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Two‐dimensional (2D) tin(II) sulfide (SnS) crystals belong to a class of orthorhombic semiconducting materials with remarkable properties, such as in‐plane anisotropic optical and electronic response, and multiferroic nature. The 2D SnS crystals exhibit anisotropic response along the in‐plane armchair (AC) and zigzag (ZZ) crystallographic directions, offering an additional degree of freedom in manipulating their behavior. Here, advantage of the lack of inversion symmetry of the 2D SnS crystal, that produces second harmonic generation (SHG), is taken to perform polarization‐resolved SHG (P‐SHG) nonlinear imaging of the in‐plane anisotropy. The P‐SHG experimental data are fitted with a nonlinear optics model, allowing to calculate the AC/ZZ orientation from every point of the 2D crystal and to map with high resolution the AC/ZZ direction of several 2D SnS flakes belonging in the same field of view. It is found that the P‐SHG intensity polar patterns are associated with the crystallographic axes of the flakes and with the relative strength of the second‐order nonlinear susceptibility tensor in different directions. Therefore, the method provides quantitative information of the optical in‐plane anisotropy of orthorhombic 2D crystals, offering great promise for performance characterization during device operation in the emerging optoelectronic applications of such crystals. [ABSTRACT FROM AUTHOR]

Thermal‐oxidative stabilization of the polyacrylonitrile (PAN) precursor was performed employing a multi‐step heat treatment strategy in an air circulating furnace. In this approach, the applied temperature was gradually increased from 200°C to 250°C employing several stages for different stabilization durations. Fifteen percent guanidine carbonate (GC) was found as optimum to incorporate with the PAN precursor fibers to accelerate the thermal‐oxidative stabilization process. Characterization techniques, including X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile strength, volume density, linear density, fiber thickness, and burning test have been performed to monitor the changes in PAN structure. Test results of the stabilized samples were compared with the reference sample results to demonstrate the accelerating effect of GC integration. Findings showed that GC pretreatment enhanced and accelerated the cyclization of nitrile groups in the PAN polymer structure and allowed the quicker formation of a thermally stable structure. The analysis of the experimental results revealed that GC integration and employing the multi‐step heat treatment strategy helps greatly to cut the overall PAN‐based carbon fiber production cost. [ABSTRACT FROM AUTHOR]

Low‐dimensional nanomaterials have attracted attention due to their excellent electrical and optical properties. The development of nonvolatile memory device based on low‐dimensional nanomaterials is important for establishing high‐performance computers. In this work, black phosphorus quantum dots (BPQDs) are physically blended with the fullerene derivative [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM), and then polyvinylpyrrolidone (PVP) is added to enhance the film‐forming properties of the material. The resulting composite thin film is sandwiched between aluminum and indium‐tin oxide (ITO) electrodes to form an Al/BPQDs/PCBM/PVP/ITO device. The device exhibits stable nonvolatile rewritable memory behavior, with on and off threshold voltages of −2.4 and +3.25 V, respectively, and an on/off ratio exceeding 103. In addition, the device exhibits a lower threshold voltage and higher conductivity upon increasing the light intensity under laser irradiation at 450 nm. Light‐induced electron paramagnetic resonance and fluorescence spectroscopy show that the existence of electric field‐induced charge transfer and light‐induced charge transfer in the composite thin film are responsible for the device's photoelectric dual‐response resistive characteristics. [ABSTRACT FROM AUTHOR]

Thickness‐dependent chemical and physical properties have gained tremendous interest since the emergence of two‐dimensional (2D) materials. Despite attractive prospects, the thickness‐controlled synthesis of ultrathin nanosheets remains an outstanding challenge. Here, a chemical vapor deposition (CVD) route is reported to controllably synthesize high‐quality PtSe2 nanosheets with tunable thickness and explore their thickness‐dependent electronic and magnetotransport properties. Raman spectroscopic studies demonstrate all Eg, A1g, A2u, and Eu modes are red shift in thicker nanosheets. Electrical measurements demonstrate the 1.7 nm thick nanosheet is a semiconductor with room temperature field‐effect mobility of 66 cm2 V−1 s−1 and on/off ratio of 106. The 2.3–3.8 nm thick nanosheets show slightly gated modulation with high field‐effect mobility up to 324 cm2 V−1 s−1 at room‐temperature. When the thickness is over 3.8 nm, the nanosheets show metallic behavior with conductivity and breakdown current density up to 6.8 × 105 S m–1 and 6.9 × 107 A cm−2, respectively. Interestingly, magnetoresistance (MR) studies reveal magnetic orders exist in this intrinsically non‐magnetic material system, as manifested by the thickness‐dependent Kondo effect, where both metal to insulator transition and negative MR appear upon cooling. Together, these studies suggest that PtSe2 is an intriguing system for both developing novel functional electronics and conducting fundamental 2D magnetism study. [ABSTRACT FROM AUTHOR]

Black phosphorus analogous tin(II) sulfide (SnS) has recently emerged as an attractive building block for photonic and optoelectronic devices due to its intrinsic anisotropic response. Two-dimensional SnS has shown to exhibit in-plane anisotropy in optical and electrical properties. However, the limitations in growing ultrasmall structures of SnS hinder the experimental exploration of anisotropic behavior in low dimension. Here, we present an elegant approach of synthesizing highly crystalline nanometer-sized SnS sheets. Ultrasmall SnS exhibits two distinct valleys along armchair and zig-zag directions due to in-plane structural anisotropy like bulk SnS. We find that in SnS nanosheets, the bandgaps corresponding to two valleys are increased due to the quantum confinement effect. Moreover, the photoluminescence (PL) from SnS quantum dots (QDs) is excitation energy dependent. Our spectroscopic studies infer that PL of SnS QDs originates from the two non-degenerate valleys. [ABSTRACT FROM AUTHOR]

