Conventional solar cells typically rely on expensive materials such as crystalline silicon, silver and indium tin oxide to function. However, a team of researchers at Stanford University has now created the first solar cell based solely on carbon, a material that undoubtedly has the potential to bring down the costs of solar.
Their all-carbon thin-film solar cell is flexible, lightweight and can be bent around surfaces – characteristics that significantly increase the number of applications for photovoltaics.
Carbon is abundant in nature while the supplies of the material that makes up the electrodes of conventional solar cells are running low. That is why there is a lot of money in finding alternative materials with appropriate characteristics for photovoltaic applications.
Another interesting benefit with carbon solar cells is extreme temperature tolerance. The material stays consistent even at temperatures of about 1,100 degrees Fahrenheit. Whether we will ever be able to create solar cells that operate as they should under these conditions is not clear at this point, but maybe carbon solar cells one day will prove useful in concentrated photovoltaics (CPV) applications?
News of all-carbon solar cells have been touted before, however this is actually the first time the solar cell is made entirely out of carbon. Previously, carbon has been limited to only certain parts of the cell (still important improvements in the race to bring down solar cell costs).
Graphene, single-walled carbon nanotubes and “buckyballs" (ball-shaped carbon molecules) were used to ensure the new all-carbon solar cell could absorb light and conduct current. Still, the solar cell never achieved peak efficiency rates higher than 1% - far from the standards of today`s PV market.
“With better materials and better processing techniques, we expect that the efficiency will go up quite dramatically." says Professor Zhanan Bao who led the research team at Stanford University.
The team will continue to work and improve their new solar cell. They are currently trying to broaden the spectrum of sunlight that can be absorbed. Currently, the solar cell only absorbs the near-infrared part of the spectrum, so there`s a lot of potential for improvements.
"We believe that all-carbon solar cells could be used in extreme environments, such as at high temperatures or at high physical stress," says Vosgueritchian. "But obviously we want the highest efficiency possible and are working on ways to improve our device."
Editor's Note: Mathias writes more on new solar technologies and their costs at Energy Informative.