Showing papers in "Materials Science & Engineering R-reports in 2019"

Zinc-ion batteries: Materials, mechanisms, and applications

Abstract: The increasing global demand for energy and the potential environmental impact of increased energy consumption require greener, safer, and more cost-efficient energy storage technologies. Lithium-ion batteries (LIBs) have been successful in meeting much of today’s energy storage demand; however, lithium (Li) is a costly metal, is unevenly distributed around the world, and poses serious safety and environmental concerns. Alternate battery technologies should thus be developed. Zinc-ion batteries (ZIBs) have recently attracted attention due to their safety, environmental friendliness, and lower cost, compared to LIBs. They use aqueous electrolytes, which give them an advantage over multivalent ion batteries (e.g., Mg2+, Ca2+, Al3+) that require more complex electrolytes. However, as with every new technology, many fundamental and practical challenges must be overcome for ZIBs to become commercial products. In this manuscript, we present a timely review and offer perspectives on recent developments and future directions in ZIBs research. The review is divided into five parts: (i) cathode material development, including an understanding of their reaction mechanism; (ii) electrolyte development and characterization; (iii) zinc anode, current collector, and separator design; (iv) applications; and (v) outlook and perspective.

Progress in high-strain perovskite piezoelectric ceramics

Abstract: High strain piezoelectric ceramics are the state-of-the-art materials for high precision, positioning devices. A comprehensive review of the latest developments of the various types of perovskite piezoelectric ceramic systems is presented herein, with special attention given to three promising families of lead-free perovskite ferroelectrics: the barium titanate, alkaline niobate and bismuth perovskites. Included in this review are details of phase transition behavior, strain enhancement approaches, material reliabilities as well as the status of some promising applications. This current review describes both compositional and structural engineering approaches that are intended to achieve enhanced strain properties in perovskite piezoelectric ceramics. The factors that affect the strain behavior of high-strain perovskite piezoelectric ceramics are addressed. The reliability characteristics of these high-strain ferroelectrics as well as the recent approaches to the long-term electrical, thermal and time-stability enhancement are summarized. Several promising applications of high-strain perovskite materials are introduced, which take advantages of their characteristics; examples include high-energy storage, pyroelectric and electro-caloric effect and luminescent properties.

Thermoelectrics: From history, a window to the future

Abstract: Thermoelectricity offers a sustainable path to recover and convert waste heat into readily available electric energy, and has been studied for more than two centuries. From the controversy between Galvani and Volta on the Animal Electricity, dating back to the end of the XVIII century and anticipating Seebeck’s observations, the understanding of the physical mechanisms evolved along with the development of the technology. In the XIX century Orsted clarified some of the earliest observations of the thermoelectric phenomenon and proposed the first thermoelectric pile, while it was only after the studies on thermodynamics by Thomson, and Rayleigh’s suggestion to exploit the Seebeck effect for power generation, that a diverse set of thermoelectric generators was developed. From such pioneering endeavors, technology evolved from massive, and sometimes unreliable, thermopiles to very reliable devices for sophisticated niche applications in the XX century, when Radioisotope Thermoelectric Generators for space missions and nuclear batteries for cardiac pacemakers were introduced. While some of the materials adopted to realize the first thermoelectric generators are still investigated nowadays, novel concepts and improved understanding of materials growth, processing, and characterization developed during the last 30 years have provided new avenues for the enhancement of the thermoelectric conversion efficiency, for example through nanostructuration, and favored the development of new classes of thermoelectric materials. With increasing demand for sustainable energy conversion technologies, the latter aspect has become crucial for developing thermoelectrics based on abundant and non-toxic materials, which can be processed at economically viable scales, tailored for different ranges of temperature. This includes high temperature applications where a substantial amount of waste energy can be retrieved, as well as room temperature applications where small and local temperature differences offer the possibility of energy scavenging, as in micro harvesters meant for distributed electronics such as sensor networks. While large scale applications have yet to make it to the market, the richness of available and emerging thermoelectric technologies presents a scenario where thermoelectrics is poised to contribute to a future of sustainable future energy harvesting and management. This work reviews the broad field of thermoelectrics. Progress in thermoelectrics and milestones that led to the current state-of-the-art are presented by adopting an historical footprint. The review begins with an historical excursus on the major steps in the history of thermoelectrics, from the very early discovery to present technology. Then, the most promising thermoelectric material classes are discussed one by one in dedicated sections and subsections, carefully highlighting the technological solutions on materials growth that have represented a turning point in the research on thermoelectrics. Finally, perspectives and the future of the technology are discussed in the framework of sustainability and environmental compatibility. An appendix on the theory of thermoelectric transport in the solid state reviews the transport theory in complex crystal structures and nanostructured materials.

