Thursday, July 5, 2012

Graphene bridges

Graphene may be able to substantially boost the efficiency of the next generation of solar panels, according to new research from Michigan Technological University.

Graphene is a two-dimensional, one-atom-thick honeycomb of carbon atoms. One of its most interesting properties is its electrical conductivity, which could make it an important part of the next generation of photovoltaic (PV) solar cells.

Dye-sensitized solar cells use common and relatively inexpensive materials, making them cheaper than solar cells based on silicon and thin-film technologies. But they do not work as well as silicon-based cells at converting light into electricity. In dye-sensitized solar cells, photons knock electrons from the dye into a thin layer of titanium dioxide, which relays them to the anode. The researchers found that adding graphene to the titanium dioxide increased its conductivity, bringing 52.4 percent more current into the circuit!

The excellent electrical conductivity of graphene sheets thus allows them to act as bridges. However, if one uses too much graphene, it will absorb the light in the solar cell and reduce its efficiency.

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