Jiuxiang Dai

A promising deep-ultraviolet nonlinear optical crystal, Cs₂KY(B₃O₆)₂ with ordered design of the largest π-conjugated B₃O₆ functional groups, has been successfully synthesized through utilizing the similar topological group substitution strategy. It exhibits excellent performance, i.e., the strongest second-harmonic generation response among the KBe₂BO₃F₂-like deep-ultraviolet borates, the best crystal growth habit along the c axis, short absorption edge, and sufficient birefringence.

Abstract

Deep-ultraviolet nonlinear optical (DUV NLO) crystals play a vitally important role in many scientific and technological fields, yet their rational design remains an ongoing challenge. Here, through utilizing the ordered structure design, a new KBe₂BO₃F₂-like DUV transparent NLO crystal Cs₂KY(B₃O₆)₂ has been successfully designed and synthesized, in which we first use the largest π-conjugated B₃O₆ functional groups to substitute the BO₃ to maximize the second-harmonic generation (SHG) response and utilize the K/YO₆ connecting groups to replace two BeO₃F groups to optimize the layer connections. Eventually, Cs₂KY(B₃O₆)₂ exhibits not only the largest SHG responses in KBe₂BO₃F₂-like DUV borates but also the best growth rate along c axis (the strong layer-habit along c axis has been being the greatest obstacle to prohibit the practical application of KBe₂BO₃F₂ and its derivative). Clearly, the substitution from BO₃ triangles to similar topological B₃O₆ groups and from (BeO₃F)₂ groups to similar topological K/YO₆ octahedra can better modulate the functional properties of materials in the larger scale. That results in the superior comprehensive properties of Cs₂KY(B₃O₆)₂ and makes it a promising DUV NLO crystal. Therefore, the ordered structure design provides some new insights for assembling the functional and connecting groups to rationally design materials with high-performance.

Nature Materials, Published online: 05 March 2025; doi:10.1038/s41563-025-02142-9

Inch-sized bulk lanthanide oxychloride single crystals and single-crystalline thin films with thickness down to the monolayer are synthesized through flux-enabled oriented attachment, providing a library of van der Waals materials with interesting dielectric and quantum properties.

MAX series materials, as non-van der Waals layered multi-element compounds, contribute remarkable regulated properties and functional dimension, combining the features of metal and ceramic materials due to their inherently laminated crystal structure that Mn+1Xn slabs are intercalated with A element layers. Oriented to the functional requirements of information, intelligence, electrification, and aerospace in the new era, how to accelerate MAX series materials into new quality productive forces? The systematic enhancement of knowledge about MAX series materials is intrinsic to understanding its low-dimensional geometric structure characteristics, and physical and chemical properties, revealing the correlation of composition, structure, and function and further realizing rational design based on simulation and prediction. Diversity also brings complexity to MAX materials research. This review provides substantial tabular information on (I) MAX’s research timeline from 1960 to the present, (II) structure diversity and classification convention, (III) synthesis route exploration, (IV) prediction based on theory and machine learning, (V) properties, and (VI) functional applications. Herein, the researchers can quickly locate research content and recognize connections and differences of MAX series materials. In addition, the research challenges for the future development of MAX series materials are highlighted.

The emergence of 2D materials, particularly MoS₂, marks a key shift in materials science, offering advances beyond Moore's law. This review explores MoS₂’s structure, wafer-scale synthesis methods, and applications in nanoelectronics and nanophotonics, including FETs, photodetectors, memristors, and lasers, while addressing challenges and future prospects for the next-generation device integration.

