Structure, Properties and Applications of Two-Dimensional Hexagonal Boron Nitride

Integrating hexagonal boron nitride-ZnO nanohybrids as multifunctional active fillers in PLA matrices to extend the shelf-life of fresh strawberries

PLA is a promising sustainable alternative to petroleum-based polymers. However, its suboptimal functional properties and lack of inherent bioactivity limit its applications in active food packaging. This study addresses these constraints and improves PLA's active functionalities through reinforcement with hexagonal boron nitride-ZnO (hBN-ZnO) binary inorganic nanofillers. PLA was fine-tuned with various ratios of hBN, and found that PLA-hBN1.5 film exhibits the optimum characteristics such as excellent film formation, highest tensile strength (62.14 MPa, 19.75 % increase), lowest water vapor permeability (1.23 ± 0.03 × 10-11 g.m-1.s-1.Pa-1, 32.04 % decrease), and improved UV-blocking and thermal resistance. Subsequently, a hydrothermally synthesized hBN-ZnO composite was incorporated into optimal PLA-hBN1.5 films, replacing pure hBN. The ZnO inclusion boosted the films antibacterial, antibiofilm, and antioxidant functionalities without significantly compromising mechanical or moisture barrier properties. Packaging studies on fresh strawberries demonstrated the superior potential of the PLA-hBN-ZnO film, making it a promising material for sustainable and active food packaging.

Two-dimensional nanozyme nanoarchitectonics customized electrochemical bio diagnostics and lab-on-chip devices for biomarker detection

Recent developments in nanomaterials and nanotechnology have advanced biosensing research. Two-dimensional (2D) nanomaterials or nanozymes, such as metal oxides, graphene and its derivatives, transition metal dichalcogenides, metal-organic frameworks, carbon-organic frameworks and MXenes, have garnered substantial attention in recent years owing to their unique properties, including high surface area, excellent electrical conductivity, and mechanical flexibility. Moreover, 2D nanozymes exhibit intrinsic enzyme-mimicking properties, including those of peroxidase, oxidase, catalase, and superoxide dismutase, making them well-suited for detecting biomarkers of interest and developing bio diagnostics at the point-of-care. Since 2D nanosystems offer ultra-high sensitivity, label-free detection, and real-time analysis, point-of-care testing and multiplexed biomarker detection, the demand is growing. Additionally, their biocompatibility and scalable fabrication make them cost-effective for widespread adoption. This review discusses the advantages of 2D nanozymes and their recent advancements in biosensing applications. This review summarizes the latest developments in 2D nanozymes, focusing on their synthesis, biocatalytic capabilities, and advancements in developing bio diagnostics and lab-on-chip devices for detecting cancer and non-cancer biomarkers. In addition, existing challenges and prospects in 2D nanozyme-based biosensors are identified, highlighting their biosensing potential and advocating for their expanded application in bio diagnostics and lab-on-chip devices.

Scalable assembly of micron boron nitride into high-temperature-resistant insulating papers with superior thermal conductivity

With the rapid development of modern electrical equipment towards miniaturization, integration, and high power, high-temperature-resistant insulating papers with superior thermal conductivity are highly desirable for ensuring the reliability of high-end electrical equipment. However, it remains a challenge for current insulating papers to achieve this goal. Herein, we demonstrate the design of high-temperature-resistant micron boron nitride (m-BN) based insulating papers with superior thermal conductivity by a universal and scalable one-step assembly strategy. Inspired by the floating shape of jellyfish in the ocean, aramid nanofibers (ANF) resembling the tentacles of jellyfish were employed to support the bell-shaped m-BN, which effectively addresses the kinetically stable dispersion and film-forming ability of m-BN. The resultant m-BN@ANF papers exhibit excellent high-temperature-resistant insulating performance with an ultra-high breakdown strength of 359.0 kV mm-1 even at a high temperature of 200 °C, far exceeding those of these previously reported systems. In addition, the optimal m-BN@ANF paper demonstrates a superior thermal conductivity of 26.4 W m-1 K-1 and an excellent thermostability with an initial decomposition temperature of 486 °C. This outstanding comprehensive performance demonstrates the promise of applying these m-BN@ANF papers in advanced electrical systems operating under high-temperature circumstances.

Fourier-Tailored Light-Matter Coupling in van der Waals Heterostructures

Dielectric structures can support low-absorption optical modes, which are attractive for engineering light-matter interactions with excitonic resonances in two-dimensional (2D) materials. However, the coupling strength is often limited by the electromagnetic field being confined inside the dielectric, reducing the spatial overlap with the active excitonic material. Here, we demonstrate a scheme for enhanced light-matter coupling by embedding excitonic tungsten disulfide (WS2) within dielectric hexagonal boron nitride (hBN), forming a van der Waals (vdW) heterostructure that optimizes the field overlap and alignment between excitons and optical waveguide modes. To tailor diffractive coupling between free-space light and the waveguide modes in the vdW heterostructure, we fabricate Fourier surfaces in the top hBN layer by using thermal scanning-probe lithography and etching, producing sinusoidal topographic landscapes with nanometer precision. We observe the formation of exciton-polaritons with a Rabi splitting indicating that the system is at the onset of strong coupling. These results demonstrate the potential of Fourier-tailored vdW heterostructures for exploring advanced optoelectronic and quantum devices.

Recent advancements on 2D nanomaterials as emerging paradigm for the adsorptive removal of microcontaminants

Water reservoirs are facing increasing prevalence of microcontaminants originating from agricultural runoff, industrial effluents, and domestic wastewater. The persistence of microcontaminants leads to disruptions in aquatic ecosystems and poses potential long-term health risks to humans, even at minimal concentrations. However, traditional wastewater treatment methods are inefficient to eliminate the microcontaminants because of their intricate chemical structures and low concentration. In this regard, nano-adsorption employing nanomaterials as adsorbents presents a viable alternative, offering enhanced efficiency and specificity towards the removal of microcontaminants. Amongst all, two-dimensional (2D) nanomaterials, including graphene oxide (GO), layered double hydroxides (LDHs), MXenes, and boron nitrides (BNs), exhibit distinctive characteristics such as a high surface area, remarkable chemical stability, and tendency of diverse surface functionalization, rendering them particularly effective in adsorbing pollutants from water. Therefore, the present review provides an exhaustive literature and comparative analysis of the aforementioned 2D nanomaterials-based adsorbents concerning their efficacy in adsorbing microcontaminants of pharmaceuticals and personal care products origin such as antibiotics, steroids, bisphenols, phthalates, parabens, and benzophenones. The different aspects of 2D adsorbents including adsorption capacity, mechanisms involved, kinetic and isotherm models followed for removal of a variety of microcontaminants have been congregated. Also, the information on recyclability, reusability, and stability of the adsorbents has been summarized to highlight their viability. Further, the limitations and future aspects related to the use of 2D nanomaterials-based adsorbents towards pollutant removal have been discussed. Overall, 2D nanomaterials holds great promise as efficient adsorbents for environmental remediation and can also be explored for industrial adsorption applications.

Conformal hexagonal boron nitride encapsulation of graphene-skinned glass fiber fabric for enhanced electrical stability

Encapsulation is crucial for protecting graphene devices, but traditional whole-package encapsulations usually add bulky structures and reduce their flexibility. Hexagonal boron nitride (h-BN) holds potential for graphene encapsulation, but faces challenges in large-area acquisition and conformal coverage due to limitations in exfoliation and transfer techniques. Graphene-skinned glass fiber fabric (GGFF), made via graphene CVD growth on each fiber of a glass fiber fabric, consists of a hierarchical conductive network, but pressure/deformation-induced inter-fiber contact resistance fluctuations destabilize its electrical conduction. Whole-package encapsulation cannot resolve this, as fails to insulate inter-fiber contacts. Herein, thick, high-quality h-BN films are CVD-grown on each fiber in GGFF, achieving conformal encapsulation. This unlocks conductive network in GGFF, stabilizing electrical conduction while preserving structure stability and flexibility. This also improves GGFF's resistance to doping and oxidation, extending its service life. This encapsulation strategy is broadly applicable to other two-dimensional materials and complex device structures, promoting reliable nanoelectronics in demanding environments.

