Doping of C 70 fullerene peapods with lithium vapor: Raman spectroscopic and Raman spectroelectrochemical studies

Raman spectroscopy and in situ Raman spectroelectrochemistry were applied to study the lithium vapor doping of C 70 @SWCNTs (peapods). A strong degree of doping was proved by the vanishing of the single walled carbon nanotubes (SWCNT’s) radial breathing mode (RBM) and by the attenuation of the tangential (TG) band intensity. In contrast to potassium vapor doping, the strong downshift of the frequency of the TG band has not been observed for Li-doping. The Li vapor treated peapods remained partly doped even if they were exposed to humid air. This has been reflected by a reduced intensity of the nanotube and the fullerene modes and by the change of the shape of the RBM band as compared to that of the undoped sample. The modes of the intratubular fullerene were almost unresolved after the contact of the Li-doped sample with water. A lithium insertion into the interior of a peapod and its strong interaction with the intratubular fullerene is suggested to be responsibl...

Martin Kalb??, Vaclav Vales, Ladislav Kavan and Lothar Dunsch

Click for full article