Heralded as a “revolutionary material” with “outstanding physical properties,” graphene emerged at the forefront of materials science in 2004, when researchers at the University of Manchester used Scotch tape to peel this single layer of interconnected carbon atoms from a graphite flake. The simplicity and affordability of the “Scotch tape method” sparked an immense amount of scientific interest, and graphene research took off at an explosive rate (see chart below).
A two-dimensional allotrope of carbon with a honeycomb lattice structure, graphene is the world’s thinnest and strongest material. It also has the greatest charge-carrying ability of any known substance—at least at room temperature—and is widely considered to be the next game-changer of the electronics industry.
Given that game-changing technologies tend to be incredibly lucrative, it is perhaps unsurprising that graphene-related patenting has increased substantially in recent years. Mentioned at least once in only 229 patent applications filed worldwide in 2003, graphene was the primary focus of 508 patent applications filed in 2010—the last year for which complete filing records are available—and was mentioned at least once in an additional 1,208 applications.
Because graphene represents the basic structural unit of most solid forms of carbon—including fullerene, graphite, and carbon nanotubes—many of the patents that mention graphene are actually related to one of these other materials. This is especially true in the case of carbon nanotube-related patents, as carbon nanotubes are often described as sheets of graphene that have been coiled into cylinders. Therefore, although graphene is the name of a basic structural unit found in many solid forms of carbon, two-dimensional graphene is also a material in its own right—and the current graphene-related hubbub is all about two-dimensional graphene.
Many of the top players in the electronics industry own patents related to two-dimensional graphene. Samsung, IBM, NEC, and Hitachi all rank among the top ten graphene patent assignees. A number of other large players, including General Electric, Sony, and Toshiba, are also active in graphene research–or, at the very least, active in acquiring the rights to graphene research.
Perhaps because graphene is a relatively emergent technology, however, universities own a surprising proportion of graphene-related patents. William Rice University, the University of California, and the University of Texas all rank among the top ten patent assignees in the two-dimensional graphene space, along with the Korea Institute of Science and Technology, a government-sponsored research organization. Nine of the top 20 patent assignees in this space are either universities or public research institutions, accounting for close to 20% of all graphene-related patent documents.
The “Scotch tape method,” which can be referred to (more scientifically) as an exfoliation process, was the first straightforward means of producing graphene; however, over the past eight years, scientists have developed many other methods of graphene production. New exfoliation processes include solvent-mediated micromechanical cleavage and dry etching in an oxygen plasma. “Unzipping” a carbon nanotube forms a “ribbon” of graphene, and a variety of graphite oxide reduction methods exist in the scientific (and patent) literature.
Arguably, epitaxial growth may be the most commercially-viable method of graphene production currently available. Usually accomplished via chemical vapor deposition on substrates such as silicon carbide and certain metals (like iridium, copper, and nickel), the success of this method evokes the optimistic prediction that graphene may eventually replace silicon as a fundamental electronic material.
Research institutions are the chief innovators in graphene production, in both cutting-edge methodology (their usual purview) and overall patenting volume. Of the top five assignees in each graphene production method shown in the graph above, only slightly more than half are private-sector companies–large or small.
Many researchers—including the original Scotch tape duo, A.K. Geim and K.S. Novoselov—caution that it may be 20 years before graphene achieves its true potential. Nevertheless, with all of the neat graphene technologies already available on the market (like this heat-transferring paint) the next two decades are likely to be very exciting!