Extraordinary Material Properties Research Articles

Unravelling the Factors Influencing Halide Perovskite Based Switchable Photovoltaics

AbstractLead halide perovskites have revolutionized the field of optoelectronics (such as photovoltaics and light emitting diodes) demonstrating extraordinary material properties despite being formed at low temperatures. However, ion migration in the bulk or at the interfaces results in stability issues especially in devices where metal electrodes directly interface with the perovskite film. Utilizing the switchable photovoltaic phenomenon (SPV) in halide perovskites as a measure of ion migration and electrochemical reactions within them, Cs0.05MA0.15FA0.70PbI2.5Br0.5 triple cation perovskite, widely used in photovoltaics is evaluated. The various factors determining the SPV, including electric field magnitudes, type of metal contacts, Illumination conditions, and temperature is systematically measured. This study reveals the roles of electrode work functions and reactivities on ion migration and local electronic structure modulation. ITO electrodes demonstrated the highest open‐circuit voltage (Voc) about 0.85 V while Ag electrodes developed conductive filaments. However, the Voc distribution for Ti and Cr electrodes shows a more pronounced linear correlation with the poling electric field strength. Insights from this lateral design are directly relevant to transistor and memristor architectures and offer inputs into the design of perovskite‐based photovoltaic/optoelectronic devices.

Rock drilling performance of rotary ultrasonic tools incorporating PZT piezoceramic and Mn:PIN-PMN-PT piezocrystal

High performance Mn:PIN-PMN-PT piezocrystal material is investigated to understand if its extraordinary properties can replace the traditional hard piezoceramic material for space exploration applications. A bolted Langevin-style ultrasonic drill tool incorporating a pair of Mn:PIN-PMN-PT piezocrystal rings is built to compare with a same configuration ultrasonic drill tool actuated with a pair of hard piezoceramic rings, which are tuned to the first longitudinal mode (L1) at around 20 kHz. From the characterisation results, it is observed that the piezocrystal material presents significantly greater values of relative permittivity, electromechanical coupling coefficient, and piezoelectric charge coefficient than the hard piezoceramic material. Despite these outstanding properties, the piezocrystal driven ultrasonic drill tool shows similar displacement amplitudes to its counterpart. Nonetheless, the impedance magnitude of the piezocrystal driven ultrasonic drill tool at resonance is a magnitude lower than the piezoceramic actuated drill tool, due to the large piezoelectric charge coefficient d33. Ultrasonic rock drilling experiments suggest that the cutting force for sandstone and marble are greatly reduced, but limestone and tuff are less affected.In general, the piezocrystal driven ultrasonic drill tool demonstrates a marginally improved cutting performance than the piezoceramic actuated drill tool, in terms of lower cutting force and motor power consumption, however, the tool wear appears slightly poorer. The research outcome of this paper indicates that the thickness mode of the piezocrystal rings might not be the optimal form of excitation, which could be due to the piezoelectric losses at high excitation levels, so other excitation conditions and vibration modes will need to be explored to fully adopt the extraordinary material properties of the piezocrystal material.

A numerical study of carbon doping effect on paraffin-reinforced silica aerogel mechanical properties: A molecular dynamics approach

Aerogels are different types of porous and solid materials that exhibit a strange set of extraordinary material properties. Aerogels have great potential for use in the fields of heat, sound, electronics, and especially thermal insulation. This paper investigates the influence of carbon doping concentration on the mechanical properties of paraffin-reinforced silica aerogel (PRSA). To do this investigation, Young’s module (YM), stress–strain curve, and ultimate strength (US) values at various carbon-doped particles of 1 to 10 % were reported by molecular dynamics (MD) simulation. The results show that the PRSA, under the influence of carbon doping, has dual performance. To be more precise, by adding the amount of carbon doped from 1 to 3 %, the US and YM of the PRSA rose from 329.96 and 1137.20 MPa to 353.73 and 1268.44 MPa. In other words, the mechanical strength of the PRSA increases in a limited ratio. However, by increasing carbon doping from 3 to 10 %, the US and YM of the PRSA reduced to 306.233 and 1041.88 MPa, respectively. So, it is expected that the mechanical behavior of the PRSA matrix to be manipulated with carbon doping for actual applications.

