New plant-mimicking photovoltaic cells that self-repair sun damage

September 6th, 2010 - 1:34 pm ICT by ANI  

London, Sept 6 (ANI): MIT scientists have developed new self-assembling photovoltaic technology that can not only mimic a plant’s ability to convert sunlight into energy but also repair itself from damage that occurs due to constant sunlight.

Sunlight leads to a gradual degradation of many systems developed to harness it.

However, plants have a way of breaking break down their light-capturing molecules and reassemble them from scratch, which keeps their sun-harnessing structures intact.

Michael Strano and his team have created a novel set of self-assembling molecules that can turn sunlight into electricity, but can also reassemble themselves just by addition or removal of an additional solution, reports Nature.

As Strano described it, the oxygen “unsnaps a tether that keeps the protein together,” but the same proteins are quickly reassembled to restart the process.

To mimic the process of reassembly and repair, Strano and his team produced synthetic molecules called phospholipids that form discs; these discs provide structural support for other molecules that actually respond to light, in structures called reaction centers, which release electrons when struck by particles of light.

The discs attach themselves spontaneously to carbon nanotubes - wire-like hollow tubes of carbon atoms that are stronger than steel and capable of conducting electricity a thousand times better than copper.

Under the right conditions spontaneously assemble themselves into a light-harvesting structure that produces an electric current. When a surfactant is added to the mix, the seven components all come apart and form a soupy solution.

Then, when the researchers removed the surfactant by pushing the solution through a membrane, the compounds spontaneously assembled once again into a perfectly formed, rejuvenated photocell.

They ran the cell through repeated cycles of assembly and disassembly over a 14-hour period, with no loss of efficiency.

These new molecular structures are about 40 percent efficient in converting sunlight, or about double the efficiency of today’s best commercial solar cells. The efficiency can be increased to about 100 percent by increasing the concentration of the structures in the solution.

Their paper on the work was published in Nature Chemistry. (ANI)

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