Russian scientists have developed a technique that allows them to visualize defects on the surface of graphene. The technique may ultimately help scientists develop a better understanding of graphene’s properties in order to find novel applications for this supermaterial.
The technique, developed by researchers at the Zelinsky Institute of Organic Chemistry in a collaborative project, employs the metal palladium, which interacts with “carbon reactivity centres” found on graphene. Graphene is an incredibly strong one-atom-thick layer of carbon touted to be an excellent conductor of heat and electricity.
Several types of defects on graphene surfaces are known to increase the reactivity of its carbon atoms: i.e. their ability to form chemical bonds. If researchers can locate these defects and manipulate them, they will be able to maximize the use of graphene’s properties.
For example, locating and removing defects is important for applications that require perfectly smooth graphene. In other applications, such as in catalysis and certain biomedical materials, some defects are actually beneficial because they allow the incorporation of additional elements, such as metals, into the graphene.
When the palladium complex Pd2(dba)3 is dissolved in chloroform, it forms a dark red solution under normal circumstances. But when graphene or another carbon material is added to the solution, the palladium is completely consumed. As a result, the solution turns from dark red to colourless.
Using advanced imaging techniques, the researchers found that the palladium clusters selectively attach to graphene’s surface according to specific patterns, depending on how reactive the carbon centres are. Individual palladium particles settle onto point defects, local accumulations of particles are present on larger defects, and short chains outline linear defects.
These defects are normally invisible under an electron microscope. The palladium particles act like a contrast agent, allowing the spatial imaging of the chemical reactivity, and thus the defects, of graphene layers.
“Metal mapping of carbon materials provides unique insights and reveals hidden information about fascinating properties at the molecular level,” says project leader Professor Valentine Ananikov.
The team’s findings indicate that using palladium markers, more than 2,000 surface defects, or reactivity centres, on graphene can be individually located, per square micrometre of surface area. The researchers say that the unexpected capacity of graphene to accommodate so many reactivity centres challenges scientists to re-examine their understanding of the electronic and structural properties of carbon materials.
Now that the researchers have learned how to recognise and characterise the defects, their next step is to develop a technique to control them. Some defects possess a dynamic nature and have the ability to “migrate” over graphene’s surface. If the researchers can control this migration, they will have a unique opportunity to form materials with customised properties. This is an outstanding direction for future studies, they say.
For further information contact:
Professor Valentine P. Ananikov
Zelinsky Institute of Organic Chemistry
Ananikov Laboratory | Research SEA
Scientists channel graphene to understand filtration and ion transport into cells
11.12.2017 | National Institute of Standards and Technology (NIST)
Successful Mechanical Testing of Nanowires
07.12.2017 | Helmholtz-Zentrum Geesthacht - Zentrum für Material- und Küstenforschung
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
11.12.2017 | Physics and Astronomy
11.12.2017 | Earth Sciences
11.12.2017 | Information Technology