Researchers at Northwestern University have developed a carbon material that could revolutionize solar cell manufacturing. This new solar cell material is a transparent conductor composed of carbon nanotubes, offering an alternative approach to solar cell production. Current solar cell technology relies on a relatively rare element.
Carbon nanotubes, abundant in carbon on Earth, hold promise for the long-term development of solar energy, offering a more cost-effective method for manufacturing solar cells. Furthermore, this material's excellent flexibility allows solar cells to be integrated into fabrics and clothing, providing portable power for personal electronics and military applications.
This research was published in the October 2011 issue of the journal Advanced Energy Materials.
Solar cells consist of a multi-layered structure, including a transparent conductive layer through which sunlight enters the cell, and through which electrical energy is transferred. Therefore, this conductor must be both conductive and transparent. Materials that possess both of these properties are rare.
Currently, indium tin oxide (ITO) is the most widely used material in transparent conductors, but it has two drawbacks: it is brittle and relies on the relatively rare element indium. Therefore, the increasing demand for solar cells will significantly drive up the price of indium.
With the widespread adoption of solar energy technology, the supply of indium may become insufficient. Therefore, there is a strong desire for an element abundant on Earth, such as carbon, to replace indium in solar energy technology.
The research team developed a material that can replace indium tin oxide using single-walled carbon nanotubes, and further identified the most efficient types of carbon nanotubes: metallic carbon nanotubes and semiconductor carbon nanotubes.
Researchers have found that when these two types of carbon nanotubes are used as transparent conductors in organic solar cells, the efficiency of metallic carbon nanotubes is 50 times that of semiconductor carbon nanotubes.
