The structural transitions of C60 nanowhiskers under an electric field characterized by in situ transmission electron microscopy and electron energy-loss spectroscopy

In situ electrical transport measurements for individual C-60 nanowhiskers are performed using a transmission electron microscope which monitors the crystal and electronic structural changes of the C-60 nanowhiskers simultaneously. Electron diffraction combined with electron energy-loss spectroscopy shows that under the external electric current, the C-60 nanowhiskers first transform from a face-centered-cubic structure to a disordered arrangement of C-60 molecules. The cage structure of the C-60 molecules then collapses to an amorphous carbon and finally, the amorphous carbon turns into graphene stacks. This process indicates the hybridization transformation from sp(2.278) to sp(2), which is different from the transition process of C-60 materials under high pressure. The obtained results also suggest that the stability of the C-60 nanowhiskers should be of crucial concern when they work as electrical devices.