Research on the Corrosion Resistance of Waterborne Epoxy Resin Coating Enhanced by Sodium Alginate-Modified Ti3C2Tx

The enhancement of dispersion stability and interfacial compatibility of nanomaterials within aqueous epoxy matrices represents a pivotal strategy for augmenting the protective performance and corrosion resistance of coatings. In this study, Ti3C2Tx Mxene functionalized with sodium alginate (TSA) was obtained by introducing sodium alginate (SA) into Ti3C2Tx Mxene (T) to improve the corrosion resistance of aqueous epoxy coatings (EP). The dispersion stability of TSA in aqueous medium was quantitatively assessed via ζ-potential measurements, revealing a significant enhancement in stability compared to the reference material T. The long-term stability of TSA/EP composite coatings was systematically evaluated via electrochemical impedance spectroscopy (EIS). Notably, the charge transfer resistance (Rc) remained at 5 × 107 Ω·cm2 after a 60-day accelerated aging test, exhibiting exceptional electrochemical durability. Compared with pure EP coating, this value is improved by 2 orders of magnitude. The improvement is attributed to the fact that active -COOH and -OH groups on the surface of SA enhance the interactions between T nanosheets and EP matrix. Specifically, these functional groups form hydrogen bonds or chemical bonds at the interface. Such interfacial bonding mechanisms enhance the compatibility and interfacial adhesion between T and the EP matrix. These conclusions are further supported by manual scratching experiments. The accessibility and greenness of SA provide a simple and environmentally friendly way of thinking for modifying T.

Influence mechanism of vacancy defect effects on the intrinsic electronic properties of h-BN and the thermodynamic and dielectric properties of h-BN/PI interfaces

Polyimide (PI), known for its excellent properties, has been widely applied across various fields. However, its thermodynamic and dielectric properties require further enhancement. Hexagonal boron nitride (h-BN) is commonly employed as a nano-modifier to enhance the properties of the PI matrix. However, the vacancy defects in h-BN limit the improvement of the composite's properties. In this study, molecular simulation techniques are utilised to investigate the effects of vacancy defects on the electronic properties of h-BN and the interfacial properties of h-BN/PI composites. The simulation results indicate that as the number of vacancy defects increases, the distortion of the h-BN geometric structure becomes more severe. Among the single-atom vacancy defects, N-atom vacancies exert a more significant impact on the geometrical structure and insulating properties of h-BN. Two defect levels are introduced into the energy band structure of the diatomic vacancy defect model, thereby weakening the insulating performance of h-BN. The band structure of the three-atom vacancy defect model undergoes greater changes, with additional defect levels introduced into the band gap, resulting in reduced insulating performance and a semi-metallic state in h-BN. As the number of vacancy defects increases, the thermal conductivity and mechanical properties of the h-BN/PI interface deteriorate. In contrast, B-atom vacancies have a more pronounced effect on interfacial heat transfer, whereas N-atom vacancies more significantly affect mechanical properties. The free volume fraction of the model increases as the vacancy defect rate rises, leading to an increase in the relative dielectric constant of the h-BN/PI interface. This paper comprehensively examines the effects of vacancy defects on the interfacial properties of h-BN/PI composites, providing a foundation for the application of h-BN as a filler in the functional modification of PI.

Challenges and future prospects of the 2D material-based composites for microwave absorption

The widespread use of electronic devices inevitably brings about the problem of electromagnetic pollution. As a result, it is important and urgent to develop efficient absorbing materials to alleviate increasing pollution issues. Recently, two-dimensional (2D) material-based microwave absorbers have attracted wide attention in microwave absorption due to their unique lamellar structure, large specific surface area, low density, good thermal and chemical stability. Through various modulation strategies such as structure configuration, pore/defect engineering, heteroatom doping and coupling of functional materials, 2D materials or 2D material-based composites exhibit excellent microwave absorption performance. In this review, the absorption mechanism is firstly introduced and then the latest progress in 2D material-based microwave absorbers is reviewed in depth. The challenges and future prospects for graphene, h-BN, and MXene-based microwave absorbers are discussed in the final part. This timely review aims to provide guidance or stimulation to develop advanced multifunctional 2D material-based microwave absorbers in this rapidly blossoming field.

Polarization Sensitive Vacuum-Ultraviolet Photodetectors Based on m-Plane h-BN

Vacuum ultraviolet (VUV) detection plays an essential role in space science, radiation monitoring, electronic industry, and fundamental research. Integrating polarization characteristics into VUV detection enriches the comprehension of the target attributes and broadens the signal dimensionality. Polarization detection has been widely developed in visible and infrared regions; however, it is still relatively unexplored in VUV light due to the lack of photoactive materials with low-symmetry structures, VUV selective response and radiation resistance. Here, the wafer-scale hexagonal boron nitride (h-BN) epitaxial films with the distinct m-plane surfaces are demonstrated that exhibit significant anisotropy due to space symmetry breaking, instead of the routinely obtained high-symmetry c-planes governed by the most thermodynamically stable growth mode. This results in notable anisotropy in light absorption and charge density distributions, yielding a dichroic ratio greater than 10 and a carrier transport efficiency ratio (μτa -axis/μτc -axis) of 24. The h-BN based detector achieves a high polarization ratio of 6.2 for 188 nm VUV polarized light, reaching the short-wavelength limit of the reported polarization-sensitive photodetectors. This work presents an effective strategy for designing polarized VUV photodetector from h-BN, and paves the road towards the novel integrated optoelectronics, photonics and electronics based on traditional 2D materials.

Hydrothermal engineering of polyethylene glycol-assisted boron nitride/hematite nanohybrid composites for high-performance supercapacitors

Developing high-performance energy storage materials is essential to meet the increasing global demand for sustainable energy solutions. In this study, a novel strategy is employed to synthesize polyethylene glycol-assisted boron nitride/hematite (PEG-BN/α-Fe2O3) hybrid composites through a hydrothermal process. Polyethylene glycol(PEG) serves as both a dispersant and a non-covalent linker that bridges hematite nanoparticles and BN sheets. With a combination of van der Waals interaction and hydrogen bonding with the component materials, PEG enables stable and homogeneous dispersion of hematite on the otherwise inert and agglomeration-prone BN surface. This dual interaction approach enables controlled interface engineering, solving one of the major challenges commonly faced in the synthesis of BN-based composites. It also acts as a functional modifier that modulates the interfacial interactions and regulates the nucleation and dispersion of α-Fe2O3 nanoparticles within the BN matrix. The incorporation of PEG enhanced the electrochemical and structural properties of the hybrid composite. Structural and morphological characterizations confirmed the uniform dispersion of α-Fe2O3 within the BN matrix, with PEG enhancing the interfacial interactions and overall material stability. TGA demonstrated that PEG incorporation significantly improved the thermal stability of the composites, delaying degradation and preserving structural integrity under high-temperature conditions. Electrochemical measurements, including CV and GCD analysis in a 6 M KOH electrolyte, revealed superior charge storage capabilities for PEG-BN/α-Fe2O3 compared to BN/α-Fe2O3. This hybrid composite exhibited a remarkable specific capacitance of 361.6 F g-1 at a current density of 3 A g-1, significantly outperforming the individual components. The GCD studies display an enhanced charge retention capability of the hybrid composite with a coulombic efficiency of 83%, indicating reduced internal resistance and improved kinetics. Additionally, electrochemical impedance spectroscopy indicated a lower charge transfer resistance and enhanced conductivity in PEG-modified composites. The composite also retained 85% of its initial capacitance after 5000 cycles, demonstrating excellent cyclic stability. The improved electrochemical performance of PEG-BN/α-Fe2O3 hybrid composites is attributed to the synergistic effects of BN and α-Fe2O3, facilitated by PEG, which acts as a thermal buffer, prevents agglomeration, and enhances electrolyte-electrode interactions. These findings underscore the potential of PEG-assisted BN/α-Fe2O3 composites as advanced electrode materials for next-generation supercapacitors and other electrochemical storage devices.

