USING GRAPHENE TO STRENGTHEN THE POWER OF SOLAR CELLS
A lot of research has gone into figuring out ways to utilize the unique characteristics of graphene so that they could be used in solar cells. Since solar cells need materials which are conductive and allow the passage of light, it is possible that the transparency and superb conductivity of graphene may help in creating the next generation of durable, low-cost and efficient photovoltaics.
Graphene is a promising nanomaterial. It has been attracting a lot of interest as a game changer for a variety of applications, from flexible transparent displays to energy storage. Graphene is essentially a network of carbon atoms patterned like a honeycomb. It is as thick as a single carbon atom – which makes it a two dimensional material. At the same time, it is two hundred times stronger than steel. The material is almost completely transparent and is an excellent conductor of electricity and heat that is very flexible and impermeable.
Although graphene is a great conductor, it is not as great for collecting the power produced by the a solar cell. But researchers have been making a lot of progress to modify the compound by experimenting with the derivatives of graphene and also with modifications like graphene oxide, which is less conductive than graphene but more conductive than conventional materials. They are also better charge collectors.
Graphene can also be used to replace ITO in the solar cells. ITO (Indium Tin Oxide) is conductive and used along with a non-conductive layer of glass as transparent electrodes in a lot of the organic solar panels. However, the material is expensive, rare and brittle.
A lot of studies have been conducted with a focus on replacing graphene with ITO in the transparent electrodes of organic photovoltaic cells. A lot of the research has focused on searching for ways in which graphene can be used to improve the overall performance of photovoltaic devices, electrodes, interfacial layers, active layers and electron acceptors.
Researchers from the Massachusetts Institute of Technology are currently developing a new type of solar cell which is made from molybdenum disulfide and graphene. The cell will be light, thin and about a thousand times as efficient as silicon panels. Its unique structure will make it possible to achieve the ultimate power conversion.Another set of researchers from the same university have developed a transparent, flexible electrode made of graphene for graphene polymer solar cells. According to their claims, it is the most efficient electrode that has ever been developed using graphene.
There have also been studies that have shown how adding a very small quantity of graphene flakes to a polymer based solar cell can improve its performance by as much as three times compared to the conventional non-graphene material. Graphene has also been shown to outperform ITO as transparent electrodes for solar panels, especially when four of those sheets were stacked together.
With the development of supercapacitator technologies for solar cells using graphene, a slow but sure revolution is brewing in the generation and storage of renewable energy. It is only matter of time before these technologies penetrate the residential and commercial solar market.