Heterostructures through Divergent Edge Reconstruction in Nitrogen‐Doped Segmented Graphene Nanoribbons

Abstract

Atomically precise engineering of defined segments within individual graphene nanoribbons (GNRs) represents a key enabling technology for the development of advanced functional device architectures. Here, the bottom-up synthesis of chevron GNRs decorated with reactive functional groups derived from 9-methyl-9H-carbazole is reported. Scanning tunneling and non-contact atomic force microscopy reveal that a thermal activation of GNRs induces the rearrangement of the electron-rich carbazole into an electron-deficient phenanthridine. The selective chemical edge-reconstruction of carbazole-substituted chevron GNRs represents a practical strategy for the controlled fabrication of spatially defined GNR heterostructures from a single molecular precursor.

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.…”

“…[1][2][3][4] Although several topdown techniques exist for fabricating GNRs, only bottom-up synthesis of GNRs from molecular 3 precursors yields nanoribbons with atomically-defined structure and dopant control. [5][6][7][8][9][10] A unique aspect of bottom-up GNRs is that they provide extensive opportunities for creating atomically precise molecular heterojunctions where two different GNR types bond at an interface.…”

Graphene-like nanoribbons periodically embedded with four- and eight-membered rings

“…In this way, the electronic and magnetic properties, such as band gap and spin-polarized edge states, can be readily tuned8910. The electronic properties of GNRs can also be modulated at nanoscale by chemical doping11121314 and formation of heterojunctions1516. At the same time, decorating non-hexagonal rings into the honeycomb lattice, which is an effective way to tailor the electronic structures and magnetic properties of such low-dimensional carbon-based structures171819, has been intensively studied.…”

Inserting Porphyrin Quantum Dots in Bottom‐Up Synthesized Graphene Nanoribbons

“…Recent advances in the bottom-up synthesis of semiconducting graphene nanoribbons (GNRs), quasi-one dimensional strips of single-layer graphene, have enabled the preparation of carbon-based nanomaterials with exquisite control over the width, [1][2][3][4][5] the crystallographic symmetry (e.g.armchair, [1][2][3][4][5][6][7][8][9][10][11][12][13] zig-zag [14] ), and the edge structure (cove, [15][16] chevron [1,[17][18][19][20] ) both in solution and on metal surfaces. While bottom-up synthesized GNRs have been touted for their intrinsic exotic electronic, [21][22][23][24][25][26][27][28][29][30][31] magnetic, [25,[29][30][31][32] and optical properties, [16,27,28,[33][34] examples for the deterministic assembly of functional bottom-up ...…”

“…While bottom-up synthesized GNRs have been touted for their intrinsic exotic electronic, [21][22][23][24][25][26][27][28][29][30][31] magnetic, [25,[29][30][31][32] and optical properties, [16,27,28,[33][34] examples for the deterministic assembly of functional bottom-up synthesized GNRs heterostructures have thus far been limited to uncontrolled copolymerization of molecular precursors on metal surfaces [6,13,18,20] or the study of smallmolecule model systems in solution. [35][36][37] We herein report the solution-based bottom-up synthesis and characterization of a GNR heterostructure comprised of two segments of solubilized cove GNRs (cGNRs) linked by a substituted tetraphenylporphyrin core (1, Scheme 1) acting as a highly tunable molecular quantum dot (QD).…”