Two-dimensional layered materials (2DLMs) such as graphene and transition metal dichalcogenides have been at the forefront of materials science in recent years due to their excellent electronic, optical, thermal, and mechanical properties. On the other hand, 2D polymeric nanosheets (2DPs), such as 2D organic frameworks with analogous layered molecular structures, have also been undergoing rapid development. Inorganic 2DLMs and 2DPs have many complementary physical and chemical properties that can be integrated into advanced hybrid materials with a precisely defined molecular and interfacial structure and high performance. In this perspective, we introduce recent representative studies and summarize the latest developments in the field of advanced 2D and 3D hybrid materials based on the integration of 2DLMs and 2DPs. The intimate contact between atomically thin 2DLMs and 2DPs induces significant property changes in the individual components and also leads to new functionalities. Such hybrid 2DLM/2DP structures are critical for the fundamental study of organic/inorganic interfaces, as well as for practical applications in energy conversion and storage, molecular separation, and flexible electronics. [ABSTRACT FROM AUTHOR]

Group‐IV monochalcogenide ferroelectric materials possess fascinating nonlinear optical properties and electro‐optical effects which play a vital role in 2D ferroelectrics, multiferroics and nonlinear optoelectronics. However, the studies of nonlinear optical properties of group‐IV monochalcogenides are still in their infancy stage. Herein, the preparation of few‐layer SnS by the molecular beam epitaxy (MBE) method is reported and the efficient second harmonic generation (SHG) of SnS monochalcogenide is systematically scrutinized by using ultrafast nonlinear optical spectroscopy. The obtained thickness‐dependent SHG is highly related with the coherence length. Second‐order nonlinear susceptibility of few‐layer SnS is also obtained. Polarization‐dependent SHG studies reveal its intrinsic anisotropy pattern and can be utilized to identify the crystalline orientation of few‐layer SnS film. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials like graphene, phosphorene, germanene, silicene, and transition metal dichalcogenides have attracted intense research attention because of their rich physics and potential for integration into next-generation electronic devices. These materials offer superior electrostatic control to their bulk counterparts, which makes them fascinating for device fabrication. After graphene and MoS2, the most intensively explored 2D material is black phosphorus (BP). During the past half-decade, BP has notably achieved excellent performance when included in transistors. This review paper aims to throw some light on BP properties and their performance in a field effect transistor device. The state-of-the-art BP transistors are reviewed, and a balanced view of both the benefits and drawbacks is provided. [ABSTRACT FROM AUTHOR]

Carbon fiber and glass fiber are two dominating reinforcements for polymer composites. Fiber‐reinforced thermoplastics are widely used in many applications. It has a higher growth rate than thermoset composites due to ease in processing and recyclability. Glass fiber has been on the market for 80 years and carbon fiber over 50 years. There are hundreds, if not thousands, of research paper to compare the performance of the two fibers and hybrid. All the studies are from commercially available products. In all those cases, these two fibers are non‐comparable. They have different fiber diameter, size and sizing content, chop length and chopping process. Taiwan Glass Industries, Corp. has cordially provided two experimental chopped strands that match the characteristics of chopped carbon fibers. The first one is for nylon reinforcement and the second one is for polypropylene. Now the glass fiber and carbon fiber have the same fiber diameter (7 microns), same size and sizing content (1%), and same chop length (6 mm). Most importantly, they are produced in identical way (off‐line chop). The only difference between two fibers is silane on glass surface. This is the first of this kind of study. It gives a true comparison of two fibers with identical characteristics. As expected, fiber diameter has the biggest influence in mechanical properties among all fiber characteristics. For nylon, the difference between 7 micron and 10 micron glass fiber is small in tensile and flexural strength. It has bigger difference in impact strength. For polypropylene reinforcement, the fiber diameter of standard polypropylene dispersion (PP) glass fiber is 13 microns; almost double that of carbon fiber. Seven‐micron PP glass actually outperforms PP carbon fiber in composite strengths. [ABSTRACT FROM AUTHOR]

Magnetic hyperthermia (MHT) is a therapeutic modality for the treatment of solid tumors that has now accumulated more than 30 years of experience. In the ongoing MHT clinical trials for the treatment of brain and prostate tumors, iron oxide nanoparticles are employed as intra-tumoral MHT agents under a patient-safe 100 kHz alternating magnetic field (AMF) applicator. Although iron oxide nanoparticles are currently approved by FDA for imaging purposes and for the treatment of anemia, magnetic nanoparticles (MNPs) designed for the efficient treatment of MHT must respond to specific physical–chemical properties in terms of magneto-energy conversion, heat dose production, surface chemistry and aggregation state. Accordingly, in the past few decades, these requirements have boosted the development of a new generation of MNPs specifically aimed for MHT. In this review, we present an overview on MNPs and their assemblies produced via different synthetic routes, focusing on which MNP features have allowed unprecedented heating efficiency levels to be achieved in MHT and highlighting nanoplatforms that prevent magnetic heat loss in the intracellular environment. Moreover, we review the advances on MNP-based nanoplatforms that embrace the concept of multimodal therapy, which aims to combine MHT with chemotherapy, radiotherapy, immunotherapy, photodynamic or phototherapy. Next, for a better control of the therapeutic temperature at the tumor, we focus on the studies that have optimized MNPs to maintain gold-standard MHT performance and are also tackling MNP imaging with the aim to quantitatively assess the amount of nanoparticles accumulated at the tumor site and regulate the MHT field conditions. To conclude, future perspectives with guidance on how to advance MHT therapy will be provided. [ABSTRACT FROM AUTHOR]

