Jiuxiang Dai

The magnetic order transition of FePS₃ from antiferromagnetic (AFM) to ferrimagnetic (FIM) and back to AFM is achieved via electron doping induced by various organic cations intercalation. The carrier doping-dependent magnetic transition offers an effective approach to engineering magnetism in 2D magnetic materials by purely electrical means for future device applications.

Abstract

Manipulating the magnetic order transition of 2D magnetic materials is an important way for the application of spintronic devices, and carrier concentration modulation is a commonly used effective regulation method. Here the magnetic ground state of FePS₃ is tuned from antiferromagnetic (AFM) to ferrimagnetic (FIM) and back to AFM by electron doping, which is achieved via the intercalation of various organic cations. The doped FePS₃ with FIM order exhibits a Curie temperature T _c of ≈110 K, a strong out-of-plane magnetic anisotropy, and particularly an unusual hysteresis loop, where with increasing temperature, the area of magnetic hysteresis loop increases below 50 K, then decreases above 50 K and eventually disappears. Theoretical calculations indicate that at a doping concentration of 0.3–0.9 electrons per cell, spin splitting of energy bands occurs, leading to the FIM order; whereas at a doping concentration of ≥ 1.0 electrons per cell, the AFM order recovers. Such AFM-FIM-AFM transition is ascribed to the competition between the Stoner exchange-dominated FM order and super-exchange-dominated AFM order. These results demonstrate an effective approach to engineering magnetism in 2D magnetic materials by purely electrical means for future device applications.

An oxygen-bonded amorphous transition metal dichalcogenide biocatalyst (aRuS-O_r) with pH-responsive reactive oxygen biocatalysis for combined antibacterial and anti-inflammatory therapies in promoting diabetic wound healing. The aRuS-O_r exhibits optimized adsorption/desorption behavior of oxygen intermediates, thereby enhancing pH-responsive ROS generation and ROS scavenging performances. The findings also validate that aRuS-O_r integrates high antibacterial action with anti-inflammatory and pro-angiogenic properties.

Abstract

Diabetic wound healing is a formidable challenge, often complicated by biofilms, immune dysregulation, and hindered vascularization within the wound environments. The intricate interplay of these microenvironmental factors has been a significant oversight in the evolution of therapeutic strategies. Herein, the design of an efficient and versatile oxygen-bonded amorphous transition metal dichalcogenide biocatalyst (aRuS-O_r) with pH-responsive reactive oxygen biocatalysis for combined antibacterial and anti-inflammatory therapies in promoting diabetic wound healing is reported. Leveraging the incorporation of Ru─O bonds, aRuS-O_r exhibits optimized adsorption/desorption behavior of oxygen intermediates, thereby enhancing both the reactive oxygen species (ROS) generation activity in acidic conditions and ROS scavenging performance in neutral environments. Remarkably, aRuS-O_r demonstrates exceptional bactericidal potency within infected milieus through biocatalytic ROS generation. Beyond its antimicrobial capability, post-eradication, aRuS-O_r serves a dual role in mitigating oxidative stress in inflammatory wounds, providing robust cellular protection and fostering an M2-phenotype polarization of macrophages, which is pivotal for accelerating the wound repair process. The findings underscore the multifaceted efficacy of aRuS-O_r, which harmoniously integrates high antibacterial action with anti-inflammatory and pro-angiogenic properties. This triad of functionalities positions aRuS-O_r as a promising candidate for the comprehensive management of complex diabetic ulcers, addressing the unmet needs in the current therapeutics.

This manuscript has unveiled the linear interplay between Raman shift and laser irradiation in vanadium dioxide, revealed the nanomechanical mechanism dominated by photothermal strain, and proposed a novel Raman-based mothed that achieves the precise characterizations of intrinsic microstructures and strain distributions in fuctional material sensitive to multiple external stimuli with high resolutions down to ten-microstrain and sub-micron.

Abstract

Vanadium dioxide as a strongly correlated electron material undergoes metal-insulator phase transitions and ferroelastic domain switching which highly couple to local strain distribution. Understanding the mechanisms and achieving the modulations require precise and high-resolution characterization of strain in vanadium dioxide. Micro-Raman spectroscopy is widely used to nondestructively characterize the strain on the surface of materials. However, vanadium dioxide is sensitive to multi-fields and with multiple physical properties correlated. It is vital and challenging to uncouple the multiple responses of vanadium dioxide to micro-Raman spectroscopy and achieve precise characterization of strain distribution. Herein, a linear relation between Raman shift and laser irradiation is revealed, which is originated from photothermal strain in monoclinic vanadium dioxide. By linear fitting and extrapolation, the strain-dependent coefficient is obtained for drifting of Raman shift and the intrinsic Raman shift without strain or laser irradiation, which enables to precisely characterize the strain distribution in vanadium dioxide.

