Cornell researchers have turned science into art as they explore the shape and size of atoms along grain boundaries in graphene, a University press release said this week. David Muller, Professor of Applied and Engineering Physics and co-Director of the Kavli Institute at Cornell for Nanoscale Science, lead a group of researchers that examined the microstructural properties of the two-dimensional form of carbon known as graphene in order to better understand its electrical and magnetic capabilities.
They found that the graphene grows in imperfect sheeets, where the hexagonal lattices do not align in perfect order. The scientists then observed the intersection of these lattices by bouncing electrons off the atoms and color-coding the different diffraction angles. What resulted was a pretty collage of colors resembling a patchwork quilt, seen to the right. The method used to display the varying orientation of the grain boundaries could potentially be used for many other one-atom thick layers of materials.
“You don’t want to look at the whole quilt by counting each thread. You want to stand back and see what it looks like on the bed. And so we developed a method that filters out the crystal information in a way that you don’t have to count every atom,” said Muller in the press release.
While conventional materials science supposes that a high number of grain boundaries would inhibit electrical conductivity, which occurs via the movement of electrons within the material, Muller’s team found that larger grain sizes and fewer boundaries didn’t necessarily mean higher conductivity. Instead, poorer conductivity is believed to be more a result of non-unifom atoms or particles that reside in the material due to manufacturing processes. With impurities as the culprit, scientists can now focus on ways to improve the graphene-forming process.
Graphene is a very commonly used one-atom thick layer of carbon, implemented in the design of solar cells, cell phone screens, and other devices. Mike Ramsey of The Wall Street Journal explored the future of energy-efficient cars yesterday, discussing the possibility of ultracapacitors replacing batteries as power sources. Ultracapacitors quickly absorb and discharge electrical energy by use of two carbon-coated conducting plates suspended in an electrolyte solution. The carbon-coating he speaks of? Graphene.
