Structures of D5d-C80 and Ih-Er3N@C80 Fullerenes and Their Rotation Inside Carbon Nanotubes Demonstrated by Aberration-Corrected Electron Microscopy

Time-dependent orientational changes of D 5 d -C 80 and I h -Er 3 N@C 80 fullerenes inside single-walled carbon nanotubes (SWNTs) were demonstrated by aberration-corrected transmission electron microscopy (TEM) at real atomic-level resolution. Detailed structure of the ellipsoidal D 5 d -C 80 fullerene, e.g., the pyrene-like tetracyclic component in its cylindrical body, was unambiguously identified by the TEM images. The Er−Er distances in I h -Er 3 N@C 80 were estimated to be 0.35 ± 0.03 nm, and the C 3 symmetry axis of the Er 3 N cluster was suggested to agree with one of the S 6 axes of the spherical I h -C 80 cage. Our results indicate that atomic-resolution TEM enables the investigation of the orientations of individual molecules inside SWNTs in relation to the interactions of the molecules with the outer graphene walls.