Nanoscience for a better world

As South Africa grapples with increasing energy demands, local and international industry experts, academics and postgraduate students believe that nanoscience can be employed to address the effective and efficient use of solar power.


Nanoscience stakeholders are meeting at the 5th South African Nanoscience and Nanotechnology Summer School taking place in Stellenbosch from 25 to 29 November 2019. The annual summer schools are designed to equip master's and PhD students with the skills needed to conduct research in nanoscience and nanotechnology. They complement other human capital development initiatives in the field, and are one of several platforms for implementing the 2005 National Nanotechnology Strategy.


The summer school is run by the National Nanoscience Postgraduate Teaching and Training Platform, a collaborative initiative between the Department of Science and Innovation, the University of the Western Cape (UWC), the University of Johannesburg, the University of the Free State and Nelson Mandela University.


The Deputy Minister of Higher Education, Science and Technology, Buti Manamela, opened the School in Stellenbosch on Monday, 25 November 2019. He said the country's National Nanoscience Strategy had been very successful in terms of human capital development.


He cited a review of the 2006 Nanoscience and Nanotechnology 10-Year Research Plan, which showed that South Africa had produced 418 master's and 398 doctoral graduates over the 10-year period, surpassing the plan's targets of 400 master's and 50 PhD graduates.  Furthermore, almost 5 000 nanotechnology publications had been produced, far exceeding the target of 150, while 44 new patents were reported against a target of 10, and three companies had been started from the research conducted at various universities.


"Today, there is no doubt that significant research activity is taking place at the majority of universities across the country. While this research is largely fundamental in nature, the scope of areas of application identified in the National Nanotechnology Strategy is being well covered. These areas of application range across water, energy, health and pharmaceuticals, chemicals and bioprocessing, mining and minerals, and advanced materials and manufacturing," he said.


The Deputy Minister praised the organising committee for making commercialisation and innovation the theme of this year's summer school.


Given the potentially massive returns nanoscience and nanotechnology can bring to the development of this country and its people, the UWC's Deputy Vice-Chancellor: Academic, Prof. Vivienne Lawack, said she was proud to be involved.


"You have the science," she told the assembled delegates. "And now the question is, what do you do with it? How do we apply this research in innovative ways, and bring new technology into common use? I encourage all of you, as you deliberate, to think of the impact your work could have, and the vast benefits that we could reap from these interventions as a society."


The gathering agreed that while nanoscience might work at the scale of millionths of millimetres, its applications were significant and far reaching.


Prof. Ruud Schropp, Extraordinary Professor in Physics at UWC, said that rapid increase in energy consumption globally and the exponential growth of the world's population were resulting in a variety of challenges.


"We need to meet our increasing energy needs in a sustainable way, and for that we need solar power. And for effective and efficient solar power, we need to employ nanoscience," he said.


In his presentation on nanostructured thin films for multiband-gap silicon tandem and triple-stacked solar cells, Prof. Schropp noted that stabilising carbon dioxide emissions at a level that limits global warming to 2°C will require that at least 14 terawatts of renewable energy capacity would have to be installed by 2050.


"If we were going to replace that amount of fossil energy with nuclear energy, we would need to build a power plant every two days, and that would come with some serious safety concerns," he said.


"Other renewable power sources are promising, but don't scale as easily. It is clear that, among the various renewable energy options, only solar energy offers ample resources to cover this demand."


Given the large scale needed, the solar technologies developed should use earth-abundant and preferably non-toxic materials. Among the various options available, silicon solar cells are dominating the market.


Silicon is the second most abundant material in the Earth's upper crust, but the high purification needed and indirect optical absorption make it an expensive source material. Therefore, further price reduction has to come from the use of thin films, the implementation of nanostructures, and the use of tandem solar cells.


"What we can do is try to make the best possible solar devices – devices that are cheap and efficient, and whose production is scalable – which will convince people to adopt solar power for their energy needs," Prof. Schropp noted. "When it comes to solar panels, thin is beautiful: the light doesn't have to travel as far, or through as much material, and that means less wasted energy."


As a source of energy, solar power is in ample supply. To meet the world's projected energy demand in 2050 using solar cells, only 1,7% of global land area would be needed.


"Renewable energy supply from solar cells can help build a sustainable society," said Schropp, "And further research can build technologies that are highly efficient and inexpensive, so that solar electricity will be abundantly available to everyone."


The five-day summer school ends on Friday.


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