Strain tuning of optical and thermoelectric properties of monolayer BAs

This study investigates the electronic, optical and thermoelectric properties of monolayer boron arsenide (BAs) using a fifth-nearest-neighbor tight-binding model based on density functional theory (DFT) calculations, with a particular focus on the effects of biaxial strain to tune its characteristics for optoelectronic and thermoelectric applications. The results show that monolayer BAs possesses a direct band gap of approximately 1.2 eV at the K-point, maintaining its semiconducting nature across a strain range of - 8% to + 8%. The band gap is observed to decrease under compressive strain and increase under tensile strain. Optical spectra exhibit two distinct peaks in the infrared and ultraviolet regions, corresponding to transitions between the valence and conduction bands at the K and M points, which are significantly modulated by strain. Specifically, compressive strain induces a red-shift in these optical peaks, while tensile strain causes a blue-shift. The strain-dependent electronic modifications also significantly influence the thermoelectric properties of BAs, leading to enhancing under compressive strain and decreasing with tensile strain.

Recent Trends in Drug Delivery Systems

Drug delivery systems are now being advanced by integrating sophisticated nanotechnologies to enhance therapeutic efficacy. Tremendous advancement has been achieved in the field of cancer therapy through the utilization of hyaluronic acid-based nanocarriers, which are well-acknowledged for their capacity to transport medication precisely to targeted regions. Quantum dots exhibit unique optical properties that allow for precise drug administration and monitoring capabilities. Carbon nanotubes provide a large surface area and exceptional strength, allowing for precise manipulation of drug delivery patterns. Dendrimers are versatile structures that can transport many drugs simultaneously, whereas mesoporous silica-functionalized nanoparticles allow exact manipulation of the release rate of pharmaceuticals. Polymer-lipid hybrid nanoparticles synergistically integrate the durability of polymers with the compatibility of lipids, hence augmenting the availability of drugs within the body. Hexagonal boron nitride nanosheets are becoming more recognized as favorable carriers due to their biocompatibility and potential for tailored administration. These achievements demonstrate the changes happening in the field of pharmaceutical administration, where nanotechnology is used to tackle issues such as restricted bioavailability and unanticipated adverse effects. This ultimately enhances the effectiveness of medicines and improves patient outcomes. Future investigations will focus on improving these technologies for broader therapeutic applications.

Molecular-Level Interface Engineering and Additive-Induced Crystallinity Tuning for High-Performance Thermally Conductive Polymer Composites

To boost up the properties of thermally conductive polymer composites, it is essential to conduct comprehensive research focused on interface engineering between the polymer matrix and fillers. Hexagonal boron nitride (BN) or expanded graphite (EG) are commonly utilized as nanofillers to improve the thermal conductivity of polymer composites. However, the interfacial interactions between the polymer matrix and nanofillers are generally weak, making effective thermal conductivity challenging. To address this issue, we have designed and synthesized an electron-rich and aromatic tetrathiafulvalene-based reactive mesogen (TRM), which not only possesses high thermal conductivity but also exhibits excellent interfacial affinity with BN and EG at the molecular level. Systematic experiments, including photophysical, thermodynamic, structural, and computational analyses, reveal that the thermal conductivity of TRM-based polymer composites is substantially enhanced due to effective interfacial interactions between TRM and fillers. The TRM composites experimentally show excellent thermal conductivity based on enhanced interfacial phonon transfer, and these results are supported by theoretical interpretations. These findings underscore the critical importance of interface engineering between the polymer matrix and fillers at the molecular level in maximizing the material properties of polymer composites.

Amorphous boron nitride: synthesis, properties and device application

Amorphous boron nitride (a-BN) exhibits remarkable electrical, optical, and chemical properties, alongside robust mechanical stability, making it a compelling material for advanced applications in nanoelectronics and photonics. This review comprehensively examines the unique characteristics of a-BN, emphasizing its electrical and optical attributes, state-of-the-art synthesis techniques, and device applications. Key advancements in low-temperature growth methods for a-BN are highlighted, offering insights into their potential for integration into scalable, CMOS-compatible platforms. Additionally, the review discusses the emerging role of a-BN as a dielectric material in electronic and photonic devices, serving as substrates, encapsulation layers, and gate insulators. Finally, perspectives on future challenges, including defect control, interface engineering, and scalability, are presented, providing a roadmap for realizing the full potential of a-BN in next-generation device technologies.

Isothermal Dehydrogenation of Ammonia Borane: Insights into BNH Polymers and Challenges in Regeneration

In this study, the BNH polymers produced by ammonia borane (AB) thermolysis under isothermal conditions were investigated. Polyaminoborane (PAB) and diammoniate of diborane (DADB) form upon releasing the first equivalent of H2 at 85 °C, followed by the formation of cross-linked polyborazylene (PB) at 140 °C. Polyiminoborane (PIB) was not detected under these conditions. The characterization of these BNH polymers, relied on solid-state techniques including IR, Raman, XPS, and 11B MAS NMR. These methods revealed the chemical diversity and structural complexity of PAB and PB, highlighting the presence of different boron environments. The stability of the BNH polymers was also investigated over time and under different atmospheres. Over six months, both PAB and PB exhibited increased polymerization, and PAB showed an interesting ability to adsorb carbon dioxide. Efforts to regenerate AB from PAB and PB through hydrogenation and ammonia-based methods were conducted. The experiments showed that the BNH polymers break into smaller molecules, showing partial rehydrogenation of -NH and -BH groups in some cases, but with limited efficiency. Higher temperatures and hydrogen pressure modified decomposition pathways, though complete regeneration remains challenging. This study offers new insights into the chemical structure of BNH polymers and their potential use as hydrogen storage materials.

Skin biocompatibility of hexagonal boron nitride: An in vitro study on HaCaT keratinocytes and 3D reconstructed human epidermis

Hexagonal boron nitride (hBN) is a promising two-dimensional (2D) material of interest to the scientific community and industry due to its revolutionary physico-chemical features. Skin contact is one of the most feasible exposure routes both for workers, producing hBN, and consumers, using hBN-enabled nanotechnologies. Hence, the toxic potential of hBN at the cutaneous level was evaluated following an in vitro approach with different degree of complexity, using a simplified cell model (HaCaT keratinocytes), and a more predictive and complete skin tissue (a 3D model of human epidermis). Despite its significant uptake by keratinocytes, hBN exerted only weak adverse effects, such as slight alterations of cells parameters indices of cytotoxicity (cell viability, cell mass and plasma membrane integrity) and mitochondrial-related dysfunctions (mitochondrial depolarization, ATP depletion and reactive oxygen species production), detectable only at high concentrations (>25 µg/mL) and mainly after a long exposure (72 h). In addition, adoption of the OECD TG 431 and 439 on the 3D reconstructed human epidermis model demonstrated hBN as a non-corrosive and non-irritant material, with an extremely low pro-inflammatory potential. These results denote a good biocompatibility of hBN at the skin level.

Research progress on the epitaxial growth of hexagonal boron nitride on different substrates by the CVD method

Hexagonal boron nitride (h-BN) has a hexagonal structure similar to graphene, comprising alternating boron and nitrogen atoms. This unique structure endows h-BN with a plethora of excellent properties, including a low dielectric constant, elevated thermal and chemical stability, substantial mechanical rigidity, and an exceptionally low friction coefficient, rendering it versatile across a spectrum of applications ranging from semiconductors to aerospace. Moreover, its smooth surface, absence of dangling bonds, and wide band gap make h-BN an optimal substrate and gate dielectric material for two-dimensional electronic devices. This article details the synthesis methodologies and research progress of h-BN epitaxial growth on solid transition metal, liquid metal, alloy, sapphire/metal and semiconductor substrates. In particular, progress in improving the quality and functionality of h-BN films by adapting processes and substrates has been rigorously reviewed. Finally, the characteristics of different substrates are summarized and the challenges faced by h-BN in future applications are discussed.

