AbstractContemporary thermoelectric literature is rife with material structure-related terminologies like interfaces and grain boundaries, signaling the significance of these structures. Interfaces decide the characteristics of electronic and thermal transport and mechanical properties of polycrystalline and nano thermoelectric (TE) materials. Understanding the relationship between grain boundaries/interphase boundaries and property connections in materials is a key component of material design with desired characteristics and performance. It is now widely recognized that the microstructure of materials is intimately connected to their bulk properties. Accordingly, microstructure control and interface manipulation have emerged as critical topics in the field of materials science and engineering, particularly in thermoelectrics. This paper narrates recent breakthroughs in high-performance TE material design from the standpoints of interface structure and grain boundary manipulation. First, it provides a glimpse of strategies for thermal conductivity reduction through nano and microstructure control, embedded nanoinclusions, grain size reduction, and all-scale hierarchical architectures. It then deliberates on electron and phonon transport decoupling via coherent interfaces, matrix/precipitate electronic band alignment, and charge carrier filtering effects. It proceeds to review the recent results on TE properties of materials prepared with aforementioned strategies emphasizing Bi2(Te,Se)3 and (Bi,Sb)2Te3, SnSe, SnTe, Cu2Se, skutterudides, PbTe-based compounds, GeTe, polymer TE composites, and other materials. At the end, possible strategies for further enhancing zT are addressed.

ABSTRACTsThe need for fully dense material with well-engineered microstructures has led to the promising emergence of innovative sintering technologies among which the Spark Plasma Sintering (SPS) is one of the most favorite. Unlike the conventional sintering processes, SPS takes advantage of a current flow passing through the sintering die and metallic powders by which fast densification with minimal grain growth and enhanced physicomechanical properties can be obtained. Albeit there is a growing interest in the exploitation of SPS in producing sufficiently consolidated metallic parts, no analytical review has been released over the effects of SPS parameters on the densification behavior, microstructure evolution, and resultant physicomechanical properties of metallic parts and their alloys. In the present review, recent developments and ongoing challenges in modeling the SPS of metallic systems are thoroughly explored. Then, the effects of main SPS parameters including sintering temperature, dwell time, heating rate, and pressure on the microstructure and physicomechanical properties of metals and alloys are comprehensively investigated. These properties are categorized into two groups: (i) physical properties including relative density, electrical and thermal conductivities; (ii) mechanical properties with a systematic focus on hardness, elastic modulus, and tensile, compressive, and bending strengths. In each section, the general trends along which SPS parameters grow to affect each corresponding property are comprehensively discussed. Additionally, various microstructural phenomena being more likely to occur at the given metallic systems are fully addressed. The present work seeks to elaborate on the aforementioned issues and provide an overview of the unresolved challenges and proposed solutions to them.

AbstractThe development of prosthesis implantation as a means to treat bone defects in the field of orthopedic surgery is booming. Some materials with excellent biocompatibility are available for practical application, while new materials are being continuously developed. Gum metal is a new type of multifunctional β-type titanium alloy, and its basic composition can be expressed as Ti-24(Ta + Nb + V)-(Zr, Hf)-O. Gum metal has a good combination of a low elastic modulus and high strength, which promotes its emergence in the biological field. Moreover, gum metal combines the advantages of nonlinear elasticity, low work hardening rate and nontoxicity, making it a new material with potential in the future. This review begins with the design origin of gum metal and the influence of various elements on this kind of alloy. Second, the fabrication process and deformation mechanism of gum metal are summarized. Finally, the properties and current application fields of gum metal are introduced.

AbstractAll-optical limiting devices are based on materials enabling light to control light, possessing a nonlinear optical response, and are reviving their popularity. One-dimensional photonic crystals (1 D PhC) are an auspicious platform for achieving novel optical limiters functioning for remarkably low limiting threshold and high damage threshold over a wider regime. 1 D PhC, a periodic nanostructure with a refractive index distribution along one direction, has been widely investigated by researchers. However, their utility to limit the high-intensity radiation to protect sophisticated optical sensors and devices is scarce in the research field. An overview of the numerically simulated, mathematically modeled, theoretically proposed, and experimentally realized 1 D PhC reflective optical limiters are provided here. This review focuses on the limited but noteworthy scrutiny of 1 D photonic crystal-based optical limiters using rare earth metals, nanocomposites, semiconductors, and phase-changing materials as defect layers.HighlightsA reliable 1D PhC reflective optical limiter is resistant to laser induced damages.Limiter mechanism relies on creation of nonlinear localized modes.1D PhC optical limiter reflects high power incident beams for a broader frequency window.Reflection based limiters are applicable for arbitrary direction of incidence.

