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Study on solar energy compares well with current state-of-the-art research in the field

01 March 2024 | Story Leonie Bolleurs | Photo SUPPLIED

“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

Media: ANC can learn a lesson from Moshoeshoe

2006-05-20

27/05/2006 20:32 - (SA)
ANC can learn a lesson from Moshoeshoe
ON 2004, the University of the Free State turned 100 years old. As part of its centenary celebrations, the idea of the Moshoeshoe Memorial Lecture was mooted as part of another idea: to promote the study of the meaning of Moshoeshoe.

This lecture comes at a critical point in South Africa's still-new democracy. There are indications that the value of public engagement that Moshoeshoe prized highly through his lipitso [community gatherings], and now also a prized feature in our democracy, may be under serious threat. It is for this reason that I would like to dedicate this lecture to all those in our country and elsewhere who daily or weekly, or however frequently, have had the courage to express their considered opinions on pressing matters facing our society. They may be columnists, editors, commentators, artists of all kinds, academics and writers of letters to the editor, non-violent protesters with their placards and cartoonists who put a mirror in front of our eyes.

There is a remarkable story of how Moshoeshoe dealt with Mzilikazi, the aggressor who attacked Thaba Bosiu and failed. So when Mzilikazi retreated from Thaba Bosiu with a bruised ego after failing to take over the mountain, Moshoeshoe, in an unexpected turn of events, sent him cattle to return home bruised but grateful for the generosity of a victorious target of his aggression. At least he would not starve along the way. It was a devastating act of magnanimity which signalled a phenomenal role change.

"If only you had asked," Moshoeshoe seemed to be saying, "I could have given you some cattle. Have them anyway."

It was impossible for Mzilikazi not to have felt ashamed. At the same time, he could still present himself to his people as one who was so feared that even in defeat he was given cattle. At any rate, he never returned.

I look at our situation in South Africa and find that the wisdom of Moshoeshoe's method produced one of the defining moments that led to South Africa's momentous transition to democracy. Part of Nelson Mandela's legacy is precisely this: what I have called counter-intuitive leadership and the immense possibilities it offers for re-imagining whole societies.

A number of events in the past 12 months have made me wonder whether we are faced with a new situation that may have arisen. An increasing number of highly intelligent, sensitive and highly committed South Africans across the class, racial and cultural spectrum confess to feeling uncertain and vulnerable as never before since 1994. When indomitable optimists confess to having a sense of things unhinging, the misery of anxiety spreads. It must have something to do with an accumulation of events that convey the sense of impending implosion. It is the sense that events are spiralling out of control and no one among the leadership of the country seems to have a handle on things.

I should mention the one event that has dominated the national scene continuously for many months now. It is, of course, the trying events around the recent trial and acquittal of Jacob Zuma. The aftermath continues to dominate the news and public discourse. What, really, have we learnt or are learning from it all? It is probably too early to tell. Yet the drama seems far from over, promising to keep us all without relief, and in a state of anguish. It seems poised to reveal more faultlines in our national life than answers and solutions.

We need a mechanism that will affirm the different positions of the contestants validating their honesty in a way that will give the public confidence that real solutions are possible. It is this kind of openness, which never comes easily, that leads to breakthrough solutions, of the kind Moshoeshoe's wisdom symbolises.

Who will take this courageous step? What is clear is that a complex democracy like South Africa's cannot survive a single authority. Only multiple authorities within a constitutional framework have a real chance. I want to press this matter further.

Could it be that part of the problem is that we are unable to deal with the notion of "opposition". We are horrified that any of us could become "the opposition". In reality, it is time we began to anticipate the arrival of a moment when there was no longer a single [overwhelmingly] dominant political force as is currently the case. Such is the course of change. The measure of the maturity of the current political environment will be in how it can create conditions that anticipate that moment rather than ones that seek to prevent it. This is the formidable challenge of a popular post-apartheid political movement.

Can it conceptually anticipate a future when it is no longer overwhelmingly in control, in the form in which it currently is and resist, counter-intuitively, the temptation to prevent such an eventuality? Successfully resisting such an option would enable its current vision and its ultimate legacy to our country to manifest itself in different articulations of itself, which then contend for social influence.

In this way, the vision never really dies, it simply evolves into higher, more complex forms of itself. If the resulting versions are what is called "the opposition" that should not be such a bad thing - unless we want to invent another name for it. The image of flying ants going off to start other similar settlements is not so inappropriate.

I do not wish to suggest that the nuptial flights of the alliance partners are about to occur: only that it is a mark of leadership foresight to anticipate them conceptually. Any political movement that has visions of itself as a perpetual entity should look at the compelling evidence of history. Few have survived those defining moments when they should have been more elastic, and that because they were not, did not live to see the next day.

I believe we may have reached a moment not fundamentally different from the sobering, yet uplifting and vision-making, nation-building realities that led to Kempton Park in the early 1990s. The difference between then and now is that the black majority is not facing white compatriots across the negotiating table. Rather, it is facing itself: perhaps really for the first time since 1994. It is not a time for repeating old platitudes. Could we apply to ourselves the same degree of inventiveness and rigorous negotiation we displayed up to the adoption or our Constitution?

Morena Moshoeshoe faced similarly formative challenges. He seems to have been a great listener. No problem was too insignificant that it could not be addressed. He seems to have networked actively across the spectrum of society. He seems to have kept a close eye on the world beyond Lesotho, forming strong friendships and alliances, weighing his options constantly. He seems to have had patience and forbearance. He had tons of data before him before he could propose the unexpected. He tells us across the years that moments of renewal demand no less.

This is an editied version of the inaugural Moshoeshoe Memorial Lecture presented by Univeristy of Cape Town vice-chancellor Professor Ndebele at the University of the Free State on Thursday. Perspectives on Leadership Challenges In South Africa

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