Replacing Platinum with Graphene in Solar Cells
When most people envision a solar cell today, they picture a flat sheet of silicon. In the future though, solar cells are more likely to be thin, flexible devices, but that future is still a ways off because as the technology requires further development and can be very expensive. Researchers at Michigan Technological University have recently found a way to drastic reduce the price of dye-sensitized solar cells by replacing platinum with a special for of graphene.
Platinum is a very special metal as it is able to act as a catalyst for many reactions, but it is also quite rare, making it very expensive. Even though a dye-sensitized solar cell will not use much platinum, it is still somewhat cost prohibitive, so researchers have been search for alternatives. The alternative the Michigan researchers found is a three dimensional version of graphene, which is typically thought of as two dimensional. To produce the graphene, lithium oxide and carbon monoxide are made to react together to produce lithium carbonate (Li2CO3) and the 3D graphene. Though they are eventually removed, the Li2CO3 particles are critical for creating the graphene structures, as it prevents the carbon from just forming graphite, which has a more chaotic structure.
With the 3D graphene as the counter electrode, the researchers tested a solar cell and found it reached to 7.8% efficiency, which almost matches that of a similar cell using platinum. Producing the 3D graphene and installing it into the solar were not difficult processes, which is important if this technology is to reach the market.