Fine tuning the charge transfer in carbon nanotubes via the interconversion of encapsulated molecules

Abstract

Tweaking the properties of carbon nanotubes is a prerequisite for their practical applications.Here we demonstrate fine-tuning the electronic properties of single-wall carbon nanotubes via filling with ferrocene molecules. The evolution of the bonding and charge transfer within the tube is demonstrated via chemical reaction of the ferrocene filler ending up as secondary inner tube. The charge transfer nature is interpreted well within density functional theory. This work gives the first direct observation of a fine-tuned continuous amphoteric doping of single-wall carbon nanotubes.

Orbital and spin magnetic moments of transforming one-dimensional iron inside metallic and semiconducting carbon nanotubes

“…2(a). The spectral shapes before annealing are in good agreement with those of ferrocene encapsulated in SWCNT, reported in the previous work on mixed 31 and separated samples. 41 The main spin-orbit splitting features L 3 and L 2 located at 710.3, 712.5 eV, and 722.6, 724.9 eV, respectively, coincide with those characteristic to the molecular orbitals of ferrocene observed in solids.…”

“…12,30 In recent years, metallocene filled and especially ferrocene filled carbon nanotubes (FeCp 2 @SWCNT) have been widely studied both experimentally and theoretically. Their electronic properties can be modified via filling followed by the transformation of the molecules inside into inner tubes and cementite clusters 14,31 utilizing a nanochemical reaction. By the decomposition of the FeCp 2 inside the nanotubes, encapsulated Fe nanowire can be formed.…”

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

“…Since this research area has been under development only for the past compounds or changes in the atomic and electronic structure of the encapsulated compounds due to forced structural deformations of the materials inside the single-walled nanotubes (Shiozawa et al, 2008). The "1D-crystal@SWNT" nanocomposite structures are most efficiently studied by high resolution transmission electron microscopy.…”

“…To overcome this problem, an elegant approach was proposed, which includes filling of the SWNTs from the vapor phase with large metalloorganic compounds like FeCp2 (Shiozawa et al, 2008) and CeCp2 with their subsequent transformation upon heating. For example, annealing in vacuum converts the encapsulated cerocene into the nano-structured cerium within the nanotubes; at the same time, the cyclopentadiene rings form an internal wall of the nanotube, thus it becomes double-walled.…”

Combined experimental andab initiostudy of the electronic structure of narrow-diameter single-wall carbon nanotubes with predominant (6,4),(6,5) chirality

“…This was successfully achieved by high-temperature annealing of peapods ͑C 60 @ SWCNTs͒ without any further catalyst [9][10][11] and by a catalytic reaction in metallocene filled SWCNTs. [12][13][14] Besides this direct growth of narrow diameter tubes, in recent years great progress in the separation of narrow diameter tubes has been achieved. [15][16][17][18][19][20][21] The main techniques comprise DNA wrapping, 15,18,22,23 chromatographic separation, 15,19 and density gradient ultracentrifugation ͑DGU͒.…”