Li+ and OH− modified single-walled carbon nanotubes (SWNTs) treated with the LiOH water solution have been investigated by soft-x-ray absorption and resonant emission spectroscopy. A reconstruction of the band structure after hydroxyl modification and intensity changes between π and σ states in the resonant emission spectra are presented and discussed. A charge transfer induced valence state near Fermi level has been detected at the resonant excitation energy of 285.5 eV, which indicates the tuning of electronic properties of SWNTs by Li+ adsorption.