A novel pantograph strip of copper mesh modified carbon fiber reinforced polymer (CFRP) composite was fabricated by impregnating copper foam with the resin mixture of carbon fiber and flaky graphite, following by mold hot‐pressing technology. Microstructure, mechanical strength, electric conductivity, friction, and wear behaviors of the composite were investigated and analyzed to explore the fracture failure and wear mechanisms. The results show that the composite obtains much lower electric resistance than that of the pure carbon strip used in China's high‐speed railway. Adding carbon fiber can improve impact strength and wear resistance considerably, but has little effect on anti‐friction performance. The electric resistance and tribological performances are graphite dependent, reduced electric resistance and friction coefficient can be obtained with the increase of flaky graphite from 0 to 15 wt% while negligible changes of impact strength and wear rate are found. However, further increasing the flaky graphite to 20 wt%, the wear rate reveals a dramatic rise. High content of flaky graphite contributes to the formation of thick tribolayer with unconsolidated structure. And the tribolayer is easy to curl and worn off from the wear surface, leading to severe wear of the composite during the current carrying friction tests. [ABSTRACT FROM AUTHOR]

This paper analyzes the reliability issues of the Heterostacked-TFET (HS-TFET) in detail. The investigation of the device reliability is carried out by examining the effect of interface trap charges (ITCs) and the temperature affectability of the HS-TFET on various analog parameters and RF FOMs. The analysis is performed at different interface trap charge densities and polarities. The presence of interface traps at the stackedsource/channel junction and the oxide/silicon interface alters the performance of the device significantly. A positive trap charge density of 3 × 1013 cm−2 degrades the current switching ratio tremendously from an order of 1010–104. The off-state current of the device deteriorates excessively at high temperatures. However, the results establish that the HS-TFET is insusceptible to the acceptor interface trap charge as compared to the donor interface trap charge for temperature variation. A high-k gate dielectric of Aluminum oxide (Al2O3) is considered and compared with Hafnium oxide (HfO2) and it is found that Al2O3 gate oxide has a better immunity to the ITC variation. [ABSTRACT FROM AUTHOR]

Novel 2D semiconductors play an increasingly important role in modern nanoelectronics and optoelectronics. Herein, a novel topology designer based on component fusion is introduced, featured by the submolecular component integration and properties inheritance. As expected, a new air‐stable 2D semiconductor PdPSe with a tailored puckered structure is successfully designed and synthesized via this method. Notably, the monolayer of PdPSe is constructed by two sublayers via PP bonds, different from 2D typical transition metal materials with sandwich‐structured monolayers. With the expected orthorhombic symmetry and intralayer puckering, PdPSe displays a strong Raman anisotropy. The field‐effect transistors and photodetectors based on few‐layer PdPSe demonstrate good electronic properties with high carrier mobility of ≈35 cm2 V−1 s−1 and a high on/off ratio of 106, as well as excellent optoelectronic performance, including high photoresponsivity, photogain, and detectivity with values up to 1.06 × 105 A W−1, 2.47 × 107%, and 4.84 × 1010 Jones, respectively. These results make PdPSe a promising air‐stable 2D semiconductor for various electronic and optoelectronic applications. This work suggests that the component‐fusion‐based topology designer is a novel approach to tailor 2D materials with expected structures and interesting properties. [ABSTRACT FROM AUTHOR]

2D transition metal chalcogenides (TMCs) have attracted tremendous interest from both the scientific and technological communities due to their variety of properties and superior tunability through layer number, composition, and interface engineering. Wafer‐scale production of 2D TMCs is critical to the industrial applications of these materials. Extensive efforts have been bestowed to the large‐area growth of 2D TMCs through various approaches. In this review, recent advances in obtaining large‐area 2D TMCs by different methods such as chemical vapor deposition (CVD), metal–organic CVD, and physical vapor deposition are first highlighted and their advantages and disadvantages are also evaluated. Then, strategies for the control of the grains, morphology, layer number, and phase to achieve controllable and uniform thicknesses and large crystal domains for 2D TMCs are discussed. Applications of large‐area 2D TMCs in electronics, optoelectronics, spintronics, etc., are also introduced. Finally, ideas and prospects for the future developments of wafer‐scale 2D TMCs are provided. [ABSTRACT FROM AUTHOR]

In this paper, we give an overview of different chemical modifications that can be done on the surface of two-dimensional (2D) layered materials. We place emphasis on the diversity of reactions that have been proposed and are now available to surface scientists working in 2D materials field. Using mainly, but not exclusively, MoS2 as example, reactions involving covalent and non-covalent interactions are discussed. [ABSTRACT FROM AUTHOR]

