Phase Separation of LaI₃ inside Single‐Walled Carbon Nanotubes

Abstract

Simple binary solids can be found to adopt unprecedented structures when confined into nanometre-sized cavities, such as the inner cylindrical bore of single-walled carbon nanotubes (SWNT). In the case of the discussed Lal(x)@SWNT encapsulation composite, the Lal2 "crystal" fragment adopts the structure of bulk Lal3, with one third of the iodine positions unoccupied. A complete characterisation of the encapsulation composite was achieved using an enhanced digital restoration approach of high-resolution transmission electron microscopy (HRTEM) images. The resulting complex exit surface wave provides information about the precise structural data of both filling material and host SWNT, establishing the SWNT's chirality and thus enabling a prediction of the composite's overall electron-transport properties.

Carbon Nanotubes as Containers

“…Sometimes, encapsulation of ionic salts produces unexpected results. For example, the stoichiometry of lanthanum iodide inserted in carbon nanotubes was found to be LaI 2 by HRTEM, which is different from the LaI 3 usually observed in the bulk [86]. This change in the salt composition upon encapsulation within a nanotube was attributed to the confinement effects permitting only two iodide anions per each metal cation and possible electronic interactions between the guest compound and the nanotube potentially stabilizing the unusual stoichiometry.…”

Capillary Imbibition of Gadolinium Halides into WS2 Nanotubes: a Molecular Dynamics View

“…As a host medium, the nanotubes can improve the long‐term chemical stability of encapsulated materials or act as a vehicle to deliver minute quantities of the guest substances ,. However, in many cases, the encapsulated compounds can also undergo further chemical transformation: e.g., BaI 2 and ErCl 3 crystallize with unusual ionic coordination, while lanthanum iodide adopts an uncommon stoichiometric composition (LaI 2 ), which may cause new electronic, luminescent, and magnetic properties.…”

Molecular-dynamics simulations of capillary imbibition of KI melt into MoS2 nanotubes

“…In many cases a compound imbibed is crystallized with unusual ionic coordination (e.g., BaI 2 [13], ErCl 3 [14]) or even with different stoichiometric composition (LaI 2 [15]), which may stimulate the appearance of new electronic, luminescent and magnetic properties [16].…”