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Analysis of multidimensional in-depth thermal response for the phenolic impregnated carbon ablator (PICA)/CV-1144-0 material system in NASA Langley Research Center Hypersonic Materials Environmenta...

We report Al0.3InAsSb/Al0.7InAsSb digital alloy n-barrier-n (nBn) photodetectors that operate in the 2-μm wavelength window. The AlxIn1-xAsySb1-y digital alloy material system exhibits near-zero valence-band offset, which is beneficial for nBn photodetectors. At 300 K these Al0.3InAsSb/Al0.7InAsSb nBn photodetectors have achieved specific detectivities of 1.7 × 10 10 and 3.0 × 10 10 Jones under 2-μm and 1.8-μm illumination, respectively. The dark current density at -0.5 V bias decreases from 3.1 × 10 -3 A/cm 2 at 300 K to 1.6 × 10 -10 A/cm 2 at 120 K, where the dominant dark current component is tunneling. The area-dependence of key performance parameters show that for mesa diameter ≤ 250 μm, surface defects assume a dominant role in the total noise.

Achieving controls on the self-assembly of cationic and block copolymer micelles has significant implications for advancing novel material systems for energy, environmental, and biological applicat...

Metallic transition-metal dichalcogenides (TMDs) are rich material systems in which the interplay between strong electron–electron and electron–phonon interactions often results in a variety of col...

The magnetic refrigeration (MR) utilizing magnetocaloric effect (MCE) has been recognized as an environmentally friendly and energy efficiency technology. Here we presented the magnetic properties and MCE in Pr-doped La1-xPrxFe12B6 (x=0.05-0.2) itinerant-electron metamagnetic (IEM) compounds. A small amount of Pr doping La site can greatly improve the peak values in the magnetic entropy change ΔSM(T) curves, especially under relatively low magnetic field changes (ΔH). Additionally, the peak temperature increases gradually and the magnetic hysteresis reduces gradually with increasing x. The observed MCE in present La1-xPrxFe12B6 compounds is related to its field-induced first-ordered IEM transition. The peak values of ΔSM for La1-xPrxFe12B6 compounds reach 13.4, 15.4, 12.5 and 13.0 J/(kg K) at TC ~58, 68, 72 and 89 K for x=0.05, 0.10, 0.15 and 0.2 under ΔH of 0-7 T, respectively. The corresponding relative cooling power values are 462.3, 480.7, 372.4 and 375.7 J/kg. The present La1-xPrxFe12B6 compounds could be good candidates for active MR application if the magnetic and thermal hysteresis can be further reduced. The present work indicates that the LaFe12B6-based material system could also exhibit promising magnetocaloric performances.

Synthesis of materials with desired structures, e.g., metal-organic frameworks (MOFs), involves optimization of highly complex chemical and reaction spaces due to multiple choices of chemical elements and reaction parameters/routes. Traditionally, realizing such an aim requires rapid screening of these nonlinear spaces by experimental conduction with human intuition, which is quite inefficient and may cause errors or bias. In this work, we report a platform that integrates a synthesis robot with the Bayesian optimization (BO) algorithm to accelerate the synthesis of MOFs. This robotic platform consists of a direct laser writing apparatus, precursor injecting and Joule-heating components. It can automate the MOFs synthesis upon fed reaction parameters that are recommended by the BO algorithm. Without any prior knowledge, this integrated platform continuously improves the crystallinity of ZIF-67, a demo MOF employed in this study, as the number of operation iterations increases. This work represents a methodology enabled by a data-driven synthesis robot, which achieves the goal of material synthesis with targeted structures, thus greatly shortening the reaction time and reducing energy consumption. It can be easily generalized to other material systems, thus paving a new route to the autonomous discovery of a variety of materials in a cost-effective way in the future.

Research into organic light emitters employing multiple resonance-induced thermally activated delayed fluorescence (MR-TADF) materials is presently attracting a great deal of attention due to the potential for efficient deep-blue emission. However, the origins and mechanisms of successful TADF are unclear, as many MR-TADF materials do not show TADF behaviour in solution, but only as particular pure solids. Here, an investigation into a well-known MR-TADF material, DABNA-1, together with other new MR materials (9H-quinolino[3,2,1-kl]phenothiazin-9-one (QPO) and 9H-quinolino-[3,2,1-kl]-phenothiazin-9-one 5,5-dioxide (QP3O)), yields new insights regarding the origin of TADF. Although a material system may support the concept of MR, inefficiency in both forward and reverse intersystem crossings forbids TADF unless a suitable host material allows an exciplex-like host–emitter interaction that boosts TADF. This boosted-TADF mechanism can be generalized to any fluorescence dye that lacks TADF in the photoluminescence measurement but has a thermally accessible S1–T1 energy gap, opening the way to high-performance organic light-emitting diodes. This study reveals the importance of host–guest interactions for effective multiple-resonance thermally activated delayed fluorescence in organic light emitters.