Boron Phosphide: A Comprehensive Overview of Structures, Properties, Synthesis, and Functional Applications

Boron phosphide (BP), an emerging III-V semiconductor, has garnered significant interest because of its exceptional structural stability, wide bandgap, high thermal conductivity, and tunable electronic properties. This review provides a comprehensive analysis of BP, commencing with its distinctive structural characteristics and proceeding with a detailed examination of its exceptional physicochemical properties. Recent progress in BP synthesis is critically examined, with a focus on key fabrication strategies such as chemical vapor deposition, high-pressure co-crystal melting, and molten salt methods. These approaches have enabled the controlled growth of high-quality BP nanostructures, including bulk crystals, nanoparticles, nanowires, and thin films. Furthermore, the review highlights the broad application spectrum of BP, spanning photodetectors, sensors, thermal management, energy conversion, and storage. Despite these advances, precise control over the growth, morphology, and phase purity of BP's low-dimensional structures remains a critical challenge. Addressing these limitations requires innovative strategies in defect engineering, heterostructure design, and scalable manufacturing techniques. This review concludes by outlining future research directions that are essential for unlocking BP's potential in next-generation electronics, sustainable energy technologies, and multifunctional materials.

First-Principles Simulations Correlating X-ray Absorption Spectroscopy Features to Point Defects in h-BN

Hexagonal boron nitride (h-BN) is a promising material for a range of emerging applications in electronics, quantum information technology, and energy storage. Soft X-ray absorption spectroscopy (XAS) is powerful to reveal atomic details of BN, especially in the presence of defects. However, correlating XAS spectral features with specific defect types remains elusive. In this Letter, we report B K-edge XAS measurements of sputter-deposited turbostratic h-BN films and use a combination of first-principles spectroscopic simulations and analysis of detailed electronic structure and local charge transfer characteristics to elucidate their unique spectroscopic features. Our results show that the two main defect-related peaks, between the main π* resonances of h-BN and B2O3, as typically observed in BN films deposited by energetic condensation or bombarded with energetic ions, are associated with electronic states of H-passivated B atoms bonded to one and two oxygen impurity atoms, respectively. These conclusions hold significant implications for applications relying on defect-mediated properties of h-BN.

Self-assembled nano-hybrid composite based on Cu/CuXO nanoflower decorated onto hBNNS for high-performance and ultra-sensitive electrochemical detection of CEA biomarker

Synergistic combination of metal/metal oxide with semiconductor as nano-hybrid composites (NHC), exhibits unmatched potential for developing nano-biosensors with superior stability, sensitivity, and selectivity. In this study, we report the fabrication of hydrothermally synthesized 3D2D NHC based on self-assembled Cu/CuXO-hBNNS for label-free detection of Carcinoembryonic Antigen (CEA). A systematic investigation into the synthesis of CuXO-NF, hBNNS, and Cu/CuXO-hBNNS NHC was carried out using extensive spectroscopic and advanced nanoscale imaging techniques. Uniform deposition of Cu/CuXO-hBNNS films onto pre-hydrolyzed ITO electrodes was achieved at a low DC potential of 15 V using electrophoretic deposition (EPD). Optimum immunoelectrode efficacy was analyzed by monitoring antibody incubation time, electrolyte pH, and control study through FTIR and electrochemical techniques. Electrode study revealed remarkably improved surface chemistry upon Cu/CuXO integration with hBNNS, yielding ∼74 % and ∼ 31 % increase in CV and DPV response along with 3-fold increase in diffusion coefficient compared to bare hBNNS. The sensing response of the BSA/Anti-CEA/Cu/CuXO-hBNNS/ITO nano-biosensor detected CEA concentrations from 0 to 50 ng/mL utilizing [Fe(CN6)3-/4-] as a redox probe and demonstrated an exceptionally low limit of detection of 3.22 pg/mL (R2 = 0.99998). Electrochemical clinical evaluation supported by ELISA test established that Cu/CuXO-hBNNS-based nano-biosensor demonstrates exceptional shelf life, low cross-reactivity, and superior recovery rates in human serum, highlighting its effectiveness for precise and reliable detection.

Neuromorphic Floating-Gate Memory Based on 2D Materials

In recent years, the rapid progression of artificial intelligence and the Internet of Things has led to a significant increase in the demand for advanced computing capabilities and more robust data storage solutions. In light of these challenges, neuromorphic computing, inspired by human brain's architecture and operation principle, has surfaced as a promising answer to the growing technological demands. This novel methodology emulates the biological synaptic mechanisms for information processing, enabling efficient data transmission and computation at the identical position. Two-dimensional (2D) materials, distinguished by their atomic thickness and tunable physical properties, exhibit substantial potential in emulating synaptic plasticity and find broad applications in neuromorphic computing. With respect to device architecture, memory devices based on floating-gate (FG) structures demonstrate robust data retention capabilities and have been widely used in the realm of flash memory. This review begins with a succinct introduction to 2D materials and FG transistors, followed by an in-depth discussion on remarkable research progress in the integration of 2D materials with FG transistors for applications in neuromorphic computing and memory. This paper offers a thorough review of the existing research landscape, encapsulating the notable progress in swiftly expanding field. In conclusion, it addresses the constraints encountered by FG transistors using 2D materials and delineates potential future trajectories for investigation and innovation within this area.

Heterojunctions Based on 2D Materials for Pulse Laser Applications

In recent years, heterostructures composed of two-dimensional (2D) materials have demonstrated broad application prospects across various domains, primarily attributed to their exceptional electrical and optical properties. The superior performance of these heterostructures is rooted in the interlayer interactions and the diversity of the constituent materials. Notably, their applications have been greatly advanced in optical fields such as photodetectors, lasers, modulators, optical sensors, and nonlinear optics. etc. This review delineates the advancement of heterostructures based on 2D materials and discusses the electronic structural properties of their interfaces and band alignments while summarizing their carrier dynamics and nonlinear optical characteristics. Furthermore, it explores the synthesis techniques of 2D heterostructures and their applications as saturable absorbers in laser Q-switching and mode-locking, emphasizing the critical role that type-I and type-II heterojunctions have played in advancing laser technology. Lastly, the challenges and future opportunities in the application of 2D heterostructures in laser technologies are reviewed, offering insights on the potential directions for further research in this field.

Van der Waals Epitaxy of High-Quality Transition Metal Dichalcogenides on Single-Crystal Hexagonal Boron Nitride

Van der Waals (vdW) heterostructures comprising of transition metal dichalcogenides (TMDs) and hexagonal boron nitride (h-BN) are promising building blocks for novel 2D devices. The vdW epitaxy provides a straightforward integration method for fabricating high-quality TMDs/h-BN vertical heterostructures. In this work, the vdW epitaxy of high-quality single-crystal HfSe2 on epitaxial h-BN/sapphire substrates by chemical vapor deposition is demonstrated. The epitaxial HfSe2 layers exhibit a uniform and atomically sharp interface with the underlying h-BN template, and the epitaxial relationship between HfSe2 and h-BN/sapphire is determined to HfSe2 (0001)[12 ¯ ${\mathrm{\bar{2}}}$ 10]//h-BN (0001)[11 ¯ ${\mathrm{\bar{1}}}$ 00]//sapphire (0001)[11 ¯ ${\mathrm{\bar{1}}}$ 00]. Impressively, the full width at half maximum of the rocking curve for the epitaxial HfSe2 layer on single-crystal h-BN is as narrow as 9.6 arcmin, indicating an extremely high degree of out-plane orientation and high crystallinity. Benefitting from the high crystalline quality of HfSe2 epilayers and the weak interfacial scattering of HfSe2/h-BN, the photodetector fabricated from the vdW epitaxial HfSe2 on single-crystal h-BN shows the best performance with an on/off ratio of 1 × 104 and a responsivity up to 43 mA W-1. Furthermore, the vdW epitaxy of other TMDs such as HfS2, ZrS2, and ZrSe2 is also experimentally demonstrated on single-crystal h-BN, suggesting the broad applicability of the h-BN template for the vdW epitaxy.

