Selective Interaction of Large or Charge-Transfer Aromatic Molecules with Metallic Single-Wall Carbon Nanotubes:  Critical Role of the Molecular Size and Orientation

Abstract

Using first principles calculations, we report for the first time that large nearly neutral aromatic molecules, such as naphthalene and anthracene, and small charge-transfer aromatic molecules, such as TCNQ and DDQ, interact more strongly with metallic single-wall carbon nanotubes (SWNTs) versus their semiconducting counterparts as the molecular orientation of DDQ is taken into account. Hence two new mechanisms for separating metallic and semiconducting SWNTs via noncovalent pi-pi stacking or charge-transfer interaction are suggested.

Exploring the alignment of carbon nanotubes dispersed in a liquid crystal matrix using coplanar electrodes

“…41 Indeed, Beless et al demonstrated that substituted biphenyl compounds, such as those in E7, are able to adsorb efficiently onto carbon nanotubes provided the aromatic rings were not sterically hindered against entering a plane with each other. 42 The electron deficient cyano group, present on all the components of E7, are known to interact with SWCNTs 43,44 via the formation of a charge transfer complex. Harrison et al reported cyano-SWCNT charge-transfer complexes to be the cause on upshifts in the SWCNT G band of þ4 cm…”

Selection of single-walled carbon nanotubes according to both their diameter and chirality via nanotweezers

“…We tentatively ascribe this discrepancy to a toluene solvent effect in the experiment, since a gas phase model is The calculated selectivities of the three nanotweezers for the zigzag tubes versus the armchair tubes are attributed to the fact that the hexagonal carbon ring of the three nanotweezers is identical with (matches) that on the zigzag tube sidewall. Our previous calculations [22,23] demonstrate that the alignment between the hexagonal ring of planar aromatic molecules and that of SWNTs can stabilize the adsorption (by atomic correlation effects). Since the hexagonal rings of the anthracene-, pentacene-, and heptacene-based nanotweezers are aligned with those on the sidewall of zigzag SWNTs, these three molecules all prefer to attach to the zigzag SWNTs.…”

“…In fact, the LDA has been widely used to study the π-π stacking interaction between molecules and SWNTs [31,33,34] and in other large systems [30,35]. We use the LDA to study the interaction between aromatic moleculebased nanotweezers and SWNTs, inspired by the fact that the our previous LDA calculations [22,23] correctly predicted the selectivity of planar aromatic molecules towards SWNTs [24].…”

“…Experimentally, Nicholas et al and Chen et al reported that fluorinebased polymers with different structures are capable of preferentially wrapping SWNTs with high chiral angles (θ > 24.5°) or certain diameters [20,21]. Lu et al [22,23] predicted theoretically that certain planar aromatic molecules can selectively interact with armchair (θ = 30°) or zigzag (θ = 0°) SWNTs depending on the structural compatibility between them, by using density functional theory (DFT) calculations. Later Meunier et al confirmed that a pentacene-based amphiphile can selectively solubilize armchair SWNTs, whereas a quaterrylene-based amphiphile can selectively solubilize zigzag SWNTs as a result of structural compatibility [24].…”

Formation of contacts between doped carbon nanotubes and aluminum electrodes

“…As CNTs are hollow, it is also possible to incorporate dopants within the interior of the CNT, i.e., endohedral doping. Endohedral dopants, such as fullerenes, 24 metallocenes, 25 and organic molecules, 24,[26][27][28][29][30] relevant CNTs. Idealized nitrogen and boron doped CNTs (i.e., we assume no additional defects) are considered for pand n-type doping, respectively, along with the endohedral dopant tetrathiafulvalene (TTF) which is known to induce ntype doping in CNTs and is stable in atmosphere.…”