Photoluminescence of Two-Dimensional MoS2 Nanosheets Produced by Liquid Exfoliation

Extraordinary properties of two-dimensional materials make them attractive for applications in different fields. One of the prospective niches is optical applications, where such types of materials demonstrate extremely sensitive performance and can be used for labeling. However, the optical properties of liquid-exfoliated 2D materials need to be analyzed. The purpose of this work is to study the absorption and luminescent properties of MoS2 exfoliated in the presence of sodium cholate, which is the most often used surfactant. Ultrasound bath and mixer-assisted exfoliation in water and dimethyl sulfoxide were used. The best quality of MoS2 nanosheets was achieved using shear-assisted liquid-phase exfoliation as a production method and sodium cholate (SC) as a surfactant. The photoluminescent properties of MoS2 nanosheets varied slightly when changing the surfactant concentrations in the range C(SC) = 0.5–2.5 mg/mL. This work is of high practical importance for further enhancement of MoS2 photoluminescent properties via chemical functionalization.

Structural, electronic, and transport properties of Janus XMoSiP2 ( S, Se, Te) monolayers: a first-principles study

Based on density functional theory calculation, herein we propose XMoSiP2 ( S, Se, Te) monolayers for new two-dimensional (2D) Janus materials. Their crystal structures with dynamical, mechanical, and thermal stabilities, electronic and transport properties are systematically investigated. The results reveal that all three XMoSiP2 monolayers exhibit isotropic elastic properties with high Young’s modulus and negative cohesive energy values, as well as the elastic constants follow the Born-Huang’s criteria, demonstrating their mechanical stability and suggesting the high ability for the experimental synthesis of these materials. From the Perdew–Burke–Ernzerhof functional, the SMoSiP2 is observed as a semiconductor with an indirect bandgap of 1.01 eV, while the SeMoSiP2 and TeMoSiP2 monolayers are observed as direct semiconductors with the bandgap energy of 1.09 and 1.12 eV, respectively. Notably, the bandgap energy of the materials is changed significantly by applying the biaxial strain, and the transition between direct and indirect semiconductors is observed. For the transport ability of the materials, the carrier mobilities are found to be anisotropic for both electron and hole in our studied materials. These findings further highlight the extraordinary properties of the 2D Janus XMoSiP2 materials and their promise for application in electronic devices.

Effects of Fuel Input on Pulsation Reactor Behavior—An Experimental Study

Material treatment in pulsation reactors (PR) brings the possibility of synthesizing powdery products with advantageous properties, such as nanoparticle sizes and high specific surface areas, at an industrial scale. The extraordinary material properties can be ascribed to special process parameters in a PR, primarily the periodically varying conditions and the consequently enhanced heat and mass transfer between the medium and the particles of the material. Understanding the connections between the PR operation parameters, such as fuel and air intake or PR geometry, and the resulting process parameters (temperature distribution, flow velocity and pressure field, and frequency of the pulsations) is essential to enabling a controllable treatment process. Despite the long history of pulsation reactor technology, many connections and dependencies remain unclear. Thus, the influence of the fuel (and air) supply on the pulsation reactor behavior is experimentally examined in this study. The investigated PR characteristics and process parameters are primarily those that have an impact on the heat and mass transfer, i.e., the temperature distribution, flow velocity, and pressure field, and frequency of the pulsations. In addition to these, the harmonic distortion of the oscillations and the heat losses are evaluated.

Reduction in Crosstalk between Integrated Anisotropic Optical Waveguides

The minimization of waveguide crosstalk is a long-standing challenge for optical engineers. Nowadays, the most popular technique to suppress crosstalk is anisotropic nanostructures, realized as subwavelength stripes between waveguides. However, the influence of material anisotropy on the efficiency of such structures remains unknown. In this work, we consider MoS2 waveguides separated by MoS2 stripes because this material has the record value of optical anisotropy. We discover that the use of MoS2 instead of Si results in a several-orders-of-magnitude-larger crosstalk distance. Therefore, we envision that by combining the extraordinary material properties with the known crosstalk-suppression methods, one can make the integration density of photonic devices close to electronics.