Abstract

The emergence of innovative 2D materials represents a significant evolution in materials science, heralding new opportunities for the advancement of information technologies in the era succeeding Moore's law. These materials span various categories, including semi-metallic, semiconductor, and insulating types, showcasing their versatility. The exceptional characteristics of these atomically thin and planar materials herald a new era in the miniaturization of devices. Integrating 2D materials into field-effect transistors (FETs) with sub-nanometer scale gate architectures demonstrates typical switching behaviors, confirming their applicability in integrated circuits. Concurrently, the development of wafer-level and silicon-compatible manufacturing techniques specifically designed for 2D materials and their devices underscores their significant promise in nanoelectronics and nanophotonics. Particularly, Molybdenum disulfide (MoS₂) stands out for its direct bandgaps and bound excitons, offering profound implications for advancing nanoelectronics and nanophotonics. This review investigates the intrinsic structure and properties of MoS₂, evaluates various methods for wafer-scale synthesis, and examines critical applications in nanoelectronics, such as 2D FETs, photodetectors, and memristors, alongside nanophotonics applications like nano-scale laser sources, exciton-plasmon interaction for advanced sensing applications, and photoluminescence manipulation. Additionally, this review addresses current challenges and future prospects for developing MoS₂-based technologies in next-generation nanoelectronic and nanophotonic devices.

Observing a spontaneous, giant, non-decaying, and tunable unusual exchange bias effect in above room-temperature van der Waals (vdW) magnet. The exchange bias filed is 2550 Oe at 3 K, along with a relatively high blocking temperature of 220 K among known vdW systems. The unusual EB effect is attributed to interface antiferromagnetic exchange coupling between Fe₃GaTe₂ and spin cluster at interface.

Abstract

Van der Waals (vdW) magnets have opened up new avenues for exploring next-generation spintronic devices. The exchange bias (EB) effect plays an undisputed role in ensuring accurate data retrieval in spintronic devices. However, the unsustainably weak EB field (H _EB) introduced by field cooling and the high-complexity of devices incompatible with silicon-based industry, limit the application of related vdW spintronic devices. Here, a compatible and simple method is reported for constructing Fe₃GaTe₂/oxidized Fe₃GaTe₂ heterostructures and achieving a spontaneous EB effect with a low-complexity device configuration. The spontaneous EB effect exhibits undecayed, tunable, and giant H _EB of 2550 Oe at 3 K, along with a relatively high blocking temperature of 220 K. Field cooling and cross-sectional microstructure studies suggest that the EB effect arises from antiferromagnetic exchange coupling between Fe₃GaTe₂ and spin clusters frozen by α-Fe₂O₃ at the disordered interface. This work provides a unique avenue for customizing, integrating, and producing related spintronic devices.

“Light-Flashable” 2D polymeric fluorescent lifetime microbarcodes with excellent control of size, components, and functionalities are prepared to optimize for nanoscale spatial programmability of encoding patterns, light-triggered dynamic output, and quantitative fluorescence lifetime output, which will be essential for achieving extremely high data densities.

Abstract

The output signals of dynamic microbarcodes with precise control over dimensions can be reversibly altered in response to external stimuli, which have emerged as a promising alternative to information encoding. However, the complexity of multi-dimensional encoding and the high requirements for precision in nano/microscale fabrication still present significant challenges. Herein, “Light-Flashable” two-dimensional (2D) polymeric fluorescent lifetime microbarcodes are prepared with excellent control of size, components, and functionalities using the technique known as living crystallization-driven self-assembly seeded growth method, optimizing for nanoscale spatial programmability of encoding patterns, light-triggered dynamic output, and quantitative fluorescence lifetime output. By carefully modulating the output signals, the integration of photoswitchable spiropyrans facilitates “Light-Flashable” dynamic signaling by controlling energy transfer between the fluorescent components and spiropyrans on the 2D platelet surfaces. This energy transfer enables the manipulation of light-responsive fluorescence lifetimes and enhances the robustness of information storage. Consequently, the development of such state-of-the-art information carriers, capable of managing complex light patterns and storing data in 3D space, will be essential for achieving extremely high data densities.

A MoS₂/MnS heterostructure featuring a hollow sphere morphology is proposed, engineered through a synergistic combination of the Ostwald ripening process and the Kirkendall effect. By integrating the rational structure design strategy with advanced characterizations, a significant impact in the development of superior anodes for sodium-ion batteries is achieved.

