14 DAY TRIAL // The solar power industry is currently reliant on organic materials such as indium-tin-oxide (ITO) for producing electrodes in solar cells. But some of these materials are expensive and difficult to come by. A group of researchers believes it may have just found a solution to this problem.
When producing solar cells, manufacturers need to respect a few common demands, such as for example producing devices that are inexpensive, lightweight and flexible at the same time.
Except for the inexpensive part, it's easy to meet these demands with organic materials, but a lot more difficult to do so with inorganic ones, such as for example carbon compounds.
However, using such materials is desirable over using expensive, highly purified silicon, such as it's currently the norm. But scientists at the Massachusetts Institute of Technology (MIT) believe they have a solution to this problem.
The experts say that using graphene to create solar cell electrodes could provide manufacturers with the properties they need, such as low costs, transparency and flexibility. The traits of the electrodes need to match those of the cells themselves in order for the entire device to work properly.
Graphene is a carbon compound that is only one atom thick. In most respects, it can be though of as two-dimensional. Its atoms are arranged in hexagons, and graphene sheets have the overall appearance of a honeycomb.
The material has amazing chemical and physical properties, and is heralded as the next big thing for the electronics industry. Two researchers at the University of Manchester won the 2010 Nobel Prize in Physics for its discovery.
According to a paper the MIT group published in the December 17 issue of the esteemed scientific journal Nanotechnology, graphene has the necessary properties to complete the functionality of solar cells. The work was authored by professors Jing Kong and Vladimir Bulović.
“Other groups had already shown that graphene exhibits good combinations of transparency and sheet resistance, but no one was able to achieve a performance with graphene electrodes that matches that of devices on conventional metal oxide (ITO) electrodes,” says Peter Peumans.
“This work is a substantial push toward making graphene a leading candidate,” adds the Stanford University assistant professor of electrical engineering, who was not a part of the work.
The investigation was funded with grant money secured from the Eni-MIT Alliance Solar Frontiers Center and a research fellowship provided by the US National Science Foundation (NSF).