Fabrication and characterization of nitinol reinforced metal matrix smart composite: A review

Metal matrix composites are becoming more popular in various industrial, automobile, naval, and aircraft applications because of their unmatchable mechanical and thermo-mechanical properties. Smart materials are known to have extra ordinary material properties which made the evolution of a new generation of materials. Shape memory alloys are the one among these smart materials which are capable of memorizing their previous shape and able to recover the plastic deformation. Nitinol is the most widely used shape memory alloy which has maximum recoverable strain among the shape memory alloys and has excellent mechanical and thermo mechanical properties. With the reinforcement of nitinol, in metal alloys, properties like high tensile strength, high fatigue strength, improved damping properties, and the very precious property of damage healing in metals, can be achieved. This review article presents a review on nitinol reinforced metal matrix composite which includes (a) mathematical and finite element method models; (b) fabrication method; (c) mechanical characterization that includes tensile behavior, interfacial bonding, and damping capacity. This paper tries to covers most of the relevant works related to nitinol reinforced metal matrix composites. However the more focus is given to the aluminium metal alloys reinforced with nitinol fiber.

Accurate prediction of topology of composite plates via machine learning and propagation of elastic waves

Composites are artificial or natural materials that exhibit extraordinary material properties over homogenous materials made of one of their constituents. Detecting the microstructure of unknown solid composites is still challenging for engineers due to the complexity and nonlinear dynamic response of the materials. The emerging of machine learning (ML) in solving complex problems has enabled scientists to find solutions for problems that were impossible before. In this article, we proposed a methodology using ML and propagation of elastic waves to accurately determine the topology of binary composite plates. Results of this study indicate that a short period of flexural elastic waves propagated through composites can efficiently collect the information of the microstructures of materials and multiple independent RF models can be leveraged to predict configurations of composites accurately by learning from the topologies of plates and their corresponding output elastic waves. The average prediction accuracy of the ML model on 8×8 composite plates can reach 96% using 100,000 samples which only occupy 1/2×1014 of all the possible combinations. This approach is the first attempt on this topic and could be modified for applications such as composite characterization, geology, and archaeology.

MODIFICATION OF MONTMORILLONITE FOR OBTAINING NANOCOMPOSITES BASED ON POLAR POLYMERS

This review covers almost all known categories of compounds used to modify montmorillonite to obtain nanocomposites based on polar polymers. Organic modifiers such as quaternary ammonium ions, quaternary phosphonium ions, amino acids and other organic compounds are commonly used to modify montmorillonite (MMT). The main directions of scientific research in this field are considered, namely the modification of MMT with ammonium surfactants, phosphonium surfactants, amino acids and nonionic surfactants. The review used 67 sources related to peer-reviewed publications, mostly from the last 10-15 years. The largest number of publications devoted to the modification of MMT was published in the period from 2004 to 2016. Nanocomposites based on epoxy resins are especially widely presented in the literature. Epoxy-based materials have been used for many years as convenient matrices for dispersing MMT due to the advantages of properties of the obtained polymer nanocomposites, such as mechanical strength, non-flammability and thermal stability. The methods of surface modification of MMT with organic modifiers considered in the article are a powerful tool for the production of polymer nanocomposite materials based on polar polymers. Amine modification of MMT allowed the formation of highly effective materials, in particular epoxy/MMT materials. These nanocomposites have demonstrated extraordinary material properties compared to virgin polymers and can therefore be used as an alternative to conventional materials such as steel and wood, reducing the cost and weight of products. Nanocomposites based on polar polymers occupy an important place among all polymer nanocomposites as modern materials used in the aerospace, automotive and electrical industries.

Review on Developments and Progress in Nickelate‐Based Heterostructure Composites and Superconducting Thin Films

AbstractIn the past decade, the rapid development of modern heterointerface growth and characterization techniques has stimulated great effort to research and design the extraordinary physical properties of transition metal heterostructure composite materials. Here, new physics originates from the rearrangement of orbital, charge, spin, and lattice and the resulting rebalancing of their mutual interactions. In this paper, recent experimental and theoretical progress in the design, preparation, characterization, and physical property measurement of LaNiO3‐based heterostructure composites and the infinite‐layer Ni1 + nickelate superconducting thin films on (001) SrTiO3 substrate is reviewed, mainly by the methods of various X‐ray spectroscopy measurements, scanning transmission electron microscopy, and magneto‐transport measurements. In these materials, the electronic structure and orbital occupation around the Fermi level are modified, enabling nickelate‐based composite materials to exhibit new states of matter and physical phenomena, which are absent in the bulk constituents. Their confined structures, superconductivity, orbital polarization, charge transfer, electronic structures, magnetic properties, and X‐ray spectroscopic analysis, are therefore highlighted, aiming at understanding unconventional superconducting mechanisms and designing new high‐Tc superconducting low‐dimensional materials for device applications.

