The life and death of carbon nanotubes

Abstract

We investigate the growth of aligned arrays of carbon nanotubes by the pyrolysis of ferrocene and toluene. These arrays are typically grown with ferrocene being introduced throughout the reaction. This continuous injection of a catalyst precursor is unusual when compared with other substrate bound carbon nanotube production routes. We have studied the activity and lifetime of the catalyst by switching from the ferrocene–toluene catalyst precursor solution to a pure toluene feedstock during growth which was monitored in situ using a laser micrometre. The catalysts' activity after the cessation of ferrocene injection was found to depend on both the concentration of the ferrocene in the initial feedstock and the time over which it was injected. The mode of growth of the array and the causes of carbon nanotube growth termination are elucidated from the data obtained.