Using Electrical Impedance Spectroscopy to Separately Quantify the Effect of Strain on Nanosheet and Junction Resistance in Printed Nanosheet Networks.

Many printed electronic applications require strain-independent electrical properties to ensure deformation-independent performance. Thus, developing printed, flexible devices using 2D and other nanomaterials will require an understanding of the effect of strain on the electrical properties of nano-networks. Here, novel AC electrical techniques are introduced to fully characterize the effect of strain on the resistance of high-mobility printed networks, fabricated from of electrochemically exfoliated MoS nanosheets.

Mn-doped WSe as an efficient electrocatalyst for hydrogen production and as anode material for lithium-ion batteries.

The ongoing energy crisis has made it imperative to develop low-cost, easily fabricated, yet efficient materials. It is highly desirable for these nanomaterials to function effectively in multiple applications. Among transition metal dichalcogenides, tungsten diselenide (WSe) shows great promise but remains understudied.

GeSe-embedded metal-oxide double heterojunctions for facilitating self-biased and efficient NIR photodetection.

Infrared radiation detection is significantly important in communication, imaging, and sensing fields. Here, we present the integration of germanium selenide (GeSe) with a metal-oxide heterojunction to achieve efficient near-infrared (850 nm) photodetection under zero bias conditions. Nickel oxide (NiO) and silicon (Si) formed a favorable energy band alignment for the efficient separation of photogenerated charge carriers, resulting in a high figure of merits.

Production of Ultrathin and High-Quality Nanosheet Networks via Layer-by-Layer Assembly at Liquid-Liquid Interfaces.

Solution-processable 2D materials are promising candidates for a range of printed electronics applications. Yet maximizing their potential requires solution-phase processing of nanosheets into high-quality networks with carrier mobility (μ) as close as possible to that of individual nanosheets (μ). In practice, the presence of internanosheet junctions generally limits electronic conduction, such that the ratio of junction resistance () to nanosheet resistance (), determines the network mobility via μ/μ ≈ / + 1.

Hydrogen Evolution Reaction Activity in MoTiCT MXene Derived from MoTiAlC MAX Phase: Insights from Compositional Transformations.

MAX phases represent a crucial building block for the synthesis of MXenes, which constitute an intriguing class of materials with significant application potential. This study investigates the catalytic properties of the MoTiAlC MAX phase and the corresponding MoTiCT MXene for the hydrogen evolution reaction (HER). Characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) revealed that despite the presence of secondary phases, the HER catalytic activity is primarily influenced by the MAX phase and its derived MXene.

Functionalisation of graphite and thermally reduced graphene oxide with bis-hydrazone copper(I) nitrate salt.

The solvothermal functionalization of graphite and thermally reduced graphene oxide (TRGO) using a bis-hydrazone copper(I) complex is demonstrated. This treatment resulted in a remarkable 328% increase in the BET specific surface area of graphite, reaching 374 m g, while the surface area of TRGO remained unchanged. The hybrid composites show promise as potential components for gas sensors.

Extremely Durable K-Ion Batteries Enabled by Heteroatom Co-Doped Highly-Ordered Porous Carbon Spheres with Nearly 100% Capacity Retention up to 11,000 Cycles.

Currently, one major target for exploring K-ion batteries (KIBs) is enhancing their cycle stability due to the intrinsically sluggish kinetics of large-radius K ions. Herein, we report a rationally designed electrode, the S/O co-doped hard carbon spheres with highly ordered porous characteristics (SPC), for extremely durable KIBs. Experimental results and theory calculations confirm that this structure offers exceptional advantages for high-performance KIBs, facilitating rapid K diffusion and (de)-intercalation, efficient electrolyte penetration and transport, improved K storage sites, and enhanced redox reaction kinetics, thus ensuring the long-term cycle stability.

Enhancing the oxygen evolution reaction activity of CuCo based hydroxides with VCT MXene.

The oxygen evolution reaction (OER) is a key reaction in the production of green hydrogen by water electrolysis. In alkaline media, the current state of the art catalysts used for the OER are based on non-noble metal oxides. However, despite their huge potential as OER catalysts, these materials exhibit various disadvantages including lack of stability and conductivity that hinder the wide-spread utilization of these materials in alkaline electrolyzer devices.

A library of 2D electronic material inks synthesized by liquid-metal-assisted intercalation of crystal powders.

Solution-processable 2D semiconductor inks based on electrochemical molecular intercalation and exfoliation of bulk layered crystals using organic cations has offered an alternative pathway to low-cost fabrication of large-area flexible and wearable electronic devices. However, the growth of large-piece bulk crystals as starting material relies on costly and prolonged high-temperature process, representing a critical roadblock towards practical and large-scale applications. Here we report a general liquid-metal-assisted approach that enables the electrochemical molecular intercalation of low-cost and readily available crystal powders.

Maximizing Potential Applications of MAX Phases: Sustainable Synthesis of Multielement TiAlC.

