A new efficiency record for graphene solar cells has been established by University of Florida in Gainesville researchers. The new solar cell, made of graphene impurified with an organic dopant now reaches an efficiency of 8.6 percent, versus the 1.9% of the previous iterations.
Sefaattin Tongay and Arthur F. Hebard, the two researchers who published the paper on this discovery, explained that the new improvements “reduced graphene’s electrical resistance by adjusting the Fermi level of graphene using a cheap and environmentally stable organic coating layer.” (Phys.org)
The new cell basically embodies a Schottky diode, with a single graphene layer put on top of a silicon wafer, resulting in what’s called a Schottky junction solar cell.
They achieved this level of efficiency by adjusting graphene’s Fermi level, and hence improving the electrical resistance of graphene. This led to a more efficient separation of the electron-hole pairs generated by the photons absorbed by the graphene.
“We expect that the efficiency can be further improved by engineering the interface, using different organic coating layers yielding higher doping effects, improving the graphene quality and graphene transfer procedure, using anti-reflection layers, and numerous other methods known by the solar cell community,” Tongay said. “This is just a beginning.”
Graphene-based solar cells have been touted for a long time for being able to reduce prices considerably.