Researchers enable graphene to be used as an electrode for solar cells

Traditionally, it has been difficult to find appropriate materials for electrodes to carry a current to and from cells. Now, a team from says it has come up with a practical way of using a possible substitute made from inexpensive and ubiquitous carbon. The proposed material is graphene, which is transparent, so that electrodes made from it can be applied to the transparent organic solar cells without blocking any of the incoming light. In addition, say the researchers, it is flexible like organic solar cells themselves, so it could be part of installations that require the panel to follow the contours of a structure, such as a patterned roof. The biggest problem with getting graphene to work as an electrode for organic solar cells has been getting the material to adhere to the panel. Graphene repels water, so typical procedures for producing an electrode on the surface by depositing the material from a solution won't work. MIT professor Jing Kong said that it was necessary to 'dope' the surface of the cell – introducing a set of impurities into the surface, which changed the way it behaved and allowed the graphene to bond tightly. According to Kong, the flexibility and light weight of organic solar cells with graphene electrodes could open up a variety of different applications that would not be possible with today's conventional silicon-based solar panels. For example, because of their transparency they could be applied directly to windows without blocking the view, and they could be applied to irregular wall or rooftop surfaces. In addition, they could be stacked on top of other solar panels, increasing the amount of power generated from a given area. And they could even be folded or rolled up for easy transportation. An analysis of how to use graphene as an electrode for such solar cells was published in the journal Nanotechnology.