Electronic and Transport Properties of Graphene Nanoribbons Based on Super-Heptazethrene Molecular Blocks

Abstract

Motivated by the recent synthesis of super-heptazethrene (S7ZTH) quantum dots, we use theoretical calculations to propose a set of nanoribbons with nontrivial edge structures conceptually based on the fusion of molecular units. As these nanoribbons can be assembled according to a broad set of linking hierarchies, as allowed by the geometry of the quantum dot, we investigate the relation between their electronic properties and details of their complex edge structures. Our simulations demonstrate that all S7ZTH nanoribbons exhibit semiconductor behavior with an electronic band gap strongly influenced by the interplay between lattice bipartition and coupling involving molecular orbitals of successive S7ZTH blocks along the nanoribbon. Carrier mobilities are also computed and compared with graphene nanoribbon counterparts. Since bottom-up routes for the synthesis of carbon nanostructures can be adapted to form intricate junction setups, we also investigated the electronic transport properties of S7ZTH-based nanojunctions composed of a central S7ZTH unit at different orientations. Our results show that the transmission spectrum is highly sensitive to the junction geometry, and we observe spin-dependent features, which can enable applications in nanoelectronics and spintronics.

On-Surface Synthesis and Characterization of Super-nonazethrene

“…The rich chemistry of zethrenes in the solution phase is in contrast to on-surface synthesis of zethrenes, which has largely remained unexplored. Only last year, we reported the on-surface synthesis of unsubstituted super-heptazethrene on Au(111), 27 investigating unconventional π-magnetism at the singlemolecule scale but also enable potential application of zethrenes in molecular electronics and optics, for example, as building blocks for high-mobility graphene nanoribbons and graphene nanoribbon-based spin filter devices 28 and as organic near-infrared dyes. 21 Here, we report a combined in-solution and on-surface synthesis of the hitherto largest zethrene compoundunsubstituted supernonazethrene (1)and its atomic-scale characterization on an inert Au(111) surface.…”

Electronic properties and carrier mobilities of nanocarbons formed by non-benzoidal building blocks

“…This interplay is also discussed in other nanoribbon systems theoretically composed by known molecular building blocks. 44,45 Considering the systems studied in this work and many others studied in the literature, 31,46,47,61,67,68,74 we point out that exploring non-graphitic structures for nanoribbons can open up new application opportunities. Non-graphitic geometries allow one to consider a broad range of structural variations to modulate the electronic properties of nanocarbons.…”

“…This results in low deformation potential values, as discussed for other systems in the literature. 44,60 Except for the E 1c value of the AGNR-9, the deformation potentials for the phpNR-1 are significantly lower than those of AGNRs with similar widths (AGNR-8 and -9) and similar gaps (AGNR-16).…”

“…This interplay is also discussed in other nanoribbon systems theoretically composed by known molecular building blocks. 44,45…”

“…These QDs can also be viewed as potential building blocks for the creation of new quasi-1D and 2D nanostructures. Many of those systems are theorized and studied by simulations, 44,45 but selected cases have also been realized experimentally. 27,34,46 On the other hand, we can cite breakthroughs in the synthesis of non-benzoidal 1D and 2D structures, such as biphenylene 47 and polyazulene nanoribbons.…”