Atomically Sharp Lateral Superlattice Heterojunctions Built‐In Nitrogen‐Doped Nanoporous Graphene

Abstract

Nanometer scale lateral heterostructures with atomically sharp band discontinuities can be conceived as the 2D analogues of vertical Van der Waals heterostructures, where pristine properties of each component coexist with interfacial phenomena that result in a variety of exotic quantum phenomena. However, despite considerable advances in the fabrication of lateral heterostructures, controlling their covalent interfaces and band discontinuities with atomic precision, scaling down components and producing periodic, lattice‐coherent superlattices still represent major challenges. Here, a synthetic strategy to fabricate nanometer scale, coherent lateral superlattice heterojunctions with atomically sharp band discontinuity is reported. By merging interdigitated arrays of different types of graphene nanoribbons by means of a novel on‐surface reaction, superlattices of 1D, and chemically heterogeneous nanoporous junctions are obtained. The latter host subnanometer quantum dipoles and tunneling in‐gap states, altogether expected to promote interfacial phenomena such as interribbon excitons or selective photocatalysis.

Molecular Bridge Engineering for Tuning Quantum Electronic Transport and Anisotropy in Nanoporous Graphene

“…21−23 In these intrinsically anisotropic structures, when adjacent ribbons are not equivalent, band mistmatch can lead to a total confinement of electrons in individual GNRs. 23 In contrast, the lateral coupling of equivalent GNRs can lead to sizable interribbon transmission, giving rise to intriguing quantum interferences that regulate the degree of anisotropy of the nanomaterial. 24 Quantum simulations on electron propagation in different proposed NPG nanoarchitectures indicate that the interribbon transmission can be switched on/off by the chemical modification of the coupling bridges.…”

“…Recently, an OSS synthetic approach based on the lateral coupling of parallel aligned nanoribbons has endowed this atomic engineering capability to the synthesis of two-dimensional nanoarchitectures that can be conceived as nanoporous graphene (NPG). − In these intrinsically anisotropic structures, when adjacent ribbons are not equivalent, band mistmatch can lead to a total confinement of electrons in individual GNRs . In contrast, the lateral coupling of equivalent GNRs can lead to sizable interribbon transmission, giving rise to intriguing quantum interferences that regulate the degree of anisotropy of the nanomaterial .…”

Scanning probe microscopy in probing low-dimensional carbon-based nanostructures and nanomaterials

“…Since the pioneering bottom-up fabrication of armchair GNR (7-AGNR) reported by Cai et al in 2010 [124], on-surface synthesis strategy has displayed its capability in the subtle regulation of the topologies and consequently precise steering of the electronic properties. So far, GNRs with AGNRs and zigzag edges [124][125][126], chiral GNRs [121,127,128], heteroatom-doped GNRs [120,[129][130][131], and extended nanoporous graphenes [132,133] have been precisely synthesized on surfaces and extensively investigated by virtue of SPM techniques. Several strategies turn out to be effective in tuning the band gaps.…”

Steering On-Surface Reactions by Kinetic and Thermodynamic Strategies

“…We note that a similar HCl zipping was recently utilized to fabricate lateral superlattice heterojunctions built-in nitrogen-doped nanoporous graphene. 73 Molecular Concentration for an Intermolecular Reaction. The pre-exponential factor A in the Arrhenius equation is also influenced by the concentration of active molecules, which determines the collision frequency of a reaction.…”

“…Therefore, it has a higher energy than the graphene isomer and is thus inaccessible to synthesize by a conventional method without HF zipping. We note that a similar HCl zipping was recently utilized to fabricate lateral superlattice heterojunctions built-in nitrogen-doped nanoporous graphene …”