Weather. The endless, bright sunshine of Africa. This is one of the continent’s most untapped resources as the harvesting and storage of solar energy remains complex and costly. There is a need to develop solutions that can work on a grand scale, that can harness solar energy and store it cheaply, and that can provide electricity to those who still live without power across the country’s rural areas.
The ability to use solar energy more effectively would not only make significant strides in mitigating the global energy crisis, but would also reduce the effects of existing energy sources on the environment. For one researcher, it has become a life mission to find a way of capturing the numerous light bands of the sun’s energy to create a solar device that can power the world.
“Growing up, we had huge electricity pylons moving through our village but no power,” says Professor Mmantsae Moche Diale, an associate professor in the department of physics at the University of Pretoria. “I knew that when I grew up, I was going to address energy-related issues. I wanted to find ways of supplying energy that was cheap and clean to everyone.”
Today Diale’s work focuses on the collection and storage of solar energy so as to reduce the effects of carbon dioxide in the atmosphere and address issues of climate change. She is driven by the need to take energy from the sun, to remove the country’s reliance on the grid and to find a better way of storing the energy collected during the day.
“The solar fuel I’m interested in is hydrogen from water splitting – so that photovoltaics and artificial photosynthesis devices can then be used to ensure the continuous supply of power,” says Diale. “This technology is novel in that it uses cheap, abundant and easy-to-synthesise, naturally occurring iron oxide.”
Over the past few years, Diale has made impressive progress in her research from materials development to device fabrication for photovoltaic and photoelectrochemical devices. The work has followed a pathway of rigorous testing, development and collaboration to find a solution that would allow for the production of clean, low-cost power.
She wants to find a way of creating a solar cell that can harness all of the sun’s electromagnetic radiation. If she succeeds, it could change the way the world perceives power. “My aim is to come up with solar cells that can get most of the energy from the sun and hand it to the people,” she says.
“Scientifically, we can harness a small portion of the electromagnetic radiation from the sun as each of the materials we use has a band gap that can tap into a particular part of light. Most solar panels are made from silicon, so this only takes a portion of the solar light. In my work I want a device that can get multiple materials together, creating a tandem structure to capture even more of this solar energy.”
Diale was recently awarded a South African Research Chair Initiative (SARChI) chair in Clean and Green Energy by the National Research Foundation, funded by the department of science and technology. The aim of SARChI is to address issues that have been included in the National Development Plan as priority areas for our economy to be sustainable and poverty to be reduced.