Route For Preparation Research Articles

Discovery and Characterization of a Metastable Cubic Interstitial Nickel-Carbon System with an Expanded Lattice.

Metastable, i.e., kinetically favored but thermodynamically not stable, interstitial solid solutions of carbon in iron are well-understood. Carbon can occupy the interstitial atoms of the host metal, altering its properties. Alloying of the host metal results in the stabilization of the FeCx phases, widening its application. Pure nickel finds niche applications, mainly focusing on catalysis, while nickel alloys are widely applied, e.g., in gas turbines, reactors, and seawater piping. Nickel carbide (Ni3C) is the well-known stable Ni-C system displaying a rhombohedral (R3̅c) crystal structure. Some reports describe an elusive cubic Ni-C system, observed during certain catalytic reactions occurring on nickel and formed by the occupation of the interstitials of the metal with carbon: to date, the stabilization and characterization of this phase have not been accomplished. Hereby, we report on the synthesis of a cubic metastable NiCx phase using chemical vapor deposition of methane on supported nickel nanoparticles. The structure was predicted by DFT/ReaxFF, synthesized and monitored with in situ time-resolved synchrotron XRD, and experimentally confirmed by Rietveld refinement and (S)TEM-EELS under ambient conditions. The results show an Fm3̅m phase with a lattice parameter of a = 3.749 ± 0.037 Å at room temperature, with the highest ever reported atomic percentage of carbon occupying the octahedral interstices of 23.1%, resulting in a NiC0.3 phase. The degree of occupation of the interstitial voids by carbon can be controlled, enabling the tuning of the host metal's d-spacing and composition, highlighting the applicability of this synthesis route for catalytic nanoparticle preparation.

Gold Nanoparticles and Chitosan as Innovative Compounds in Medicine and Cosmetology:A Review of Current Applications.

The medical and cosmetic industries have developed in recent years, there has been a growing demand for new materials. Gold nanoparticles (Au NPs) and chitosan (CS) have been known and used for many years. Unfortunately, despite their numerous advantages and possible applications, such materials may possess certain disadvantages and limitations that constitute a problem in medical or cosmetic applications. Au NPs may have potential toxicity depending on their size, shape, charge, surface coatings, and tendency to agglomerate into larger clusters. On the other hand, the CS production process requires strict control due to the possibility of uncontrolled hydrolysis or chemical modifications during polymer isolation. The combination of Au NPs and CS that differ in chemical and phase in one composite (Au/CS) allows for acquiring of new material with many advantages. The obtained composite has good mechanical properties and is biocompatible due to the presence of CS and the antibacterial properties of Au NPs. Therefore, it can be successfully used in many branches of medicine, including gene delivery, cell encapsulation, wound healing process, or as a preservative ingredient of cosmetics. Moreover, Au/CS nanocomposites are used in the food industry and environmental protection. This review highlights the preparation routes, properties, and applications of Au NPs and CS as separate materials. Moreover, the last part presents the advantages of combining these two materials into one nanocomposite. Specifically, we described the role of CS in the synthesis of Au NPs and possible subsequent applications of such nanomaterials as an element of biosensors, scaffolds, and an intelligent drug release system or tissue engineering.

A Review on Reliable and Standardized Animal Models to Study the Pathogenesis of Schmallenberg Virus in Ruminant Natural Host Species.

In the late summer of 2011, the Netherlands reported a cluster of reduced milk yield, fever, and diarrhea in dairy cattle. In March 2012, congenital malformations appeared, and Schmallenberg virus (SBV) was identified, becoming one of the few orthobunyaviruses distributed in Europe. Initially, little was known about the pathogenesis and epidemiology of these viruses in the European context, so assumptions were largely extrapolated from related viruses and other regions worldwide. To study SBV's pathogenesis and its ability to cross the placental barrier, standardized and repeatable models that mimic clinical signs observed in the field are essential. This review discusses some of the latest experimental designs for infectious disease challenges involving SBV, covering infectious doses, routes of infection, inoculum preparation, and origin. Special attention is given to the placental crossing associated with SBV.

A low-temperature ionic liquid system for topochemical synthesis of Si nanospheres for high-performance lithium-ion batteries.

