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 <CuBr <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 est