Single‐Walled Carbon Nanotubes: Functionalization by Intercalation

Abstract

The article reviews recent progresses in functionalization of single‐walled carbon nanotubes (SWCNTs). We describe detailed studies of electronic, chemical, and structural properties of intercalated and filled carbon nanotubes using state‐of‐the‐art spectroscopic and microscopic techniques. Intercalation with alkali metal allows one to finely tune the electron doping level of SWCNTs. A photoemission study of potassium intercalation compounds of SWCNT bundles unveils a transition of the metallic ground state of an SWCNT bundle from a Tomonaga–Luttinger liquid state to a Fermi liquid state. In turn, the filling of SWCNTs with fullerenes and organic molecules facilitates a reality of nanochemistry using carbon nanotubes as a nanoreactor. Spectroscopic and microscopic studies of the interconversion of encapsulated fullerenes and organic molecules show catalytic and noncatalytic processes for the inner tube growth from different filling precursors. Unique atomic wires and clusters can be created inside SWCNTs. We present that such chemical reactions of the encapsulated molecules result in the evolution of doping and bonding properties of the carbon nanotube host.

Treatment of Multi-Walled Carbon Nanotubes with Dichromic Acid: Oxidation and Appearance of Intercalation

“…The appearance of such reflections with interlayer spacing higher than d 002 can be considered as the formation of intercalation compounds, since such an effect usually causes an increase of interlayer spacing [ 45 , 46 ]. In CNTs, it is clearly seen for intercalation with chlorides [ 47 , 48 ] and other compounds [ 49 , 50 ]. It is worth noting that there were no reflections related to chromium oxides or any other compounds in the XRD patterns.…”