Facile Growth of h-BN Films by Using Surface-Activated h-BN Powders as Precursors

Atomically thick hexagonal boron nitride (h-BN) films have gained increasing interest, such as nanoelectronics and protection coatings. Chemical vapor deposition (CVD) has been proven to be an efficient method for synthesizing h-BN thin films, but its precursors are still limited. Here, it is reported that a novel and easily available precursor, surface-activated h-BN (As-hBN), with NH3/N2 as an additional nitrogen source is used for CVD growth of monolayer h-BN films on the Cu foils. The as-grown h-BN films can significantly enhance the anti-oxidation ability of copper. Molecular dynamics simulations reveal that the reactivity of the As-hBN precursors is attributed to the decomposition of unstable BO3 and O-terminal edges on the surface under H2 atmosphere. This method provides a more reliable approach for fabricating h-BN films.

Boron Nitride-Polymer Composites with High Thermal Conductivity: Preparation, Functionalization Strategy and Innovative Structural Regulation

The escalating thermal challenges posed by increasing power densities in electronic devices emerge as a critical barrier to maintain their sustained and reliable operation. Addressing this issue requires the strategic development of materials with superior thermal conductivity properties to facilitate progress in high-power electronics development. Thermal conductive polymer composites by incorporating ceramic material renowned for their exceptional thermal conductivity adjustability, insulating properties, and moldability, are emerging as a promising solution to this urgent challenge. Hexagonal boron nitride (h-BN) nanomaterials emerge as highly promising candidates for thermal management applications, owing to their exceptional mechanical properties, superior thermal stability, remarkable thermal conductivity coefficients, minimal thermal expansion characteristics, and outstanding chemical inertness. In this work, the progress of ≈10 years on high thermal conductive boron nitride-filled polymer composites is thoroughly summarized. Moreover, strategies for h-BN and other boron nitride nanomaterials-filled polymer composites at synthesis, functionalization, and innovative structural design are discussed in detail. The main challenges and future development of boron nitride-polymer composites in thermal management are also proposed, which will provide meaningful guidance for the design and practical applications of thermal management materials.

Impact of Hexagonal Boron Nitride Encapsulation on the Photophysical Dynamics of MAPbI3 Perovskite Crystals

Metal halide perovskites are known to suffer from instability due to their high sensitivity to external stimuli. Although encapsulation can considerably improve their stability, the impact of encapsulation on the intrinsic photophysical properties of perovskites remains unclear. Here, we investigate the effect of hexagonal boron nitride (hBN) encapsulation on the photoluminescence (PL) dynamics of MAPbI3 perovskite crystals at the individual crystal level. The results demonstrate that hBN encapsulation leads to PL decline, PL lifetime shortening, and spectral broadening in MAPbI3 crystals, which can be ascribed to the stress exerted by hBN encapsulation on MAPbI3 crystals that promotes defect formation and subsequent nonradiative recombination losses. Furthermore, although hBN encapsulation can delay degradation, the effect of hBN-induced stress and the poor sealing due to single-sided encapsulation would further broaden the spectra over time. This work provides new insights into the photophysical effects of encapsulation on perovskites and has significance for the selection of perovskite encapsulation strategies.

The Effect of Al2O3 Nanoparticles on Hexagonal Boron Nitride Films Resulting from High-Temperature Annealing

A simple two-step approach was proposed to obtain hBN thin films with high crystalline quality, meaning that the films were initially prepared by using an RF magnetron sputtering technique and subsequently followed by a post-annealing process at a high temperature. In the case of introducing Al2O3 nanoparticles, the effects of annealing temperature from 1000 °C to 1300 °C and annealing time from 0.5 h to 1.5 h on the recrystallization process of the grown hBN films were systematically studied by using XRD and SEM technologies. The introduction of Al2O3 impurities during the annealing process successfully reduced the transition temperature of hexagonal phase BN by more than 300 °C. The crystalline quality of hBN films grown by RF magnetron sputtering could be effectively enhanced under annealing at 1100 °C for 1 h. The DUV detectors were prepared using the hBN films before and after annealing, and showed a notable improvement in detector performance by using annealed films. It has significant application value in further enhancing the performance of DUV photodetectors based on high-quality hBN films.

Physics of 2D Materials for Developing Smart Devices

Rapid industrialization advancements have grabbed worldwide attention to integrate a very large number of electronic components into a smaller space for performing multifunctional operations. To fulfill the growing computing demand state-of-the-art materials are required for substituting traditional silicon and metal oxide semiconductors frameworks. Two-dimensional (2D) materials have shown their tremendous potential surpassing the limitations of conventional materials for developing smart devices. Despite their ground-breaking progress over the last two decades, systematic studies providing in-depth insights into the exciting physics of 2D materials are still lacking. Therefore, in this review, we discuss the importance of 2D materials in bridging the gap between conventional and advanced technologies due to their distinct statistical and quantum physics. Moreover, the inherent properties of these materials could easily be tailored to meet the specific requirements of smart devices. Hence, we discuss the physics of various 2D materials enabling them to fabricate smart devices. We also shed light on promising opportunities in developing smart devices and identified the formidable challenges that need to be addressed.

Engineering Two-Dimensional Nanomaterials for Photothermal Therapy

Two-dimensional (2D) nanomaterials offer a transformative platform for photothermal therapy (PTT) due to their unique physicochemical properties and exceptional photothermal conversion efficiencies. This Minireview summarizes the photothermal mechanisms of common 2D nanomaterials and details their synthesis, surface modification, and optimization strategies. Recent advances leveraging 2D nanomaterials for enhanced PTT are highlighted, with particular emphasis on synergistic therapeutic modalities. Despite the significant potential of 2D nanomaterials in PTT, challenges persist, including scalable and reproducible manufacturing, precise targeted delivery, understanding of the underlying biological interactions, and comprehensive assessment of long-term biocompatibility and toxicity. Looking forward, emerging technologies such as machine learning are expected to play a crucial role in accelerating the design and optimization of 2D nanomaterials for PTT, enabling the prediction of optimal structures, properties, and therapeutic efficacy, and ultimately paving the way for personalized nanomedicine.

Recent advances in nanoarchitectonics of two-dimensional nanomaterials for dental biosensing and drug delivery

Two-dimensional (2D) nanoarchitectonics involve the creation of functional material assemblies and structures at the nanoscopic level by combining and organizing nanoscale components through various strategies, such as chemical and physical reforming, atomic and molecular manipulation, and self-assembly. Significant advancements have been made in the field, with the goal of producing functional materials from these nanoscale components. 2D nanomaterials, in particular, have gained substantial attention due to their large surface areas which are ideal for numerous surface-active applications. In this review article, nanoarchitectonics of 2D nanomaterials based biomedical applications are discussed. We aim to provide a concise overview of how nanoarchitectonics using 2D nanomaterials can be applied to dental healthcare, with an emphasis on biosensing and drug delivery. By offering a deeper understanding of nanoarchitectonics with programmable structures and predictable properties, we hope to inspire new innovations in the dental bioapplications of 2D nanomaterials.

Two-Photon Absorption in Twisted Graphene/Hexagonal Boron Nitride Heterojunction Tuned by Vertical Electric Field

We theoretically investigate the comprehensive modulation effect of interlayer twisting and external electric field to the two-photon absorption (TPA) in twisted graphene/hexagonal boron nitride (tG/hBN) heterojunction with small twist angles (2° < θ < 10°) starting from an effective continuum model. It is found that the TPA of tG/hBN is extended to the visible light band from infrared light band of that in twisted bilayer graphene (tBLG) due to the increase in energy band gap caused by twisting and the potential energy of the boron nitride atomic layer. And the TPA coefficient is enhanced several times via an external electric field, which increases the density of states, leading to an increase transition probability for two-photon absorption.

