GNRs

Researchers from the Max Planck Institute, National Center for Nanoscience and Technology in Beijing, University of Warsaw, TUD Dresden University of Technology, University of Münster, Sichuan University, Friedrich-Alexander-Universität Erlangen-Nürnberg, Empa and Chinese Academy of Science have developed a cyclophane-based molecular shielding strategy that enables the isolation of individual graphene nanoribbons (GNRs) while simultaneously tuning their optoelectronic properties.

Graphene nanoribbons' practical use has long been limited by strong π–π stacking interactions that drive aggregation into bundles, masking intrinsic properties and preventing reliable integration into single-ribbon devices. To address this, the team designed cyclophane-type bridges that sterically shield the GNR backbone while introducing controlled internal strain. Three cyclophane-shielded GNRs (CsGNRs), labeled 1a–c, were synthesized with different tether lengths (benzene–C20–benzene for 1a, C20 for 1b, and C14 for 1c). These structures were derived from ethynyl-substituted cyclopentadienone-based cyclophane monomers, alongside model nanographenes (2a–c) based on a hexa-peri-hexabenzocoronene core.

Researchers from Pohang University of Science and Technology, Griffith University and King Khalid University have developed a graphene-based nanofiltration system that can selectively extract lithium ions from magnesium‑rich brines using sunlight as the driving force. The approach combines edge‑functionalized graphene nanoribbons (GNRs) with photothermally reduced graphene oxide (PrGO), forming sub‑nanometer ion‑coordination channels that enable efficient lithium transport while rejecting competing ions such as magnesium.

Recovering lithium from natural brines is difficult because lithium typically exists at much lower concentrations than other dissolved salts. In South American salt‑flat brines, for example, magnesium concentrations can exceed lithium by ratios of 20:1 or higher. The challenge arises from the similar chemical behavior of the ions, even though their hydration energies differ significantly. Magnesium ions bind water molecules roughly four times more strongly than lithium ions. The new membrane exploits this difference by creating functionalized transport pathways that encourage lithium ions to partially shed their hydration shells and migrate through the membrane while magnesium remains strongly hydrated and effectively blocked.

A recent review by researchers at the Catalan Institute of Nanoscience and Nanotechnology (ICN2) and the Universitu of Barcelona provides an overview of an emerging class of carbon nanomaterials: nanoporous graphenes (NPGs). The work highlights how these structures, conceived as two-dimensional arrays of laterally bonded graphene nanoribbons (GNRs), could transform the future of nanoelectronics and spintronics.

Built through bottom-up on-surface synthesis, this approach enables atomic precision in assembling carbon nanoarchitectures, offering tunable electronic and magnetic properties. While GNRs have long been central to nanoelectronics due to their semiconducting and π-conjugated characteristics, NPGs extend their functionality by providing an intrinsic platform to regulate electronic coupling between adjacent ribbons. This feature allows for the controlled emergence of quantum anisotropy, where electrical conduction varies according to direction.

Researchers from Empa, Chinese Academy of Sciences, the Chinese University of Hong Kong and Max Planck Institute for Polymer Research have developed a hybrid system in which porphyrins are attached to graphene nanoribbons (GNRs) in a precise and well-defined manner. 

Image credit: Credit: Swiss Federal Laboratories for Materials Science and Technology

Graphene nanoribbons with zigzag edges are promising materials for spintronic devices, owing to their tunable bandgaps and spin-polarized edge states. Porphyrins offer complementary optoelectronic benefits. In the new system, a graphene ribbon just one nanometer wide with zigzag edges is used as a molecular wire, along which porphyrin molecules are docked at perfectly regular intervals, alternating between the ribbon’s left and right sides.

Researchers from the National University of Singapore (NUS), working with teams from University of California, Kyoto University and others, have reported a breakthrough in the development of next-generation graphene-based quantum materials, opening new horizons for advancements in quantum electronics.

An atomic model of the Janus graphene nanoribbons (left) and its atomic force microscopic image (right). Image credit: NUS
 

The innovation involves a novel type of graphene nanoribbon (GNR) named Janus GNR (JGNR). The material has a unique zigzag edge, with a special ferromagnetic edge state located on one of the edges. This unique design enables the realization of one-dimensional ferromagnetic spin chain, which could have important applications in quantum electronics and quantum computing.