Abstract

Molybdenum disulfide (MoS₂), characterized by its two-dimensional structure and high theoretical specific capacity, is considered a prospective anode of Na-ion battery. However, the cycling and rate capabilities are hampered by its sluggish charge transfer kinetics and poor structural stability. To overcome the issues, most efforts have been focused on optimizing the structure of MoS₂. Nevertheless, rationally designing a structure that can present rapid and durable Na-ion storage while ensuring large charge storage remains challenges. Herein, a MoS₂/MnS heterostructure featuring a sphere-like hollow morphology is rationally designed according to Ostwald ripening process and Kirkendall effect. This construction can effectively establish an interfacial built-in electric field activated by MnS and MoS₂, which exhibit P-type and N-type semiconductor characteristics, respectively, thereby promoting electrochemical kinetics. Moreover, excellent structural stability of MoS₂/MnS after repeated (de)sodiation processes is remarkably achieved thanks to the robust morphology design, significantly achieving outstanding tolerance to structural changes. Consequently, the MoS₂/MnS anode delivers high specific capacity (594.8 mAh g⁻¹ at 0.1 A g⁻¹), superior rate performance (up to 100 A g⁻¹), and ultrastable cycling capability (30 000 cycles with ≈81.4% retention). The work affords an effective structural optimization tactic to rationally develop high-performance conversion-type electrodes for alkali-ion batteries.

Nature Synthesis, Published online: 04 March 2025; doi:10.1038/s44160-025-00763-1

Among the first-row p-block elements that can form neutral triple-bonded species (boron, carbon, nitrogen and oxygen), all combinations have been realized except that of boron and carbon. Here the synthesis of a neutral, uncoordinated boryne is described, closing the remaining gap in neutral first-row p-block compounds with triple bonds.

This is a comprehensive review of amorphous/crystalline heterostructured nanomaterials (AC-HNMs), highlighting their synthesis strategies and applications in electrochemical energy storage devices, including metal-ion batteries, metal–air batteries, lithium–sulfur batteries, and supercapacitors. The structure–activity relationships among amorphous/crystalline heterostructure, performance, and mechanism are thoroughly analyzed. Challenges and future perspectives for the optimization of AC-HNMs are also proposed.

Abstract

With the expanding adoption of large-scale energy storage systems and electrical devices, batteries and supercapacitors are encountering growing demands and challenges related to their energy storage capability. Amorphous/crystalline heterostructured nanomaterials (AC-HNMs) have emerged as promising electrode materials to address these needs. AC-HNMs leverage synergistic interactions between their amorphous and crystalline phases, along with abundant interface effects, which enhance capacity output and accelerate mass and charge transfer dynamics in electrochemical energy storage (EES) devices. Motivated by these elements, this review provides a comprehensive overview of synthesis strategies and advanced EES applications explored in current research on AC-HNMs. It begins with a summary of various synthesis strategies of AC-HNMs. Diverse EES devices of AC-HNMs, such as metal-ion batteries, metal–air batteries, lithium–sulfur batteries, and supercapacitors, are thoroughly elucidated, with particular focus on the underlying structure–activity relationship among amorphous/crystalline heterostructure, electrochemical performance, and mechanism. Finally, challenges and perspectives for AC-HNMs are proposed to offer insights that may guide their continued development and optimization.

The sparse arrangement of atoms on the high-index copper surface leads to weak interfacial coupling with growing graphene. The strength of interfacial coupling essentially determines the amount and dispersion of graphene orientation, and thus it is expected that precise control of mono- and multilayer graphene growth can be achieved by modulating the interfacial coupling.

Abstract

Controlled and precise synthesis of materials has been a central pursuit in academia and industry. With the rise of twistronics research, there is growing demand for synthesizing orientation-controlled 2D materials with atomic precision. Previous theories for 2D materials can predict graphene (Gr) growth on low-index metal substrates but fail to explain the discrete orientations on most high-index substrates, inconsistent with experimental data. Using density functional theory (DFT) and ab-initio molecular dynamics (AIMD), this study explores graphene growth on high-index substrates, showing that atomic steps do not dominate in trapping C atoms or driving preferential graphene nucleation at high temperatures. Thus, the possibility of intrinsic atomic steps in inducing graphene orientation on high-index substrates is ruled out. Interfacial coupling strength between graphene and substrates is quantified using a close contact index (CCI), linking atomic structure and electronic states. The coupling between graphene and high-index Cu surfaces is generally weak, reducing substrate anchoring and increasing graphene orientation dispersion. The extension of this theory to bilayer graphene (BLG) reveals competition between Gr/Cu interfacial coupling and Gr/Gr interlayer coupling, offering insights for controlling twist angles. This theory explains the discrete orientations on high-index substrates, providing a theoretical basis for synthesizing orientation-controlled graphene.

