A flower-like defect in graphene, detailed in a newly published paper, could give scientists more control over the properties of graphene, potentially making sheets of the material more flexible and resistant to tearing.
Researchers in the US have described seven defects which could occur naturally in graphene, or under the right conditions, could be induced in the material. One is the so-called "flower" defect, which you can see in this gorgeous image.
According to the US National Institute for Science and Technology (NIST) the defects form when graphene is made by heating silicon carbide in an extreme vacuum. NIST fellow Joseph Stroscio says that the high temperatures mean the carbon atoms can move around, most easily into rings with five or seven carbon atoms instead of the normal honeycomb six. These rings can be looped together to create the flower defect.
Researcher Eric Cockayne is quoted on the NIST blog:
"As the graphene forms under high heat, sections of the lattice can come loose and rotate. As the graphene cools, these rotated sections link back up with the lattice, but in an irregular way. It's almost as if patches of the graphene were cut out with scissors, turned clockwise, and made to fit back into the same place, only it really doesn't fit, which is why we get these flowers."
With more work, the researchers hope to be able to fine tune the production of the defects, allowing them to produce sheets of graphene that are either entirely free of the defects, or have them appear exactly where they want them.
The paper, Grain boundary loops in graphene, was published in Physical Review B. 83, on 12 May this year.