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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

UFS withdraws interdict against SASCO and ANCYL
2003-11-25

The Rector and Vice-Chancellor of the University of the Free State, Prof Frederick Fourie, announced today that a court order against the South African Students Congress (SASCO) and the ANC Youth League (ANCYL) had been withdrawn.

The withdrawal of the court order follows after a written statement by SASCO and the ANCYL in which they “unconditionally withdraw or retract statements threatening to render the institution ungovernable” and give their “commitment not to proceed with our threats to establish our own democratic SRC and occupy the current SRC offices”.

The UFS management obtained the court order in October after SASCO and the ANCYL refused to accept the outcome of the recent student referendum and SRC elections and threatened to disrupt the campus.

Prof Fourie also welcomed the undertaking by SASCO and the ANCYL to act in accordance with the prescribed procedures to resolve any grievance that the organisations may have, saying the UFS management remains committed to a constructive dialogue with all student organisations to manage a campus of diversity, tolerance and non-racialism.

In September students voted in a referendum to test support for a system of proportional representation (PR) for the SRC. A vast majority of students voted against the PR system, a system favoured by SASCO and the ANCYL..

Following allegations of fraud in the referendum, the UFS management asked the auditing firm PriceWaterhouseCoopers to conduct an independent audit of the ballot papers.

The auditors found that a total of 180 ballot papers out of 3513 – only 5.12% - of the votes cast - appeared to have been altered by means of erasing and then changing the student number.

According to the auditors, with all potentially altered and suspicious ballot papers excluded, a huge majority of 60,8% of students voted against the proportional representation system.

A few days after the referendum, the actual SRC election was held. However, at no stage were there any complaints from any organization about the integrity of the SRC election itself.

Despite this and the findings of the auditors, SASCO and the ANCYL refused to accept the outcome.

Law student Quintin du Plessis was elected SRC president. He welcomed the stance taken by SASCO and the ANCYL to pursue their objectives through the existing structures and said the SRC was always willing to engage with these organisations on issues of student governance.

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