We simulate transport for proposed low excess-noise avalanche photodiode InAlAs/InAsSb type-II superlattice materials to evaluate their impact ionization coefficients; a key metric in determining avalanche photodiode performance. The ensemble Monte Carlo method is utilized to develop a stochastic transport kernel suitable for superlattice transport in the static field approximation. The electronic band structure and impact ionization rates are computed from a 14-band superlattice envelope function $$\varvec{K}\cdot \varvec{p}$$ formalism. We reveal that band engineering through superlattice design can be utilized to enhance the electron-to-hole impact ionization ratio in the InAlAs/InAsSb superlattice material system.

Cesium copper (I) halides, as a lead-free halide material system, have shown great potential in optoelectronic devices due to their environmental friendliness, high quantum efficiency, and extraord...

Liquid crystalline elastomers (LCEs) are crosslinked polymer networks that combine the elastic properties of rubber with the anisotropic properties of liquid crystals. Multifunctionality and responsivity can be programmed into LCEs by patterning their local orientation, which is difficult to achieve in other monolithic material systems. Advances in the synthesis and alignment of LCEs have paved the way for their functional integration in robotics, optics, consumer products, energy and healthcare devices. In this Review, we discuss recent advances in materials chemistry and processing that have contributed to the resurgence in LCE research. We examine the mechanical response of LCEs to stimuli and survey approaches for mechanical alignment, surface-enforced alignment, field-induced alignment and rheological alignment. The Review concludes with an over-the-horizon outlook discussing current challenges and emerging research opportunities. Liquid crystalline elastomers are stimuli-responsive polymeric materials whose mechanical properties can be programmed by patterning their local orientation, making them promising candidates to serve as low-density actuators and functional elements in various applications. This Review discusses the synthesis and processing of liquid crystalline elastomers, with a focus on alignment methods and potential applications.

Copper (Cu) and its alloys are prospective materials in fighting covid-19 virus and several microbial pandemics, due to its excellent antiviral as well as antimicrobial properties. Even though many studies have proved that copper and its alloys exhibit antiviral properties, this research arena requires further research attention. Several studies conducted on copper and its alloys have proven that copper-based alloys possess excellent potential in controlling the spread of infectious diseases. Moreover, recent studies indicate that these alloys can effectively inactivate the covid-19 virus. In view of this, the present article reviews the importance of copper and its alloys in reducing the spread and infection of covid-19, which is a global pandemic. The electronic databases such as ScienceDirect, Web of Science and PubMed were searched for identifying relevant studies in the present review article. The review starts with a brief description on the history of copper usage in medicine followed by the effect of copper content in human body and antiviral mechanisms of copper against covid-19. The subsequent sections describe the distinctive copper based material systems such as alloys, nanomaterials and coating technologies in combating the spread of covid-19. Overall, copper based materials can be propitiously used as part of preventive and therapeutic strategies in the fight against covid-19 virus.

The establishment of superlow friction in moist air is very important for the engineering application of hydrogenated diamond-like carbon (H-DLC) films. Nevertheless, water molecules in the surrounding atmosphere always result in the failure of the near-frictionless state. This work aims to explore the effects of water molecules in the environment and the material of the counterparts on the tribological performance of a composite structure prepared by depositing MoS2 on a H-DLC film. The results indicated that the existence of water molecules in the atmosphere is beneficial for achieving stable superlubricity for the material system because it helps retain the in-situ formed MoS2 transfer film on the counterpart. In the presence of water molecules, the wear interface was replaced by a robust and incommensurate MoS2 tribolayer/H-DLC sliding interface, which was responsible for the superlow friction achieved in this work. The results also revealed that the ZrO2 counterpart was capable of retaining the as-formed MoS2 transfer film and establishing long-lasting superlow friction even in dry air. The mechanisms behind this phenomenon are also discussed in this paper.

