[font face=Serif][font size=5]All-Carbon Solar Cells Will Mean Cheap and Flexible Solar Panels[/font]
[font size=4]Flexible photovoltaics made of carbon promise low cost and durability, if their performance can be improved.[/font]
By Katherine Bourzac on November 15, 2012
[font size=1]Carbon cell: The all-carbon solar cell consists of a photoactive layer between two electrodes.[/font]
[font size=3]Using a grab bag of novel nanomaterials, researchers at Stanford University have built the first all-carbon solar cells. Their carbon photovoltaics dont produce much electricity, but as the technology is perfected, all-carbon cells could be inexpensive, printable, flexible, and tough enough to withstand extreme environments and weather.
The goal is not to replace solar cells made from silicon and other inorganic materials, says
Zhenan Bao, professor of chemical engineering at Stanford University, who led the work. Rather, it is to fill new niches. Carbon is one of the most abundant elements on earth, and it is versatile, Bao says.
Carbon is remarkably toughatom-thick graphene and long, thin carbon nanotubes are two of the strongest materials ever tested. So carbon photovoltaics might be sprayed on the sides of buildings, or rolled up and taken into the desert. Various forms of carbon can be printed to make thin, flexible, transparent, and even stretchable electronics.
The all-carbon photovoltaics convert less than 1 percent of the energy in light into electricity (by comparison, a silicon solar cell converts around 20 percent of light into electricity). However, Bao says that her group worked mostly with off-the-shelf materials, with just a bit of tuning. She attributes part of the problem to the roughness of the carbon films, which trips up traveling charges, and says it should be possible to smooth them out by working on the processing methods.
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