Recent Development of Nano-Carbon Material in Pharmaceutical Application: A Review.

Carbon nanomaterials have attracted researchers in pharmaceutical applications due to their outstanding properties and flexible dimensional structures. Carbon nanomaterials (CNMs) have electrical properties, high thermal surface area, and high cellular internalization, making them suitable for drug and gene delivery, antioxidants, bioimaging, biosensing, and tissue engineering applications. There are various types of carbon nanomaterials including graphene, carbon nanotubes, fullerenes, nanodiamond, quantum dots and many more that have interesting applications in the future. The functionalization of the carbon nanomaterial surface could modify its chemical and physical properties, as well as improve drug loading capacity, biocompatibility, suppress immune response and have the ability to direct drug delivery to the targeted site. Carbon nanomaterials could also be fabricated into composites with proteins and drugs to reduce toxicity and increase effectiveness in the pharmaceutical field. Thus, carbon nanomaterials are very effective for applications in pharmaceutical or biomedical systems. This review will demonstrate the extraordinary properties of nanocarbon materials that can be used in pharmaceutical applications.

(Digital Presentation) Fully Integrated Strain-Neutralized 2D Transistors

As performant and well-established as conventional silicon-based electronics have become, the era of wearable electronics and the Internet-of-Things has created a demand for robust electronic devices that can conform to the surfaces of the human body. Whereas the mechanical mismatch between rigid silicon electronics and the human body represents a fundamental limit to conventional non-invasive health sensing, wearable electronics and electrodes that can conform to the microscopic features of the skin1,2 can circumvent most of the motion artifacts inherent to conventional, rigid sensing devices, and facilitate continuous health monitoring as is required for modern, more proactive healthcare. Unfortunately, without addressing this fundamental mechanical incompatibility, devices that leverage the high density of transistors available in rigid silicon-based integrated circuits are handicapped by how well they can maintain contact with the body, and consequently are prone to failure at the sensor-circuit interface.The extraordinary properties of two-dimensional materials pose a unique opportunity for addressing this mechanical mismatch. Their unusual mechanical strength combined with their ultimate thinness, optical transparency, and favorable electronic transport properties3 makes them ideal candidates for the next generation of highly conformable wearable electronics free of the constraints of a rigid silicon circuit board—however, minimizing local strain in the vicinity of the active devices to ensure reliable operation remains a priority. Using a design informed by finite element method (FEM) simulations, our proposed strain-neutralizing 2D transistors are configured to resist applied strains on the order of the 30% strains human skin can withstand by redistributing strain away from active regions. Tight binding simulations of the transistor channels helps with further compensation of residual strain in the active regions, alongside careful consideration of materials and device architecture during fabrication. Together, these considerations help realize the possibility of fully integrated strain-neutralized 2D transistors compatible with state-of-the-art conformable wearable sensors.[1]S. Kabiri Ameri et al., “Graphene electronic tattoo sensors,” ACS Nano, 11, 7634–7641, 2017.[2] S. Kabiri Ameri et al., “Imperceptible electrooculography graphene sensor system for human–robot interface”, npj 2D Materials and Applications, 2, 1-7, 2018.[3] A. H. Castro Neto, F. Guinea, N. M. R. Peres, K. S. Novoselov, and A. K. Geim, “The electronic properties of graphene,” Rev. Mod. Phys., vol. 81, no. 1, pp. 109–162, Jan. 2009, doi: 10.1103/RevModPhys.81.109.

A cohesive effort to assess the suitability and disparity of carbon nanotubes for water treatment.

