Atomic Arrangement of Iodine Atoms inside Single-Walled Carbon Nanotubes

Abstract

We report atomic resolution Z-contrast scanning transmission electron microscopy images that reveal the incorporation of I atoms in the form of helical chains inside single-walled carbon nanotubes. Density functional calculations and topological considerations provide a consistent interpretation of the experimental data. Charge transfer between the nanotube walls and the I chains is associated with the intercalation.

Formation of ordered ice nanotubes inside carbon nanotubes

“…In the widest SWCN (18,18), however, crystallization was not observed within the timescale of simulation. In the narrower SWCNs (14,14) and (15,15), the potential energy also drops markedly on cooling below 300 K, but the change is not as sharp as in the wider nanotubes. Structural analysis shows that confined water has liquid-like disordered structure at high T but turns into solid-like ordered structure at low T-a square nanotube in (14,14) and a pentagonal nanotube in (15,15) In real-world experiments, the atomic structures of Q1D crystals can be determined by using transmission electron microscopy.…”

“…1c. In the narrower (14,14) and (15,15) SWCNs, the liquid phase has a hollow-tube structure (Fig. 2d and e), in sharp contrast to the liquid phase in (16,16) SWCN.…”

“…The ability to encapsulate a material in a nanotube also offers new possibilities for investigating dimensionally confined phase transitions 15 . Particularly intriguing is the conjecture 16 that matter within the narrow confines of a carbon nanotube might exhibit a solid-liquid critical point 17 beyond which the distinction between solid and liquid phases disappears.…”

“…11 Simulations provide this information directly. Figure 2 displays snapshots of the Q1D n-gonal (n = 4-6) ice nanotubes and the corresponding Q1D liquid phases inside the (14,14), (15,15) and (16,16) SWCNs, showing that the disordered liquid-like structures are transformed at low T into distinct n-gonal nanotube structures with long-range order in the axial direction. The n-gonal ice nanotubes satisfy the 'bulk ice rule': every water molecule serves as a double donor and a double acceptor of hydrogen bonds, and every water molecule is hydrogen-bonded to exactly four nearest-neighbour molecules.…”

Raman Spectroscopy of Optical Transitions and Vibrational Energies of ∼1 nm HgTe Extreme Nanowires within Single Walled Carbon Nanotubes

“…10 The interactions between host tube and filling are also interesting. In this respect, the majority of recent studies have focused on charge transfer with both hole doping, from fillings such as iodine 11,12 and more recently graphene nanoribbons, 13 and electron doping, from fillings such as zinc, 14 copper 15 and cadmium halides 16 being demonstrated. Another hypothesised interaction that has received some experimental verification 17 is that electrostatic interactions between ionic fillings and electrons in the nanotube could alter the local electronic bandstructure of the tubes, There is a significant body of work on magnetic nanowires including Fe 18 and Co 19 and EuI 3 .…”