Intralaminar cracking in relatively thick 90-plies of [[Formula: see text]]s laminates is analyzed using experimental data for two Glass fiber/Epoxy (GF/EP) material systems. Weibull parameters for transverse failure stress of the 90-ply are obtained from experimental intralaminar crack density versus applied strain data, showing that a reliable analysis requires sufficient amount of data in so called noninteractive crack density region. Monte Carlo simulations of cracking were performed using stress distribution between two cracks calculated using two models: Hashin’s model and a novel model that ensures that the average stress is exactly the same as in FEM solution. Due to its features, the Hashin’s model predicts too low intralaminar crack density (it predicts too strong interaction between cracks). The results emphasize the importance of having a proper stress distribution model when performing Monte Carlo simulations. Simulations were used not only to simulate intralaminar cracking in high and very low crack density regions but also for improving the procedure of Weibull parameter determination.

Hydrogen is identified as the most promising zero-carbon fuel of the future. Naturally, in this regard, the hydrogen evolution reaction (HER), being a first critical step of the hydrogen technology and economy, attracts much attention. Conventionally, noble metals have been used as the electrocatalyst for HER, which in part holds back the hydrogen technology to become a large scale and heavily distributed energy technology. This has encouraged scientists to study cost-effective strategies for HER. Transition metal disulfides, being a low-cost material system with a great degree of engineering versatility, have recently emerged as a potential candidate that can significantly promote hydrogen evolution. Several studies have demonstrated that the control and manipulation of the structure and morphology of these materials can improve their proton reduction performance. This review covers many of the decisive factors and strategies to advance transition metal sulfides for HER applications.

In this study, S0.4Co4Sb11.2Te0.8 skutterudites with a highly porous structure inside grains are prepared by a one-step hot-pressing (OS-HP) method. The effect of the pressure relief treatment at the heating stage on the micro-morphology and thermoelectric properties of materials is investigated. When the temperature corresponding to the pressure relief treatment is less than 723 K, the grain size dramatically increases from ∼1 to ∼50 μm, and a large number of pores are distributed inside these large grains. Compared with those samples prepared by the conventional method, the thermal conductivity of samples prepared by the pressure relief treatment is significantly reduced due to the high porosity. The ZT values of samples prepared by the pressure relief treatment are greater than 1.6 at 825 K. This newly developed OS-HP method can be employed for the rapid fabrication of highly porous structured skutterudites with low-melting-point compositions as well as of other material systems.

Near-infrared persistent phosphors (NIR-PPs) are an emerging category of luminescent materials that can continuously emit NIR luminescence with super-long decay time of minutes, hours, or even days after the excitation ceases. Their unique excitation-free long-lasting afterglow, together with the NIR emission, has not only attracted wide research interests in the areas of photochemistry, photophysics, spectroscopy, and materials science, but also stimulated advanced applications in biosensing, bioimaging, biomedicine, and therapy in the past decade. Beyond these bio-related applications, the active research field triggers a number of novel applications recently. In this review, a brief outline of NIR-PPs including the luminescence mechanism, main material systems, and how they were applied into various fields was depicted. Particular emphasis was put on the emerging applications outside the field of biology. Future perspectives in this exploration research area were also presented. We hope this review can help researchers grab the latest information in the fast-growing field of NIR-PPs.

Microgels are soft colloids that show responsive behavior and are easy to functionalize for applications. They are considered key components for future smart colloidal material systems. However, so far microgel systems have almost exclusively been studied in classical responsive switching settings using external triggers, while internally organized, autonomous control mechanisms as found in supramolecular chemistry and DNA nanotechnology relying on fuel‐driven out‐of‐equilibrium concepts have not been implemented into microgel systems. Here, we introduce chemically fueled transient volume phase transitions (VPTs) for poly(methacrylic acid) (PMAA) microgels, where the collapsed hydrophobic state can be programmed using the fuel concentration in a cyclic reaction network. We discuss details of the system behavior as a function of pH and fuel amount, unravel kinetically trapped regions and showcase transient encapsulation and time‐programmed release as a first application., Moving past classical passive responsive behavior, transient volume phase transitions of poly(methacrylic acid) microgels can be achieved through the use of a chemical fuel. The deswelling creates a transient hydrophobic environment with a lifetime tunable via pH and fuel concentration with possible applications for encapsulation/release.

