Watching carbon atoms in motion

Improvements in electron microscopy have enabled scientists to see how materials made from carbon can rapidly change their structure atom by atom.

An international team led by Oxford University scientists report in this week’s Nature Nanotechnology how they used new advanced electron microscopy to image carbon atoms in graphene, a material that is of particular interest because of its remarkable electronic properties.

The new state-of-the-art electron microscopes commercially available are fitted with a special component that reduces aberrations and this produces images with higher resolution.

'It is important to be able to image carbon based molecules and nanostructures in real time in order to track their motion. Nature has constructed life based on carbon atoms and man-made synthetic carbon nanomaterials are the future of nanotechnology applications,' said Jamie Warner of Oxford University’s Department of Materials, lead author of the paper.

'However, carbon atoms are particularly hard to image because they are light and structures they are arranged in are so easy to destroy using high energy electron beams.’ 

‘We were able to use a lower energy electron beam in an electron microscope and adjust the imaging conditions to enable fast frame acquisition (12 per second) at a magnification of 2 million times. That’s about 10 times faster than anyone has managed before.’

This enabled the team to monitor a variety of shape and structural changes occurring in graphene, which is the key to some of the material’s unusual properties.

Jamie told us: ‘The way in which the low energy electrons interacted with graphene layers was unique. Normally, high energy electrons punch many holes through layered graphene sheets, however in our case the low energy electrons eroded single sheets of graphene one by one and smoothed out the edges of the material.'

'This opens new insights into the creation and modification graphene structures which may lead to improvements in their utilization in electronic devices.’ 

The research was carried out by a team including scientists from Oxford University, IFW Dresden (Germany), the STFC Rutherford Appleton Laboratory, and Imperial College London.