Silicon is utilized as a functional material in various fields such as semiconductors, bio-medicine, and solar energy. To prepare Si materials, researchers have proposed methods including carbothermal reduction, hydrothermal reduction, and magnesiothermal reduction, but these strategies often involve high temperatures or unwanted by-products. Herein, we present a low-temperature ionic liquid reduction system to prepare Si nanospheres based on 1-butyl-3-methylimidazolium chloride-aluminum chloride ([Bmim]Cl-AlCl3). In this low-temperature solution system, AlCl3 not only absorbs the heat generated in the reaction, but also can be reduced by metallic Mg to active intermediates, which participate in the reduction of SiO2. Furthermore, spherical SiO2 can be gently reduced to spherical nano-Si with preserved morphology in the [Bmim]Cl-AlCl3 system. When the prepared Si nanosphere electrode is employed as the anode in lithium-ion batteries, it demonstrates an initial coulombic efficiency of 82.9% and a capacity retention of 94.2% after 100 cycles at 0.5 A g-1. Moreover, the SVC electrode, obtained by reducing SiO2@C, exhibits almost no capacity decay after 100 cycles and retains a specific capacity of 914 mA h g-1 after 600 cycles at 2 A g-1. This study provides an alternative, mild preparative route to Si-based functional materials with preserved morphology and components of the Si precursors.

In English

Model well-defined MoO3/Al2O3 and MoO3/SiO2 systems were rationally designed by anchoring of MoOCl4 on the supports surface of fumed Al2O3 and SiO2 nanoparticles. The subsequent hydrolysis of the anchored groups by water vapours followed by thermal treatment resulted in the formation of Mo(VI) oxo-species on the supports surface. By application of the anchoring – hydrolysis cycles the model MoO3/Al2O3 systems with the molybdena loading of 1.10, 1.92 and 2.34 Mo/nm2 were synthesised. The synthesised MoO3/SiO2 systems had a molybdena loading of 0.82, 1.05 and 1.21 Mo/nm2. X-ray diffraction patterns characteristic for MoO3 crystallites were not observed in the synthesised MoO3/Al2O3 and MoO3/SiO2 systems up to the highest achieved molybdena loading of 2.34 and 1.21 Mo/nm2 respectively. This confirms that the used preparation route resulted in the formation of highly dispersed Mo(VI) oxo-species on the surface of both Al2O3 and SiO2 supports. The degree of aggregation of Mo(VI) oxo-species depends on the nature of the support surface and molybdena loading. Increase of the molybdena loading on the surface of both Al2O3 and SiO2 supports results in an increase of the degree of aggregation of Mo(VI) oxo-species. On Al2O3 support, at a molybdena loading which corresponds to the population of surface hydroxyl groups, monomeric Mo(VI) oxo-species appear to be predominant. At higher molybdena loading, the formation of polymeric Mo(VI) oxo-species was detected. On SiO2 support, at a molybdena loading which corresponds or exceeds the population of surface hydroxyl groups, simultaneous presence of monomeric and polymeric Mo(VI) oxo-species was observed.

Facile Preparation Route of Cellulose-Based Flame Retardant by Ball-Milling Mechanochemistry.

In this study, a sustainable cellulose-based flame-retardant additive was developed, characterized, and incorporated into polypropylene (PP). Microcrystalline cellulose (Cel) was chemically modified with P2O5 using the solvent-free ball-milling mechanochemistry approach at room temperature. This modification enabled phosphorus grafting onto cellulose, significantly enhancing the cellulose charring ability and improving the thermal stability of the char as revealed by thermogravimetric analysis (TGA). The resulting product, Cel-P, containing 4.15 wt.% phosphorus, was incorporated and uniformly dispersed as a flame-retardant (FR) additive at 30 wt.% in PP through melt processing. The PP+30-Cel-P composite demonstrated improved char formation and FR properties, including reduction of both peak heat release rate (pHRR) and total heat release (THR) in mass loss cone calorimetry (MLC). Moreover, lower light absorptivity was obtained by smoke opacity tests as compared to PP filled with unmodified cellulose.

Synthesis and Characterization of Optically Transparent and Electrically Conductive Mo-Doped ZnO, F-Doped ZnO, and Mo/F-Codoped ZnO Thin Films via Aerosol-Assisted Chemical Vapor Deposition.