By comparing the Li plating behavior on Cu with different 2D materials, it is found that interfacial Li deposition can only be observed on the nanocrystalline graphene (NG)/Cu substrate. Detailed characterizations and simulations reveal that the low electrical conductivity and the high density of defects on NG film are the keys to confining the electroplated Li at the interface.

Abstract

Owing to the nanoscale thickness, excellent mechanical and chemical stabilities, 2D materials including graphene and hexagonal boron nitride have emerged as promising artificial solid electrolyte interphase (SEI) candidates for lithium metal batteries. However, whether the implementation of 2D materials is beneficial to electrochemical performance remains controversial, and the key to confining the electroplated Li beneath the 2D materials remains elusive. Here, a nanocrystalline graphene (NG) film is synthesized on high-carbon Cu and the Li plating/stripping behavior on Cu grown with different 2D materials is investigated. Interestingly, in contrast to the commonly obtained Li particles on other substrates during nucleation, a smooth Li layer is obtained on NG/Cu, leading to a compact Li layer with more stable electrochemical performance. The finite element method simulations validate that the low electrical conductivity and the high density of defects on NG film drive the fast entry of electrolytes into the NG/Cu interface and promote homogenous Li nucleation. This work reveals the principles of confining electroplated Li beneath the 2D materials, and paves the way for the applications of 2D materials in artificial SEIs and anode-free lithium metal batteries.

In this study, the effect of the chemical environment on edge reconstruction in bilayer H-MoS₂ is investigated, and the most stable closed reconstructed edges are identified. These edges enhance the hydrogen evolution reaction activity, with a Gibbs free energy of 0.073 eV, providing insights into cost-effective, high-performance alternatives to Pt-based catalysts for energy applications.

Abstract

Edge reconstruction in monolayer 2D materials has received extensive attention owing to its potential applications in electronics, catalysis, and nanomaterial design. However, research on the reconstructed edges of bilayer 2D materials, particularly transition metal dichalcogenides (TMDCs), remains limited. Bilayer TMDCs, with unique interlayer interactions, may exhibit novel edge properties, making them promising for catalytic applications. Here, bilayer H-MoS₂ is used as a model system to investigate how the chemical environment influences the reconstructed edges in 2D TMDCs through first-principles calculations. The results show that the closed reconstructed edge is the most stable configuration, exhibiting high thermodynamic stability under molybdenum-rich concentrations and low sulfur chemical potentials. The closed reconstructed edges can reduce the band gap of bulk bilayer H-MoS₂. These closed reconstructed edges also increase the specific surface area and density of states at the Fermi level, increasing the catalytic activity for the hydrogen evolution reaction (HER) and achieving a hydrogen adsorption Gibbs free energy (|ΔG _H|) of 0.073 eV. This value is significantly closer to the ideal value of zero than that of Pt(111) (|ΔG _H| = 0.168 eV), indicating superior HER performance. This study provides insights for cost-effective, high-performance alternatives to Pt-based catalysts in energy applications.

The strong built-in electric field at the PtSe₂/MoTe₂ interface has effectively addressed the large dark current issue of topological semimetal PtSe₂, achieving excellent sensitivity and response speed in the mid-wave infrared (MWIR) spectral range. This work might provide a feasible pathway for next-generation high-performance room-temperature MWIR photodetectors.

Abstract

Mid-wave infrared (MWIR) sensing technology provides tremendous support for cutting-edge applications in autonomous navigation, quantum information, and optical telecommunications. Recent researchers have reported substantial advancements in the MWIR photodetection based on 2D topological semimetal platinum selenide (PtSe₂). However, its application prospect has been constrained by limited sensitivity and sluggish response speed. Herein, an uncooled MWIR photodetector integrating PtSe₂ with MoTe₂ is reported, which features high responsivity (R) of 8.4–2.5 A W⁻¹ and specific detectivity (D*) of 4.5 × 10⁹–1.3 × 10⁹ cm Hz^1/2W⁻¹ from 2.75 to 4.25 µm. At 10.6 µm wavelength, it is still able to showcase a decent R of 0.12 A W⁻¹. Notably, the photodetector achieves the brilliant photoresponse speed of 3–5 µs from visible to near-infrared (NIR) spectral ranges with a competitive 3 dB frequency of 0.13 MHz. Meanwhile, a promising fast response speed of 560 µs is demonstrated at 4050 nm in MWIR range, which unveils its conspicuous ability to track ultrafast and broadband light signals. It might be attributed to the high carrier mobility and strong built-in electric field at the PtSe₂/MoTe₂ interface. This research can provide a viable pathway for next-generation room-temperature MWIR photodetectors with high sensitivity and fast response speed.