AbstractThe rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) infections that were first detected in Wuhan, China, at the end of 2019 led to the state of the global COVID-19 pandemic declared by the World Health Organization in March 2020. Thus, the world faces a new challenge to control the spread of the virus. The pandemic highlighted the need for rapid detection of infections that would be able to accurately screen the population much more rapidly and economically than the gold standard molecular biology-based tools such as quantitative real-time reverse transcription polymerase chain reaction. Such screening measures would be able to isolate infected individuals, including those showing no symptoms, and provide early treatments before more serious complications develop, thus allowing for the spread of infections to be better controlled without the implementation of socioeconomically crippling lockdowns. In this review, we present a comprehensive overview of the major advances in the use of electrolyte-gated field effect transistor-based biosensors for the detection of viruses, including their use for SARS-CoV-2 detection. We describe the main types of bioreceptors used for the detection of viruses in general and those used for COVID-19 in detail.

AbstractSilicon (Si)-based materials are intensively pursued as the most promising anode materials for next-generation lithium-ion batteries (LIBs) owing to their high theoretical mass-specific capacity, moderate working potential, and high abundance in the earth’s crust. Therefore, it has attracted widespread attention both from academia and industries. Despite the above advantages, the electrochemical performance is hampered by severe volume variation, resulting in poor cyclability and subsequently electrode failure. In this regard, nanostructured Si anodes and their composite electrodes might overcome these problems holding back the utilization of Si-based anodes in LIBs by providing facetious strain relaxation, short lithium diffusion distance, improved mass transport, and efficacious electrical contact. This review offers a holistic summary of chemistry, uniqueness, synthetic strategies, and practical applications of Si-based materials with a focus on presenting the development in the Si nanotubes, nanoparticles, nanowires, porous Si, SiOx, their composite materials with carbon, graphene cages, metals, and metal oxides as anode materials in LIBs. In the end, we present the research outlook for the development of Si/SiOx/C-based materials in the future, including fundamental design and various applications in addressing the challenges mentioned earlier.

AbstractThere is an increasing demand of highly sensitive, stable and highly selective gas sensors to detect toxic gases. This is inspired by the need to monitor the concentration of these gases in order to guarantee humans, animals and environmental safety. Metal ferrites (AFe2O3, where A is a metal) based sensors are paramount in this field of sensing. Among the gases detectable using metal ferrites includes carbon monoxide (CO), liquefied petroleum gas (LPG), hydrogen sulfide (H2S), petrol and methane (CH4). This reviews presents various parameters which plays key role in the design of ferrite gas sensors. They include; operating temperatures, dopants, grain size, particle size, selectivity, surface area, concentration of the gas, sensitivity as well as recovery time. In addition, the various methods which are used to synthesize ferrite gas sensors are briefly explained. Key considerations in the designing of excellent ferrite gas sensors such as calcination temperature, working temperature, dopants, and concentration as well as optimization condition among others are outlined. In addition this paper reviews the various metal ferrites such as nickel ferrites and nickel doped ferrites, cobalt and cobalt doped ferrites, zinc and zinc doped ferrites, magnesium and magnesium doped ferrites among others that have been researched as gas sensors.

AbstractIn order to reduce oil consumption and avoid fossil fuel-related environmental problems, scientists are always looking for lightweight structural materials that show high performance during both processing and application. Among various candidates, Mg seems to be the most promising. Mg is ∼33, 60, and 75% lighter than Al, Ti, and steel, respectively. However, the vast applications of Mg are impeded due to its intrinsic brittleness at room temperature, which is related to the hexagonal close-packed crystal structure of Mg. In this crystal structure, the limited number of independent slip systems available at room temperature leads to brittle behavior and low fracture toughness. Thus, engineers and scientists all over the world have shown a great deal of interest in fabricating Mg-based materials with improved ductility. In this review, accordingly, the origin of low ductility in pure Mg and the fundamentals of designing highly ductile Mg alloys will be presented and critically discussed. In addition, the recent advances achieved in the field of Mg alloys with high ductility via control of structure and composition will be outlined. Finally, various properties of highly ductile Mg-based materials, including creep, fatigue, corrosion, and formability, will be discussed.