Publication date: September 2025

Source: Progress in Materials Science, Volume 153

Author(s): Pedram Yousefian, Betul Akkopru-Akgun, Clive A. Randall, Susan Trolier-McKinstry

Nature Physics, Published online: 28 February 2025; doi:10.1038/s41567-024-02770-z

The pairing mechanism in kagome superconductors is still not fully understood. Now, CsV3Sb5, which belongs to this family, is shown to have orbital-selective pairing with two distinct superconducting domes that are not separated by any phase boundary.

Light: Science & Applications, Published online: 26 February 2025; doi:10.1038/s41377-025-01749-6

Nonlinear synthesis of spatial coherence using second-order nonlinear photonic crystals. The coherence induced by the smiley face is synthesized in the far field of the crystal.

This study introduces a contamination-free approach to fabricating arrayed Josephson junctions (JJs) with sub-nanometer sharp interfaces. Both Bi and Pb thin films are grown using molecular beam epitaxy, with a self-assembled Bi buffer layer forming the framework for Pb-JJs. Scanning tunneling microscopy results demonstrated superconducting correlations within JJs. This work establishes an in-vacuo deposition method for fabricating pristine superconducting devices.

Abstract

A distinguishing characteristic of Josephson junctions (JJs) is their nonlinear current-voltage response, which fulfills the requirements for superconducting quantum computing. Achieving atomically sharp interfaces between superconductors and weak links in JJs can realize the superconductivity proximity effect, advancing the investigation of intrinsic properties in unconventional superconductors and their potential applications. Here, a contamination-free approach to fabricating planar JJs using molecular beam epitaxy (MBE) is presented. The self-assembled Bi buffer layer forms a ladder-like framework on Si (111) 7 × 7 reconstructions, consisting of a wetting layer of Bi interspersed with Bi crystalline islands. Upon depositing Pb on this Bi buffer layer, Pb atoms dominantly nucleate on the Bi wetting layer, bypassing the Bi islands to form arrayed JJs. The selective area growth of Pb thin films is attributed to the higher nucleation densities for Pb on the Bi wetting layer compared to Bi crystalline islands. In situ scanning tunneling microscopy (STM) measurements reveal the superconducting correlations within the interior of junctions. The study establishes an in-vacuo deposition method for fabricating pristine JJs, facilitating the potential investigation of emergent superconducting phenomena in designed heterostructures.

This perspective is focused on advanced materials that might allow the new device class of quantum batteries to be developed. These systems include microcavities with organic molecules, inorganic nanostructures and perovskites, and superconductor circuits. The different systems proposed are introduced and discussed, and an overview of the potential material platforms for the experimental realization is presented.

Abstract

In the context of quantum thermodynamics, quantum batteries have emerged as promising devices for energy storage and manipulation. Over the past decade, substantial progress is made in understanding the fundamental properties of quantum batteries, with several experimental implementations showing great promise. This perspective provides an overview of the solid-state materials platforms that can lead to fully operational quantum batteries. After briefly introducing the basic features of quantum batteries, organic microcavities are discussed, where superextensive charging is already demonstrated experimentally. Now, this explores other materials, including inorganic nanostructures (such as quantum wells and dots), perovskite systems, and (normal and high-temperature) superconductors. Key achievements in these areas, relevant to the experimental realization of quantum batteries, are highlighted. The challenges and future research directions are also addressed. Despite their enormous potential for energy storage devices, research into advanced materials for quantum batteries is still in its infancy. This paper aims to stimulate interdisciplinarity and convergence among different materials science research communities to accelerate the development of new materials and device architectures for quantum batteries.

