Interaction between single walled carbon nanotube and 1D crystal in CuX SWNT X Cl, Br, I nanostructures

CuX SWCNT X Cl, Br, I nanostructures were prepared by capillary filling of 1.4 1.6 nm single walled carbon nanotubes SWCNT with copper halides. The structure of CuX SWCNT X Cl, Br, I represents a distorted two layer hcp of halogen atoms arranged along the SWCNT. The EXAFS and the high angle angular dark field HAADF HRTEM data indicate that Cu is partially coordinated by C. According to the optical absorption, valence band photoemission spectroscopy and work function measurements, a Fermi level FL downshift as compared with the initial value for the nanotubes and a corresponding charge transfer from the nanotubes to the 1D crystals is observed for CuX SWCNT nanostructures. The FL shift increases in the sequence CuI lt; CuBr lt; CuCl due to an increase of the electron affinity for the halogen atoms. The XPS data confirm the acceptor effect of copper halides and indicate that metallic and semiconducting nanotubes behave differently. Raman spectroscopy performed under electrochemical charging allowed estimation of the value of charge transfer between the nanotube walls and the intercalated 1D crystal. The X ray absorption and emission spectra for carbon and copper thresholds revealed a new energy level composed of the carbon 2pz and copper 3d orbitals. This indicates the Cu C bonding, which in line with the structural HAADF HRTEM and EXAFS dat