Van der Waals encapsulation of 2D materials in hBN stacks could be a promising way to create ultrahigh-performance electronic devices. However, current approaches for achieving van der Waals encapsulation, which involve artificial layer stacking using mechanical transfer techniques, are difficult to control, prone to contamination and unscalable. 

Researchers at Shanghai Jiao Tong University, Wuhan University, Ulsan National Institute of Science and Technology, National Institute for Materials Science and Tel Aviv University recently reported the transfer-free direct growth of high-quality graphene nanoribbons (GNRs) in hexagonal boron nitride (hBN) stacks. The as-grown embedded GNRs exhibited highly desirable features being ultralong (up to 0.25 mm), ultranarrow (<5 nm) and homochiral with zigzag edges. 

A team of scientists, led by David Serrate, CSIC scientist at the Instituto de Nanociencia y Materiales de Aragón, INMA (a joint institute of the CSIC and the University of Zaragoza), has imaged for the first time the magnetic behavior of a graphene nanostructure. The team has not only revealed the magnetic state of narrow graphene ribbons (~2 nm), but has also shown the method they developed to magnetically characterize any planar nanographene.

Starting with a specifically designed organic precursor, the researchers synthesized the ribbons directly onto a magnetic surface, obtaining atomically precise edges that contain an alternating sequence of zig-zag graphene segments. This geometry strongly confines the graphene electron cloud around the edge, which causes the instability responsible for the intrinsic magnetism of the graphene nanostructure –a remarkable fact taking into account that the ribbon is formed just by non-magnetic carbon and hydrogen atoms.

Researchers from the University of Illinois at Urbana─Champaign and the University of Nebraska─Lincoln have developed a method for "wiring up" graphene nanoribbons (GNRs). Using a direct-write scanning tunneling microscopy (STM) based process, the nanometer-scale metal contacts were fabricated on individual GNRs and could control the electronic character of the GNRs. 

The team says that this is the first demonstration of making metal contacts to specific GNRs with certainty and that those contacts induce device functionality needed for transistor function.

Researchers from Empa and ETH Zurich, in collaboration with partners from Peking University, the University of Warwick and the Max Planck Institute for Polymer Research, have succeeded in attaching electrodes to individual atomically precise graphene nanoribbons, paving the way for precise characterization of the ribbons and their possible use in quantum technology.

Researchers attach carbon nanotube electrodes to individual atomically precise nanoribbons. (Image credit: Empa, from: Nanowerk)

In the coming decades, quantum technology is expected to provide various technological breakthroughs: smaller and more precise sensors, highly secure communication networks, and powerful computers that can help develop new drugs and materials, control financial markets, and predict the weather much faster than current computing technology ever could. To achieve this, there is a need so-called quantum materials: substances that exhibit pronounced quantum physical effects. One such material is graphene. Giving it a ribbon-like shape,  for example, gives rise to a range of controllable quantum effects.

Researchers from Columbia University, Technical University of Denmark, Aarhus University, Université Paris-Saclay and Japan's National Institute for Materials Science have designed a simple fabrication technique that could help study the fundamental properties of twisted layers of graphene and other 2D materials in a more systematic and reproducible way. The team used long “ribbons” of graphene, rather than square flakes, to create devices that offer a new level of predictability and control over both twist angle and strain.

Graphene devices have typically been assembled from atom-thin flakes of graphene that are just a few square millimeters. The resulting twist angle between the sheets is fixed in place, and the flakes can be tricky to layer together smoothly. “Imagine graphene as pieces of saran wrap—when you put two pieces together you get random little wrinkles and bubbles,” says Columbia postdoc Bjarke Jessen, a co-author on the paper. Those bubbles and wrinkles are akin to changes in the twist angle between the sheets and the physical strain that develops in between and can cause the material to buckle, bend, and pinch randomly. All these variations can yield new behaviors, but they have been difficult to control within and between devices.