Doping Graphene for Photovoltaic Gain
Graphene, our favorite atom-thick material, has been combined with another material to create a solar cell more efficient than previous graphene cells. Though graphene already has amazing electrical conductance, researchers at the University of Florida added trifluoromethanesulfonyl-amide (TFSA) as a dopant to improve conductivity and increase electric field potential within the cell. This results in higher energy electrons being produced as a result of the photoelectric effect.
Graphene solar cells have been made before, because graphene has extraordinary electrical properties and potentially can be made very cheaply. Unfortunately these cells were only about 2.9% efficient, at the most. By adding TFSA as a dopant, the researchers were able to reach 8.6%, which is a significant improvement.
This new cell places a single layer of graphene on top of a piece silicon, with gold surrounding it. The silicon and graphene create a Schottky junction, which only allows electrons to flow in one direction. The researchers hope to reach 10% efficiency by doping graphene, because, if they can keep costs down, the resulting solar cell will be economically viable. Before that happens though, a replacement for the silicon may have to be found, as it is not the most economical material for this design.