Self-renewing solar cells grow like plants

Scientists at MIT mimic plant processes to build solar cells that renew themselves like living beings.

Living things don't have that many advantages over machines. We're not as quick, or as precise, and we don't have as good a memory. Moreover, while they are made of tough stuff, we are mostly composed of things that go squish. One of the limited advantages we have is that when we go squish, we have built-in repair shops. When they go crunch, they're crunched.

Self-renewal has been a goal of many different technology manufacturers, but especially the makers of solar cells. For years scientists have looked resentfully at their solar cells, the components of which wear out or break, and envied plants, which have a built-in systems that take apart and renew any worn-out bits.

MIT researchers have found a way to imitate this process:

The complexes are made up of light-harvesting proteins, single-walled nanotubes and disc-shaped lipids. The proteins (which are isolated from a purple bacterium, Rhodobacter sphaeroides) contain a light reaction centre (carried by the lipids) comprising bacteriochlorophylls and other molecules. . . . The nanotubes also serve to align the lipid discs in neat rows, ensuring that the reaction centres are uniformly exposed to sunlight.

Or at least that's what they do when there isn't a surfactant present. Surfactants are chemicals which lower the surface tension of liquids. The most commonly used surfactants are in soaps and laundry detergents. By lowering the surface tension of liquids, they let water leak into and break apart grease and debris, as well as breaking up the debris itself. That's how soap cleans your hands - by using a surfactant to break things down.

The surfactant does the same in these solar cells. It breaks down the structures into pieces and stops the cell from working. When the surfactant is removed, the pieces reassemble on their own, like new. This process can be repeated without end. The result is a three hundred percent increase in efficiency and a limitless lifespan.

Via Physics World and Nature Chemistry.