Tobacco plants used to grow solar cells
Researchers at UC Berkeley have hacked tobacco plants to grow synthetic photovoltaic cells which can then be extracted and sprayed onto any substrate to create solar cells.
How? The scientists tweaked a few genes within the tobacco mosaic virus to build tiny structures called chromophores. Once the plant is sprayed with the virus, the new chromophores will group into tightly coiled formations. Chromophores are structures that turn light into high powered electrons.
Each formation is hundreds of nanometers long and about three nanometers away from its neighbor. That spacing is very important. Just one atom closer would impede any electrical current. Harvesting the electrons would be nearly impossible.
“Over billions of years, evolution has established exactly the right distances between chromophore to allow them to collect and use light from the sun with unparalleled efficiency,” said Matt Francis. “We are trying to mimic these finely tuned systems using the tobacco mosaic virus.”
While they aren’t as efficient as silicon cells, they are a lot more eco-friendly. Along with being biodegradable, no environmentally toxic chemicals are required to make biologically derived solar cells. And probably most important, they’re very very cheap!
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Trapped inside the tobacco plant, scientists will have to harvest the plant, chop it up and extract the structures. Dissolved in a liquid solution, chromophores can then be sprayed over a substrate coated to hold them in place.
“It’s very difficult to recreate photosynthesis,” said Angela Belcher, a researcher at MIT who uses viruses to build batteries and other structures. “The precision of each structure is very important, and it’s very hard to pick up one molecule and put it where you want it to be.”
Growing biologically derived solar cells could definitely put farmers back to work. The harvested electrons could also generate chemical energy much like plants do. This could mean hydrocarbons that could power cars or aircraft.
Francis and his colleagues were also successful using this process with the E. coli bacteria.