Scientists from Stanford University have contributed to the push to lower costs of photovoltaic cells by creating one entirely made of carbon.
Current commercially available solar cells are made of silicon, making them relatively expensive to produce. But the Stanford research team has created a low-cost, all-carbon solar cell made of electrodes and photoactive layers made from a combination of three carbon allotropes—fullerenes, graphene and nanotubes.
While these carbon elements have all been incorporated in the creation of solar cells before, this is the first time they have been used in an all-carbon device.
Photo credit: Standford University
“Carbon has the potential to deliver high performance at a low cost,” said Zhenan Bao, chemical engineering professor at Stanford and head of the research team.
“To the best of our knowledge, this is the first demonstration of a working solar cell that has all of the components made of carbon,” he added.
The prototype can only absorb sunlight and convert it to electricity at a modest rate of 1 percent, in part because carbon is more reactive to near infrared light, instead of more abundant visible light. That means the carbon solar cell’s efficiency is a tiny fraction of what standard cells can deliver, which is at around 12 percent for dye-based solar cells and 25 percent for those made from crystalline semiconductors.
“We clearly have a long way to go on efficiency. But with better materials and better processing techniques, we expect that the efficiency will go up quite dramatically,” said Bao.
