|Grass clippings could be turned into solar cells using inexpensive chemicals and materials, according to new research.|
"That's the dream," Andreas Mershin, a researcher at the Massachusetts Institute of Technology and co-author of a paper describing the process, told me.
The powder in the bag is an inexpensive chemical cocktail that stabilizes the molecules in green plants that carry out photosynthesis known as photosystem-I so that they can be used to generate electricity.
Instructions on how to build the rest of the so-called biophotovoltaic would be printed on a cartoon included with the baggie.
One step is to extract and concentrate photosystem-I from yard waste, for example, with a membrane such as cheesecloth and spinach. "It is not that hard," Mershin promised. "The green stuff is easy."
In addition, these do-it-yourselfers will need to roughen up a piece of glass or metal, which increases the surface area, to stick the stabilized green goo onto.
Wires connected to this plate would deliver the trickle of electricity to a battery, cell phone or a light.
Mershin and his colleagues explain their process for building one of these biophotovoltaics in the open access journal Scientific Reports.
The research improves on previous work by Mershin's MIT colleague Shuguang Zhang, who coated photosystem-I on a flat glass surface.
This produced an electric current, but such a small amount that it was practically useless. In addition, the stabilizing chemicals used were expensive and assembling it all involved expensive lab equipment.
Mershin looked to nature for inspiration and found a potentially better design in forests of pine trees that allow "for more light to be absorbed," he said.
He mimicked this forest effect with zinc oxide nanowires and a sponge-like titanium-dioxide nanostructure.
When this chip is coated with the light-harvesting material extracted from plants, it creates a solar cell with 0.1 percent efficiency.
"At 0.1 percent, you can only do this as a proof-of-principle," Mershin said. "Nobody is going to be doing this in real life until we get to about 1 or 2 percent efficiency and about 12 months of lifetime."
The hope is that researchers around the world will replicate the results — which can be done with inexpensive materials and equipment — and improve on the design to reach that milestone.
If so, this technology could be a way to bring electricity to the 1.2 billion people in the world who live without it today.
Ideally, he said, not even the plastic baggie with the powder will be required. "We'll just send out fliers that have the information."