Composite solid electrolytes for all-solid-state lithium batteries

Abstract: Compared to currently used liquid-electrolyte lithium batteries, all-solid-state lithium batteries are safer and possess longer cycle life and have less requirements on packaging and state-of-charge monitoring circuits. Among various types of solid electrolytes, composite solid electrolytes, which are composed of active or passive inorganic fillers and polymer matrices, have been considered as promising electrolyte candidates for all-solid-state lithium batteries. Incorporation of inorganic fillers into the polymer matrices has been demonstrated as an effective method to achieve high ionic conductivity and excellent interfacial contact with the electrodes. In this review article, we first summarize the historical development of composite solid electrolytes. Contribution of both inert inorganic fillers and active Li-ion conductors to the ionic conductivity, electrochemical stability, and mechanical properties of the composite solid electrolytes are elaborated. Possible mechanisms of conductivity enhancement by inorganic fillers are broadly discussed. Examples of different composite solid electrolyte design concepts, such as inorganic nanoparticle/polymer, inorganic nanofiber/polymer, and other inorganic/polymer composite solid electrolytes, are introduced and their advantages and disadvantages are discussed. Inorganic filler/polymer composite solid electrolytes studied for use in various Li battery systems including Li-ion, Li-sulfur, and Li-metal batteries are evaluated. Promising designs of composite solid electrolytes and cathode materials used in all-solid-state Li batteries are also introduced. Finally, future perspectives on current requirements of composite solid electrolyte technologies are highlighted.

Low dimensional metal halide perovskites and hybrids

Abstract: Organic-inorganic metal halide hybrids are an important class of crystalline materials with exceptional structural and property tunability. Recently metal halide perovskites with ABX3 structure have been extensively investigated as new generation semiconductors for various optoelectronic devices, including photovoltaic cells, light emitting diodes, photodetectors, and lasers, for their exceptional optical and electronic properties. By controlling the morphological dimensionality, low dimensional metal halide perovskites, including 2D perovskite nanoplatelets, 1D perovskite nanowires, and 0D perovskite quantum dots, have been developed to exhibit distinct properties from their bulk counterparts, due to quantum size effects. Besides ABX3 perovskites, organic-inorganic metal halide hybrids, containing the same fundamental building block of metal halide octahedra (BX6), can also be assembled to possess other types of crystallographic structures. Using appropriate organic and inorganic components, low dimensional organic-inorganic metal halide hybrids with 2D, quasi-2D, corrugated-2D, 1D, and 0D structures at the molecular level have been developed and studied. Due to the strong quantum confinement and site isolation, these low dimensional metal halide hybrids at the molecular level exhibit remarkable and unique properties that are significantly different from those of ABX3 perovskites. In light of the rapid development of low dimensional metal halide perovskites and hybrids, it is indeed timely to review the recent progress in these areas. Also, there is a need to clarify the difference between morphological low dimensional metal halide perovskites and molecular level low dimensional metal halide hybrids, as currently the terminologies of low dimensional perovskites are not appropriately used in many cases. In this review article, we discuss the synthesis, characterization, application, and computational studies of low dimensional metal halide perovskites and hybrids.

Transformable soft liquid metal micro/nanomaterials

Abstract: Liquid metal is a liquid-state metallic material with a low melting point at or around room temperature. Owing to their high thermal or electrical conductivity, low viscosity and superior fluidity, liquid metals are emerging as a highly desirable candidate in a broad array of areas, such as flexible electronics, thermal management, soft machines and biomedical materials. However, bulk liquid metal is not readily utilized because of its high surface tension and large dimension-induced dexterity limitations. To address this challenge, liquid metals have been innovated with micro/nanotechnology to endow the bulk liquid metals with remarkably diversified performances. These new functional materials not only possess the softness of classical liquid metals but also have many outstanding properties, including great thermal conductivity, self-healing ability and stimuli-responsive deformability. Compared to rigid inorganic micro/nanoscale materials, soft liquid metal micro/nanoparticles demonstrate their unconventionally superior flexibility, compliance and tunability. This review is dedicated to summarize the state-of-the-art progress in fabricating methods, highlight unique features, and discuss applications of liquid metal micro/nanoparticles in biomedicine, soft electronics, thermal management and soft motors. Future outlooks, including both opportunities and scientific challenges of liquid metal micro/nanoparticles, are also presented here.