Design of materials with special properties benefits from establishing deep structural and electronic analogies between emerging and existing materials. The Zintl anion [Al2Si2]2− is both isostructural and isoelectronic to bilayer silicene; it thus makes a promising building block to assemble electronic materials. Here, we show that nanoscale films of SrAl2Si2, a semimetal formed by alternating [Al2Si2] and Sr layers, exhibit a high carrier mobility, exceeding 10 000 cm2 V−1 s−1. The dominant role of the anionic bilayers in the electronic structure and transport properties is established by band structure calculations. To synthesize monocrystalline epitaxial films of SrAl2Si2 with atomically sharp interfaces, a general two-step route involving a sacrificial 2D template is devised. A distinct advantage of the films is their natural integration with silicon technology. The results establish a platform for engineering layered ionic nanomaterials. [ABSTRACT FROM AUTHOR]

Generally, electrospun silk fibroin scaffolds collected by traditional plates present limited pore size and mechanical properties, which may restrict their biomedical applications. Herein, regenerated Antheraea pernyi silk fibroin (RASF) with excellent inherent cell adhesion property was chosen as a raw material and the conductive metal meshes were used as collectors to prepare modified RASF scaffolds by electrospinning from its aqueous solution. A traditional intact plate was used as a control. The morphology and mechanical properties of the obtained scaffolds were investigated. Schwann cells were further used to assess the cytocompatibility and cell migration ability of the typical scaffolds. Interestingly, compared with the traditional intact plate, the mesh collector with an appropriate gap size (circa 7 mm) could significantly improve the pore size, porosity and mechanical properties of the RASF scaffolds simultaneously. In addition, the scaffold collected under this condition (RASF-7mmG) showed higher cell viability, deeper cell permeation and faster cell migration of Schwann cells. Combined with the excellent inherent properties of ASF and the obviously enhanced scaffold cytocompatibility and mechanical properties, the RASF-7mmG scaffold is expected to be a candidate with great potential for biomedical applications. [ABSTRACT FROM AUTHOR]

GeSe, a black phosphorus analogue, has great potential in the applications of optoelectronic devices due to its distinct optical properties and air stability. Developing techniques that can boost the photoresponsivity of GeSe‐based photodetectors is essential to promoting their practical applications. Herein, ferroelectric PbZrxTi1−xO3 (PZT) gating is introduced as an effective method to enhance the performance of GeSe‐based transistors. Comparative study on the performance of conventional Si/SiO2‐ and PZT‐gated GeSe phototransistors demonstrates a 3.1 times increase in photoresponsivity under zero gate voltage by ferroelectric gating. Furthermore, the PZT‐gated photodetector shows a rise time of 52 ms and a maximal external quantum efficiency (EQE) of 45% across the visible and near‐infrared range. These results indicate that ferroelectric gating is a promising methodology to enhance the performance of GeSe‐based photodetectors. This work paves a new pathway toward developing high‐performance photodetectors. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) materials have attracted tremendous research attention in recent days due to their extraordinary and unique properties upon exfoliation from the bulk form, which are useful for many applications such as electronics, optoelectronics, catalysis, etc. Liquid exfoliation method of 2D materials offers a facile and low‐cost route to produce large quantities of mono‐ and few‐layer 2D nanosheets in a commercially viable way. Optoelectronic devices such as photodetectors fabricated from percolating networks of liquid‐exfoliated 2D materials offer advantages compared to conventional devices, including low cost, less complicated process, and higher flexibility, making them more suitable for the next generation wearable devices. This review summarizes the recent progress on metal–semiconductor–metal (MSM) photodetectors fabricated from percolating network of 2D nanosheets obtained from liquid exfoliation methods. In addition, hybrids and mixtures with other photosensitive materials, such as quantum dots, nanowires, nanorods, etc. are also discussed. First, the various methods of liquid exfoliation of 2D materials, size selection methods, and photodetection mechanisms that are responsible for light detection in networks of 2D nanosheets are briefly reviewed. At the end, some potential strategies to further improve the performance the devices are proposed. [ABSTRACT FROM AUTHOR]

In 2D materials, the quantum confinement and van der Waals‐type interlayer interactions largely govern the fundamental electronic and optical properties, and the dielectric screening plays a dominant role in the excitonic properties. This suggests strongly layer‐dependent properties and a central topic is to characterize and control the interlayer interactions in 2D materials and heterostructures. Black phosphorus is an emerging 2D semiconductor with unusually strong interlayer interactions and widely tunable direct bandgaps from the monolayer to the bulk, offering an ideal platform to probe the layer‐dependent properties and the crossover from 2D to 3D (i.e., the scaling effects). In this review, a comprehensive and thorough summary of the fundamental physical properties of black phosphorus is presented, with a special focus on the layer‐dependence character, including the electronic band structures, optical absorption and photoluminescence, and excitonic properties, as well as the band structure engineering by means of electrical gating, strain, and electrochemical intercalation. Finally, an outlook is given for the future research. [ABSTRACT FROM AUTHOR]

In this paper, a charge plasma-based phosphorene double-gate tunnel FET (CP-BPDGTFET) is investigated. A hybrid simulation technique involving both atomistic and technology computer-aided design (TCAD) has been used to simulate the device characteristics. First, the density functional theory has been used to simulate phosphorene electrical characteristics (monolayer to few-layer, including armchair and zigzag directions). The parameters such as band gap and effective mass obtained using an atomistic simulator tool are exported into Sentaurus TCAD to simulate the device characteristics. The drain current characteristics are calibrated for conventional double gate phosphorene tunnel FET with non-equilibrium Green's function results. The DC characteristics of the proposed device are studied. The device performance is analysed by varying the device parameters such as gate length (Lg), spacer length (Ls), and gate workfunction (ϕm). Based on the study, an optimised device is designed, and its characteristics are obtained. The optimised device offers an on-current value of 405 µA/µm, SS = 79 mV/dec, Ion/Ioff = 1.13 × 106 for 30 nm gate length. It establishes that CP-BPDGTFET is a suitable candidate for energy-efficient circuit applications. [ABSTRACT FROM AUTHOR]

