Typical solar cells use expensive rare earth minerals. Researchers at Stanford University have come up with an alternative method of creating solar cells made entirely of carbon
Stanford University scientists have built the first solar cell made entirely of carbon, a promising alternative to the expensive materials used in photovoltaic devices today. The results are published in the journal ACS Nano.
"Carbon has the potential to deliver high performance at a low cost," said study senior author Zhenan Bao. "To the best of our knowledge, this is first demonstration of a working solar cell that has all of the components made of carbon."
Unlike rigid silicon solar panels that adorn many rooftops, Stanford's thin film prototype is made of carbon materials that can be coated from solution. "Perhaps in the future we can look at alternative markets where flexible carbon solar cells are coated on the surface of buildings, on windows or on cars to generate electricity," Bao said.
The coating technique also has the potential to reduce manufacturing costs, said student Michael Vosgueritchian, co-lead author of the study with Marc Ramuz.
"Pricessing silicon-based solar cells requires a lot of steps," Vosgueritchian explaimed. "But our entire device can be built using simple coating methods that don't require expensive tools and machines."
CARBON NANOMATERIALS
The Bao groups's experimantal solar cell consists of a photoactive layer, which absorbs sunlight, sandwiched between two electrodes. In a typical thin film solar cell, the electrodes are made of conductive metals and indium tin oxide (ITO).
"Materials like indium are scarce and becoming more expensive as the demand for solar cells, touchscreen panels and other electronic devices grow," Bao said. "Carbon, on the other hand, is low cost and Earth-abundant."
For the study, Bao and her colleagues replaced the silver and ITO used in conventional electrodes with graphene - sheets of carbon that are one atom thick and single-walled carbon nanotubes that are 10,000 times narrower than a human hair. "Carbon nanotubes have extraordinary electrical conductivity and light-absorption properties," Bao said.
For the active layer, the scientists used material made carbon nanotubes and "buckyballs" - soccer ball-shaped carbon molecules just one nanometer in diameter. The research team recently filed a patent for the entire device.
"Every component in our solar cell, from top to bottom, is made of carbon materials," Vosgueritchian said. "Other groups have reported making all-carbon solar cells, but they were referring to just the active layer in the middle, not the electrodes."
One drawback of the all-carbon prototype is that it primarily absorbs near-infrared wave-lengths of light, contributing to a laboratory efficiency of less than 1 per cent - much lower than commercially available solar cells..
"We clearly have a long way to go on efficiency," Bao said. "But with better materials and better processing techniques, we except that the efficiency will go up quite dramatically."
Stanford University scientists have built the first solar cell made entirely of carbon, a promising alternative to the expensive materials used in photovoltaic devices today. The results are published in the journal ACS Nano.
"Carbon has the potential to deliver high performance at a low cost," said study senior author Zhenan Bao. "To the best of our knowledge, this is first demonstration of a working solar cell that has all of the components made of carbon."
Unlike rigid silicon solar panels that adorn many rooftops, Stanford's thin film prototype is made of carbon materials that can be coated from solution. "Perhaps in the future we can look at alternative markets where flexible carbon solar cells are coated on the surface of buildings, on windows or on cars to generate electricity," Bao said.
The coating technique also has the potential to reduce manufacturing costs, said student Michael Vosgueritchian, co-lead author of the study with Marc Ramuz.
"Pricessing silicon-based solar cells requires a lot of steps," Vosgueritchian explaimed. "But our entire device can be built using simple coating methods that don't require expensive tools and machines."
CARBON NANOMATERIALS
The Bao groups's experimantal solar cell consists of a photoactive layer, which absorbs sunlight, sandwiched between two electrodes. In a typical thin film solar cell, the electrodes are made of conductive metals and indium tin oxide (ITO).
"Materials like indium are scarce and becoming more expensive as the demand for solar cells, touchscreen panels and other electronic devices grow," Bao said. "Carbon, on the other hand, is low cost and Earth-abundant."
For the study, Bao and her colleagues replaced the silver and ITO used in conventional electrodes with graphene - sheets of carbon that are one atom thick and single-walled carbon nanotubes that are 10,000 times narrower than a human hair. "Carbon nanotubes have extraordinary electrical conductivity and light-absorption properties," Bao said.
For the active layer, the scientists used material made carbon nanotubes and "buckyballs" - soccer ball-shaped carbon molecules just one nanometer in diameter. The research team recently filed a patent for the entire device.
"Every component in our solar cell, from top to bottom, is made of carbon materials," Vosgueritchian said. "Other groups have reported making all-carbon solar cells, but they were referring to just the active layer in the middle, not the electrodes."
One drawback of the all-carbon prototype is that it primarily absorbs near-infrared wave-lengths of light, contributing to a laboratory efficiency of less than 1 per cent - much lower than commercially available solar cells..
"We clearly have a long way to go on efficiency," Bao said. "But with better materials and better processing techniques, we except that the efficiency will go up quite dramatically."
No comments:
Post a Comment