Efficient Photosensitizer Delivery by Neutrophils for Targeted Photodynamic Therapy of Glioblastoma

Background/Objectives: Glioblastoma (GBM) is the deadliest type of brain tumor and photodynamic therapy (PDT) is a promising treatment modality of GBM. However, insufficient photosensitizer distribution in the GBM critically limits the success of PDT. To address this obstacle, we propose tumoritropic neutrophils (NE) as active carriers for photosensitizer delivery to achieve GBM-targeted PDT. Methods: Isolated mouse NE were loaded with functionalized hexagonal boron nitride nanoparticles carrying the photosensitizer chlorin e6 (BNPD-Ce6). In vitro experiments were conducted to determine drug release from the loaded NE (BNPD-Ce6@NE) to mouse GBM cells and consequential photo-cytotoxicity. In vivo experiments were performed on mice bearing intracranial graft GBMs to demonstrate GBM-targeted drug delivery and the efficacy of anti-GBM PDT mediated by BNPD-Ce6@NE. Results: BNPD-Ce6@NE displayed good viability and migration ability, and rapidly released BNPD-Ce6 to co-cultured mouse GBM cells, which then exhibited marked reactive oxygen species (ROS) generation and cytotoxicity following 808 nm laser irradiation (LI). In the in vivo study, a single intravenous bolus injection of BNPD-Ce6@NE resulted in pronounced Ce6 distribution in intracranial graft GBMs 4 h post injection, which peaked around 8 h post injection. A PDT regimen consisting of multiple intravenous BNPD-Ce6@NE injections each followed by one extracranial tumor-directed LI 8 h post injection significantly slowed the growth of intracranial graft GBMs and markedly improved the survival of host animals. Histological analysis revealed massive tumor cell damage and NE infiltration in the PDT-treated GBMs. Conclusions: NE are efficient carriers for GBM-targeted photosensitizer delivery to achieve efficacious anti-GBM PDT.

First-principles elucidation of defect-mediated Li transport in hexagonal boron nitride

Hexagonal boron nitride (hBN) is a promising candidate as a protective membrane or separator in Li-ion and Li-S batteries, given its excellent chemical stability, mechanical robustness, and high thermal conductivity. In addition, hBN can be functionalized by introducing defects and dopants, or be directly integrated into other active components of batteries, which further augments its appeal to the field. Here, we use first-principles simulations to evaluate the role of atomic defects in hBN in regulating the Li-ion diffusion mechanism and associated kinetics. Specifically, the following four distinct types of vacancy defects are considered: isolated single B and N vacancies, a B-N vacancy pair, and a B3N vacancy cluster. It is found that these defect sites generally favor Li intercalation and out-of-plane diffusion but slow down in-plane Li-ion diffusion due to a strong Li trapping effect at the defect sites. Such a trapping effect is, however, highly local such that it does not necessarily affect the overall Li-ion conductivity in defected hBN layers. The present systematic evaluation of the impact of atomic defects on Li ion migration and accompanied charge analysis of hBN lattice in response to Li-ion diffusion provide a mechanistic understanding of Li-ion transport behavior in defected hBN and highlight the potential of defect engineering to achieve optimal material performance.

Challenges in Synthesizing Hexagonal Boron Nitride "Quantum" Dots

Fluorescent nanodots derived from hexagonal boron nitride (h-BN) have garnered significant attention over the past decade. As a result, various synthesis methods─encompassing both bottom-up hydrothermal reactions and top-down exfoliation processes─have been deemed "successful" in producing BN nanodots. Nevertheless, this Perspective emphasizes that substantial challenges remain in the synthesis of "true" nanodots composed mainly of h-BN units, as many so-called successful syntheses reported in the literature involve some mischaracterizations. Here, we highlight the crucial necessity for strict synthesis conditions to facilitate the production of authentic BN nanodots. Furthermore, it is imperative to re-evaluate the optical properties and photoluminescence mechanisms of these nanodots, entailing the establishment of clear criteria for what constitutes "true" BN nanodots.

Surface functionalization of two-dimensional nanomaterials beyond graphene: Applications and ecotoxicity

Two dimensional (2D) nanomaterials have emerged as promising candidates in nanotechnology due to their excellent physical, chemical, and electronic properties. However, they also pose challenges such as environmental instability and low biosafety. To address these issues, researchers have been exploring various surface functionalization methods to enhance the performance of 2D nanomaterials in practical applications. Moreover, when released into the environment, these 2D nanomaterials may interact with natural organic matter (NOM). Both intentional surface modification and unintentional environmental corona formation can alter the structure and physicochemical properties of 2D nanomaterials, potentially affecting their ecological toxicity. This review provides a comprehensive overview of covalent functionalization strategies and non-covalent interactions of 2D nanomaterials beyond graphene with organic substances, examining the resultant changes in material properties after modification. Covalent functionalization methods discussed include nucleophilic substitution reactions, addition reactions, condensation, and coordination. Non-covalent interactions are classified by substance type, covering interactions with NOM, in vivo biomolecules, and synthetic compounds. In addition, the review delves into the effects of surface functionalization on the toxicity of 2D nanomaterials to bacteria and algae. This discussion contributes to a foundational understanding for assessing the potential ecological risks associated with 2D nanomaterials.

Synergistic photocatalytic degradation of methylene blue and ibuprofen using Co₃O₄-Decorated hexagonal boron nitride (hBN) composites under Sun-like irradiation

In this study, we report the synthesis and photocatalytic performance of Co₃O₄-decorated hexagonal boron nitride (hBN) composites for degrading methylene blue (MB) and ibuprofen (IBF) under sunlight irradiation. Using a dry impregnation method, the composites were prepared with varying Co₃O₄ loadings (0.5%, 1%, 2%). Comprehensive characterization confirmed the successful incorporation and uniform distribution of Co₃O₄ on the hBN matrix. Photocatalytic experiments revealed that 1% Co₃O₄-hBN composite exhibited the highest activity, achieving nearly 100% MB degradation in 60 min and 90% IBF degradation in 120 min. The enhanced photocatalytic efficiency is attributed to the synergistic effects between Co₃O₄ and hBN, which extend light absorption and promote charge separation. Our findings demonstrate the potential of Co3O₄-decorated hBN composites as effective photocatalysts for environmental remediation. The study provides a foundation for further exploration of these materials, including their long-term stability and application to a broader range of pollutants.

Halbach Array Induced Magnetic Field Alignment in Boron Nitride Nanocomposites

Thermal conductivity enhancement in polymers is vital for advanced applications. This study introduces a novel method to align hexagonal boron nitride (hBN) nanosheets within polydimethylsiloxane (PDMS) matrices using a Halbach array to create a highly uniform magnetic field. This technique achieves significant improvements in thermal conductivity by effectively aligning hBN nanosheets. This research shows that hBN nanosheets, when aligned, can drastically enhance thermal conductivity in PDMS composites. Specifically, 10 wt.% vertically aligned hBN nanosheets in a rotating magnetic field achieve a thermal conductivity of 3.58 W mK-1, an impressive 1950% increase over pure PDMS. Additionally, the study explores the effects of orientation on dielectric properties, finding that the orientation of hBN nanosheets also improves electrical insulation and increases the dielectric constant while maintaining extremely low dielectric losses. For a vertically oriented sample, the dielectric constant reaches ≈14, and dielectric losses are as low as 0.0049 at 100 Hz, highlighting their potential for energy storage capacitors. This approach not only enhances thermal management but also maintains or improves electrical insulation, offering promising advances for polymer composites in various technological applications.