We investigate the physical properties of compressed gray phosphorus through density functional plus dynamical mean-field theory, showing self-doping and s -wave electronic structure reconstruction. At commensurate electron density, the 3 p spectrum is shown to be almost unaffected by electronic correlations, however upon self-doping largely the normal and superconducting states. These findings provide a microscopic understanding of pressure-induced hole carrier superconductivity on the normal state coherence of s -wave superconductors with well-defined Bogoliubov quasiparticles at low temperatures. Upon internal thermalization, the s -wave superconducting state loses its phase coherence. [ABSTRACT FROM AUTHOR]

In this article, we report an investigation of analog performance, linearity, and harmonic distortion (HD) characteristics for both symmetric and asymmetric InGaAs n-channel MOSFETs at elevated temperatures. Analog performance parameters such as transconductance and voltage gain are found to be better for the asymmetric InGaAs MOSFETs than their symmetric counterparts. The linearity metrics such as gm2, gm3, voltage intercept points 2 (VIP2), VIP3, IIP3, and third-order intermodulation distortion (IMD3) have been analyzed. Asymmetric devices are found to perform better in terms of linearity. Moreover, distortion is also found to be less for the asymmetric devices than the symmetric ones. A comparison of the linearity and distortion characteristics of InGaAs devices with a similarly sized Si device reveals that, although the Si device performs better in terms of linearity, particularly at elevated temperatures, InGaAs devices have an edge in terms of distortion over the Si device. [ABSTRACT FROM AUTHOR]

With the development of novel optoelectronic materials and nanofabrication technologies, integrated photonics is a rapidly developing field that will promote the development and application of next‐generation photonic devices. In recent years, emerging two‐dimensional materials (2DMs) including graphene, transition metal dichalcogenides (TMDCs), black phosphorus (BP), and ternary compounds show many complementarities and unique characteristics over those of traditional optoelectronic materials including broadband absorption, ultrafast carrier mobility, strong nonlinear effects, and compatibility for monolithic integration. Herein, the recent progress on waveguide‐integrated active devices for a full photonic circuit based on 2DMs is reviewed. Both the development of nanofabrication techniques and the working mechanism of active photonic components based on 2DMs containing integrated light sources, waveguide‐integrated modulators, photodetectors, as well as some advanced 2DMs‐based optoelectronic devices are illustrated in detail. In the end, the existing challenges and perspectives on novel 2DMs‐integrated photonics are summarized and discussed. [ABSTRACT FROM AUTHOR]

Photocatalytic and electrocatalytic N2 reduction reactions (N2RR) for NH3 synthesis from abundant N2, H2O, solar energy, and renewable electricity is very attractive. 2D catalysts, including photocatalysts (TiO2, Bismuth‐based materials, layered double hydroxides (LDHs), carbon nitride, Fe@Graphene, MoS2 et al.) and electrocatalysts (metal, graphene, carbon, boron nitride (BN), boron carbide (B4C), black phosphorus (BP), boron, transition‐metal oxide/sulfide/nitride/phosphide), have emerged as promising candidates for N2RR due to their unique physical, chemical and electronic properties. Compared with their bulk counterparts, 2D catalysts usually possess the shortened carrier diffusion pathways, higher specific surface areas and conductivity, more vacancy‐type defects as well as exposed edge sites, which is beneficial to the separation of photogenerated carriers, and the adsorption and activation of N2 molecules. This review highlights the recent progress and developments in 2D catalysts for photocatalytic and electrocatalytic N2RR for the first time. First, the prospects for photocatalytic and electrocatalytic N2RR for NH3 synthesis, and the advantages of 2D catalysts are briefly introduced. Second, the application of 2D catalysts for N2 photoreduction and electroreduction is systematically summarized. Finally, the major challenges and future outlook of this burgeoning area are provided. [ABSTRACT FROM AUTHOR]

This paper reports unique InGaAs-based ion-sensitive field-effect transistor (ISFET) sensor devices having a sensing gate in addition to the traditional floating gate with different kinds of barrier materials such as no barrier, single barrier (InP) and double barrier (InP and InAlAs), at sub-100 nm technology node. The impact of barrier layers coupled with the modified gate architecture on the sensing performance of the proposed devices has been investigated and compared thoroughly in terms of different performance metrics, e.g., threshold voltage sensitivity, ON-current sensitivity, and ON/OFF-current sensitivity. Interestingly, it has been found that the sensor device with a single barrier exhibits the highest threshold voltage sensitivity of ~ 67 mV/pH and largest ION/IOFF ratio sensitivity of 25/pH, compared to the other devices. Furthermore, it is worth mentioning that the threshold voltage sensitivity of the single-barrier sensor device crosses the conventional Nernst limit of 59 mV/pH at room temperature, by 14%. Critically analyzing the results, it is found that the sensor device with a single barrier has evolved as the most promising device for pH-sensing application, not only from the standpoint of high sensitivity parameters, but also from the fabrication point of view. [ABSTRACT FROM AUTHOR]