This study employs the molten-salt-shielded method to dope the TiAlC MAX phase with Nb and Mo, aiming to expand the intrinsic potential of the material. X-ray diffraction confirms the preservation of the hexagonal lattice structure of TiAlC, while Raman and X-ray photoelectron spectroscopic analyses reveal the successful incorporation of dopants with subtle yet significant alterations in the vibrational modes and chemical environment. Scanning electron microscopy with energy-dispersive X-ray spectroscopy characterizations illustrate the characteristic layered morphology and uniform dopant distribution.

2D Rhenium- and Niobium-Doped WSe Photoactive Cathodes in Photo-Enhanced Hybrid Zn-Ion Capacitors.

Designing a multifunctional device that combines solar energy conversion and energy storage is an appealing and promising approach for the next generation of green power and sustainable society. In this work, we fabricated a single-piece device incorporating undoped WSe, Re- or Nb-doped WSe photocathode, and zinc foil anode system enabling a light-assisted rechargeable aqueous zinc metal cell. Comparison of structural, optical, and photoelectric characteristics of undoped and doped WSe has further confirmed that ionic insertion of donor metal (rhenium and niobium) plays an important role in enhancing photoelectrochemical energy storage properties.

Unconventional superconductivity in chiral molecule-TaS hybrid superlattices.

Chiral superconductors, a unique class of unconventional superconductors in which the complex superconducting order parameter winds clockwise or anticlockwise in the momentum space, represent a topologically non-trivial system with intrinsic time-reversal symmetry breaking (TRSB) and direct implications for topological quantum computing. Intrinsic chiral superconductors are extremely rare, with only a few arguable examples, including UTe, UPt and SrRuO (refs. ).

Electronic Band Structure and Optical Properties of HgPS Crystal and Layers.

Transition metal thiophosphates (MPS) are of great interest due to their layered structure and magnetic properties. Although HgPS may not exhibit magnetic properties, its uniqueness lies in its triclinic crystal structure and in the substantial mass of mercury, rendering it a compelling subject for exploration in terms of fundamental properties. In this work, we present comprehensive experimental and theoretical studies of the electronic band structure and optical properties for the HgPS crystal and mechanically exfoliated layers from a solid crystal.

Doping-control of excitons and magnetism in few-layer CrSBr.

Magnetism in two-dimensional materials reveals phenomena distinct from bulk magnetic crystals, with sensitivity to charge doping and electric fields in monolayer and bilayer van der Waals magnet CrI. Within the class of layered magnets, semiconducting CrSBr stands out by featuring stability under ambient conditions, correlating excitons with magnetic order and thus providing strong magnon-exciton coupling, and exhibiting peculiar magneto-optics of exciton-polaritons. Here, we demonstrate that both exciton and magnetic transitions in bilayer and trilayer CrSBr are sensitive to voltage-controlled field-effect charging, exhibiting bound exciton-charge complexes and doping-induced metamagnetic transitions.

Probing the Band Splitting near the Γ Point in the van der Waals Magnetic Semiconductor CrSBr.

This study investigates the electronic band structure of chromium sulfur bromide (CrSBr) through comprehensive photoluminescence (PL) characterization. We clearly identify low-temperature optical transitions between two closely adjacent conduction-band states and two different valence-band states. The analysis on the PL data robustly unveils energy splittings, band gaps, and excitonic transitions across different thicknesses of CrSBr, from monolayer to bulk.

Study of VCT-MXene Based Immunosensor for Sensitive Label-Free Impedimetric Detection of SARS-CoV-2 Spike Protein.

Rapid and reliable immunosensing is undoubtedly one of the priorities in the efficient management and combat against a pandemic, as society has experienced with the SARS-CoV-2 outbreak; simple and cost-effective sensing strategies are at the forefront of these efforts. In this regard, 2D-layered MXenes hold great potential for electrochemical biosensing due to their attractive physicochemical properties. Herein, we present a VCT MXene-based sensing layer as an integral part of a label-free immunosensor for sensitive and selective detection of the SARS-CoV-2 spike protein.

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The exploration of 1D magnetism, frequently portrayed as spin chains, constitutes an actively pursued research field that illuminates fundamental principles in many-body problems and applications in magnonics and spintronics. The inherent reduction in dimensionality often leads to robust spin fluctuations, impacting magnetic ordering and resulting in novel magnetic phenomena. Here, structural, magnetic, and optical properties of highly anisotropic 2D van der Waals antiferromagnets that uniquely host spin chains are explored.

Effect of Surface Oxidation and Crystal Thickness on the Magnetic Properties and Magnetic Domain Structures of CrGeTe.

van der Waals (vdW) magnetic materials, such as CrGeTe (CGT), show promise for memory and logic applications. This is due to their broadly tunable magnetic properties and the presence of topological magnetic features such as skyrmionic bubbles. A systematic study of thickness and oxidation effects on magnetic domain structures is important for designing devices and vdW heterostructures for practical applications.

Ultrafast Formation of Charge Transfer Trions at Molecular-Functionalized 2D MoS Interfaces.

In this work, we investigate trion dynamics occurring at the heterojunction between organometallic molecules and a monolayer transition metal dichalcogenide (TMD) with transient electronic sum frequency generation (tr-ESFG) spectroscopy. By pumping at 2.4 eV with laser pulses, we have observed an ultrafast hole transfer, succeeded by the emergence of charge-transfer trions.