Organic mechanochromic materials(also known as piezochromic materials), whose color or emission changes under mechanical force, have attracted great interest owing to their potential applications in pressure sensors, rewritable materials, optical storage, and security ink. Organic mechanochromic materials with aggregation-induced emission(AIE) features have better development prospects and research value owing to their excellent optical properties. To date, mechanochromism has mostly been realized by means of mechanical grinding. Nevertheless, the magnitude of the grinding force is usually uncontrollable and its direction is anisotropic, making it awkward to study the mechanism of mechanochromic materials. On the contrary, hydrostatic pressure, whose magnitude and direction are controllable, is a more valid and governable method to investigate the mechanism of mechanochromic materials, which can help us to construct a meaningful structure-property relationship and understand the latent origin of the mechanochromism. Furthermore, it is conducive to developing other mechanochromic material systems with desired chemical and physical properties. In this review, we focus on the recent progress in the mechanism of organic mechanochromic materials with AIE features under hydrostatic pressure. Four types of mechanisms are included: intermolecular interaction change, intramolecular conformation change, transformation from locally excited state to intramolecular charge-transfer state, and intra- and inter-molecular effects induced by hydrostatic pressure, respectively.

Attributable to complex structural characteristics, the 3-D hierarchical structures possess different failure modes as compared to the traditional laminate structures, resulting in improved impact resistance properties. In this work, a comprehensive study of ballistic performance of 3-D woven and 3-D knitted structures has been undertaken and suitability of these structures for various applications on the basis of their geometrical distinctiveness has also been described. Different material systems have been investigated which are considered to be suitable for ballistic applications. Ballistic testing has been performed on leading 3-D hierarchical structures woven/knitted by polyamides (aramid, PA-6) and ultra-high-molecular-weight-polyethylene (UHMWPE) filaments to study their failure mechanisms against 30. Cal FMJ projectiles. The experimentation has been performed utilizing light-gas gun apparatus, under the instructions provided by internationally known standard NIJ-0101.06. Furthermore, appropriate sabot design has been scrutinized which is crucial to the whole experimental procedure, as sabots hold the projectile into the gas gun barrel and plays the key role in keeping the projectile straight and maintaining its velocity. Damage patterns were found to be different in knitted and woven structures; as knitted structures showed smaller damage affected region as compared to woven preforms.

Multifunctional organic field effect transistors (OFETs) that integrate different functions in one device have attracted significant interest due to their significance for practical applications of OFETs. The past decade has witnessed the fast development of OFETs constructed with photochromic molecules as photo-responsive electronics. Photochromic molecules can undergo interconversion or isomerization between two stable/meta-stable states under alternate irradiation. The unique photo-switching performance endows photochromic molecules with an important role in a series of photo-responsive OFETs. The output signals of a photochromic OFET can be reversibly tuned by light triggers via introducing photochromic units into the electronic material system, resulting in a remote-controllable device with potential applications. This review summarizes the recent development of photochromic OFETs in the past decade based on different photochromic categories, e.g. diarylethenes, spiropyrans, and azobenzenes. A brief perspective of photochromic OFETs and their future challenges are also presented.

Many studies, experimental, theoretical, and numerical, have been done on polymer nanocomposites, but nearly all of them have focused on a particular type of material system or some specific material properties. A comprehensive understanding of this complicated material system is still quite lacking. The objective of this study is to use mesoscale finite element simulation to gain insights on the reinforcing efficiencies of different types of carbon nanofillers as distinguished by their geometries and interfacial strengths. It is demonstrated that CNT (carbon nanotube) and CNF (carbon nanofiber) have larger load carrying capacity and potentially higher reinforcing efficiency than GNP (graphite nanoplatelet) due to their larger aspect ratio and physical length. However, the higher load carrying capacity is also associated with higher interfacial stress which can lead to earlier debonding, particularly for CNT. GNP, on the other hand, has lower load carrying capacity, and is thus less sensitive to the bonding condition and less susceptible to debonding. The overall reinforcing efficiency is a manifestation of the interplay between the load carrying capacity of the filler, which is limited by filler’s geometry, and the load transfer capability at the interface, which is limited by the filler/matrix interfacial strength. This interplay is also reflected in the effects of filler orientation on reinforcing efficiency. The insights gained from this study can be used to devise a strategy for developing advanced nanocomposites, such as hybrid composites.

