Researchers at the Massachusetts Institute of Technology have developed a new way to make large tracts of high-quality, atomic-thin graphene. The researchers believe the new method could create ultra-light, flexible solar cells, as well as two new types of light-emitting devices and other thin-film electronics. It is reported that the process is relatively easy to achieve the scale of industrial production.
The process involves an intermediate “buffer” material layer, which is the key to the success of manufacturing technology. The buffer layer makes the ultra-thin graphene sheet less than 1 nanometer thick and can easily be lifted from its substrate, enabling fast roll-to-roll manufacturing. Scientists have been working to find a way to create thin, large-area, transparent electrodes that stabilize in the open air.
Such materials can be used in a variety of applications in optoelectronic devices such as computers and smartphone screens. One of the great benefits of graphene is that it is a form of pure carbon, with atoms arranged into flat hexagonal arrays with good electrical and mechanical properties. This material is very thin, very flexible in physics, and built with rich and inexpensive materials.
The material is easy to use copper as a seed layer, using chemical vapor deposition to grow large areas of material. The trickiest part is finding a way to release graphene from its native copper substrate. New technology developed by mIT researchers can reliably make large areas of graphene.
The key is reportedly a buffer layer made of a polymer called xylene, which is consistent with graphene sheets deployed on it at the atomic level. The production of xylene by chemical vapor deposition simplifies the manufacturing process and extensibility. The current prototype graphene-based solar cell increases the power of transmission by about 36 times per unit of weight, compared with 1/200 per cent of the transparent electrode used in the unit area material.