AbstractThe Gd3Ru4Al12 structure type compounds, where the rare-earth magnetic ions form a breathing kagome lattice present a promising material landscape for exploring the various magnetic frustration-driven exotic states of matter. Here, we highlight the various magnetic, thermodynamic, and transport properties of several of the Gd3Ru4Al12 structure type magnets and provide intuitive insights into their rich electronic and magnetic ground states. The realization of key properties such as spin trimerization and skyrmion textures accompanied by a large topological (geometrical) Hall effect (THE) in some of these compounds is currently at the heart of several research endeavors searching for efficient data storage and spintronic devices. Features such as helical ordering and anomalous Hall effect (AHE) arising from the formation of Berry curvature by the Weyl fermions present an open window to tuning the electron spins for several practical applications. Therefore, these compounds are projected as promising candidates for investigating several other topological phases of matter accessible through the interplay of the degree of frustration and crystal field symmetry of the rare-earth ions.

AbstractIn the last decade, nanostructuration is a demanding research topic due to the observation of interesting properties and, in consequence, applications on these nanostructures. This review collects the synthesis and possible applications of ZnO nanowires grown by electrodeposition and electroless methods. Respect to the synthesis of ZnO nanowires, growth mechanism and parameters are analysed depending on the technique used, electrodeposition or electroless. The mechanism growth of the nanowires using templateless and hard-templates is analysed resulting in different architecture of the ZnO nanowires. Moreover, ZnO nanowires and hybrid materials based on ZnO are also considered. Depending on the architecture of ZnO nanowires, the properties and applications are different. This review also studies the properties and applications in which ZnO nanowires can be used and how these applications are different depending on the architecture of the nanostructure. This review gives a complete perspective referent to the synthesis, properties and application of ZnO nanowires grown by electrosynthesis techniques.

AbstractShape memory alloys (SMAs) are able to recover large inelastic strains due to their thermal-/stress-induced phase transformation between austenite and martensite. Stress raisers can either initially exist in SMA components as the manufacturing-induced micro-defects, or may nucleate upon monotonic/cyclic loading, for instance, due to decohesion of the second particles or local cyclic plastic deformations. Furthermore, from a physical point of view, there is a problem why SMAs can withstand tens of millions of cycles if they deform elastically but only thousands of cycles if the martensitic transformation is involved in their cyclic deformation under the stress, even if the martensitic transformation is reversible. One of the possibilities is the nucleation and propagation of cracks from the stress raisers since the evolution of the transformation and local mechanical gradients are completely different at the high-stress zones at stress raisers than that being experienced within the elastic bulk. Thus, the successful implementation of SMA elements into engineering applications requires understanding and analysis of the role of the stress raisers in fracture and fatigue crack growth properties of shape memory alloys. The linear and non-linear Fracture Mechanics theories, commonly used to describe the fracture processes in typical structural alloys, need to be enhanced to capture the complex deformation mechanisms characterizing SMAs. In the present paper, first, the latest progress made in experimental, numerical, and theoretical analyses on the role of the stress raisers in the fracture parameters of SMAs are reviewed and discussed under both pure mechanical and thermomechanical loading conditions. Then, the state-of-arts in fatigue crack growth are addressed. In the end, summary and future topics are outlined.

AbstractArtificial synapses in neuromorphic computing systems hold potential to emulate biological synaptic plasticity to achieve brain-like computation and autonomous learning behaviors in non-von-Neumann systems. 2D materials, such as graphene, graphene oxide, hexagonal boron nitride, transition metal dichalcogenides, transition metal oxides, 2D perovskite, and black phosphorous, have been explored to achieve many functionalities of biological synapses due to their unique electronic, optoelectronic, electrochemical, and mechanical properties that are lacking in bulk materials. This review features the current development in the state-of-the-art artificial synaptic electronic devices based on 2D materials. The structures of these devices are first discussed according to their number of terminals (two-, three-, four-, and multi-terminals) and geometric layouts (vertical, horizontal, hybrid). Since different 2D materials have been utilized to fabricate these devices, their underlying physical mechanisms and principles are further discussed, and their artificial neuron synaptic functionalities and performances are analyzed and contrasted. Finally, a summary of the current research status and major achievements is concluded, and the outlooks and perspectives for this emerging and vibrant field and the potential applications of these devices for neuromorphic computing are presented.