The paper presents the results of a study to determine the degree of attenuation of a detonation wave pulse generated by a spherical ceresin-phlegmatized hexogen charge, by spaced material systems. The systems were mounted on a ballistic pendulum and the amount of energy absorbed was determined based on the change in pendulum swing. The spaced panels with absorbing elements, simulated the flat bottom of a vehicle exposed to a single blast.

Nanoscale vacuum channel transistors based on field emission have gained attention recently, and device demonstrations using various material systems have been reported. Whereas solid-state electro...

The exploration of novel carbon material systems has emerged as a promising strategy for yielding unique and unconventional functional properties. In this study, a cationic nitrogen-doped carbon-wr...

The phase mixture CsPb2Br5/CsPbBr3 has raised interest as a promising material system for light emission, light detection, and even for photovoltaic devices owing to its high luminescence yield and...

In this study, we report all-polymer solar cells enabled by a joint effect of p-doping and ternary blend strategies. We apply the p-doping strategy for two material systems based on a new polymer d...

La2O3-CaO-B2O3-TiO2 (LCBT) glass has been designed to prepare compact M-type Sr-hexaferrite magnets with fine grains and enhanced magnetic properties. The results showed that LCBT glass suppressed the grain growth along the basal-plane and promoted densification, while degree of orientation increased firstly and then decreased with further rising LCBT glass content. Doping an appropriate amount of LCBT glass has been demonstrated to be very conducive to preparing a dense microstructure with fine grains. Due to these desired behaviors, LCBT glass markedly improved the magnetic properties of the sintered hexaferrites. The resulted magnet by adding 0.1 wt% LCBT glass exhibited high integrated magnetic properties, including Br = 453.2 mT, Hcb = 318 kA/m, Hcj = 365 kA/m and (BH)max = 39.6 kJ/m3. LCBT glass additive seems promising to be applied to other material systems to obtain dense microstructures with fine grains, such as soft magnetic ferrites or dielectric ceramics.

The evolution of cellular morphology during interfacial instability for liquid–solid transition for pure unary material systems is studied using the maximum entropy production (generation) rate principle (MEPR) for steady-state directional solidification. This approach is dependent on a quantity called maximum entropy production rate density which inherently contains key solidification parameters that governs cellular evolution for liquid–solid transformation. The maximum entropy production rate density is computationally measured from the solid–liquid interface in diffuse form and considers steady-state solidification at low velocities for both near and far from equilibrium conditions. The results are presented in mathematical expressions for morphological instability that corresponding to the evolution of a cellular morphology which emanates from the solid–liquid interface. The model is formulated to evaluate the solid–liquid interface thickness, the solidification velocity, grain boundary energy, and the size of the cellular morphological at instability. The results are tested with a number of pure single element materials at different temperature gradients which compare well with available experimental data.

Sub-picosecond hole transfer has been recently observed in several narrow band gap nonfullerene small-molecule acceptor (NFA)-based binary blended organic solar cell (OSC) systems operating with ne...

Reversible and switchable wrinkling surfaces in response to various external stimuli have extensive potential applications. In this Letter, we prepared the reversible wrinkling on poly(dimethylsiloxane) (PDMS) surfaces, responsive to the solvents, by ultraviolet-ozone (UVO) treatment with/without mechanical prestrain. Based on the solvent-responsive wrinkling, three types of optical transparency dynamics were achieved easily in a single and simple film-substrate system, including (I) completely reversible transparency with controlled relaxation time and isotropic light scattering; (II) completely reversible transparency with anisotropic light scattering and tunable diffusion degree; and (III) incompletely reversible transparency. The reversibility and stability of wrinkles can be controlled by tailoring the solvent type, UVO exposure time, and mechanical prestrain. The underlying mechanisms for the three wrinkling dynamics have been clearly elucidated. The extremely simple material system and the facile but efficient technique pave a novel way for realizing versatile optical dynamics for smart displays.

The search for decent material systems is the most desirable to obtain superior performances in resistive random access memory (RRAM) devices. Nitride switching materials have attracted much attent...