Mo-doped ZnO (MZO), F-doped ZnO (FZO), and Mo/F-codoped ZnO (MFZO) films have been deposited using a simple, cheap, and effective thin-film preparation route, aerosol-assisted chemical vapor deposition (AACVD). ZnO was successfully doped with Mo and/or F, confirmed by X-ray photoelectron spectroscopy (XPS) and by a decrease in unit cell parameters from X-ray diffraction (XRD). XRD also confirmed that all of the films had hexagonal wurtzite ZnO structures. Scanning electron microscopy showed that all of the films had well-defined surface features. The undoped ZnO film had a high resistivity of ∼102 Ω·cm, determined by Hall effect measurements, and a visible light transmittance of 72%, determined by ultraviolet-visible (UV-vis)-IR spectroscopy. The transmittance of the doped and codoped films was improved to 75-85%. The ZnO film codoped with 6.2 atom% Mo and 3.6 atom% F, deposited at 550 °C achieved the minimum resistance (5.084 × 10-3 Ω·cm) with a significant improvement in carrier concentration (5.483 × 1019 cm-3) and mobility (21.78 cm2 V-1 s-1).

A Universal Strategy for Synthesis of Large-Area and Ultrathin Metal Oxide/rGO Film Towards Scalable Fabrication of High-Performance Wearable Microsupercapacitors.

High-performance wearable microsupercapacitor (MSC) as energy storage components is highly desirable for developing self-powering wearable electronics. However, synthesis of MSC electrode film concurrently possessing large area, ultrathin thickness, and high areal energy storage capability is still challenging. Herein, a universal strategy is reported to synthesize large-area and ultrathin metal oxide nanoparticles (MONPs)/reduced graphene oxide (rGO) hybrid-structured films by attaching self-assembled film of a wide range of MONPs onto self-assembled rGO film and subsequent carbonization. Combining a template-assisted patterning strategy and a floating film salvaging process, flexible symmetric and asymmetric MSCs based on MONPs@C/rGO films can be easily prepared in large areas. MONP agglomeration is avoided and its pseudocapacitive behavior is well utilized, thereby realizing a high areal specific capacitance of 9.32 mF cm-2 in Fe3O4@C/rGO-based symmetric MSC at a film thickness of only 275 nm, corresponding to a high volumetric specific capacitance of 338.9 F cm-3. Moreover, the MnO@C/rGO‖Fe3O4@C/rGO-based asymmetric MSC delivers a high volumetric energy density of 69.8 mWh cm-3. The MSCs also demonstrate their efficient power supply in wearable self-powering systems. This work provides a new route for scalable preparation of high-performance wearable MSCs, and also enables customizable fabrication and performance tuning of MSCs.

The electrochemical performance deterioration mechanism of LiNi0.83Mn0.05Co0.12O2 in aqueous slurry and a mitigation strategy

Integrating high-nickel layered oxide cathodes with aqueous slurry electrode preparation routes holds the potential to simultaneously meet the demands for high energy density and low-cost production of lithium-ion batteries. However, the influence of dual exposure to air and liquid water as well as the heating treatment during aqueous slurry electrode processing on the high-nickel layered oxide electrode is yet to be understood. In this study, we systematically investigate the structural evolution and electrochemical behaviors when LiNi0.83Mn0.05Co0.12O2 (NMC83) is subjected to aqueous slurry processing. It was observed that the crystal structure near the surface of NMC83 is partially reconstructed to contain a mixture of rock-salt and layered phases when exposed to water, leading to the deteriorated rate capability of the NMC83 electrodes. This partial surface reconstruction layer completely converts into a pure rock-salt phase upon cycling, accompanied by the release of O2, Ni leaching, catalyzed decomposition of the electrolyte, and the formation of a thick cathode electrolyte interphase layer. The byproducts of the electrolyte and dissolved Ni could shuttle to the Li metal side, causing a crosstalk effect that results in a thick and unstable solid electrolyte interphase layer on the Li surface. These in combination severely undermined the cycling stability of the NMC83 electrodes obtained from the aqueous slurry. A mitigation strategy using molecular self-assembly technique was demonstrated to enhance the surface stability of water-treated NMC83. Our findings offer new insights for tailoring ambient environment stability and aqueous slurry processability for ultra-high nickel layered oxide and other water-sensitive cathode materials.

A novel approach for the preparation of furandiamines utilizing biomass platform chemicals as substrates via Gabriel synthesis

Primary diamines are significant chemical intermediates and raw materials for high-added-value chemical products, which are regarded as essential monomers in the synthesis of polyamides and polyurethanes. Primary diamines are also particularly pronounced in the automotive, aerospace, and pharmaceutical fields. Among them, 2,5-bis(aminomethyl)furan (BAF) has garnered grant attention as a highly promising renewable diamine. In this work, a new route for the reduction preparation of BAF using a platform compound 5-chloromethylfurfural (CMF) utilizing the Gabriel method was developed, which reasonably avoids the disadvantage of molecular internal polymerization that often occurs in traditional routes that converting BAF from 5-hydroxymethylfurfural (HMF) and HMF derivatives. Additionally, under mild reaction conditions, this novel route yields BAF efficiently by employing Ni/SiO2 as the catalyst. According to the kinetic analysis the reduction process was proved to be predominant. In addition, the analysis of the mechanism showed that compared to other catalysts, Ni/SiO2 contains more active sites and more hydrogen active components (Ni0), achieving an impressive yield of 82.35 % under mild conditions. This work provides a pioneering method for the preparation of BAF, which is crucial for the development of primary diamine preparation.

