Published on July 5th, 2012 | by James Ayre4
Next-Gen Solar Cells Receive Efficiency Boost from Graphene
July 5th, 2012 by James Ayre
Graphene, a greatly promising new nanomaterial, 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. It’s a much-hyped material because of its unique and radical properties, potentially allowing for great innovation and improvements in efficiency across a wide variety of fields. CleanTechnica has posted numerous stories on graphene in recent years.
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 allows them to act as bridges, accelerating electron transfer from the titanium dioxide to the photoelectrode,” said Yun Hang Hu, a professor of materials science and engineering.
The researchers also created a “comparably foolproof method for creating sheets of titanium dioxide embedded with graphene. It first made graphite oxide powder, then mixed it with titanium dioxide to form a paste, spread it on a substrate (such as glass) and then baked it a high temperatures.”
“It’s low-cost and very easy to prepare,” said Hu. But not just any recipe will do. “If you use too much graphene, it will absorb the light in the solar cell and reduce its efficiency,” he said.
The researchers presented a talk on their work, “Graphene for Solar Cells,” at the US-Egypt Joint Workshop on Solar Energy Systems, held March 12-14 in Cairo. It was funded by the American Chemical Society Petroleum Research Fund and the National Science Foundation.
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