Automated fibre placement (AFP) is an advanced manufacturing process with a built-in heat and pressure system, an effective method for in situ consolidation of composite parts. In the present study, carbon fibre PA-6 prepregs were laminated by an IR-assisted AFP system, and the effect of process parameters on the resulting part quality was studied. Of the six fundamental process parameters, two parameters, i.e., laying speed and IR power were identified to be critical. Hence, the current study is focussed on the optimization of these two parameters while keeping the others constant. Three different combinations of IR power and laying speed were deduced to be optimised parameters for the material system used. In general, the laying speed should be increased along with the appropriate increase in IR power. Through visual and microstructural inspection, the laminate manufactured with these optimised parameters were found to have fewer defects and better consolidation when compared with samples manufactured with unoptimised combinations.

Gallium–zinc oxynitride (GZNO) is a promising material system for solar-driven overall water splitting, as it exhibits a tunable band gap in the visible range, beneficial positions of valence and c...

Although artificial semiconductor heterostructures have long been the core material system for the generation, detection and manipulation of carriers, at TeraHertz (THz) frequencies, the discovery of graphene and the related intriguing abilities have triggered an unprecedented interest in inorganic two-dimensional (2D) materials, as black phosphorus and boron nitride, amongst many others. They offer a unique platform for developing efficient devices, without the need of lattice matching, and with a variety of physical properties, that can be engineered from scratch, exploiting the material structures, the layer thickness or their inherent anisotropy.

The recent decades have seen various attempts at accelerating the process of developing materials targeted towards specific applications. The performance required for a particular application leads to the choice of a particular material system whose properties are optimized by manipulating its underlying microstructure through processing. The specific configuration of the structure is then designed by characterizing the material in detail, and using this characterization along with physical principles in system level simulations and optimization. These have been advanced by multiscale modeling of materials, high-throughput experimentations, materials data-bases, topology optimization and other ideas. Still, developing materials for extreme applications involving large deformation, high strain rates and high temperatures remains a challenge. This article reviews a number of recent methods that advance the goal of designing materials targeted by specific applications.

High-speed X-ray imaging is synchronized with dynamic loading systems to provide real-time dynamic behavior and fracture mechanisms in a variety of materials. X-ray imaging provides a unique advantage for investigating subsurface fracture mechanisms in opaque materials. The basic principles of high-speed X-ray phase-contrast imaging are described. Various modifications are required to properly synchronize the dynamic loading apparatus with the X-ray imaging setup. These modifications and synchronization schemes between the loading and imaging setups are presented. Representative results from two material systems: granular particles and polymer-bonded explosives are presented. Some recommendations for future upgrades in the apparatus and analysis methods are described.

In recent years, a plethora of material systems have been designed and prepared to increase the performance of light harvesting and light-emitting technologies, and to develop new and attractive applications. Limitations of state-of-the-art devices based on organics (bothconjugated polymersor small molecules/oligomers) derive largely from material stability issues after prolonged operation. This challenge could be tackled by leveraging the enhanced stability ofcarbon nanostructures(CNSs, including carbon nanotubes and the large family of graphene-based materials) in carefully designed nano-hybrid or nano-composite architectures to be integrated within photo-active layers, paving the way to the exploitation of these materials in contexts in which their potential has not been yet fully revealed. In this review, we discuss the theoretical and experimental background behind CNSs hybridization with other materials for the establishment of novel optoelectronic properties and provide an overview of the existing examples in the literature that allow to forecast interesting future perspectives for use in real devices.

Interfaces often govern the thermal performance of nanoscale devices and nanostructured materials. As a result, accurate knowledge of thermal interface conductance is necessary to model the temperature response of nanoscale devices or nanostructured materials to heating. Here, we report the thermal boundary conductance between metals and insulators that are commonly used in spin-caloritronic experiments. We use time-domain thermoreflectance to measure the interface conductance between metals such as Au, Pt, Ta, Cu, and Al with garnet and oxide substrates, e.g., NiO, yttrium iron garnet (YIG), thulium iron garnet (TmIG), ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$, and sapphire. We find that, at room temperature, the interface conductance in these types of material systems range from 50 to $300\phantom{\rule{0.16em}{0ex}}\mathrm{MW}\phantom{\rule{0.16em}{0ex}}{\mathrm{m}}^{\ensuremath{-}2}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$. We also measure the interface conductance between Pt and YIG at temperatures between 80 and 350 K. At room temperature, the interface conductance of Pt/YIG is $170\phantom{\rule{0.16em}{0ex}}\mathrm{MW}\phantom{\rule{0.16em}{0ex}}{\mathrm{m}}^{\ensuremath{-}2}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$ and the Kapitza length is \ensuremath{\sim}40 nm. A Kapitza length of 40 nm means that, in the presence of a steady-state heat current, the temperature drop at the Pt/YIG interface is equal to the temperature drop across a 40-nm-thick layer of YIG. At 80 K, the interface conductance of Pt/YIG is $60\phantom{\rule{0.16em}{0ex}}\mathrm{MW}\phantom{\rule{0.16em}{0ex}}{\mathrm{m}}^{\ensuremath{-}2}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$, corresponding to a Kapitza length of \ensuremath{\sim}300 nm.

