The structure of 1D CuI crystals inside SWNTs

Abstract

SummaryNanocomposites consisting of one-dimensional CuI crystals inside single-walled carbon nanotubes were obtained using the capillary technique. high-resolution transmission electron microscopy investigations of the atomic structure of the encapsulated 1D CuI crystals revealed two types of 1D CuI crystals with growth direction <001> and <110> relative to the bulk hexagonal CuI structure. Atomic structure models were proposed based on the high-resolution transmission electron microscopy images. According to the proposed models and image simulations, the main contrast in the 1D crystal images arises from the iodine atoms whereas copper atoms, with lower atomic number giving lower contrast, are thought to be statistically distributed.

The structure of nanocomposite 1D cationic conductor crystal@SWNT

“…Later however, hexagonal AgBr was found at high pressure (Schock and Jemison, 1969). Nevertheless the observed images are similar to the images of 1D CuI@SWNT (Kiselev et al, 2008) and 1D CuBr@SWNT, supporting the hexagonal structure. This is attributed to the constrained space of the SWNT's inner channel and interatomic forces between the AgBr and the cylindrical graphene layer.…”

“…Between these rows a zigzag arrangement of dark (bright at + f ) contrast is sandwiched. The observed image resembles that of 1D CuI@SWNT (Kiselev et al, 2008). Here bromide forms the anion sublattice whereas the Cu cations occupy octahedral positions (Ivanov-Shitz & Murin, 2000;Ivanov-Shitz, 2007).…”

“…In a previous paper (Kiselev et al, 2008), we observed several types of the 1D CuI@SWNT images and suggested a hexagonal anion sublattice.…”

One-Dimensional Crystals inside Single-Walled Carbon Nanotubes: Growth, Structure and Electronic Properties

“…Peapods can also be considered as the "1D-crystal@SWNT" nanocomposites (Smith et al, 1998). It stands to mention that in the SWNTs of various diameters the encapsulated compounds (for instance, KI, PbI 2 , CuI, HgTe) can form structures that differ by the number of atoms in the nanotube cross section or by symmetry (Carter et al, 2006;Flahaut et al, 2006a;Kataura et al, 2002;Kiselev et al, 2008). The structure of such nanocrystals differs substantially from the bulk substances both with regards to their symmetry, bond lengths, and bond angles.…”

“…Geometry of non-interacting atomic packing within one-dimensional cavity Apparently, the nanocrystal structure can change upon variation of the nanotube diameter (e.g. for CuI@SWNT and PbI 2 @SWNT) (Flahaut et al, 2006a;Kiselev et al, 2008). Recently it has been experimentally determined that copper and silver bromides (MHal) 6 /2 can change their symmetry from mm 2 P in the (19,0) and (18,0) SWNTs to m 2 P in the (17,0) SWNTs due to contraction of the <111> and extension of the <112> axis .…”