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Stimulated emission depletion (STED) microscopy is compromised by the trade-off between resolution and photobleaching. Here, the authors present ReSTED, a reactivatable STED microscopy using fluorescence-recoverable nanographene that enables hour-long, super-resolution 3D imaging without bleaching.

Chemical functionalization of graphene is a useful method for modulating its properties, although this is limited by a lack of control and resulting in poorly defined structures. Here the authors report the atomically precise chlorination of nanographenes and apply the methods to graphene nanoribbons.

Quintulene, a quintuple non-graphitic cycloarene, is challenging to synthesize. Here, the authors synthesize and characterize the cone-shaped extended quintulene and its bilayer dimer, and disclose its dimerization as an entropy-driven, second-order reaction with a substantial activation energy.

The optical properties of nanographenes can be engineered by designing their size, shape, and edges. Here, the authors show that graphene quantum dots are single photon emitters at room temperature, and their emission wavelength can be controlled by edge functionalization.

Graphene nanoribbons show promise for high-performance field-effect transistors, however they often suffer from short lengths and wide band gaps. Here, the authors use a bottom-up synthesis approach to fabricate 9- and 13-atom wide ribbons, enabling short-channel transistors with 10⁵ on-off current ratio.

On-surface synthesis relies on carefully designed molecular precursors that are thermally activated to afford desired, covalently coupled architectures. Here, the authors study the intramolecular reactions of vinyl groups in a poly-para-phenylene-based model system and provide a comprehensive description of the reaction steps taking place on the Au(111) surface under ultrahigh vacuum conditions.

Metal single-atom catalysts offer great potential in bridging the gap between heterogeneous and homogeneous catalysis. Here the authors demonstrate a multilayer stabilization strategy for fabricating high-loading single-atom catalysts including non-precious and noble metals.

Molecular graphene nanoribbons hold promise for quantum experiments in single-electron transistors but require improvements in their debundling. Here, the authors demonstrate ultra-clean transport devices by enhancing nanoribbon solubility via bulky groups on the nanoribbon edges.

Numerous fabrication methods have been developed so far for the production of graphenes and nanographenes. However, how practical is the bulk production of these fascinating materials? This Perspective discusses recent advances in graphene fabrication and possibilities for translation to large-scale production.

In this review, we summarize the use of Diels–Alder reaction in the synthesis of arylene-based polymers, including polyphenylenes and ladder polymers, as well as graphene nanoribbons. These polymer materials are structurally related to each other, but rarely discussed all together in a same context. The importance and versatility of the Diels–Alder polymerization is highlighted for the synthesis of such polymers with various potential applications, for example, as polymer electrolyte membrane and organic semiconductors.

Open-shell nanographenes are promising for quantum technologies, but their magnetic stability has remained limited by weak exchange coupling. Now, two large rhombus-shaped nanographenes with zigzag peripheries, one with 48 carbon atoms and the other with 70, have been synthesized on gold and copper surfaces. The 70-carbon compound exhibits a large magnetic exchange coupling exceeding 100 meV.

The insertion of metal atoms and heteroaromatic units provides a way to tune the optical, electronic and magnetic properties of graphene nanoribbons. Now the synthesis of a porphyrin-fused graphene nanoribbon with a narrow bandgap and high charge mobility has been achieved, and this material used to fabricate field-effect and single-electron transistors.

Graphene nanoribbons confine electrons to just one dimension and this gives rise to strong electron–hole interactions. Here, the authors investigate the creation and recombination of biexcitons in these structures by ultrafast optical pulses using femtosecond transient absorption spectroscopy.

Two-dimensional material heterostructures enable unique electronic features by introducing periodic potentials. Here, Gobbiet al. use a monolayer supramolecular lattice with a tunable one-dimensional periodic potential to modify the electronic structure of graphene.

The presence of graphitic nitrogen atoms within graphene nanoribbons has been predicted to strongly affect their electronic properties, but its experimental formation within such structures remains challenging. Here, the authors report on the on-surface synthesis of pyridine-extended 7-armchair graphene nanoribbons on Au(111), whereby graphitic nitrogen is preferentially formed after complete planarization through the formation of C–N bonds.

On-surface methods can be used to synthesize organic molecules, polymers and nanomaterials, however, the diversity of conceivable products is limited by the number of known on-surface reactions. Now, a phenylene ring-forming reaction on a gold surface by intermolecular oxidative coupling of isopropyl substituents on arenes is reported. The reaction is probed using bond-resolved imaging and computational modelling.

The bottom-up fabrication of structures with robust performance in the nm-to-μm scale usable for integrated carbon nanodevices is challenging. Here the authors report micrometer-long, highly conducting nanographene wires following self-assembly, photo-crosslinking and thermal annealing of anthracene derivatives on hexagonal boron nitride sheets.

Polyaromatic hydrocarbons can be precisely manipulated to yield ever more complex and discrete graphene analogs, such as nanographenes. Here, the authors use azomethine ylide homocoupling to insert an antiaromatic pyrazine ring into the core of a nanographene, and characterize the molecule’s unique electronic character.

A critical milestone for the advancement of nanoscale organic circuitry is the fabrication of well-defined conjugated polymers on non-metal substrates. Here, the authors demonstrate extended polycyclic aromatic chains from repetitive cycloadditions which form not only on metals, but also on boron nitride layers and in the solid state.

Liquid-phase-processable graphene nanoribbons (GNRs) over 200 nm long and with well-defined structures have now been synthesized by a bottom-up method, and are found to have a large optical bandgap of 1.88 eV. Scanning probe microscopy revealed highly ordered self-assembled monolayers of the GNRs, and the high intrinsic charge-carrier mobility of individual ribbons was characterized by terahertz spectroscopy.

By functionalizing molecular graphene nanoribbons with stable spin-bearing nitronyl nitroxide radical groups, delocalized magnetic edge states are observed, with microsecond-scale spin coherence times.

Graphene nanoribbons are used to design robust nanomaterials with controlled periodic coupling of topological boundary states to create quasi-one-dimensional trivial and non-trivial electronic quantum phases.

Efficient terahertz harmonic generation—challenging but important for ultrahigh-speed optoelectronic technologies—is demonstrated in graphene through a nonlinear process that could potentially be generalized to other materials.

The intrinsic flexibility of molecules opens the door to unusual physical properties. Now, a large thermal expansion coefficient of 980 ± 110 × 10⁻⁶ K⁻¹ is observed by scanning probe microscopy in a supramolecular network on a gold surface.