Carbonless DNA

Carbonless DNA was designed by replacing all carbon atoms in the standard DNA building blocks with boron and nitrogen, ensuring isoelectronicity. Electronic structure quantum chemistry methods (DFT(ωB97XD)/aug-cc-pVDZ) were employed to study both the individual building blocks and the larger carbon-free DNA fragments. The reliability of the results was validated by comparing selected structures and binding energies using more accurate methods such as MP2, CCSD, and SAPT2+3(CCD)δMP2. Carbonless analogs of DNA components, including cytosine, thymine, guanine, adenine, and deoxyribose, were investigated, showing strong resemblance to the carbon-based versions in terms of spatial structure, polarity, and molecular interaction capabilities. Complementary base pairs of the carbonless analogs exhibited a similar number and length of hydrogen bonds as those found in their carbon-containing counterparts, with binding energies for A-T and G-C analogs remaining comparable. Carbonless DNA fragments containing two and six base pairs were studied, revealing double-helix structures analogous to natural DNA. Structural parameters such as fragment size, hydrogen bond lengths, and rise per base pair were consistent with those observed in unmodified DNA. Docking simulations with a 12 base pair fragment and netropsin as a ligand indicated a slight shift in binding preference for the carbonless DNA through the minor groove, with an approximate 25% increase in binding affinity compared to natural DNA.

Efficient adsorption of ofloxacin in a novel nanocomposite formed by nano-hexagonal boron nitride fused with zeolite imidazolite skeleton-8: Experimental and molecular dynamics simulation studies

With the widespread application of antibiotics in the medical field, associated wastewater pollution has become a critical environmental issue, creating potential risks to ecosystems and public health. This study synthesized three novel nanocomposite materials, ZIF-8@h-BN-X, using an in-situ growth method by adjusting h-BN content. Compared to pure two-dimensional hexagonal boron nitride (h-BN), their adsorption capacities for ofloxacin (OFL) in solution were evaluated. Results showed that zeolitic imidazolate framework-8 (ZIF-8) attached and grew on the h-BN surface, altering surface functional groups and significantly enhancing the nanocomposite's adsorption effect on OFL. Adsorption capacity depended on the initial h-BN content, with lower X content resulting in more active sites and stronger adsorption capacity. Equilibrium adsorption capacities were 145.46, 124.91, and 58.16 mg·g-1 for X values of 29.82 %, 45.93 %, and 62.95 %, respectively. Molecular dynamics simulations revealed interaction energies of -109.13 kcal·mol-1 between ZIF-8@h-BN-X and OFL, compared to -84.78 kcal·mol-1 between pure h-BN and OFL, demonstrating the superior adsorption performance of ZIF-8@h-BN-X. OFL adsorption on ZIF-8@h-BN-X followed the Langmuir isotherm model and pseudo-second-order adsorption kinetics. Thermodynamic parameters indicated that the adsorption process of ZIF-8@h-BN-X was exothermic and spontaneous when compared to h-BN alone. This study highlights the significant potential of ZIF-8@h-BN-X in treating antibiotic-contaminated wastewater, while providing theoretical and practical insights for developing novel, efficient two-dimensional nanocomposite adsorbents.

Comparative analysis of modified Johnson-Cook model and artificial neural network for flow stress prediction in BN-reinforced AZ80 magnesium composite

Boron nitride (BN), renowned for its exceptional optoelectrical properties, mechanical robustness, and thermal stability, has emerged as a promising two-dimensional material. Reinforcing AZ80 magnesium alloy with BN can significantly enhance its mechanical properties. To investigate and predict this enhancement during hot deformation, we introduce two independent modeling approaches a modified Johnson-Cook constitutive model and an artificial neural network (ANN). These models aim to capture both linear and nonlinear deformation characteristics. Hot compression tests conducted across various temperatures and strain rates provided a comprehensive dataset for model validation. The MJCC model, accounting for strain rate and temperature effects, achieved a correlation coefficientRof 0.96 and an average absolute relative error (AARE) of 6.28%. In contrast, the ANN, trained on experimental data, improved the correlation coefficient toRof 0.99 and reduced the AARE to below 1.5%, significantly enhancing predictive accuracy. These results indicate that while the modified J-C model provides reliable predictions under moderate conditions, the ANN more effectively captures complex behaviors under extreme deformation conditions. By comparing these modeling approaches, our study offers valuable insights for accurately predicting the rheological behavior of BN-reinforced AZ80 magnesium composite, aiding process optimization in industrial applications.

Impact of Boron Nitride on the Thermoelectric Properties and Service Stability of Cu2-xSe

Improving the thermoelectric performance and service stability is essential for the effective use of cuprous selenide (Cu2-xSe). In this study, hexagonal boron nitride (h-BN) was incorporated into nano-Cu2-xSe, with the goal of enhancing thermoelectric performance and service stability. It was found that Cu2-xSe-0.005 wt % BN showed a higher thermoelectric figure of merit (zT) value (∼1.76 at 923 K), which was 11% greater than that of pure Cu2-xSe, mainly due to a significant reduction in lattice thermal conductivity (kL) to about 50% (0.13 W m-1 K-1). Additionally, the formation of an ion-blocking interface by hexagonal boron nitride effectively shortens the migration path of Cu+ ions, improving service stability while maintaining the contribution of Cu+ transitions to thermal conductivity. Finally, an increase in hardness of ∼11.1% was observed, reaching 0.7 GPa in Cu2-xSe-0.02 wt % BN. This research is a feasible approach to improving the service stability of Cu2-xSe.

Two-Dimensional Organic-Inorganic van der Waals Hybrids

Two-dimensional organic-inorganic (2DOI) van der Waals hybrids (vdWhs) have emerged as a groundbreaking subclass of layer-stacked (opto-)electronic materials. The development of 2DOI-vdWhs via systematically integrating inorganic 2D layers with organic 2D crystals at the molecular/atomic scale extends the capabilities of traditional 2D inorganic vdWhs, thanks to their high synthetic flexibility and structural tunability. Constructing an organic-inorganic hybrid interface with atomic precision will unlock new opportunities for generating unique interfacial (opto-)electronic transport properties by combining the strengths of organic and inorganic layers, thus allowing us to satisfy the growing demand for multifunctional applications. Here, this review provides a comprehensive overview of the latest advancements in the chemical synthesis, structural characterization, and numerous applications of 2DOI-vdWhs. Firstly, we introduce the chemistry and the physical properties of the recently rising organic 2D crystals (O2DCs), which feature crystalline 2D nanostructures comprising carbon-rich repeated units linked by covalent/noncovalent bonds and exhibit strong in-plane extended π-conjugation and weak interlayer vdWs interaction. Simultaneously, representative inorganic 2D crystals (I2DCs) are briefly summarized. After that, the synthetic strategies will be systematically summarized, including synthesizing single-component O2DCs with dimensional control and their vdWhs with I2DCs. With these synthetic approaches, the control in the dimension, the stacking modes, and the composition of the 2DOI-vdWhs will be highlighted. Subsequently, a special focus will be given on the discussion of the optical and electronic properties of the single-component 2D materials and their vdWhs, which will be closely relevant to their structures, so that we can establish a general structure-property relationship of 2DOI-vdWhs. In addition to these physical properties, the (opto-)electronic devices such as transistors, photodetectors, sensors, spintronics, and neuromorphic devices as well as energy devices will be discussed. Finally, we provide an outlook to discuss the key challenges for the 2DOI-vdWhs and their future development. This review aims to provide a foundational understanding and inspire further innovation in the development of next-generation 2DOI-vdWhs with transformative technological potential.

Defective h-BNs-Supported Pd Nanoclusters: An Efficient Photocatalyst for Selective Oxidation of 5-Hydroxymethylfurfural

5-hydroxymethylfurfural (HMF) is one of the most promising biomass-based chemicals that is used to produce many kinds of important compounds. Especially, the selective conversion of HMF to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), an important chemical feedstock, has high industrial significance but is technically challenging. In this study, we present a high-performance photocatalyst for selective oxidation of HMF to HMFCA. By integrating an ultrasmall amount of palladium (Pd) nanoclusters (1.12‰ in weight) on defective hexagonal boron nitride nanosheets (Pd/defective h-BN nanosheets (dh-BNs)), outstanding photocatalytic performance can be achieved, resulting in up to a 95% HMF conversion ratio with an 82% HMFCA selectivity. The performance is considerably higher than that of pristine dh-BNs and Pd on defect-free h-BNs. More importantly, this Pd/dh-BNs catalyst maintains a high catalytic activity after eight cycles, demonstrating robust catalytic stability. Density functional theory calculations indicate that Pd/dh-BNs can lower the energy barrier for HMF oxidation and facilitate the desorption of HMFCA, which contributes to the high selectivity catalytic performance. This study not only introduces a promising photocatalyst for sustainable chemical transformations but can also provide valuable insights into the design of advanced photocatalytic material for biorefinery applications.

