For years, solar energy researchers have tried to imitate the success of photosynthesis by building devices like an artificial leaf and a solar cell that hijacks chemistry of photosynthetic bacteria. Now researchers at MIT have come up with an innovative technique that also happens to be very cheap: all you need is some “stabilizing powder” and plant waste. Mowed your lawn lately?
The stabilizing powder is a mix of safe, easily attainable chemicals that preserves photosystem I, a protein complex that captures light energy in plant cells. (In contrast, the newest photovoltaic cells in solar panels require metals that are rare or toxic.) The powder is mixed with plant matter such as grass clippings and crushed, and the resulting green goo is spread onto glass or metal substrate. Hook up wires to capture the electric current and that’s your solar panel.
The efficiency of these solar panels is only 0.1%, compared to the 15 to 18% efficiency of solar panels out in the market right now. Lead researcher Andrew Mershin says the technology still needs to improve 10-fold to become practical. After all, being able to power only one lightbulb with a whole house covered in solar panels isn’t much help. But the great advantage of all this is that it’s easy and
dirt grass cheap. Because the barrier to entry is so low, anyone would be able to order a bag of chemicals and make their own solar panel. Mershin hopes home tinkerers experiment with the cells and find new ways to make improvements.
Correction, February 6: We eliminated a reference to mulch in the headline: mulch is low in chlorophyll, so it wouldn’t actually work for these plant-powered solar cells.
What’s the News: In traditional solar cells, sunlight is absorbed by the cell (made from silicon or titanium dioxide), freeing electrons, which travel across the cell to an electron collector, or electrode. A problem with solar cells is that many electrons don’t find their way to the electrode; carbon nanotubes can be used as bridges between the loosened electrons and the electrode, but nanotubes tend to bunch up, decreasing the efficiency and causing short circuits. Researchers have now created genetically engineered viruses can be used to keep the nanotubes in place, increasing energy conversion by nearly one-third. “A little biology goes a long way,” research group leader Angela Belcher told MIT News, noting that the entire virus-nanotube bridging layer represents only 0.1% of the finished cell’s weight.