Transcutaneous plasma stress: From soft-matter models to living tissues

Abstract: This review critically examines the multiple effects of low-temperature, atmospheric pressure plasma stress on the “on top” (collectively termed cutaneous) materials, to reveal the effects of this stress on the materials that lay underneath, collectively termed sub-cutaneous materials. Plasma generated reactive agents presents stress and trigger relayed effects within the cutaneous layers, leading to transcutaneous penetration of the plasma-induced stress into sub-cutaneous materials. Among the many possibilities from the areas spanning soft matter and life sciences, the effects of reactive plasma agents help improve the outcomes of cutaneous wound healing, reduce skin cancer tumors, and eradicate biofilms on biomedical implant materials. Cutaneous materials include animal skin or laboratory models using soft matter such as liquid media, gels, and cell cultures. Here we examine permeable interfaces of cutaneous materials and sub-cutaneous living tissues subjected to low-temperature atmospheric-pressure plasmas as a multi-modal reactive system producing stress on materials through multiple reactive agents including radicals, excited atoms and molecules, ions, heat, UV, and electric fields. Interaction of plasma-radiative stress with cutaneous materials leads to the unexpected, yet effective transmission of the reactive agents through to sub-cutaneous tissues, potentially systemically through the body. We examine the penetration of plasma-generated stress through the skin or skin models leading to the many interesting effects. In a broader context, this knowledge is relevant to several fields of materials science and engineering from soft matter to biomaterials and may help advance diverse applications ranging from non-thermal processing of soft and flexible materials for flexible electronics and soft robotics to direct skin disease treatment in vivo.

Recent advances on kinetic analysis of solder joint reactions in 3D IC packaging technology

Abstract: We review five solder joint reactions in 3D IC packaging technology which are of wide interest: (1) Scallop-type growth of Cu6Sn5 in solid-liquid interdiffusion reaction, (2) Whisker-type growth of Sn crystals at room temperature, (3) Layer-type intermetallic compound (IMC) growth in solid state aging, (4) Porous-type growth of Cu3Sn in μ-bumps, and (5) Pillar-type growth of Cu/Sn IMC down to 1 μm in diameter. The first two have been well covered in books and reviews on solder joint technology, so only certain specific comments will be given here. On the other three, the layer-type IMC growth has been a long standing kinetic problem due to the extremely small concentration gradient across a stoichiometric IMC, but it has been resolved now, following Wagner’s approach. The porous-type Cu3Sn was found in 2014. Kinetically, it is a complete cellular precipitation, containing a set of lamellar pores. It is rare because up to now all cellular precipitations are incomplete. The pillar-type Cu/Sn reactions down to 1 μm in diameter were carried out in 2016. Owing to a large surface/volume ratio, the reaction is controlled by surface diffusion, accompanied by interstitial diffusion of Cu in Sn.

Mesoporous silica/organosilica nanoparticles: Synthesis, biological effect and biomedical application

Abstract: The interdisciplinary integration among material science, nanotechnology and biology has been promoting the emergences of a large number of feasible nanoplatforms for diverse biomedical applications. Thanks to the unique mesoporous structure, large specific surface area, abundant surface chemistry and tunable framework composition, mesoporous silica nanoparticles (MSNs) and mesoporous organosilica nanoparticles (MONs) have been extensively applied for diverse therapeutic, or diagnostic applications. The past two decades have witnessed the blooming growth of researches on the elaborate design and fabrication of multifunctional MSNs/MONs-based nanosystems, which have greatly pushed forward the development of next-generation theranostic biomaterials. These mesoporous silica-based nanomaterials feature varied structural, compositional and morphological characteristics, leading to the great diversity in their downstream physicochemical properties and theranostic performances, which further catalyzes the emergence of advanced therapeutic strategies for optimized treatment efficacies and mitigated side effects. In this review, we will comprehensively elucidate very-recent advances on the construction of MSNs/MONs-based theranostic nanoplatforms for various therapeutic and diagnostic applications, and discuss the underlying material chemistry of these exquisite nanosystems that confers varied theranostic functionalities. Especially, the interdependent relationship among the synthesis, biological effects and biomedical applications of MSNs and MONs will be discussed in depth, and their further clinical-translation potential/challenge will be clarified and outlooked. It is highly expected that we will witness a second leap-forward development of the biomedical applications of MSNs and MONs in the next one or two decades, especially for the further clinical translation.