One-step synthesis of spherical Al3Ta alloy powder by electrolyzing solid Ta2O5 in molten fluorides

Aluminum-tantalum powders are emerging as new raw materials for additive manufacturing (AM) technologies, but their preparation in bulk quantities and in powder form via conventional metallurgical methods is challenging. In this study, we report a one-step synthesis of spherical Al3Ta powder by direct electrolyzing solid Ta2O5 cathode (vs. a graphite anode) in molten Na3AlF6-K3AlF6-AlF3-LiF-Al2O3. Cyclic voltammetry and constant potential electrolysis techniques were employed to characterize the electrochemical reaction process, along with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for the structural and morphological analyses. The process involves an initial Ta2O5 electro-deoxygenation process, the subsequent electrodeposition of Al3+ on the formed Ta particles and an in-situ alloying process. The innovative use of Ta2O5 cathodes with a novel hierarchical porous structure allows for a controlled transformation of cathode particle morphology and facilitates the rapid generation of nanoscale tantalum particles. Al3+ from the electrolyte is then electrodeposited onto these particles, initiating an in-situ alloying reaction. This is an exothermic process that facilitates the diffusion of aluminum atoms into tantalum, and reduces the interfacial energy promoting the formation of spherical Al3Ta particles. Such powders are in demand for AM techniques. The findings may now guide the way to establishing the electrochemical route for the short-process preparation of other high-temperature alloy powders.

Hybrid Ag-mesh/Ta-doped TiO2 thin film configuration as a visible and near-infrared transparent electrode

This study focuses on the fabrication of a hybrid Ag-mesh/Ta-doped TiO2 (TTO) electrode that has a low sheet resistance and high transparency in the visible and near-infrared region, thereby holding significant commercialization potential. Here, ∼82 nm thick TTO film is deposited on the glass substrate using radio frequency magnetron sputtering technique, over which Ag mesh is carved using the metal aerosol jet printing method. As compared to TTO, sheet resistance of the entire hybrid configuration is found to show a 2-3 order improvement, with the loss of a mere ∼12 % in the visible and ∼8 % in NIR transmittance. The electronic structure of the Ag/TTO interface demonstrates the formation of an ohmic junction, thereby making it suitable for the fabrication of a network-based transparent electrode. Moreover, the overall functionality and preparation route of this electrode makes it more promising as compared to those of the conventional metal mesh and metal-oxide electrodes.

Morphological and dynamic mechanical properties of biobased epoxy composites with anisotropic, green carbon aerogels as reinforcement

Hierarchically porous, anisotropic, and green carbon aerogels (CAs) prepared from second most abundant and underutilized biopolymer lignin is used together with biobased epoxy resin to prepare green composite materials with superior mechanical properties. Green and facile preparation route involving ice-templating, lyophilization followed by carbonization was followed for the preparation of CAs. Ice-templating cooling rate is an important parameter in determining the porous structure of the CAs and by choosing a slower cooling rate bigger macropores can be achieved which facilitate the capillary impregnation of the epoxy resin through the CA structure. Hence in this study a cooling rate of 5 K/min was used and the CAs were prepared at 1000 °C from lignin/CNF suspensions containing 3, 5 and 7 wt% of total solid contents. Composites prepared using these CAs as reinforcements showed interesting morphologies which were analyzed using scanning electron microscopy and X-Ray microtomography. Prepared composites contained a mass fraction of 5–9 wt% of CAs. Composites showed remarkable 72 % higher dynamic mechanical properties compared to neat epoxy. Thus, this study introduces new synthesis strategy for carbon composites with completely biobased anisotropic CAs as oriented and strong reinforcements.