First-principles investigations of As-doped tetragonal boron nitride nanosheets for toxic gas sensing applications

Pristine and arsenic-doped tetragonal boron nitride nanosheets (BNNS and As-BNNS) have been reported as potential candidates for toxic gas sensing applications. We have investigated the adsorption behavior of BNNS and As-BNNS for CO2, H2S, and SO3 gas molecules using first-principles density functional theory (DFT). Both BNNS and As-BNNS possess negative cohesive energies of -8.47 and -8.22 eV, respectively, which indicates that both sheets are energetically stable. Successful adsorption is inferred from the negative adsorption energy and structural deformation in the vicinity of the adsorbent and adsorbate. As-doping results in a significant increase in adsorption energies from -0.094, -0.175, and -0.462 eV to -2.748, -2.637, and 3.057 eV for CO2, H2S and SO3 gases, respectively. Due to gas adsorption, the electronic bandgap in As-BNNS varies by approximately 32% compared to a maximum of 24% in BNNS. A notable fluctuation in the energy gap and electrical conductivity is seen, with ambient temperature being the point of maximal sensitivity. For SO3, the maximum charge transfer during adsorption in BNNS and As-BNNS is determined to be 0.08|e| and 0.25|e|, respectively. Due to the interaction with gases, all structures exhibit an extremely high absorption coefficient on the order of 104 cm-1 with minimal peak shifting. Additionally, doping an As atom on BNNS' surface remarkably improved its ability to sense CO2, H2S, and SO3 gasses.

Poly(vinyl alcohol)-Assisted Exfoliation and Grafting Modification of Boron Nitride Nanosheets with a High Aspect Ratio via a Continuous Production Method for Energy Storage and Thermal Management

Hexagonal boron nitride nanosheets (BNNS) integrating many extraordinary properties are usually combined with polymers to fabricate multifunctional dielectric materials for energy storage and thermal management. Unfortunately, the existing technologies for producing BNNS generally have the disadvantages of inefficiency and low product quality, which significantly hinder the wide application of high-value nanocomposites. Herein, a novel poly(vinyl alcohol) (PVA)-assisted pan-milling method based on the innovative solid-state shear milling (S3 M) technology is reported for the production of high-quality BNNS. The uniform three-dimensional (3D) shear force field generated by pan milling not only ensured the high aspect ratio of BNNS (the average lateral size of ∼954 nm and the average thickness of ∼3.7 nm) but also induced the mechanochemical reaction between PVA and BNNS to achieve in situ grafting modification on the BNNS surface. The simultaneous high-quality exfoliation and surface modification of BNNS positively contributed to the mechanical, dielectric, and thermal conduction properties of BNNS/PVA nanocomposites. At the BNNS content of 10 wt %, the BNNS/PVA composite film exhibited excellent robustness (Young's modulus of 5305 MPa and the tensile strength of 83 MPa), with a satisfactory breakdown strength (Eb of 134.7 MV/m) and dielectric constant (∼5 at 1000 Hz). In addition, the substantial improvement of thermal conductivity (from 0.88 to 5.59 W·m-1·K-1) guaranteed the stability of the dielectric properties of the nanocomposites at high temperatures. This pan-milling method characterized by green and efficiency is highly scalable to other two-dimensional (2D) layered materials, providing a practical strategy for the industrial fabrication of nanocomposites in elevated-temperature energy storage.

Algae-Derived Nacre-like Dielectric Bionanocomposite with High Loading Hexagonal Boron Nitride for Green Electronics

The surging demand for electronics is causing detrimental environmental consequences through massive electronic waste production. Urgently shifting toward renewable and eco-friendly materials is crucial for fostering a green circular economy. Herein, we develop a multifunctional bionanocomposite using an algae-derived carbohydrate biopolymer (alginate) and boron nitride nanosheet (BNNS) that can be readily employed as a multifunctional dielectric material. The adopted rational design principle includes spatial locking of superhigh loading of BNNS via hydrogel casting followed by layer-by-layer assembly via solvent evaporation, successive cross-link engineering, and hot pressing. We harness the hierarchical assembly of BNNS and the molecular interaction of alginates with BNNS to achieve synergistic material properties with excellent mechanical robustness (tensile strength ∼135 MPa, Young's modulus ∼18 GPa), flexibility, thermal conductivity (∼4.5 W m-1 K-1), flame retardance, and dielectric properties (dielectric constant ∼7, dielectric strength ∼400 V/μm, and maximum energy density ∼4.33 J/cm3) that outperform traditional synthetic polymer dielectrics. Finally, we leverage the synergistic material properties of our engineered bionanocomposite to showcase its potential in green electronic applications, for example, supercapacitors and flexible interconnects. The supercapacitor device consisting of aerosol jet-printed single-walled carbon nanotube electrodes on our engineered bionanocomposite demonstrated a volumetric capacitance of ∼7 F/cm3 and robust rate capability, while the printed silver interconnects maintained conductivity in various deformed states (i.e., bending or flexing).

Two-dimensional boron nitride allotrope Irida-B12N12 with 3-6-8 membered rings and wide-bandgap semiconducting properties

We present a novel two-dimensional (2D) boron nitride allotrope, Irida- B 12 N 12 (Ir-BN), analogous to the all-carbon Irida-Graphene (Ir-G). The predicted structure of Ir-BN consists of alternating boron and nitrogen atoms, forming three distinct lattices with 3-, 6-, and 8-membered ring patterns. First-principles calculations based on density functional theory (DFT) formalism and ab initio molecular dynamics (AIMD) simulations were performed to investigate its structural, mechanical, electronic, and optical properties. The Ir-BN lattices exhibit good dynamical and thermal stability, supporting their viability as new 2D materials. Substantial anisotropy is observed in the mechanical properties, with in-plane stiffness ranging from 16 to 142 N/m, depending on the direction, and bulk moduli between 78 and 95 N/m. The electronic structure analysis reveals that Ir-BN is a wide-bandgap semiconductor, with band gaps ranging from 2.4 to 3.2 eV. The material shows optical activity particularly in the visible and ultraviolet regions.

Synthesis and modification of boron nitride nanomaterials for gas sensors: from theory to application

Boron nitride (BN) has gradually emerged as a significant focus of research due to its unique physical and chemical properties. Over the past few years, substantial advancements have been achieved in the domains of gas adsorption and sensing, driven by improvements in modification technology and a deeper understanding of gas sensing mechanisms. BN-based nanomaterials have been instrumental in these advancements. The application of some properties of BN in the fabrication of gas sensing components is anticipated to lead to new breakthroughs. Furthermore, BN is projected to become one of the most promising materials for high-performance gas sensors, owing to its high thermal stability, chemical stability, and exceptional mechanical properties. While numerous review articles have been published regarding BN, primarily focusing on its synthesis, properties, and functionalities, few have made significant contributions to the realm of gas adsorption and detection through theoretical calculations and practical applications. This review comprehensively examines the integration of BN with various gas adsorption and sensing techniques, covering aspects such as model development, theoretical computations, material synthesis, and real-world applications. These methods provide valuable insights into the potential of BN for gas sensing applications. Furthermore, the paper discusses the challenges encountered in utilizing BN-based gas sensors and offers recommendations for overcoming these challenges. Finally, the future prospects for the advancement of BN-based gas sensors are considered, highlighting new possibilities and areas for improvement within this field.