title: LaI2@(18,3)SWNT: the unprecedented structure of a LaI2 "Crystal," encapsulated within a single-walled carbon nanotube.
abstract: The novel crystallization properties of nano-materials represent a great challenge to researchers across all disciplines of materials science. Simple binary solids can be found to adopt unprecedented structures, when confined into nanometer-sized cavities, such as the inner cylindrical bore of single-walled carbon nanotubes (SWNT). Lanthanum iodide was encapsulated within SWNTs and the resulting encapsulation composite was analyzed using energy-dispersive X-ray microanalysis (EDX) and high-resolution transmission electron microscopy (HRTEM) imaging techniques, to reveal a one-dimensional crystal fragment, with the stoichiometry of LaI2, crystallizing in the structure of LaI3 with one third of the iodine positions unoccupied. A complete characterization of the encapsulation composite was achieved using an enhanced image restoration technique, which restores the object wave from a focal series of HRTEM images, providing information about the precise structural data of both filling material and host SWNT, and thereby enabling the identification of the SWNT chirality.
authors.affiliation: Nanoscience Centre, University of Cambridge, 11 J.J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom. sf334@cam.ac.uk
authors.forename: Steffi
authors.initials: S
authors.lastname: Friedrichs
authors.forename: Angus I
authors.initials: AI
authors.lastname: Kirkland
authors.forename: Rüdiger R
authors.initials: RR
authors.lastname: Meyer
authors.forename: Jeremy
authors.initials: J
authors.lastname: Sloan
authors.forename: Malcolm L H
authors.initials: ML
authors.lastname: Green