Solution-processed inorganic p-channel transistors: Recent advances and perspectives

Abstract: For decades, inorganic n-type metal-oxide semiconductors have attracted great interest across a wide range of applications due to their excellent electrical property, low cost, high optical transparency, and good ambient stability. The next attention has focused on the development of high-performance p-type semiconductors with comparable opto/electric properties to n-type counterparts. This paper provides a comprehensive overview of recent progress in solution-processed inorganic p-type semiconductors that can be applied as channel layers in thin-film transistors and complementary metal-oxide semiconductor-based integrated circuits. We first introduce conventional p-type oxide semiconductors and review their achievements on related devices. Then, we pay a specific focus on emerging (pseudo)halide materials for realization of transparent, low-temperature and high-performance printable electronics and circuits.

Design and synthesis of high performance π-conjugated materials through antiaromaticity and quinoid strategy for organic field-effect transistors

Abstract: Organic field-effect transistors (OFETs) have received significant interest due to potential applications from low-cost active circuit to wearable health care devices. Organic semiconductors as one of the key components in OFETs have drawn great attentions during last decades. Among them, antiaromatic and quinoidal materials have become the most intensively studied semiconductors. Therefore, this review describes the chemical structures and efficiency characteristics of π-conjugated materials through antiaromaticity and quinoid strategy for OFETs. In addition, rational designs and synthetic methods for these materials will be summarized, and a practical guideline for accelerating the development of high-performance semiconducting materials and devices will be provided.

Silicon nanocrystals: unfading silicon materials for optoelectronics

Abstract: As the most fundamental material for microelectronics, silicon (Si) has bourgeoned in the past more than half a century. However, given the indirect bandgap of Si, the use of Si in optoelectronics is relatively limited due to its mediocre optical absorption and rather poor optical emission. During many years of efforts for extending the use of Si in optoelectronics Si nanocrystals (NCs) that are one type of the most important Si nanostructures have attracted significant attention owing to their remarkable electronic and optical properties. Si NCs are actually crystalline Si nanoparticles, which may be called Si quantum dots if their size is smaller than ∼10 nm. With the manipulation of the size, surface and doping of Si NCs great tunability for the light emission from Si NCs with the quantum yield of more than 60% has been realized. Based on the efficient light emission from Si NCs high-performance Si-NC light-emitting devices have been demonstrated. In the meantime, the efficient light emission from Si NCs has also been utilized for synaptic simulations in neuromorphic computing and down-shifting in photovoltaics. Broadband optical absorption ranging from the ultraviolet to mid-infrared has been recently obtained for Si NCs mainly by taking advantage of doping. This has enabled the use of Si NCs in novel solar cells, photodetectors and optoelectronic synaptic devices. The continuous improvement of the electronic and optical properties of Si NCs has made Si NCs unfading Si materials for optoelectronics, contributing to the development of Si-based optoelectronic integration.

The quest for blood-compatible materials: Recent advances and future technologies

Abstract: The development of blood-compatible materials represents a grand challenge in biomaterials science. Blood is a complex fluid containing many types of living cells, functional proteins, and other signaling molecules, which work together to protect the circulatory system from injury, pathogens, and foreign materials. Blood-contacting biomaterials include the components of cardiovascular implants (such as stents, shunts, and valves) and extracorporeal circuit components (such as tubing, membranes, and pumps). The engineered materials used in these applications are distinctly unlike the biological tissues that make up the cardiovascular system in their physical, chemical, and biological properties, leading to undesirable—and sometimes catastrophic—blood-material interactions. The pursuit of blood-compatible materials challenges nearly every aspect of materials design, including composition, mechanical properties, structure across multiple length scales, tribology, surface physical-chemistry, and biochemical functionalization. Materials have been designed to bind or reject specific blood proteins, interact favorably with specific cell types, or to interact with particular biochemical pathways in blood. This review summarizes the important blood-material interactions that regulate blood compatibility, organizes recent developments in this field from a materials perspective, and recommends areas for future research.