Since the discovery of graphene, 2D materials have attracted significant attention for their unique properties. Monoelemental 2D materials (ME2DMs) are of particular interest because of their superiority in synthetic exploration, excellent mobility, and wide range of band gaps over other 2D compounds. Substantial efforts are devoted to fabricate high‐quality materials through various substrates and reveal the growth mechanism at the atomic scale. In this review, the recent progress in the preparation of these ME2DMs is explored, the roles of different substrates is highlighted, and the challenges of and perspectives on their heterostructures is discussed. [ABSTRACT FROM AUTHOR]

Flexible and transparent optoelectronics based on 2D materials are promising candidates for next‐generation technologies. Among all 2D materials, it is of numerous practical implications to explore nonmetal, earth‐abundant candidates. Herein, an exciting addition is unearthed—2D hydrogenized amorphous carbon (α‐C:H). The 2D α‐C:H nanosheets, with layered structural feature, are composed of crystalline sp2 nanoclusters embedded in sp3 amorphous matrix. The typical "vapor–solid" mechanism governs the growth of these nanosheets under the temperature–pressure combination above the Berman–Simon line. Their high transmittance over 97.7% covers the 425–1300 nm wavelength region. Optical characterizations also reveal a spectral overlap between the π–π* absorption edge and σ–σ* photoluminescence peak. Self‐powered and flexible photodetectors based on the 2D α‐C:H/ZnO heterostructure exhibit a remarkable photoresponse, with a broadened photosensitivity responsivity of 195.16 mA W−1 and a 267‐fold decrease of the rise time. This performance enhancement originates from the type II band alignment, the pyroelectric and piezo‐phototronic effects. As a new member in the 2D family, α‐C:H nanosheets promise to be appealing in transparent flexible optoelectronics with ultralow power consumption and real‐time, on‐site response. [ABSTRACT FROM AUTHOR]

Immunotherapies directed at T-cell activation through antibodies targeting checkpoint proteins, such as programmed cell death 1 (PD1), are rapidly becoming the new standard of care in the treatment of several malignancies. Cemiplimab is a monoclonal antibody targeting PD1 that has recently emerged as a highly active treatment for locally advanced and metastatic cutaneous squamous cell carcinoma (CSCC). Patients who have received an organ transplant (OTRs) have been traditionally excluded from clinical trials with checkpoint inhibitors (CIs), given concerns for organ rejection. Renal transplant recipients (RTRs) are more likely to develop cancers than the general population, and skin cancers are among the most frequent malignancies. We report the case of a 72-year-old man with a history of a kidney transplant who presented with a rapidly growing, locally advanced squamous cell carcinoma (SCC) of the scalp that recurred within four weeks from surgical resection. The patient was able to safely receive ten cycles of cemiplimab so far with significant clinical benefit, and no issues with his kidney function, while continuing immunosuppression with low dose prednisone alone. An ongoing clinical trial (NCT04339062) is further exploring the safety of CIs in patients with metastatic CSCC who have previously received allogeneic hematopoietic stem cell transplant or a kidney transplant. [ABSTRACT FROM AUTHOR]

Excessive consumption of fossil fuels gives rise to the increasing emission of carbon dioxide (CO2) in the atmosphere and furthers the ecocrisis. Electrochemical CO2 reduction (ECR) has both functions of dwindling greenhouse gas concentration and converting it into valuable products. Due to the intrinsic chemical inertness of CO2 molecules, the study on efficient and low‐cost catalysts has attracted much attention. Recently isolated atoms, dispersed in stable support, play an important role in decreasing energy barriers of intermediate steps and obtaining target products with high activity and selectivity for ECR. The effective regulation of central atoms or coordination environment is significant to realize the desired performances of ECR with a high efficiency and selectivity. Hence, a comprehensive summary about strategies for improving the performance of ECR on single atom catalysts (SACs) is necessary. Herein, the SACs on various supports are introduced, the methods to design stable SACs are discussed, and the strategies for tuning the performance of ECR on SACs are summarized. The localized environment manipulation is widely used for high‐performance SACs design, including regulating central atoms and coordination environment. Finally, the perspectives are discussed to shed light on the rational design of intriguing SACs for ECR. [ABSTRACT FROM AUTHOR]

Idiopathic CD4 T cell lymphocytopenia (ICL) is a rare entity characterized by CD4 T cell count of <300 cells/mm3 along with opportunistic infection for which T cell marker expression remains to be fully explored. We report an ICL case for which T lymphocyte phenotype and its costimulatory molecules expression was analyzed both ex vivo and after overnight stimulation through CD3/CD28. The ICL patient was compared to five healthy controls. We observed higher expression of inhibitory molecules PD-1/PDL-1 and CTLA-4 on CD4 T cells and increased regulatory T cells in ICL, along with high activation and low proliferation of CD4 T cells. The alteration in the expression of both the costimulatory pathway and the apoptotic pathway might participate to down-regulate both CD4 T cell functions and numbers observed in ICL. [ABSTRACT FROM AUTHOR]