Construction of multi-functional silicone rubber/reduced graphene oxide/multi-walled carbon nanotube composites with segregated structure by surfactant-free Pickering emulsion method

Polymer composites with segregated structure (PC–S) have the advantages of low filler usage and excellent functionality. Emulsion blending combined with direct molding technology is the main method for the preparation of PC-S. However, due to the high fluidity of low-viscosity silicone rubber (SR), PC-S cannot be prepared by this technique. In addition, surfactants affect the heat resistance of the final SR composites (SRC). In order to solve the above problems, in this study, a Pickering emulsification combined with pre-crosslinking technology for SR was successfully developed by using graphene oxides (GO)/multi-walled carbon nanotubes (MWCNTs) hybrid fillers (GM) as emulsifiers, and SR/reduced GO (RGO)/MWCNTs composites with segregated structure (SSGM) were prepared. When RGO content is 4.5 wt%, MWCNTs content is 3.2 wt%, SSGM shows the highest electrical conductivity of 12.5 S/m, the highest electromagnetic interference shielding efficiency (EMI SE) of 41.4 dB, and an excellent flame retardant performance. The whole preparation process avoids the use of organic solvents and surfactants, which reduces the production cost of SSGM and the environmental pollution, and provides a feasible preparation route for the industrialized production of SSGM.

Endochondral ossification: Insights into the cartilage mineralization processes achieved by an anhydrous freeze substitution protocol

Growth plate cartilage (GP) serves as a dynamic site of active mineralization and offers a unique opportunity to investigate the cell-regulated matrix mineralization process. Transmission electron microscopy (TEM) provides a means for the direct observation of these mechanisms, offering the necessary resolution and chemical analysis capabilities. However, as mineral crystallinity is prone to artifacts using aqueous fixation protocols, sample preparation techniques are critical to preserve the mineralized tissue in its native form. We optimized cryofixation by high-pressure freezing followed by freeze substitution in anhydrous acetone containing 0.5 % uranyl acetate to prepare murine GP for TEM analysis. This sample preparation workflow maintains cellular and extracellular protein structural integrity with sufficient contrast for observation and without compromising mineral crystallinity. By employing appropriate sample preparation techniques, we were able to observe two parallel mineralization processes driven by chondrocytes: 1) intracellular- and 2) extracellular-originating mineralized vesicles. Both mechanisms are based on sequestering calcium phosphate (CaP) within a membrane-limited structure, albeit originating from different compartments of the chondrocytes. In the intracellular originating pathway, CaP accumulates within mitochondria as globular CaP granules, which are incorporated into intracellular vesicles (500–1000 nm) and transported as granules to the extracellular matrix (ECM). In contrast, membrane budding vesicles with a size of approximately 100–200 nm, filled with needle-shaped minerals were observed only in the ECM. Both processes transport CaP to the collagenous matrix via vesicles, they can be differentiated based on the vesicle size and mineral morphologies. Their individual importance to the cartilage mineralization process is yet to be determined. Statement of SignificanceWe do not fully understand the process by which epiphyseal cartilage mineralizes - a vital step in endochondral bone formation. Previous work has proposed that mitochondria and intracellular vesicles are storage sites for the delivery of mineral to collagen fibrils. However, these concepts are founded on results from in vitro models of mineralization; no prior work has observed mineral-containing intracellular vesicles or mitochondria in developing epiphyseal cartilage. Here we developed a new cryofixation preparation route for transmission electron microscopy (TEM) imaging that has disclosed a cell-regulated process of mineralization in epiphyseal cartilage. High resolution TEM images revealed an involvement of mitochondria and intracellular and extracellular vesicles in delivering transient mineral phases to the collagen fibrils to promote cartilage mineralization.

Reductive C(sp2)–Si Cross‐Couplings by Catalytic Sodium‐Bromine Exchange

The metal‐halogen exchange reaction constitutes one of the most important preparative routes towards polar organometallic reagents such as aryllithium or Grignard reagents. However, despite extensive developments over the past eight decades, this fundamental organometallic elementary step has only been exploited stoichiometrically. Against this background, we demonstrate that the sodium‐bromine exchange reaction can be implemented in a catalytic setting as a mean to activate C(sp2)–Br bonds in a transition metal‐free manner en route to the regioselective and general preparation of (hetero)aryl silanes. Simply treating structurally diverse (hetero)aryl bromides with N‐tert‐butyl‐N’‐silyldiazenes (tBu–N=N–Si) as silylating reagents and inexpensive sodium alkoxides as catalytic promoters yields a range of aromatic organosilicon compounds under ambient conditions. Mechanistic studies provide solid evidence for the involvement of tert‐butyl sodium as the C(sp2)–Br metalating agent.