Population growth, industrialization, and the extensive use of chemicals in daily life have all contributed to an increase in waste generation and an intensified release of organic pollutants into the aquatic environment. To ensure the quality of water (including natural resources), the removal of these pollutants from wastewater has become a challenging task for scientific community. Conventional physical, chemical, and biological treatment methods are commonly used in combinations and are not very effective. Recently, carbon nanotubes (CNTs) emerged as the most reliable and adaptable choice for efficient water treatment due to their extraordinary material properties appearing as a single-step solution for water treatment. High surface area, exceptional porosities, hollow and layered structures, and ease of chemical activation and functionalization are some properties which makes it excellent adsorption material. Hence, this review paper discusses the recent advances in the synthesis, purification, and functionalization of CNTs for water and wastewater treatment. In addition, this study also also provides a quick overview of CNTs-based advance technologies employed in water treatment and carefully assesses the benefits versus risks during large-scale water treatment. Furthermore, it concludes that identified risks to the environment and human health cannot be easily ignored and strict regulatory requirements are a must for producing low-cost innoxious CNTs.

Ultrasensitive Anisotropic Room-Temperature Terahertz Photodetector Based on an Intrinsic Magnetic Topological Insulator MnBi2Te4.

Terahertz photodetectors based on emergent intrinsic magnetic topological insulators promise excellent performance in terms of highly sensitive, anisotropic and room-temperature ability benefiting from their extraordinary material properties. Here, we propose and conceive the response features of exfoliated MnBi2Te4 flakes as active materials for terahertz detectors. The MnBi2Te4-based photodetectors show the sensitivity rival with commercially available ones, and the noise equivalent power of 13 pW/Hz0.5 under 0.275 THz at room-temperature led by the nonlinear Hall effect, allowing for the high-resolution terahertz imaging. In addition, a large anisotropy of polarization-dependent terahertz response is observed when the MnBi2Te4 device is tuned into different directions. More interestingly, we discover an unprecedented power-controlled reversal of terahertz response in the MnBi2Te4-graphene device. Our results provide feasibility of manipulating and exploiting the nontrivial topological phenomena of MnBi2Te4 under a high-frequency electromagnetic field, representing the first step toward device implementation of intrinsic magnetic topological insulators.

Carbonene Fibers: Toward Next-Generation Fiber Materials.

The development of human society has set unprecedented demands for advanced fiber materials, such as lightweight and high-performance fibers for reinforcement of composite materials in frontier fields and functional and intelligent fibers in wearable electronics. Carbonene materials composed of sp2-hybridized carbon atoms have been demonstrated to be ideal building blocks for advanced fiber materials, which are referred to as carbonene fibers. Carbonene fibers that generally include pristine carbonene fibers, composite carbonene fibers, and carbonene-modified fibers hold great promise in transferring the extraordinary properties of nanoscale carbonene materials to macroscopic applications. Herein, we give a comprehensive discussion on the conception, classification, and design strategies of carbonene fibers and then summarize recent progress regarding the preparations and applications of carbonene fibers. Finally, we provide insights into developing lightweight, high-performance, functional, and intelligent carbonene fibers for next-generation fiber materials in the near future.

Zinc oxide (ZnO) hybrid metasurfaces exhibiting broadly tunable topological properties

Abstract Extreme light confinement observed in periodic photonic structures, such as the vortex singularities in momentum (k) space, has been associated with their topological nature. Consequently, by exploiting and tuning their topological properties, optical metasurfaces have been demonstrated as an attractive platform for active photonics. However, given the fact that most active media under external excitations can only provide limited refractive index change, the potential advancements offered by the topological character of active metasurfaces have remained mostly unexplored. Zinc oxide (ZnO), which has recently exhibited optically-induced extraordinarily large permittivity modulations at visible and near-infrared frequencies, is an excellent active material for dynamic metasurfaces exhibiting strong tuning. This work demonstrates that a hybrid metasurface consisting of an array of ZnO nanodisks on a silver backplane displays broadly tunable topological properties. In particular, by performing k-space scattering simulations using measured pump-fluence-dependent material properties of ZnO, we study in detail the light reflection from the hybrid metasurface. Our results validate that the large k-space topology tuning of the metasurface can result in enormously strong polarization manipulation of near-infrared light in the vicinity of the topological features. The observed polarization switching effect is highly sensitive to the polarization and wavelength of an incident wave, owing to the symmetry and dispersion characteristics of the proposed system. Our study indicates that leveraging a combination of the extraordinary material properties and the k-space topology, hybrid metasurfaces based on ZnO may open new avenues for creating all-optical switchable metadevices.

