Graphene crystals were first isolated in 2004. They are two-dimensional (one-atom in thickness), harder than diamonds and far stronger than steel, providing unprecedented stiffness, electrical and thermal properties. By viewing the atomic and bonding configurations of individual graphene atoms, scientists are able to suggest ways to optimize materials so they are better suited for specific applications.
In a paper published in Physical Review Letters, a team of researchers from Oak Ridge National Laboratory and Vanderbilt University used aberration-corrected scanning transmission electron microscopy to study the atomic and electronic structure of silicon impurities in graphene.
"We have used new experimental and computational tools to reveal the bonding characteristics of individual impurities in graphene. For instance, we can now differentiate between a non-carbon atom that is two-dimensionally or three-dimensionally bonded in graphene. In fact, we were finally able to directly visualize a bonding configuration that was predicted in the 1930s but has never been observed experimentally," said ORNL researcher Juan-Carlos Idrobo. Electrons in orbit around an atom fall into four broad categories - s, p, d and f - based on factors including symmetry and energy levels.
"We observed that silicon d-states participate in the bonding only when the silicon is two-dimensionally coordinated," Idrobo said. "There are many elements such as chromium, iron, and copper where the d-states or d-electrons play a dominant role in determining how the element bonds in a material."
By studying the atomic and electronic structure of graphene and identifying any impurities, researchers can better predict which elemental additions will improve the material's performance.
Slightly altering the chemical makeup of graphene could customize the material, making it more suitable for a variety of applications. For example, one elemental addition may make the material a better replacement for the platinum catalytic converters in cars, while another may allow it to function better in electronic devices or as a membrane.
Graphene has the potential to replace the inner workings of electronic gadgets people use every day because of its ability to conduct heat and electricity and its optical transparency. It offers a cheaper and more abundant alternative to indium, a limited resource that is widely used in the transparent conducting coating present in almost all electronic display devices such as digital displays in cars, TVs, laptops and handheld gadgets like cell phones, tablets and music players.
Researchers expect the imaging techniques demonstrated at ORNL to be used to understand the atomic structures and bonding characteristics of atoms in other two-dimensional materials, too.
The authors of the paper are Wu Zhou, Myron Kapetanakis, Micah Prange, Sokrates Pantelides, Stephen Pennycook and Idrobo.
This research was supported by National Science Foundation and the DOE Office of Science. Researchers also made use of Oak Ridge National Laboratory's Shared Research Equipment User Facility along with Lawrence Berkeley National Laboratory's National Energy Research Scientific Computing Center, both of which are also supported by DOE's Office of Science.
ORNL is managed by UT-Battelle for the Department of Energy's Office of Science. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov.
Jennifer Brouner | EurekAlert!
NUS engineers develop novel method for resolving spin texture of topological surface states using transport measurements
26.04.2018 | National University of Singapore
European particle-accelerator community publishes the first industry compendium
26.04.2018 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP
Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
26.04.2018 | Power and Electrical Engineering
26.04.2018 | Life Sciences
26.04.2018 | Power and Electrical Engineering