We report the realization of fully compensated synthetic antiferromagnets (SAFs) in $\mathrm{Pt}/\mathrm{Co}/\mathrm{Ru}/{\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Tb}}_{x}$ multilayers with perpendicular magnetic anisotropy, pronounced anomalous Hall resistances and magneto-optical responses. In particular, the properties of SAFs are systematically investigated through optimizing the thicknesses of the $\mathrm{Co}$ layer, the $\mathrm{Ru}$ spacer, and the concentration (x) of the ferrimagnet (FIM) ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Tb}}_{x}$ layers. The incorporation of the FIM ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Tb}}_{x}$ films into SAFs accelerates the search for a magnetic multilayer with fully compensated magnetism and exhibiting pronounced anomalous Hall resistance and magneto-optical signals. These advantages enable spin-orbit-torque switching and magneto-optical Kerr effect imaging experiments on the fully compensated SAFs to be readily investigated. Through incorporating FIMs into SAFs, we believe that the present material system could provide a promising platform not only for adequately addressing the fully compensated spin dynamics of SAFs at room temperature, but also for developing intriguing SAF-based spin-orbitronic devices.

Many natural and human-made material systems (e.g., bone, shale, and cement-based composites) exhibit heterogeneous microstructures. Lattice models have reemerged to simulate such material ...

Nanodielectrics have been regarded as a class of material system that can provide significantly improved chemical, mechanical and dielectric properties over conventional microcomposites. This is due to the presence of a high volume fraction of the interphase between nanoparticles and polymers. However, precise effects of nanodielectrics are not well understood, leading to difficulties in interpreting the dielectric behaviours of nanodielectrics. In the current work, effects of nanoparticle distributions, interparticle distances, nanoparticle sizes, interphase permittivities and interphase thicknesses on the possible electric field variations within a nanodielectric model have been simulated using Finite Element Method Magnetics (FEMM) 4.2. The results demonstrate that different nanoparticle and interphase configurations lead to different effects on the electric field intensity within the nanodielectric model. Mechanisms leading to changes in dielectric properties based on the observed electric field variations are discussed.

The colloidal quantum dots (CQDs) are a promising nanometer-sized material system for optoelectronic applications due to the low cost, room temperature processing and substrate compatibility. Solution-processed technology such as spin-coating can make CQDs large-scale deposition on the substrates, whereas it inevitably brings about CQDs adherence to the edges even bottom of the substrates. As a result, the devices are not isolated and vertical leakage current occurs from the surface of CQDs to the substrates. In this work, two kinds of CQDs patterning techniques named etching-assisted patterning (EAP) and lift-off assisted patterning (LAP) have been put forward to significantly suppress the vertical current from several nanoampere to a few picoampere. Meanwhile, the CQDs photoconductor detectors have also been fabricated through these two patterning methods on the SiO2/Si substrates. Compared with un-patterning (UP) photodetectors, these two techniques both can enhance the photocurrent and promote the optoelectrical quality factors such as the responsivity and the specific detectivity, which make it possible to manufacture CQDs detector arrays and promote CQDs in optoelectronic applications.

The synthesis, electronic structure and temperature dependent transport properties of polycrystalline Cu1+xMn2-xInTe4 (x = 0, 0.2, 0.3) are reported for the first time. These quaternary chalcogenides were synthesized by direct reaction of the elements, followed by solid state annealing and hot press densification. The thermal conductivity is low for all specimens and intrinsic to the material system. Furthermore, the off-stoichiometry specimens illustrate the sensitivity of the transport properties to stoichiometry, with a greater than two-orders-of magnitude increase in carrier concentration with increased Cu content. First principles calculations of the electronic structure are also reported, and are in agreement with the experimental data. This fundamental investigation shows the potential towards further optimization of the electrical properties that, in addition to the intrinsically low thermal conductivity, provides a basis for further research into the viability of this material system for potential energy-related applications.

