A study published in a 2013 edition of Nature Physics heralded graphene’s amazing property: how it efficiently converts light into electricity. Most materials, when struck by light, emit only one electron for every photon of light absorbed. Graphene produces multiple excited electrons. This means it has the potential to offer better electrical signals than most materials.
Scientists from the University of Manchester produced the first samples of graphene in 2004, and they were awarded in 2010 with the Nobel Prize in Physics for their work with the amazing carbon material.
Graphene is 100% carbon. It is a sheet of carbon atoms arranged in the traditional honeycomb pattern. Graphene is also remarkably lightweight. The mass of one square meter of graphene sheet is only 0.77 milligrams. Since the thickness of the graphene sheet corresponds to the thickness of the carbon atom, it is basically a two-dimensional elemental material—the first of its kind. It is currently the thinnest material known to man. But graphene’s thinness does not make it weak. When tested, it is one hundred times stronger than steel.
What’s amazing about graphene is that when the sheet is struck by light, its electrons do not disperse, which is the natural tendency among most materials, such as silicon. Thus, the first applications that researchers steered graphene for were those related to the semiconductor industry. Computer transistors based on graphene would run twice as fast as conventional silicon-based ones.
Graphene is now being developed for use in solar panels. Two sheets of graphene serve as sandwiching layers for photovoltaic cells that convert the sun’s clean energy into electricity. The resulting graphene-based solar panels will be flexible and light enough for molding onto any exposed surface, such as an automobile’s body, an item of clothing, a backpack, or a piece of furniture.
Graphene is also perfect for making foldable, unbreakable smartphones and tablets, as well as for developing new bionic devices, such as ear implants and artificial hearts. However, at this point, such graphene applications are still speculative.
A major challenge in working with graphene is the difficulty encountered when making the sheets perfectly pure and wide enough for commercial applications. Maintaining and achieving purity is an issue when working with graphene. If there are non-carbon atoms interspersed in the sheet, the honeycomb pattern is disrupted and the promising properties of graphene are negatively affected. As of this writing, methods to refine graphene are not yet viable enough for commercial applications.
Another challenge is in finding a way to efficiently tap the electrical current produced by graphene’s production of excited electrons and convert it into usable electricity. There’s also the problem with improving the light absorption capacity of graphene. More photons of light absorbed means more excited electrons, which in turn lead to more electrical currents.
A February 2013 paper published in Nature Physics explains how little is currently understood about the mechanism that enables graphene to efficiently convert the photons of light absorbed into excited electrons, a measure of how well it can produce electrical currents.
The members of the team of researchers involved in the said study were based in many parts of the world—Graphenea S.L. Donostia-San Sebastian (Spain), Institute of Photonic Science, Massachusetts Institute of Technology (USA), and Max Planck Institute for Polymer Research (Germany). Given this level of interest in developing graphene for efficient power production, it is likely that the issues associated with the carbon material will be solved much faster. It could become a great source of cheap electricity and provide us with much more energy than alternative fuels - though research is still a long way from concrete results.