AbstractNowadays, advanced aluminum matrix composites (AAMCs) are known as the dominant emerging materials employable in different industrial sectors. The reason behind the use of AAMCs originates from the urgent need for weight reduction as well as high efficiency in the automotive, agriculture, aerospace, mining, and electronic applications. This paper deeply reviewed several recent progresses of AMMCs in architecture designs and advanced manufacturing technologies to break through the limitations and promote the overall performance of the AMMCs. The discussion offers a deep understanding of specific issues mainly related to the well-known strength-ductility conflict. As a matter of fact, the dependency of the properties of materials on the microstructure (size dependent) and their components (e.g. high-performance nano reinforcements) could simultaneously provide high efficiency and a series of size-dependent effects. Designing tailored architectures (e.g. harmonic structure, hierarchical structure, multimodal distributions, layered architectures, network structure, gradient structures, heterogeneous laminated structures), known as most promising, provides new routes for attaining high-efficiency and mechanical properties optimization. It is worth noting that special distribution concept in architecture design is to be used carefully, as a homogenous distribution suggests all the reinforcements are distributed in the undifferentiated locations while inhomogeneous distribution stands for the selective distributed locations following certain regularities. These novel architecture designs could be achieved through applying the advanced manufacturing technologies (e.g. severe plastic deformation, additive manufacturing, and powder metallurgy-based technologies) with the potential to be used on a large scale by employing innovative techniques for the preparation, processing, and producing of AAMCs. This paper aims to correlate the most important factor namely size dependency (in the opinion of the authors) to mechanical properties in architectural designs in AMMCs, and should serve as a guide for research on AMMCs, to design target performance levels for applications to numerous and different industrial applications.

AbstractThe selectivity of a sensor is the ability to discriminate the target from the interference molecules and display a target-specific sensor response. It is a critical trait for gas sensors that are used in real-time air pollution control, hazardous materials detection, food quality inspection and personal health monitoring. Attaining high target selectivity ensures that sensors will exhibit accurate information about the existence and concentration of a target gas, which is essential for reliable sensor response. To obtain target selectivity, it is critical to determine the optimum modification technique and receptor materials as well as to understand how each method works and how it could be designed for a specific target. For this purpose, in this review we present the working principles of the three leading chemical modification methods including catalyst decoration, composite formation, and surface functionalization, as well as the selection criteria of various recognition materials. Throughout the report, we offer a rich apprehension of these techniques by providing mechanistic insights, application areas, advantages, disadvantages, and plausible applications for the invention of the target-specific gas sensors.

AbstractThe applications of carbon allotrope-reinforced Ti-based composites have witnessed enormous expansion in recent times owing to their light weight and competitive properties. However, a consistent controversy still exists on the process of in-situ TiC formation (during powder preparation, reinforcement dispersion and synthesis), its site within the composite and particularly the role it plays on the properties of the bulk composite. Although some authors have opined that the presence of TiC in the bulk composite enhances its overall properties, others hold a contrary opinion. Hence, this current study is aimed at reviewing the positions of the previous studies on this seemingly controversial subject up to date; with a view to broadening the available knowledge base on this crucial area of interest.

AbstractThe waste-to-wealth practice has evolved into the circular economy concept, in which every by-product is converted into a usable product, enabling the concept of zero-waste. As a result, research on converting wastes, particularly bio and agricultural wastes, into usable products is prioritized. Activated carbons are one of these products, which are derived through a variety of physical and chemical processes from agricultural and biowaste. These activated carbons have applications in various fields, including energy storage, catalysis, and water purification. However, the quality of this activated carbon is dependent on the bioresource's structure and chemical composition. As a result, many sources to produce activated carbon, including stems, wood, leaves, root, bark, fiber, flower, and seeds, have been identified and are being explored for their potential use as an electrode material for supercapacitors. Out of these sources, fiber from different bioresources shows improved performance as supercapacitor electrodes due to their higher cellulose and lignin contents. In this study, we systematically review various sources of activated carbon and their performance as supercapacitor electrodes. The electrochemical characterization methodologies used to characterize this fiber-based activated carbon are examined critically, and factors influencing its improved/poor performance are collated. Additionally, the most performing fiber-based sources of activated carbon for supercapacitor electrodes are identified, along with a future perspective.