Silicon (Si) photonics have established as leading technologies in addressing the rapidly increasing demands of huge data transfer in optical communication systems with compact footprints, small power consumption, and ultradense bandwidth, which are driven by the next generation supercomputers and big data era. Particularly, Si photonics will penetrate into optical communication links at an ever‐small scale, namely chip‐to‐chip and on‐chip. However, the nanostructures made of Si with an indirect bandgap are not ideal candidates for on‐chip light sources, modulators, and photodetectors, which most‐frequently require optical materials with direct bandgap. Thanks to the advent of graphene, transition metal dichalcogenides and other two‐dimensional (2D) materials, which can facilitate extraordinary progresses in improving device performance at the ultrathin scale, their integration with Si photonics furnishes a heterogeneous platform to construct fully functional and highly integrated photonic communication systems. In this work, the current advancements in the on‐chip applications of Si photonics‐2D materials heterostructures, inclusive of all essential chip‐scale modules and integrated circuits, as well as the future prospective and challenges are reviewed and discussed. The present study sets out to objectively measure the feasibility of the hybrid integration between Si photonics and 2D materials in on‐chip optical communications and the advanced applications beyond. [ABSTRACT FROM AUTHOR]

We study the optical properties of highly elongated, highly flattened quantum dot structures, also referred to as quantum dashes, characterized by the presence of two trapping centers located along the structure. Such a system can exhibit some of the properties characteristic for double quantum dots. We show that sub- and super-radiant states can form for certain quantum dash geometries, which is manifested by a pronounced transfer of intensity between spectral lines, accompanied by the appearance of strong electron-hole correlations. We also compare exciton absorption spectra and polarization properties of a system with a single and double trapping center and show how the geometry of multiple trapping centers influences the optical properties of the system. We show that for a broad range of trapping geometries the relative absorption intensity of the ground state is larger than that of the lowest excited states, contrary to the quantum dash systems characterized by a single trapping center. Thus, optical properties of these structures are determined by fine details of their morphology. [ABSTRACT FROM AUTHOR]

The family of emerging low‐symmetry and structural in‐plane anisotropic two‐dimensional (2D) materials has been expanding rapidly in recent years. As an important emerging anisotropic 2D material, the black phosphorene analog group IVA–VI metal monochalcogenides (MMCs) have been surged recently due to their distinctive crystalline symmetries, exotic in‐plane anisotropic electronic and optical response, earth abundance, and environmentally friendly characteristics. In this article, the recent research advancements in the field of anisotropic 2D MMCs are reviewed. At first, the unique wavy crystal structures together with the optical and electronic properties of such materials are discussed. The Review continues with the various methods adopted for the synthesis of layered MMCs including micromechanical and liquid phase exfoliation as well as physical vapor deposition. The last part of the article focuses on the application of the structural anisotropic response of 2D MMCs in field effect transistors, photovoltaic cells nonlinear optics, and valleytronic devices. Besides presenting the significant research in the field of this emerging class of 2D materials, this Review also delineates the existing limitations and discusses emerging possibilities and future prospects. [ABSTRACT FROM AUTHOR]

Often, a student comes in excited by a revolutionary idea. When this happens, we invite the student to check the literature carefully and, moreover, to extend the search way back, for more than a century, in fact. For example, encouraged by Albert Einstein, Edward H. Synge introduced the concept of a near-field scanning microscope in the 1928 paper "A Suggested Method for Extending Microscopic Resolution Into the Ultramicroscopic Region" [1]. He claimed to have overcome the "...axiom in microscopy, that the only way to extend resolving power lies in the employment of light of smaller wavelength." For subwavelength resolution of a biological sample, Synge proposed to place an opaque screen with a 10-nm diameter pinhole within 10 nm of the sample (Figure 1). Light passing through the pinhole and the sample is focused on a photodetector. By moving the screen laterally in 10-nm steps, the sample is imaged with 10-nm resolution, regardless of the wavelength of the light. Later, what he proposed became known as a scanning near-field optical microscope (SNOM). [ABSTRACT FROM AUTHOR]

Various requirements for 3D printing raised by actual applications in different fields have provoked the rapid development of technologies together with various specific materials. A protocol combining 3D printing with surface modification has stood out recently due to its outstanding capabilities to meet requirements in fields where surface properties are critical, allowing the surface performances of 3D-printed architectures to be controlled. So-called surface-functionalized 3D printing, via adding a new functional dimension to the surface of 3D-printed objects, is believed to be a robust, time-saving, cost-effective, and highly desirable approach for 3D printing, meeting a variety of demands, compared to developing special-purpose materials for each solo case. The general strategy and methods, including etching, deposition processing, micro-/nano-composition coating, and polymer brush assisted surface modification, are summarized in this review, as are the various applications and feasibilities for use in biomedicine, engineering, flexible electronics, smart devices, and so forth, due to the acquired features originating from postprocessing, including wettability, biocompatibility and bioactivity, high strength and conductivity, etc. [ABSTRACT FROM AUTHOR]

Unceasing efforts have been devoted to photonics based on black phosphorus ever since it came under the spotlight of two-dimensional materials research six years ago. The direct bandgap of black phosphorus is tunable by layer number, vertical electric field, and chemical doping, covering a broad spectrum for efficient light manipulation. The optical anisotropy further enables the identification and control of light polarization. Along with high carrier mobility, nonlinear optical properties, and integration capability due to its layered lattice structure, black phosphorus manifests itself as a promising multipurpose material for chip-scale optoelectronics. In this manuscript, we review the research on black phosphorus photonics, with a focus on the most fundamental active functions in photonic circuits: photodetection, electro-optic modulation, light emission, and laser pulse generation, aiming at evaluating the feasibility of integrating these black phosphorus-based components as a compact system for on-chip applications. [ABSTRACT FROM AUTHOR]

