Dimerization-Initiated Preferential Formation of Coronene-Based Graphene Nanoribbons in Carbon Nanotubes

Abstract

We have investigated the growth mechanism of coronene-derived graphene nanoribbons (GNRs) using two different precursors: coronene and a dimer form of coronene, so-called dicoronylene (C48H20). For both of the precursors, the formation of nanoribbon-like materials inside carbon nanotubes (CNTs) was confirmed by transmission electron microscope observations. Experimental and theoretical Raman analysis reveals that the samples also encapsulated dicoronylene and linearly condensed other coronene oligomers, which can be regarded as analogues to GNRs. Interestingly, it was found that the present doping condition of coronene yields dicoronylene prior to encapsulation due to the thermal dimerization of coronene. These results indicate that the dimerization before the encapsulation drives the preferential formation of the coronene-based GNRs within CNTs.

Growth of carbon nanotubes via twisted graphene nanoribbons

“…Cross-referencing to the simulated Raman spectra of PTCDA and its oligomers, as well as to those of perylene (Supplementary Fig. S10), indicates that the embedded molecules exist as a heterogeneous mixture of monomers (1,296, 1,370, 1,426 and 1,452 cm −1 at a 488 nm excitation) and dimers (1,253, 1,285 and 1,360 cm −1 at 633 nm excitation) as in that of coronene-filled CNTs discussed by Fujihara et al 6. These encapsulated precursors aligned themselves into two linear arrays within CNTs18 as suggested by the dark inner line contrast shown in Fig.…”

“…To tackle this unresolved issue, the nanotesttube chemistry2, in which a CNT is generally used as a container-cum-reactor34, is found to be promising. There are several studies devoted to the fabrication of graphene nanoribbons (GNRs) in CNTs through the confined polymerization of polycyclic aromatic hydrocarbon molecules56. In addition, the theoretical models proposed by Jiang et al 7.…”

Heterospin Junctions in Zigzag-Edged Graphene Nanoribbons

“…Theory predicts a broad set of singular properties [14][15][16], and advances in GNR fabrication have evolved at a fast pace. For instance, it is now feasible to grow narrow and pristine systems through pre-programmed and large-scale synthesis techniques [11,[17][18][19][20][21]. Even though the precise, controlled and scalable fabrication of carbon nanostructures with complex geometries remains a challenge from the experimental point of view, the developing bottom-up synthesis approaches of specific structures provide strong support to the eventual realization of this goal.…”

Thin single-wall BN-nanotubes formed inside carbon nanotubes

“…Single-wall carbon nanotubes (SWCNTs)12345, nano-scale cylinders consisting of single graphene sheet, are one of the most promising candidates for the fabrication of novel one-dimensional (1D) nanomaterials. To date, specific one-dimensional nanostructures, such as 1D crystalline array of molecules6789101112, metal complex nanowires13141516 and metal atomic wires171819, have been created inside SWCNTs, in which the properties of these are substantially different from their bulk counterparts: spontaneous chiral symmetry breaking20 and enlargement of magnetic moment19. However, the small band gap of SWCNTs typically ranging from 0 to about 1 eV23 has so far precluded one from investigating the intrinsic optical and electronic properties of 1D nanostructures formed in SWCNTs.…”