Towards the Single-Walled B - And/or N -Doped Carbon Nanotubes

Soon after the discovery of carbon nanotubes (CNTs) in the early 1990's, the B - and/or N -doped CNTs began to attract increasing interest owing to their modified structural, physical and chemical properties. In comparison with the multi-walled nanotubes and nanofibers, substitutional doping of the single-walled nanotubes (SWNTs) has proved to be much more difficult, and it is only in very recent years that some experimental studies concerning the B - and/or N -doped SWNTs are emerging. This paper intends to provide an up-to-date overview of current research on the doped SWNTs, with scopes covering both the binary system of CB x- and CN x-SWNTs and the ternary B x C y N z-SWNTs. A survey of the latest achievements in the syntheses of doped SWNTs through either the direct syntheses methods or the post-synthetic substitution reaction route is first presented; then the aspects concerning their structural features, elemental compositions, dopants bonding configuration and atomic distributions, as well as their physical and chemical properties are discussed.