A feasible synthesis method is reported for amorphous monolayer carbon (AMC) via chemical vapor deposition using commercially available polycyclic molecules. This method proves effective in repeatably obtaining AMC with a controllable degree of disorder and large sizes. These results mark a significant step toward understanding the AMC growth mechanism and pave the way for electronic devices employing 2D amorphous materials.

Abstract

Amorphous monolayer carbon (AMC), a new type of carbon nanomaterials created by merging modulations of the crystallinity and dimension, is of particular research interest since it has shown unprecedented properties that its crystalline counterpart–graphene–does not possess. The conductivity of AMC is controlled by its degree of disorder and can be continuously tuned with nine orders of magnitude. As one emergent carbon nanomaterial, the fundamental properties of AMC and its potential in applications remain largely unexplored. However, its current synthesis relies on one specific, lab-synthesized molecule, hampering further extensive investigations. Here, the feasible synthesis of AMC is reported by chemical vapor deposition using commercial polycyclic molecules, which prove to be effective in repeatably obtaining AMC with a controllable degree of disorder and large sizes. By the backward-compatible regrowth, the in-plane, crystalline-amorphous heterostructures are demonstrated in one monolayer of carbon with mechanical continuity across the homojunction. Conductance measurements confirm in such monolayers the precise controls over both the spatial location and electrical properties, which are not only conductive or insulating but continuously tuned. These results represent a significant step toward understanding the mechanism of AMC growth and pave the way for electronic devices using 2D amorphous materials.

The discovery ten years ago of “giant” electrostriction has welcomed new members: substituted La₂Mo₂O₉. Gd substitution enhances one order of magnitude of the electrostrictive strain compared with unsubstituted La₂Mo₂O₉. Complementing the results underlying the differences between the giant electrostriction in ceria-based systems, this result shows that Gd has a special influence on “giant” electrostriction, for both systems.

Abstract

“Giant” electrostrictors are materials that exhibit anomalously large quadratic electromechanical coupling. Few such materials have been discovered and the origin of their remarkable properties is still under debate. Here several new giant electrostrictors based on iso- and alio-valent substitutions in La₂Mo₂O₉ are reported. The dielectric, elastic, anelastic and electrostrictive properties of La₂Mo₂O₉-based materials are measured and show no correlation with the ionic radius of the substituent element, contrary to what has been reported for doped ceria. The substitutions on the La site affect the electrostrictive properties more than on the Mo site, opposite to their effect on the dielectric properties. No correlation is found between the anelasticity or the oxygen vacancy density and the electrostrictive properties. The mechanism underlying “giant” electrostriction in La₂Mo₂O₉-based materials thus appears to be different from that proposed for ceria-based materials.

Nature Reviews Materials, Published online: 27 February 2025; doi:10.1038/s41578-025-00786-2

An article in Science Advances demonstrates a dual closed-loop robotic system that uses biodegradable materials and features an origami-based design.

Altermagnetism, a new magnetic phase, has been theoretically proposed and experimentally verified to be distinct from ferromagnetism and antiferromagnetism. Although altermagnets have been found to possess many exotic physical properties, the limited availability of known altermagnetic materials hinders the study of such properties. Hence, discovering more types of altermagnetic materials with different properties is crucial for a comprehensive understanding of altermagnetism and thus facilitating new applications in the next generation of information technologies, e.g., storage devices and high-sensitivity sensors. Since each altermagnetic material has a unique crystal structure, we propose an automated discovery approach empowered by an AI search engine that employs a pre-trained graph neural network to learn the intrinsic features of the material crystal structure, followed by fine-tuning a classifier with limited positive samples to predict the altermagnetism probability of a given material candidate. Finally, we successfully discovered 50 new altermagnetic materials that cover metals, semiconductors, and insulators confirmed by the first-principles electronic structure calculations. The wide range of electronic structural characteristics reveals that various novel physical properties manifest in these newly discovered altermagnetic materials, e.g., anomalous Hall effect, anomalous Kerr effect, and topological property. Noteworthy, we discovered 4 i-wave altermagnetic materials for the first time. Overall, the AI search engine performs much better than human experts and suggests a set of new altermagnetic materials with unique properties, outlining its potential for accelerated discovery of the materials with targeted properties.

