Imagine using the solar energy captured by your lawn clippings to charge a mobile phone. That’s the aim of research currently being carried out at the Massachusetts Institute of Technology (MIT).
Researcher Dr. Andreas Mershin says that by extracting the light-absorbing proteins (green stuff) in raw agricultural waste, mixing it with a stabiliser and spreading the resulting paste onto a flat substrate such as glass or metal, people all over the world may soon be able to make their own solar panels.
Mimicking photosynthesis in plants for solar power is not new to MIT. Mershin’s work expands on a project begun eight years ago by Shuguang Zhang and Michael Graetzel. The pair found that by isolating and stabilising a complex of molecules known as photosystem-I (PS-I) – the tiny structures within plant cells that carry out photosynthesis – and layering it on a glass plate, they could produce electricity when exposing it to light.
While Zhang’s system was inefficient and required expensive equipment, Dr. Mershin says his system is 10,000 times more efficient than previous efforts.
Dr. Mershin, a research scientist from MIT’s Center for Bits and Atoms, spent several years working on creating a tiny forest of zinc oxide nanowires and sponge-like titanium dioxide nanostructures coated with light-collecting materials from bacteria to increase the surface area of a tiny solar cell.
He states the process has now been simplified to a point it could be carried out at colleges or even in high school science labs, allowing researchers around the world to start exploring the process and making further improvements.
With further development, efficiency of the system should reach 1-2 percent, a decent level for this type of solar cell; especially given the materials used are so cheap and readily available. The PS-I molecules can be extracted from green waste using a filtration system developed by Mershin’s team. The only ingredient needing to be purchased would be the safe and inexpensive compounds to stabilise the molecules, which could be packaged in a plastic bag.
"You can use anything green, even grass clippings,” Mershin says.
Dr. Mershin’s work appears in the journal Scientific Reports.
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