Lead-free double perovskites have great potential as stable and nontoxic optoelectronic materials. Recently, Cs2AgBiBr6 has emerged as a promising material, with suboptimal photon-to-charge carrier conversion efficiency, yet well suited for high-energy photon-detection applications. Here, the optoelectronic and structural properties of pure Cs2AgBiBr6 and alkali-metal-substituted (Cs1−xYx)2AgBiBr6 (Y: Rb+, K+, Na+; x = 0.02) single crystals are investigated. Strikingly, alkali-substitution entails a tunability to the material system in its response to X-rays and structural properties that is most strongly revealed in Rb-substituted compounds whose X-ray sensitivity outperforms other double-perovskite-based devices reported. While the fundamental nature and magnitude of the bandgap remains unchanged, the alkali-substituted materials exhibit a threefold boost in their fundamental carrier recombination lifetime at room temperature. Moreover, an enhanced electron–acoustic phonon scattering is found compared to Cs2AgBiBr6. The study thus paves the way for employing cation substitution to tune the properties of double perovskites toward a new material platform for optoelectronics.

For potassium sodium niobate (KNN)-based ferroelectrics, a critical contradictory relationship exists where higher piezoelectricity is often achieved at the cost of their Curie temperature, and this severely restricts the practical applications of these ferroelectrics. How to resolve this contradiction is one of the urgent concerns in high-temperature piezoelectric applications. Herein, a new material system, 0.965K0.54Na0.46Nb1−xSbxO3-0.03Bi0.5Na0.5ZrO3-0.005BiFeO3 (KNNSx-BNZ-BF, 0 ≤ x ≤ 0.03), was obtained by compositional selection. A significant progress with respect to the simultaneous realization of a large d33 (∼505 pC N−1) and a high TC (∼285 °C) was achieved in this ferroelectric, which are superior to those of the KNN-based ferroelectrics reported to date. In addition, good temperature-independent strain properties were attained for this material due to its high TC values. Therefore, this KNN-based system may promote the practical application of lead-free materials in high-temperature fields.

A thorough study of phase separation in borosilicate glasses synthesized in the material system soda – colemanite – quartz sand was performed. The ranges of crystallization-resistant glasses and phase separation prone glasses were determined. It is shown that the complex raw material colemanite can be used to obtain glasses that are transparent or opaque in the bulk. The limiting content of raw materials in the material makeup of glass batches are recommended.

This work presents a framework for collectively modeling shear viscosities of grouped polymeric materials. The viscosity model has been derived from the multi-modal White-Metzner constitutive equation. Simplification to the multi-modal viscosity has resulted in a viscosity model that controls gradual transition between two conventional viscosity models. It facilitates mathematical representation of multiple sets of viscosity data at the same time. A conventional shear viscosity function, which is common to the group, is multiplied by a material-specific function with one or two constants to form the collective viscosity model. The proposed framework has been applied to several polymeric systems such as polymers with varying molecular weight, polymer solutions with different concentrations, polymers with different filler loadings, and polymer blends with various composition ratios. It has been shown that the K-index in the proposed viscosity model and the variable in the material system such as concentration or compounding ratio can be correlated with each other to predict the viscosities of untested cases.

We report Al0.8In0.2As0.23Sb0.77 avalanche photodiodes with high gain ( $M>1300$ ) and low dark current at room temperature. Impact ionization coefficients for this material system are also extracted, indicating electron-dominant impact ionization. Low avalanche breakdown temperature dependence is demonstrated.

In this current outlook, we critically review the most vital new outcomes in the field of rechargeable Li, Na and K-ion batteries. We deliberate current discoveries like the progress of electrospinning and their applications in future. Mainly, we discuss freestanding and binder-free electrodes structural and morphological effect when it undergoes long term cycling. Finally, this short review grants the up-to-date advancement on novel processing strategies of various carbon-based electrospun composites as anodes whose performance are similar with or even can beat that of the commercial anode material system.

The ceramic materials structure formation with the given esthetics-consumer properties is the most important mission of the modern production and should be based on the knowledge of physical and chemical processes, which are flowing past in masses based on the systems differing in the content of alkaline, alkaline-earth oxides and oxides of iron in clay raw materials.