MIT creates solar cell from grass clippings

A researcher at MIT, Andreas Mershin, has created solar panels from agricultural waste such as cut grass and dead leaves. In a few years, Mershin says it’ll be possible to stir some grass clippings into a bag of cheap chemicals, paint the mixture on your roof, and immediately start producing electricity.

If you remember high school biology classes, you will hopefully remember a process called photosynthesis, whereby plants turn sunlight into energy. Mershin has found a process which extracts the photosynthesizing molecules, called photosystem I, from plant matter. Photosystem I contains chlorophyll, the protein that actually converts photons into a flow of electrons.

These molecules are then stabilized and spread on a glass substrate that’s covered in a forest of zinc oxide nanowires and titanium dioxide “sponges.” When sunlight hits the panels, both the titanium dioxide and the new material absorb light and turn it into electricity, and the nanowires carry the electricity away. In essence, Mershin has replaced the layer of silicon in conventional photovoltaic cells with a slurry of photosynthesizing molecules. “It’s like an electric nanoforest,” he says.

So far so good — now time for the reality check. At the moment, even with the efficiency-boosting nanoforest, Mershin’s solar panel only has an efficiency of 0.1%. To be of any use — to power more than a single LED light from an entire house covered in these cheap solar panels — an efficiency of 1 or 2% is required. With such a low barrier to entry, though, Mershin hopes that scientists the world over can now work on boosting the efficiency.

Ultimately the goal is to create a cheap plastic bag that comes pre-filled with the necessary chemicals, and “one sheet of cartoon instructions, with no words.” The idea is that you’ll add agricultural waste to the bag, stir it around, and then just slosh it onto a sheet of glass. Suffice it to say, such an invention would revolutionize power generation in low-density areas that are off the grid and developing nations.