An Approach to Assessing S960QL Steel Welded Joints Using EBW and GMAW

In recent years, ultra-high-strength structural (UHSS) steel in quenched and tempered (Q+T) conditions, for example, S960QL has been found in wider application areas such as structures, cranes, and trucks due to its extraordinary material properties and acceptable weldability. The motivation of the study is to investigate the unique capabilities of electron beam welding (EBW) compared to conventional gas metal arc welding (GMAW) for a deep, narrow weld with a small heat-affected zone (HAZ) and minimum thermal distortion of the welded joint without significantly affecting the mechanical properties. In this study, S960QL base material (BM) specimens with a thickness of 15 mm were butt-welded without filler material at a welding speed of 10 mm/s using the high-vacuum (2 × 10−4 mbar) EBW process. Microstructural characteristics were analyzed using an optical microscope (OM), a scanning electron microscope (SEM), fractography, and an electron backscatter diffraction (EBSD) analysis. The macro hardness, tensile strength, and instrumented Charpy-V impact test were performed to evaluate the mechanical properties. Further, the results of these tests of the EBW joints were compared with the GMAW joints of the same steel grade and thickness. Higher hardness is observed in the fusion zone (FZ) and the HAZ compared to the BM but under the limit of qualifying the hardness value (450 HV10) of Q+T steels according to the ISO 15614-11 specifications. The tensile strength of the EBW-welded joint (1044 MPa) reached the level of the BM as the specimens fractured in the BM. The FZ microstructure consists of fine dendritic martensite and the HAZ predominantly consists of martensite. Instrumented impact testing was performed on Charpy-V specimens at −40 °C, which showed the brittle behavior of both the FZ and HAZ but to a significantly lower extent compared to GMAW. The measured average impact toughness of the BM is 162 J and the average impact toughness value of the HAZ and FZ are 45 ± 11 J and 44 ± 20 J, respectively.

A room temperature self-healing and thermally reprocessable cross-linked elastomer with unprecedented mechanical properties for ablation-resistant applications

High-performance ablative composites demonstrate promising applications in the field of aerospace for thermal protection. In this work, a mechanically strong, fast room temperature self-healing and thermally recyclable crosslinked elastomer was prepared by constructing high-density hydrogen bonds and dynamic disulfide bonds. The tensile strength of the prepared poly(urea-urethane) elastomers (PIDA) reached as high as 31.0 MPa after self-healing for 48 h at room temperature, exhibiting a self-healing efficiency of 93.6%. The PIDA-based composite with 10 wt% hollow phenolic microspheres possessed a tensile strength of 8.67 MPa and exceptional ablative performance with a line ablation rate of 0.0643 mm/s. The extraordinary mechanical properties of PIDA-based materials were related to the presence of reversible disulfide bonds, meticulously engineered hydrogen bonds and chemical cross-linking sites consisting of 2,4-diamino-6-hydroxypyrimidine (DAHP) and urethane moieties that linked by flexible alicyclic hexatomic spacers. Incorporating DAHP allowed the rapid formation of hydrogen bonds at the crosslinking sites, which increased the interaction force of the repair surface during the initial stages of self-healing and provided support for further exchange reactions of disulfide bonds. This work opens an avenue toward developing ultra-robust room temperature self-healing materials for potential thermal protection in aerospace industry.

Designing Artificial Vibration Modes of Piezoelectric Devices Using Programmable, 3D Ordered Structure with Piezoceramic Strain Units

Piezoelectric ceramic devices, which utilize multifarious vibration modes to realize electromechanical coupling and energy conversions, are extensively used in high-technological fields. However, the excitation of basic modes is mainly subjected to natural eigenfrequency of ceramic devices, which is related to the structure and material parameters. Herein, inspired by metamaterial theory, a programmable, 3D ordered structure with piezoceramic strain units (3D OSPSU) is developed to artificially generate basic modes in a broad frequency band other than only in narrow eigenfrequency. A (2 × 2 × 2) arrayed, co-fired, multilayer 3D OSPSU is painstakingly designed and fabricated for generating basic modes, such as flexural, extension, shear, torsion, and even coupled modes at nonresonance. To validate the 3D OSPSU method, a five-degree-of-freedom micro-nano actuating platform based on only one co-fired multilayer ceramic is constructed. The proposed methodology provides a new paradigm for creating extraordinary material properties of piezoelectric ceramics and will inspire brand-new piezoelectric device designs.