Few‐layer black phosphorus (BP) is an emerging 2D material suitable for energy applications. However, its controllable preparation remains challenging. Herein, a highly efficient route is presented for the scalable production of few‐layered BP nanosheets using a pulsed laser in low‐boiling point solvents. Changing the laser irradiation time, energy, and solvent type leads to precise control over the layer number and lateral size of the nanosheets with a narrow distribution. The process is understood by a plasma quenching mechanism and interlayer interaction weakened by the in situ generated vapor bubbles. The excellent control of the BP nanosheets enables morphological effects on Li‐ion battery performance to be studied. Low layer numbers benefit both charge transfer and Li+ ion diffusion, while a high aspect ratio can not only improve the charge transfer but also increase the Li+ ion diffusion path. This study delivers insights on the tailored fabrication of thin 2D materials using lasers for morphology‐dependent electrochemical energy conversion and storage. [ABSTRACT FROM AUTHOR]

The immune system against tumors acts through a complex dynamical process showing a dual role. On the one hand, the immune system can activate some immune cells to kill tumor cells (TCs), such as cytotoxic T lymphocytes (CTLs) and natural killer cells (NKs), but on the other hand, more evidence shows that some immune cells can help tumor escape, such as regulatory T cells (Tregs). In this paper, we propose a tumor immune interaction model based on Tregs-mediated tumor immune escape mechanism. When helper T cells' (HTCs) stimulation rate by the presence of identified tumor antigens is below critical value, the coexistence (tumor and immune) equilibrium is always stable in its existence region. When HTCs stimulation rate is higher than the critical value, the inhibition rate of effector cells (ECs) by Tregs can destabilize the coexistence equilibrium and cause Hopf bifurcations and produce a limit cycle. This model shows that Tregs might play a crucial role in triggering the tumor immune escape. Furthermore, we introduce the adoptive cellular immunotherapy (ACI) and monoclonal antibody immunotherapy (MAI) as the treatment to boost the immune system to fight against tumors. The numerical results show that ACI can control TCs more, while MAI can delay the inhibitory effect of Tregs on ECs. The result also shows that the combination of both immunotherapies can control TCs and reduce the inhibitory effect of Tregs better than a single immunotherapy can control. [ABSTRACT FROM AUTHOR]

Antibody‐based immunotherapies play a pivotal role in cancer research with efficient achievements in tumor suppression. Tumor survival is assisted by modulation of immune checkpoints to create imbalances between immune cells and cancer cell's environment. The modulation results in T‐cell signal inhibition ultimately inert its proliferation and activation against various tumor cells. PD‐L1, a 40 kDa transmembrane protein of B7 family, binds with PD‐1 on the membrane of T cells which results in inhibition of T‐cell proliferation and activation. PD‐L1/PD‐1 pathway has generated novel target sites for antibodies that can block PD‐L1/PD‐1 interactions. The blockage results in T‐cell proliferation and tumor cell suppression. The PD‐L1 immune checkpoint strategies' development, expression and regulations, signal inhibitions, and developmental stages of PD‐L1/PD‐1 antibodies are briefly discussed here in this review. All this information will provide a base for new therapeutic development against PD‐L1 and PD‐1 immune checkpoint interactions and will make available promising treatment options. [ABSTRACT FROM AUTHOR]

Compared to other two-dimensional (2D) crystals with single or binary elements, 2D ternary layered materials have unique physical properties for potential applications due to the stoichiometric variation and synergistic effect. Here, we report the first investigation of lattice dynamics and interactions between the exciton and lattice degrees of freedom in a 2D ternary semiconductor: indium-selenide-bromide (InSeBr). Via linear polarization resolved Raman scattering measurements, we uncover three Raman modes in few-layer InSeBr, including two A1g and one Eg modes. Moreover, through the combination of temperature-dependent Raman scattering experiments and theoretical calculations, we elucidate that few-layer InSeBr would harbor strong coupling between excitons and phonons. Our results may provide a firm basis for the development and engineering of potential optoelectronic devices based on 2D ternary semiconductors. [ABSTRACT FROM AUTHOR]

As a "hot" member of two-dimensional (2D) materials, black phosphorus (BP) has received growing interest in a variety of fields in physics, chemistry, materials, and biomedicine since 2014. Owing to the exclusive 2D layered structure, some fantastic properties such as tunable band structure, high charge mobility, and in-plane anisotropy provide BP with great potential for application in electronic/optoelectronic devices, energy source conversion and storage, etc. However, with in-depth investigations, the performance deficiencies of BP-based devices are exposed, originating from the poor chemical stability of BP. To address the above issues, a variety of BP/carbon hybrid composites have been constructed as an emerging type of multifunctional materials by the integration of the unique properties of carbon materials with the merits of BP into a single hybrid heterostructure, showing improved performance for applications. In this review, the enhanced stability of BP is presented based on the fundamental chemistry of BP degradation, which originates from the formation of P–C/P–O–C bonds or van der Waals interactions in BP/carbon hybrid composites. Recent research studies focusing on the utilization of BP/carbon hybrid composites for electrochemical energy storage, photocatalytic hydrogen production and optoelectronic devices are summarized, in which approaches toward the assembly of BP/carbon hybrid composites are introduced. Finally, the extant challenges and potential applications of BP/carbon hybrid materials are also proposed. [ABSTRACT FROM AUTHOR]