AbstractNucleation is of great interest to materials scientists, physicists, and chemists studying fundamental scientific aspects of this phenomenon, as well as engineers working to develop glass-ceramics. Fundamental research in this field is indispensable for understanding the nature of the glassy state and the development of new products such as nanostructured glass-ceramics. However, experimental results on nucleation in inorganic oxide (mostly silicate) glasses and their theoretical interpretation in the framework of various mathematical models are still the subjects of significant debate. Difficulties during the early studies of nucleation partly arose from restrictions in experimental tools employed to study micron-sized or larger crystals, which cannot be directly applied to study nuclei of critical sizes or medium-range order in the parent glass, which are on a length scale of a few nanometers. Advanced tools, e.g., transmission electron microscopy, anomalous small-angle X-ray scattering, small-angle neutron scattering, X-ray absorption spectroscopy, Raman spectroscopy, nuclear magnetic resonance, advanced optical spectroscopy, together with computational modelings provide critical insight into the complicated and rapidly changing environments in which nucleation happens. The new findings from these sophisticated techniques and modeling approaches helps us evaluate hypotheses, modify available models, and develop new nanostructured glass-ceramics. Therefore, this paper reviews state-of-the-art solutions in instrumental and modeling analyses to measure and ultimately control nucleation. We propose adopting these tools and future impactful research in this exciting and challenging open field.

AbstractBoron Nitride Nanotubes (BNNTs), a 1D nanomaterial with extraordinary mechanical properties, are structurally like carbon nanotubes. BNNTs possess superior thermal stability of ∼900 °C, higher resistance to oxidation at elevated temperatures, and enhanced neutron shielding capacity. These benefits open a wider processing window for manufacturing BNNT-reinforced metal matrix composites (MMC) and hold promise for several structural applications, including radiation shielding. This critique presents the current status, challenges, and future scientific possibilities of BNNT-reinforced MMC. Particular emphasis is laid on the progress made in this area regarding the synthesis, manufacturing, and characterization of BNNT-MMCs to date. The challenges associated with various processing techniques, including additive manufacturing (AM), are discussed in the fabrication of BNNT-MMCs. The experimental mechanics and structure-property relationship modeling are examined in detail to establish the utilization of BNNT-reinforced MMCs. Additionally, prospective research areas with a huge untapped potential for BNNT-MMCs are suggested. The scientific framework behind these methods’ chronological development is analyzed, and a pathway for subsequent advancement is projected. By providing a comprehensive overview, this critique aims to facilitate further progress in BNNT-reinforced MMCs.

AbstractThe poor mechanical and tribological properties limit the higher requirements of aluminum alloys in engineering and industrial applications, which leads to the rapid development of aluminum matrix composites (AMCs). Particulate reinforced AMCs have attracted extensive attention in automobile, electronics and military industries due to their low density, high strength, and excellent wear resistance. However, the interfacial reaction between reinforcements and the Al matrix tends to occur in conventional preparation processes owing to the higher reaction temperatures. The spark plasma sintering (SPS) technique is considered to be an efficient method for the fabrication of metal matrix composites, which can achieve rapid sintering, lower sintering temperatures, and higher densities than conventional fabrication processes. In addition, SPS can produce AMCs with excellent non-porous microstructure, fine grain size, and a strong bonding interface between reinforcement and Al matrix. Therefore, the interfacial reaction is effectively controlled and the structural integrity is maintained, resulting in enhanced strength and ductility. Based on the advantages of particulate reinforced AMCs and the SPS technique, the particulate reinforced AMCs fabricated by SPS have been extensively studied in recent decades, but have not been systematically evaluated. Therefore, this paper reviews the state-of-the-art particulate reinforced AMCs fabricated by SPS, focusing on the microstructure characterization, strengthening mechanisms, and mechanical and physical properties. Furthermore, the future research priorities and challenges of the high-performance particulate reinforced AMCs fabricated by SPS are also prospected.

AbstractMetal halide perovskite photocatalysts (MHPPs) exhibit unique electronic and optical properties, making them attractive for diverse photocatalytic applications. Their exceptional properties can be tuned by adjusting the halide ion or cation size. MHPPs have shown promise in solar energy conversion, water splitting, and air purification. However, synthesis and stability challenges hinder practical applications. This comprehensive review presents the properties, applications, and challenges of MHPPs, proposing future research directions. Although dogged by many issues, MHPPs demonstrate remarkable charge separation capabilities, rendering them advantageous in many photocatalytic applications. They offer flexibility through the manipulation of elements, crystal structures, surface chemistry, and morphologies. The review also discusses Type-II, Z-scheme heterojunction, as well as the emerging S-scheme heterojunction, which is a recent, improved alternative. Consolidating current knowledge, this review serves as a valuable resource, providing insights into MHPPs’ potential and guiding further advancements. MHPPs have significant applications in water splitting, air purification, pollutant degradation, and energy conversion. Their unique properties and versatility enable tailored optimization. This overview is a crucial reference for researchers, engineers, scholars, and students, inspiring innovative and sustainable photocatalytic solutions.