X-ray photoemission spectroscopy study of fluorinated single-walled carbon nanotubes

We have investigated the change of atomic and electronic structures of fluorinated single-walled carbon nanotubes (SWCNTs) using x-ray photoemission spectroscopy (XPS), electrical resistivity measurements, and transmission electron microscopy (TEM). The fluorine content increases with increasing reaction temperature up to 300 degreesC. XPS indicated that the fluorinated SWCNT reveals an ionic-bonding character at low concentration and covalent-bonding character at high concentration. The resistivity increases with reaction temperatures, resulting from the band gap enlargement at high fluorine concentration. It is also observed from TEM that the fluorination at reaction temperature above 250 degreesC leads to the disintegration of the CNT structures and formation of various phases such as multiwall-like and turbostratic morphologies. (C) 2002 American Institute of Physics.