Conversion of pristine and p-doped sulfuric-acid-treated single-walled carbon nanotubes to n-type materials by a facile hydrazine vapor exposure process

► Discovery of a facile method to n-dope carbon nanotubes by vapor-phase hydrazine. ► Confirming covalently bound sulfonic groups on CNTs treated with sulfuric acid. ► Spectroscopic investigation of CNTs' bonding structures after hydrazine treatment. ► Proposing a cycloaddition reaction between graphenic domains of CNTs and reactive nitrogen-containing radicals thermally decomposed from hydrazine. ► Establishing aziridine as a probable n-doping chemical entity on hydrazine-treated CNTs.