Van der Waals (vdW) confined space provides distinct environment from free space, enabling the production of two-dimensional Janus materials, like highly asymmetric hydrogenated graphene (AH-Gr). Here, we develop a vdW confined space assisted hydrogenation method to produce AH-Gr. The confined space between graphene and the substrate aggregates hydrogen radicals, making the bottom-side of graphene more prone to hydrogenation. The dense and homogeneous confined spaces between adjacent vdW crystals promote rapid and uniform distribution of carbon-hydrogen (C-H) bonds. The hydrogen-to-carbon atomic (H/C) ratios can be quantitatively controlled by adjusting the permeated proton dose. All AH-Gr, regardless of H/C ratios, remain vacancy-free. The spatial distributions of C-H bonds significantly influence the electrical and magnetic properties of AH-Gr. Asymmetric hydrogenation transforms graphene from a semi-metal to a semiconductor, suppresses the quantum Hall effect, and reduces the phase coherence length. This study provides new insights into the preparation and characteristics of hydrogenated graphene, broadening the applications of vdW confined space.

In this work, a heterostructure between highly crystalline Fe₂O₃ nanoflakes and WS₂ nanosheets are fabricated using drop casting technique. The first principles calculations are performed to understand the interfacial charge transfer mechanism. The staggered band alignment with built-in electric field is found to be contributing for the multi-fold enhancement in photocurrent density in the heterostructure.

Abstract

Fe₂O₃-based photoanodes show great potential in photoelectrochemical water splitting due to their excellent stability, moderate band gap, and abundance. However, a short hole diffusion length limits its photocurrent density. Here, a multi-fold enhancement in photocurrent density from Fe₂O₃ nanoflakes – WS₂ nanosheets heterojunction is reported. The heterojunction exhibits a synergistic photocurrent density of 0.52 mA cm⁻² at 1.3 V (versus RHE) under AM 1.5G simulated sunlight, which is 2.23 times higher than pristine Fe₂O₃ nanoflakes. The Mott–Schottky and Nyquist plots indicate a higher charge density with lower charge transfer resistance at the semiconductor-electrolyte junction. The density functional theory (DFT) -based first-principles calculations are performed by designing a heterostructure between Fe₂O₃(110) and WS₂(001) similar to the experimentally found arrangement of crystal planes. Free energy analysis and relative band extrema positions, obtained from DFT calculations and valence band spectroscopy, indicate the formation of type II heterojunction with partial oxygen terminated surface of Fe₂O₃. The type-II band alignment with a charge transfer of 4.8 × 10⁻⁴ e per interfacial WS₂ to Fe₂O₃, helps in easy separation of photogenerated charges. The work establishes both an experimental design and a theoretical framework of highly crystalline nanoflakes-nanosheet heterojunctions for efficient photoelectrochemical solar energy conversion.

Interfacially-driven synthesis of 2D core-crown SnS₂ /SnSe₂ heterostructure with epitaxial relationship between the components provides a generalizable approach for the synthesis of epitaxial heterostructures with designer size, crystallinity, crystallographic alignments, and electronic structure for optoelectronic devices.

Abstract

Developing generalized strategies for controlled synthesis of 2D heterostructures remains a significant challenge because the existing approaches often suffer from poor reproducibility and scalability. In this study, a solution synthesis approach for epitaxial core-crown heterostructures with controlled band alignment, that overcomes these challenges is reported. Polyvinylpyrrolidone (PVP) is used as a structure-directing agent to reduce lattice mismatch between SnS₂ and SnSe₂ (10-10) surfaces and direct epitaxial growth of SnSe₂ crown on SnS₂ seed. Additionally, PVP adsorption to the basal plane prevents van der Waals stacking and stabilizes 2D heterostructures during synthesis. Driven by interfacial thermodynamics, the formation of the core-crown heterostructure is highly reproducible and the size of the 2D heterostructure and relative areas of the core and the crown can be precisely controlled in a two-step process by varying synthesis times for the seed and the crown. The identified growth pathway for 2D heterostructures can be generalized to other combinations of van der Waals materials to provide a platform for synthesizing micron-size epitaxial heterostructures with a desired electronic structure for catalysis and microelectronics.