Nitrogen-Doping Induced Self-Assembly of Graphene Nanoribbon-Based Two-Dimensional and Three-Dimensional Metamaterials

Abstract

Narrow graphene nanoribbons (GNRs) constructed by atomically precise bottom-up synthesis from molecular precursors have attracted significant interest as promising materials for nanoelectronics. But there has been little awareness of the potential of GNRs to serve as nanoscale building blocks of novel materials. Here we show that the substitutional doping with nitrogen atoms can trigger the hierarchical self-assembly of GNRs into ordered metamaterials. We use GNRs doped with eight N atoms per unit cell and their undoped analogues, synthesized using both surface-assisted and solution approaches, to study this self-assembly on a support and in an unrestricted three-dimensional (3D) solution environment. On a surface, N-doping mediates the formation of hydrogen-bonded GNR sheets. In solution, sheets of side-by-side coordinated GNRs can in turn assemble via van der Waals and π-stacking interactions into 3D stacks, a process that ultimately produces macroscopic crystalline structures. The optoelectronic properties of these semiconducting GNR crystals are determined entirely by those of the individual nanoscale constituents, which are tunable by varying their width, edge orientation, termination, and so forth. The atomically precise bottom-up synthesis of bulk quantities of basic nanoribbon units and their subsequent self-assembly into crystalline structures suggests that the rapidly developing toolset of organic and polymer chemistry can be harnessed to realize families of novel carbon-based materials with engineered properties.

Atomically precise graphene nanoribbon heterojunctions from a single molecular precursor

“…1a). 3,5,8,10,20 Fig. 1b shows a representative STM topographic image of a GNR functionalized with fluorenone substituents recorded with a CO-functionalized tip.…”

Fluorescence from graphene nanoribbons of well-defined structure

“…Likewise, pump/probe ultrafast transient absorption experiments demonstrated exciton-exciton annihilation and biexciton stimulated emission, with a bi-exciton binding energy of ∼250 meV [24]. Nevertheless, the photoluminescence (PL) properties of GNRs have remained largely underexplored [22,25].…”

Tuning the Electronic Properties of Atomically Precise Graphene Nanoribbons by Bottom‐Up Fabrication

“…(k) and (l) STM image of the NCGNRs with a DFT‐based STM simulation model and its corresponding dI/dV spectra, respectively . (m) and (n) STM image of an 8N‐GNR and its STM dI/dV point spectra, respectively, Scale bars: 2 nm. (o, q) and (p, r) STM images and corresponding NC‐AFM images of two type sulfur‐doped CGNRs, respectively .…”

“…In recent years, GNRs have been extensively investigated as promising building blocks for nanoelectronics and spintronics . Moreover, the electronic properties of GNRs can be modulated at atomic level by changing width of AGNRs, “doping” with heteroatoms and formation of heterojunctions . At the same time, introduction of non‐benzenoid rings into the honeycomb lattice is an effective way to modulate the electronic structures properties of two dimensional carbon‐based structures .…”