A new and effective way of harnessing solar power comes from the researchers at MIT. Once again trying to mimic the way green plants work, the scientists now have a different approach, pointing to the fact that, otherwise invisible, the effects of sunlight over solar cells are often damaging.
Plants, though, have a natural mechanism to defeat the damage and restore the efficiency of photosynthesis.
The researchers have created a synthetic, self-assembling chloroplast that can be broken down and reassembled repeatedly. What it actually the chloroplast does is mimicking the process that happens every 45 minutes in every leaf exposed to direct sunlight during those hot summer days.
The system that they tried to replicate uses seven compounds, including carbon nanotubes, providing the structure and acting as an electricity conductor, synthetic phospholipids, forming discs that also provide structural support, and other molecules that assemble into “reaction centers” – the ones that actually harvest the photons to produce electricity. In a natural chloroplast, the reaction centers transform the energy of photons into chemical energy.
Put under certain conditions, these seven compounds assemble themselves into uniformly-structured solar cells. When damaged, after about 45 minutes, a surfactant is released (something like those used in soaps) which breaks the compounds from each other into nanotubes, phospholipids and other constituent molecules. Then, the surfactant along with the “soup” of solar cell constituents is pushed through a filtering membrane. The surfactant is thus removed and the other particles reassemble into fully working, undamaged solar cells.
The scientists claim that their nature-mimicking solar cells have a 40 percent efficiency, and that they can tweak them to even more. Not being able to degrade over time, they are perfect candidates for future generations of organic solar cells, which suffer from the process of light damaging more than others. Also, the search for solar cells whose mechanisms closely resemble natural ones can be pursued with increased courage, knowing that they can’t be damaged without then restoring themselves virtually forever.