This study explores the site-selective Eu³⁺substitution within Fe₃O₄ thin films at the Fe tetrahedral sites to enhance magnetic properties, employing DFT calculations and experimental investigations. The total magnetic moment of Eu³⁺, parallel to those of the octahedral Fe²⁺ and Fe³⁺ but opposite to that of the tetrahedral Fe³⁺, positively contributed to the saturation magnetization of Fe₃O₄ owing to noncollinearity.

Abstract

Substituting rare-earth Eu ions with a large atomic number into 3d transition metal oxides can precisely control their magnetic properties through significant spin-orbit coupling, leading to noncollinear magnetism. Experimental investigations are combined with density functional theory to explore site-selective Eu³⁺ substitution as a strategy to enhance the magnetic properties of Fe₃O₄ thin films. The substitution location of Eu³⁺, that is, octahedral versus tetrahedral, is confirmed by electrical resistivities and valence band photoemission measurements. Tetrahedrally Eu-substituted Fe₃O₄ exhibited an exceptionally enhanced saturation magnetization M _S of up to 4.4 μ_B/f.u. because of noncollinearity, whereas octahedrally Eu-substituted Fe₃O₄ showed significantly reduced M _S. X-ray absorption spectroscopy and X-ray magnetic circular dichroism measurements clearly revealed that in the tetrahedrally Eu-substituted Fe₃O₄, the Eu³⁺ magnetic moment positively contributed to the orbital magnetic moment that exhibited strong magnetic anisotropy. The deviation of the observed M _S from the lower value predicted by Néel's theory of collinear ferrimagnetism further supported the role of noncollinearity. These results provide empirical evidence for the spin configuration of tetrahedrally Eu-substituted Fe₃O₄ and a new perspective for designing practical ferrimagnetic 4f compounds with exceptional M _S.

Nature Electronics, Published online: 24 February 2025; doi:10.1038/s41928-025-01351-z

A photoreactive crosslinker can be used to directly pattern thin films of exfoliated two-dimensional flakes, and the technique can be performed sequentially to create patterned van der Waals heterostructures at wafer scales.

This paper presents the engineering of the semiconducting properties and crystallinity of 2–5 nm-thick antimony-doped indium oxide (AIO) through precise control of the native oxidation kinetics during liquid metal printing at plastic-compatible process temperatures (175°C). These two-dimensional AIO films are integrated into ultrathin channel transistors, exhibiting steep switching and high linear mobility (∼35 cm2/Vs), showing their utility for high-performance transparent electronics.

Light: Science & Applications, Published online: 25 February 2025; doi:10.1038/s41377-024-01710-z

The CNN-Transformer parallel network UI-Trans enables high-quality light sheet zebrafish heartbeat imaging, with ultra-economical acquisitions in terms of light dosage and acquisition time.

Nature Electronics, Published online: 21 February 2025; doi:10.1038/s41928-025-01360-y

Photodiodes promote electrochemical synthesis

npj 2D Materials and Applications, Published online: 21 February 2025; doi:10.1038/s41699-025-00530-y

High-throughput numerical modeling of the tunable synaptic behavior in 2D MoS₂ memristive devices

Nature Materials, Published online: 21 February 2025; doi:10.1038/s41563-025-02127-8

A wax-aided immersion methodology is developed to yield graphene rolls with tunable chiral angles; these graphene rolls exhibit promising chiral electronic properties beyond those of other carbon allotropes.

Two-dimensional semiconductors demonstrate unprecedented stability in extreme space conditions, enabling next-generation electronics for advanced space technologies in harsh cosmic environments.

The epitaxial growth of hexagonal boron nitride (h-BN) multilayer films on graphene, synthesized on a miscut SiC (0001) substrate, is demonstrated using nitrogen plasma-assisted molecular-beam epitaxy. Robust ferroelectricity with switchable out-of-plane polarization via interlayer sliding is supported by theoretical and experimental insights, providing a scalable pathway for integrating ferroelectric vdW materials into advanced 2D devices with diverse functionalities.

