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3D Graphene Could Replace Platinum In Solar Cells

Paul Nastu

Honeycomb grapheneA Michigan scientist and his team have developed an inexpensive three-dimensional graphene honeycomb that they say can replace the very expensive platinum used in solar cells.

Dye-sensitized solar cells are thin and flexible and easy to make, says Michigan Tech News, but a critical component that goes into making them is platinum. The cells require very little platinum, but even for miniscule amounts, the metal is prohibitively expensive at $1,500 per ounce. Michigan Technological University’s Yun Hang Hu, a material science and engineering professor, and his team have developed a 3D version of graphene that is shaped like a honeycomb.

They did this by pairing lithium oxide with carbon monoxide to create lithium carbonate which helps to shape and separate the graphene sheets so they don’t stick together and become standard 2D graphene. Michigan Tech News reports that the researchers found that the new version of graphene has good conductivity and catalytic activity, which led to their exploring it for energy storage.

When they replaced the platinum in solar cells with the 3D graphene, they discovered it had a conversion rate of 7.8 percent, which is very close to the 8 percent rate of a typical dye-sensitized solar cell with platinum in it. Hu’s team published their findings in a paper published in July — 3D Honeycomb-Like Structured Graphene and Its High Efficiency as a Counter-Electrode Catalyst for Dye-Sensitized Solar Cells.

Scientists focusing their efforts on lowering the cost of solar cells are seeing results using different materials. The Department of Energy’s National Renewable Energy Laboratory announced a new high of 31.1 percent conversion efficiency for a two-junction solar cell under one sun of illumination, which beats the previous record of 30.8 percent efficiency from Alta Devices, and is part of a program focused on lowering the cost of solar power. The tandem solar cell is made of a gallium indium phosphide cell laid on top of a gallium arsenide cell.



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