It’s the structure, silly: Diamonds and graphene are both made up of carbon atoms, but any geoscientist worth their salt knows that their atomic structure is what separates gems from batteries, solar panels, etc.
While diamonds’ carbon atoms are arranged in a tetrahedral structure with four covalent bonds, graphene’s carbon atoms are arranged in a single layer with a hexagonal lattice resembling a honeycomb and three covalent bonds.
Good and bad: Sudden craving for Honeycomb cereal aside, the structure of graphene plays a huge role in its industrial uses, but also in its shortcomings.
Thin, but strong: The honeycomb structure of graphene gives it very high tensile strength, and it’s also known as the thinnest 2D material in the world (sparking a whole new field of research).
Its 2D properties give rise to other cool things like transparency and high conductivity, but the story isn’t all sunshine and roses.
David Duncan, associate professor at the University of Nottingham, explains, “While perfect graphene is remarkable, it is sometimes too perfect. It interacts weakly with other materials and lacks crucial electronic properties required in the semiconductor industry.”
How do you improve something that’s already nearly perfect? You make it imperfect, of course.
What they did: Scientists from the University of Nottingham’s School of Chemistry, University of Warwick, and research center Diamond Light Source, including Dr. Duncan, added structural defects to graphene that improve the performance of the material.
Mimicry is the highest flattery: The team developed a single-step process to grow graphene-like films using a molecule, azupyrene, whose shape mimics that of the desired defect.
How it works: The honeycomb lattice of graphene requires six carbon atoms to make a whole honeycomb, and adding azupyrene creates a defect where neighboring rings have five or seven carbon atoms.
Dr. Duncan said, “We found the defects can make graphene more ‘sticky’ to other materials, making it more useful as a catalyst, as well as improving its capability of detecting different gases for use in sensors. The defects can also alter the electronic and magnetic properties of the graphene, for potential applications in the semiconductor industry.”
Driven by temperature: Azupyrene’s shape causes the irregular layout of carbon atoms, and when it’s used to grow graphene, the rate of growth of the defect can be controlled by modulating the temperature conditions.
One small step for man: Researchers at the National Graphene Institute in Manchester demonstrated that the defects remain in the graphene upon transfer to different surfaces, which is a big step toward applying the films to other devices.
Innovations and advancements galore: Aside from the innovative thought process of considering a defect an improvement, the work used advanced microscopy and spectroscopy at the Diamond Light Source in Oxfordshire, the MAX IV Laboratory in Sweden, and the UK’s national supercomputer ARCHER2 to study the defect’s presence and impacts on the defective graphene’s chemical and electronic properties.
Learn more: To learn the specifics behind the work, go here, and to read the full journal article, go here.
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