GaN in different dimensionalities: Properties, synthesis, and applications

Abstract: Wurtzite GaN materials underpin many aspects of optoelectronic applications due to the special tetrahedral-coordinated structure. Compared with three dimensional (3D) GaN, low dimensional GaN provides structural and electronic changes, such as different geometrical configuration, surface trapped states and quantum confinement effect, which impose dramatic effects on the properties and even the ultimate applications. To construct desirable devices and expand the scope of applications for GaN, it necessitates an in-depth understanding of the dimensionality-dependent property. In this review, we firstly review the structure and properties of GaN in different dimensionalities. Successively, strategies for realizing the synthesis of GaN with various dimensionalities are generalized. Afterwards, we examine how their structure and properties are utilized in the significant applications involving microelectronic devices and energy conversion fields. Finally, we conclude by outlining a few research directions of GaN semiconductors that might be worthwhile for exploration in the future.

Sp2-carbon dominant carbonaceous materials for energy conversion and storage

Abstract: Sp2-carbon (Sp2-C) based carbonaceous materials, featured by its inherent unit structural characteristics of chemical tunability, conjugated network, as well as the topological structure of the carbon-carbon double bond, have been considered as a dazzling star in both scientific research and industrial applications. Compared with defect-free Sp2-carbon bonded carbon materials, Sp2-C dominant carbonaceous materials with abundant functionalities and tunable pore structures are more attractive as a candidate for energy storage and conversion systems due to their synergistic effects of the conjugated Sp2 carbon network and the introduced extra functions induced by defects, heteroatoms, many other structure characters, thereby resulting in the combination of the firm and flexible skeleton network, improved electron/ion transport, as well as the rich and exposed active sites. In this Review, we try to give a comprehensive overview of the latest development of Sp2-C dominant carbonaceous materials for energy conversion and storage. First, we provide a brief summary of the structural features of Sp2-C dominant carbonaceous materials. Second, the controllable synthesis of these Sp2-C dominant carbonaceous materials are extensively discussed according to two representative approaches: the “bottom-up” approach via monomer-controlled synthesis, biopolymer transformation, and chemical vapor deposition, and “top-down” approach involving the chemical exfoliation, electrochemical exfoliation and unzipping. Particularly, after a thorough discussion of their applications as electrode materials for energy storage and conversion applications, the mechanism and the targeted structure-property relationships of the Sp2-C dominant carbon materials for specific energy storage and conversion are highlighted. Finally, we draw conclusions on the rational construction and engineering of the Sp2-C dominant carbon materials for energy-related systems and their opportunities in the future.

The path towards functional nanoparticle-DNA origami composites

Abstract: Nanoparticles (NPs) hold tremendous promise for diverse applications in fields such as imaging, sensing, nanorobotics, and for optical and electronic materials. These applications often require precisely controlled interactions between multiple NPs or between NPs and other components. Hence, the organization of NPs into composite materials has been an active area of research. DNA origami nanotechnology offers a promising path forward with unparalleled control over complex nanoscale geometry and functionalization, programmed dynamic and mechanical properties, stimulus response to local or externally applied triggers, and capability of assembly into higher-order 1D, 2D, or 3D materials. Furthermore, DNA origami self-assembly is rapid and scalable, overcoming limitations of top-down NP organization methods. In this review, we outline the challenges, recent advances, and opportunities for NP-DNA origami composites. We go into depth on aspects of DNA origami that enhance materials function, such as dynamic actuation, and we discuss practical aspects involved in making NP-DNA composites. Whereas the vast majority of research in NP-DNA origami composite synthesis focuses on gold NPs, these methods can be generalized to other DNA-coated NPs, and therefore more broadly establish a path towards functional NP-DNA origami composites. We envision this review will serve as a guide to materials science and engineering researchers to pursue new materials based on NP-DNA composites.