Carbon and solar energy are two of the most plentiful resources on Earth, and researchers at Northwestern University say they have found a way to use one to harvest the other. Existing methods for harvesting solar energy from photovoltaic cells involve an indium tin oxide-based conductor technology. This material is mechanically brittle, and dependent on indium, a relatively rare mineral. As demand for solar energy technology increases, a reliance on indium could drive up the cost of solar panels.
The solution, according to Northwestern chemistry, materials science and engineering professors Mark C. Hersam and Tobin J. Marks, is a new solar cell material made of single-walled carbon nanotubes: tiny, hollow cylinders of carbon just one nanometer in diameter. “If solar technology really becomes widespread, as everyone hopes it will, we will likely have a crisis in the supply of indium,” Hersam said. “There’s a great desire to identify materials – especially earth-abundant elements like carbon – that can take indium’s place in solar technology.”
In addition to carbon’s abundance, the material is also lighter, and mechanically flexible. This could allow solar cells to be integrated into fabrics and clothing, leading to many new applications for portable energy supplies on everything from clothing, backpacks or purses to military equipment. “With this mechanically flexible technology, it’s much easier to imagine integrating solar technology into everyday life, rather than carrying around a large, inflexible solar cell,” Hersam said.
The research was featured on the cover of the October issue of Advanced Energy Materials, a new journal that specializes in science about materials used in energy applications.