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

Abstract

In situ electrical transport measurements for individual C₆₀ nanowhiskers are performed using a transmission electron microscope which monitors the crystal and electronic structural changes of the C₆₀ nanowhiskers simultaneously. Electron diffraction combined with electron energy-loss spectroscopy shows that under the external electric current, the C₆₀ nanowhiskers first transform from a face-centered-cubic structure to a disordered arrangement of C₆₀ molecules. The cage structure of the C₆₀ 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 sp², which is different from the transition process of C₆₀ materials under high pressure. The obtained results also suggest that the stability of the C₆₀ nanowhiskers should be of crucial concern when they work as electrical devices.