Researchers are now able to measure single atoms in a graphene-based ‘petri-dish,’ a discovery that could be beneficial in a number of applications.
A team from the University of Manchester have demonstrated that graphene and boron nitride can be combined to create a nano petri-dish, where liquid samples inside the dish can be imaged with single atom sensitivity. This also makes it possible to measure their elemental composition at the nanometre length scale.
This could lead to better designs of nanomaterials for batteries and a better understanding of the degradation of battery materials to improve their performance.
The properties found in the 2D materials could also lead to functional and antibacterial coatings, bioanalysis and targeted drug delivery. Scanning / transmission electron microscopy (S/TEM) is one of only few techniques that allows imaging and analysis of individual atoms. However, the S/TEM instrument requires a high vacuum to protect the electron source and to prevent electron scattering from molecular interactions.
Several recent studies have revealed that the structure of functional materials at room temperature in a vacuum can significantly differ from that in their normal liquid environment.
The graphene liquid cells were built from 2D material-building blocks, consisting of a boron nitride spacer drilled with holes and encapsulated with graphene on both sides.
Graphene is strong enough to protect the sample from a high vacuum environment, while also being thin enough so that the resolution of the electron beam is not compromised.
“Unlike some previous designs our graphene liquid cells allow us to image the atoms for many minutes,” Daniel Kelly, the lead author of the study, said in a statement. “We were even able to resolve individual atoms in water and observe them dancing under the electron beam.”
The team also found that the graphene liquid cells improved the quality of elemental analysis, after studying the deposition of a one-nanometer shell of iron on gold to grow core-shell nanoparticles. The ability to monitor small concentrations over small length-scales is necessary for complex chemical structures of high-performing nanocatalysts.
“We are getting to understand how to make these more and more reliably, this makes the 2D petri-dish a promising route to further in situ TEM advancements, including imaging of small biological structures such as proteins,” Mingwei Zhou, a student at the University of Manchester, said in a statement.