Abstract

Ferroelectricity realized in van der Waals (vdW) materials with non-centrosymmetric stacking configurations holds promise for future 2D devices with nonvolatile and reconfigurable functionalities. However, the epitaxial growth of ferroelectric vdW materials often struggles to achieve an energetically unfavorable stacking configuration that enables electric polarization. This challenge is particularly evident when performing heteroepitaxy on another vdW substrate to create versatile and scalable ferroelectric building blocks designed for large-area, atomic-scale thicknesses. Here, epitaxial hexagonal boron nitride (h-BN) multilayer films are successfully grew on single-crystal graphene synthesized on a miscut SiC (0001) substrate. Theoretical calculations illustrate that the moiré-patterned h-BN/graphene hetero-interface intrinsically exhibits polarization, leading to a polarized AB stacking in multilayer h-BN films to minimize the total formation energy, which is validated experimentally by the layer-dependent band dispersions. The as-grown multilayer h-BN layers demonstrated robust, homogeneous ferroelectricity with switchable out-of-plane polarization via interlayer sliding. This study establishes an effective route for stacking-controlled heteroepitaxy, enabling the large-scale integration of vdW materials with ferroelectricity and versatile functionalities, offering a promising platform for next-generation 2D ferroelectric devices.

Chemical vapor transport-synthesized RETe₃ (RE = La, Ce, Pr, Nd, Sm, and Dy) single crystals enable broadband photodetection and mid-wave infrared transmission imaging at room temperature. This research underscores the exceptional potential of RETe₃ charge density wave materials for high-performance, self-powered photodetection. This work advances the development of next-generation room-temperature mid-wave infrared detection strategies.

Abstract

Charge density wave (CDW), as an ordered electronic state, typically leads to the opening of a narrow bandgap, which can be excited by relatively low-energy photons, such as infrared light. Compounds with CDW, therefore, hold significant potential for high-performance broadband photodetectors. In this work, rare-earth tritellurides (RETe₃, where RE = La, Ce, Pr, Nd, Sm, and Dy), a well-known series with CDW transitions above room temperature, are investigated for the first time for room-temperature, broadband, and self-powered photodetection. RETe₃-based photodetectors demonstrate a broadband response spanning 380 to 4400 nm, covering the ultraviolet to mid-wave infrared range. Notably, the DyTe₃-based photodetector achieves a responsivity of 27 mA W⁻¹ at 3500 nm in the mid-wave infrared region, with a detectivity of 1.26 × 10⁹ Jones and a response time of 78 ms, comparable to photodetectors dominated by the photothermoelectric effect based on graphene. This work establishes RETe₃ as a promising new family for low-power, room-temperature, and broadband photodetection applications.

SnS and SnSe van der Waals crystals exhibit strong anisotropy of the optical properties, which makes them perfect candidates for applications in polarization-sensitive photodetection. The phenomenon is investigated by means of optical spectroscopy and explained in terms of  its origins in the electronic band structure.

Abstract

Tin monochalcogenides SnS and SnSe, belonging to a family of Van der Waals crystals isoelectronic to black phosphorus, are known as environmentally friendly materials promising for thermoelectric conversion applications. However, they exhibit other desired functionalities, such as intrinsic linear dichroism of the optical and electronic properties originating from strongly anisotropic orthorhombic crystal structures. This property makes them perfect candidates for polarization-sensitive photodetectors working in near-infrared spectral range. A comprehensive study of the SnS and SnSe crystals is presented, performed by means of optical spectroscopy and photoemission spectroscopy, supported by ab initio calculations. The studies reveal the high sensitivity of the optical response of both materials to the incident light polarization, which is interpreted in terms of the electronic band dispersion and orbital composition of the electronic bands, dictating the selection rules. From the photoemission investigation the ionization potential, electron affinity and work function are determined, which are parameters crucial for the design of devices based on semiconductor heterostructures.

Nature Communications, Published online: 22 February 2025; doi:10.1038/s41467-025-57200-2

Oxide-based thin film transistors (TFTs) hold promise for low-power electronics, but their fabrication usually requires high temperatures. Here, the authors report a low-temperature pressure-assisted liquid-metal printing method to fabricate high-performance β-Ga2O3 TFTs and logic inverters.

npj 2D Materials and Applications, Published online: 22 February 2025; doi:10.1038/s41699-025-00537-5

Altermagnetism, piezovalley, and ferroelectricity in two-dimensional Cr₂SeO altermagnet

Nature Communications, Published online: 23 February 2025; doi:10.1038/s41467-025-57061-9

Experimental evidence for charge coupling to ferroelectric soft mode is scarce. Here, the authors find a photogenerated coherent phonon coupling to the electronic transition above the bandgap in the van der Waals ferroelectric semiconductor NbOI2.

Publication date: June 2025

Source: Progress in Materials Science, Volume 152

Author(s): Muhammad Muqeet Rehman, Yarjan Abdul Samad, Jahan Zeb Gul, Muhammad Saqib, Maryam Khan, Rayyan Ali Shaukat, Rui Chang, Yijun Shi, Woo Young Kim