MONDAY 06 SEPTEMBER, 2010 |
MIT's Self Repairing Solar Cells
Self assembling and self-repairing solar cells - there's something very
Terminator about it.
While solar panels are very long lasting and most manufacturers now provide a 25
year power output warranty, the cells do degrade over time due to constant
bombardment by the sun. A traditional solar
may function for decades, but with each passing year its efficiency in
converting sunlight to electricity slightly lessens.
Conventional silicon-based photovoltaic cells suffer little degradation, but
significant degradation can be experienced by thin film based solar
Plants are exposed to the same sort of harsh conditions, but being living
creatures; they are able to repair any damage done. Plants continually
deconstruct their damaged light capturing molecules and rebuild them.
Massachusetts Institute of Technology
scientists have succeeded in replicating a key aspect of that process, a first
step towards the creation of self-repairing and self-assembling solar cells.
Charles and Hilda Roddey Associate Professor of Chemical Engineering Michael
Strano and his team have produced synthetic molecules called phospholipids that form
discs and provide structural support for other light-responsive molecules in structures called reaction
centers, which release electrons when struck by particles of light.
The discs are in a solution where they attach themselves spontaneously to carbon nanotubes
- hollow tubes of carbon atoms capable of conducting electricity a thousand times better than copper. The nanotubes act as wires to collect and
route the flow of electrons knocked loose by the reactive molecules.
When a surfactant is added to the mix, the components disintegrate and form a soupy solution.
When the surfactant is removed by forcing the solution through a membrane, the compounds spontaneously
reformed into a rejuvenated photocell, with no loss of efficiency.
The efficiency of these molecular structures in converting sunlight is an
impressive 40 percent and could theoretically be brought to close to 100
percent. However, the concentration of the structures in the solution is low and
the team are now working towards finding ways to greatly increase the concentration.
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