucas Erasmus, Junior Researcher in the Department of Physics at the University of the Free State (UFS), who has just returned from Ghent, Belgium, where he had his public defence of a joint PhD with Ghent University, titled: Luminescent solar concentrators – where Sm2+ doped phosphors shine.

The research project is part of a bilateral collaboration between the Department of Physics at the UFS and the Department of Solid State Sciences at Ghent University. In this study, the strengths, experience, and resources of both research groups – experienced in developing luminescent materials for various applications – are used to ensure a stronger final product. To meet the requirements stipulated in the cooperation agreement between the two institutions for the joint supervision and certification of Dr Erasmus’ doctoral studies, research was conducted both at the UFS and at Ghent University.

Dr Erasmus’ research is significant in the light of rising energy prices, energy scarcity, and the pursuit of a carbon-free society, where there are strong incentives to develop new and renewable energy sources.

Combining windows and solar cells increase their relevancy in many applications

He says that although solar panels play an essential role in renewable energy – since they provide a route to directly convert solar radiation into electricity – there are limitations to installing conventional panels, which are bulky, rigid, and opaque. He believes that combining windows and solar cells could increase their relevance in the built environment, agricultural sector, and modern consumer electronics.

Explaining about the luminescent solar concentrator (LSC) in his study, he states that it is a device used as a large-area solar radiation collector that converts and emits radiation. The emitted radiation is directed to photovoltaic cells located in the small side area of the device. According to him, a basic LSC consists of a transparent waveguide with an embedded luminescent material and a strategically placed photovoltaic cell on the edge.

Dr Erasmus continues, “The large area of the waveguide collects a portion of the solar radiation, while the luminescent material absorbs the energy and downshifts it to longer wavelengths. Internal reflection directs the emitted photons towards smaller areas on the sides where the photovoltaic cells are used to convert the concentrated light into electricity.”

In his view, creating a large and efficient LSC is a challenging endeavour that requires an in-depth study of multiple domains. “This includes developing and optimising the luminescent material, studying its behaviour and the characteristics of the waveguide, and finally adding these two components and developing, characterising, and simulating the hybrid device,” he remarks.

“While the current prototype we have developed delivers good results, it is still far from perfect and not commercially viable,” he says, stating that this study could, however, serve as a guide for future researchers interested in developing LCSs. Dr Erasmus believes the underlying science behind the results contributes to a general understanding of the materials, making this study valuable to other fields and contributing to the larger body of science. At the end of the study, he also makes some recommendations for future research in this field. 

Study a reflection of theoretical knowledge and a practical system

The public defence consisted of both an internal and an external defence. The internal defence took place in January at the UFS between Dr Erasmus and the examination committee. The external defence occurred at Ghent University and was also open to the broader public. Also present at this event in Belgium were colleagues from the UFS – Prof David Motaung, an examiner; Prof Koos Terblans, co-supervisor; and Prof Hendrik Swart, supervisor for the PhD thesis.

Dr Erasmus’ experience of the oral examination was that the examiners were primarily positive in their critique but also thorough in their questioning. According to him, some of their remarks pointed out that they were impressed with the meticulous planning, execution, and interpretation of the experimental results and that the researchers involved ensured that any parameter that might have influenced the device was maximised. “Moreover, they liked the fact that I went all the way from theoretical knowledge to a practical system. The examiners also noted that the study compares well with the current state-of-the-art research in the field,” adds Dr Erasmus.

He says that having the public defence in Belgium was a once-in-a-lifetime experience, allowing him to interact and deliberate directly with the examiners and communicate their findings and conclusions to the broader public. Dr Erasmus hopes that this will lead to stronger collaboration and better public sentiment toward spending funding for scientific projects.

For future steps, he states, the research group involved in the project plans to continue this research by further increasing the device's efficiency. “To this end, we have already developed another luminescent material that can address some of the challenges we encountered while developing the first prototype device. This forms part of the work that Johané Odendaal is doing in her master’s degree, of which I am a co-supervisor. We also plan to enlarge the scope of our research to consider the challenges that are currently hampering the next generation of photovoltaic cells and to find ways in which we could address these issues,” comments Dr Erasmus.

News Archive

Fracking in the Karoo has advantages and disadvantages
2012-05-25

 

Dr Danie Vermeulen
Photo: Leatitia Pienaar
25 May 2012

Fracking for shale gas in the Karoo was laid bare during a public lecture by Dr Danie Vermeulen, Director of the Institute for Groundwater Studies (IGS). He shared facts, figures and research with his audience. No “yes” or “no” vote was cast. The audience was left to decide for itself.

The exploitation of shale gas in the pristine Karoo has probably been one of the most debated issues in South Africa since 2011.
 
Dr Vermeulen’s lecture, “The shale gas story in the Karoo: both sides of the coin”, was the first in a series presented by the Faculty of Natural and Agricultural Science under the theme “Sustainability”. Dr Vermeulen is a trained geo-hydrologist and geologist. He has been involved in fracking in South Africa since the debate started. He went on a study tour to the USA in 2011 to learn more about fracking and he visited the USA to further his investigation in May 2012.
 
Some of the information he shared, includes:

- It is estimated that South Africa has the fifth-largest shale-gas reserves in the world, following on China, the USA, Argentina and Mexico.
- Flow-back water is stored in sealed tanks and not in flow-back dams.
- Fracturing will not contaminate the water in an area, as the drilling of the wells will go far deeper than the groundwater aquifers. Every well has four steel casings – one within the other – with the gaps between them sealed with cement.
- More than a million hydraulic fracturing simulations took place in the USA without compromising fresh groundwater. The surface activities can cause problems because that is where man-made and managerial operations could cause pollution.
- Water use for shale-gas exploration is lower than for other kinds of energy, but the fact that the Karoo is an arid region makes the use of groundwater a sensitive issue. Dr Vermeulen highlighted this aspect as his major concern regarding shale-gas exploration.
- The cost to develop is a quarter of the cost for an oil well in the Gulf of Mexico.
- Dolerite intrusions in the Karoo are an unresearched concern. Dolerite is unique to the South African situation. Dolerite intrusion temperatures exceed 900 °C.

He also addressed the shale-gas footprint, well decommissioning and site reclamation, radio activity in the shale and the low possibility of seismic events.
 
Dr Vermeulen said South Africa is a net importer of energy. About 90% of its power supply is coal-based. For continued economic growth, South Africa needs a stable energy supply. It is also forecast that energy demand in South Africa is growing faster than the average global demand.
 
Unknowns to be addressed in research and exploration are the gas reserves and gas needs of South Africa. Do we have enough water? What will be the visual and social impact? Who must do the exploration?
 
“Only exploration will give us these answers,” Dr Vermeulen said.

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