Reductive C(sp2)–Si Cross‐Couplings by Catalytic Sodium‐Bromine Exchange

The metal‐halogen exchange reaction constitutes one of the most important preparative routes towards polar organometallic reagents such as aryllithium or Grignard reagents. However, despite extensive developments over the past eight decades, this fundamental organometallic elementary step has only been exploited stoichiometrically. Against this background, we demonstrate that the sodium‐bromine exchange reaction can be implemented in a catalytic setting as a mean to activate C(sp2)–Br bonds in a transition metal‐free manner en route to the regioselective and general preparation of (hetero)aryl silanes. Simply treating structurally diverse (hetero)aryl bromides with N‐tert‐butyl‐N’‐silyldiazenes (tBu–N=N–Si) as silylating reagents and inexpensive sodium alkoxides as catalytic promoters yields a range of aromatic organosilicon compounds under ambient conditions. Mechanistic studies provide solid evidence for the involvement of tert‐butyl sodium as the C(sp2)–Br metalating agent.

Facet-Dependent Diversity of Pt-O Coordination for Pt1/CeO2 Catalysts Achieved by Oriented Atomic Deposition.

The surface chemistry of CeO2 is dictated by the well-defined facets, which exert great influence on the supported metal species and the catalytic performance. Here we report Pt1/CeO2 catalysts exhibiting specific structures of Pt-O coordination on different facets by using adequate preparation methods. The simple impregnation method results in Pt-O3 coordination on the predominantly exposed {111} facets, while the photo-deposition method achieves oriented atomic deposition for Pt-O4 coordination into the "nano-pocket" structure of {100} facets at the top. Compared to the impregnated Pt1/CeO2 catalyst showing normal redox properties and low-temperature activity for CO oxidation, the photo-deposited Pt1/CeO2 exhibits uncustomary strong metal-support interaction and extraordinary high-temperature stability. The preparation methods dictate the facet-dependent diversity of Pt-O coordination, resulting in the further activity-selectivity trade-off. By applying specific preparation routes, our work provides an example of disentangling the effects of support facets and coordination environments for nano-catalysts.

Facet‐Dependent Diversity of Pt−O Coordination for Pt1/CeO2 Catalysts Achieved by Oriented Atomic Deposition

AbstractThe surface chemistry of CeO2 is dictated by the well‐defined facets, which exert great influence on the supported metal species and the catalytic performance. Here we report Pt1/CeO2 catalysts exhibiting specific structures of Pt−O coordination on different facets by using adequate preparation methods. The simple impregnation method results in Pt−O3 coordination on the predominantly exposed {111} facets, while the photo‐deposition method achieves oriented atomic deposition for Pt−O4 coordination into the “nano‐pocket” structure of {100} facets at the top. Compared to the impregnated Pt1/CeO2 catalyst showing normal redox properties and low‐temperature activity for CO oxidation, the photo‐deposited Pt1/CeO2 exhibits uncustomary strong metal‐support interaction and extraordinary high‐temperature stability. The preparation methods dictate the facet‐dependent diversity of Pt−O coordination, resulting in the further activity‐selectivity trade‐off. By applying specific preparation routes, our work provides an example of disentangling the effects of support facets and coordination environments for nano‐catalysts.

Integrated mid-infrared sensing and ultrashort lasers based on wafer-level Td-WTe2 Weyl semimetal

There is an urgent need for infrared (IR) detection systems with high-level miniaturization and room-temperature operation capability. The rising star of two-dimensional (2D) semimetals with extraordinary optoelectronic properties can fulfill these criteria. However, the formidable challenges with regard to large-scale patterning and substrate-selective requirements limit material deposition options for device fabrication. Here, we report a convenient and straightforward eutectic-tellurization transformation method for the wafer-level synthesis of 2D type-II Weyl semimetal WTe2. The non-cryogenic WTe2/Si Schottky junction device displays an ultrawide detection range covering 10.6 μm with a high detectivity of ∼109 Jones in the mid-infrared (MIR) region and a short response time of 1.3 μs. The detection performance has surpassed most reported IR sensors. On top of that, on-chip device arrays based on Schottky junction display an outstanding MIR imaging capability without cryogenic cooling, and 2D WTe2 Weyl semimetal can serve as a saturable absorber for stable Q-switched and mode-locked laser operation applications. Our work offers a viable route for wafer-scale vdW preparation of 2D semimetals, showcasing their intriguing potential in on-chip integrated MIR detection systems and ultrafast laser photonics.