Using epitaxy and the misfit strain imposed by an underlying substrate, it is possible to elastically strain oxide thin films to percent levels—far beyond where they would crack in bulk. Under such strains, the properties of oxides can be dramatically altered. In this article, we review the use of elastic strain to enhance ferroics, materials containing domains that can be moved through the application of an electric field (ferroelectric), a magnetic field (ferromagnetic), or stress (ferroelastic). We describe examples of transmuting oxides that are neither ferroelectric nor ferromagnetic in their unstrained state into ferroelectrics, ferromagnets, or materials that are both at the same time (multiferroics). Elastic strain can also be used to enhance the properties of known ferroic oxides or to create new tunable microwave dielectrics with performance that rivals that of existing materials. Results show that for thin films of ferroic oxides, elastic strain is a viable alternative to the traditional method of chemical substitution to lower the energy of a desired ground state relative to that of competing ground states to create materials with superior properties.

The commercialization of lithium-ion batteries has intimately changed our lives and enabled portable electronic devices, which has revolutionized communications, entertainment, medicine, and more. After three decades of commercial development, researchers around the world are now pursuing major advances that would allow this technology to power the next generation of light-duty, electric, and hybrid-electric vehicles. If this goal is to be met, concerted advances in safety and cost, as well as cycle-life and energy densities, must be realized through advances in the properties of the highly correlated, but separate, components of lithium-ion energy-storage systems.

The ability of cancer-targeted nanoparticles (NPs) to reach their site of action and evoke a desired biological response after intravenous injection is critical to achieve clinically significant in vivo efficacy. Throughout their journey in the body, NPs must successfully traverse biological environments such as blood circulation and tumor microenvironments. The interactions that occur at the interface between NPs and biological components are complex, requiring a thorough understanding of the “nano-bio” interactions to design NPs with maximal therapeutic indices. In this article, we review the challenges presented by the multiscale, important biocompartments that NPs face, describe the crucial nano-bio interactions present at each stage, and discuss potential strategies to overcome those challenges. This review suggests design considerations for NPs to optimally modulate their physicochemical properties to achieve desired biological responses, which are expected to aid chemists, engineers, and clinical scientists to design and develop highly effective delivery platforms for cancer therapy.

The class of topological insulator materials is one of the frontier topics of condensed matter physics. The great success of this field is due to the conceptual breakthroughs in theories for topological electronic states and is strongly motivated by the rich variety of material realizations, thus making the theories testable, the experiments operable, and the applications possible. First-principles calculations have demonstrated unprecedented predictive power for material selection and design. In this article, we review recent progress in this field with a focus on the role of first-principles calculations. In particular, we introduce the Wilson loop method for the determination of topological invariants and discuss the band inversion mechanism for the selection of topological materials. Recent progress in quantum anomalous Hall insulators, large-gap quantum spin Hall insulators, and correlated topological insulators is also covered.

A growing trend in tissue engineering and regenerative medicine is to view cells, matrices, and whole tissues from a materials science perspective. The rationale behind this novel approach to considering biological problems is that the material properties at these different length scales both define their physical stability and also provide instructive cues. These cues can maintain homeostasis in healthy tissues or drive dynamic events during development, wound healing, and disease progression. However, one must map and characterize the physical properties of the natural extracellular matrix environment found in vivo in order to guide the design of synthetic or naturally derived materials to control cell function. This article reviews the study of natural tissues as materials, and sheds light on the use of this information to develop novel synthetic materials that guide cell function.

Diamond has been attracting the attention of many researchers because of its potential for new applications such as in quantum devices and power electronics. These applications are enabled by the progress made in improving the quality of undoped, boron-doped, and phosphorus-doped diamond films grown by chemical vapor deposition techniques. Recent progress in diamond film growth and heterostructures of diamond and other compound semiconductors to realize these electronics applications are reported.

The solid–water interface is ubiquitous in natural and synthetic systems as the primary site for chemical reactions under near-ambient conditions. Examples include the interactions of contaminants with mineral–water interfaces in natural environments, electrochemical reactions at the electrode-electrolyte interface relevant to energy storage (e.g., ion adsorption/electrical double layer formation, ion insertion), and oxidation of structural materials (e.g., rust). Yet many of these phenomena remain largely mysterious at a mechanistic level. The x-ray reflectivity technique, using highly penetrating hard x-rays, directly probes the solid–water interfaces through in situ studies. This approach has provided new insights into the molecular-scale structures and processes that occur at these “wet” interfaces. In this article, we review recent advances in the understanding of these systems, focusing specifically on the organization of interfacial “hydration layers” and the important role of adsorbed ions at charged solid–liquid interfaces.

Owing to the development of new ion source technology, users of focused ion beams (FIBs) have access to superior performance when compared with the industry standard Ga+ liquid metal ion source. FIBs equipped with an inductively coupled plasma (ICP) ion source are better able to carry out large volume milling applications by providing up to 2 µA of Xe+ ions focused into a sub-5 µm spot. However, ICP FIBs are presently limited to 25 nm imaging resolution at 1 pA.The gas field ionization source (GFIS) relies upon an ion source that is the size of a single atom and correspondingly gains high brightness through its very small source size. The high brightness allows the GFIS to produce a very small focused probe size (<0.35 nm for helium), but with comparatively small beam currents (less than 2 pA). The Cs+ low temperature ion source, still being developed, has a projected sub-nm focal spot size at 1 pA, a maximum current of several nanoamps, and has the potential to offer integrated secondary ion mass spectrometry capabilities.

We review the first 10 years of research on organic spin-valve devices in the field of organic spintronics. The device figure of merit, magnetoresistance, is governed by the hyperfine interaction of the organic interlayer and the ability of the ferromagnetic electrodes to inject spin-polarized carriers. By choosing a deuterated π-conjugated polymer with a relatively long spin diffusion length as the organic interlayer and using a thin LiF buffer layer to raise the Fermi level of the cathode, a bipolar spin-valve device could be obtained in which the electroluminescence emission intensity is controlled by an external magnetic field. We show that the underlying physics of this spin-organic light-emitting diode is very different from that of a unipolar organic spin valve because of the magnetic properties of the spin-polarized bipolar space charge limited current in the device.

Solid-oxide fuel cells (SOFCs) are an energy conversion technology with unique potential to have the highest energy conversion efficiency with the least environmental impact, as well as broad fuel flexibility from renewable to conventional fuels. Lowering the SOFC operating temperature will further lower system and operational costs, increase long-term durability, and allow more rapid start-up, providing feasibility for load following and transportation applications. Unfortunately, at reduced temperatures, the thermally activated nature of ionic conduction and electrochemical reactions increase polarization resistances, thus decreasing cell and system performance. However, lower operating temperatures also create the opportunity to employ nanostructured materials with higher surface area-to-volume ratios and greater interphase and interfacial regions, which can greatly enhance electrochemical performance. Here, we review recent progress in the development of various nanostructured electrodes and electrolytes and discuss their effects on the enhancement of the electrocatalytic activity of oxygen reduction and fuel oxidation, as well as oxygen-ion conduction, in order to achieve high-performance low-temperature SOFCs.

Conventional silicon transistor scaling is fast approaching its limits. An extension of the logic device roadmap to further improve future performance increases of integrated circuits is required to propel the electronics industry. Attention is turning to III–V compound semiconductors that are well positioned to replace silicon as the base material in logic switching devices. Their outstanding electron transport properties and the possibility to tune heterostructures provide tremendous opportunities to engineer novel nanometer-scale logic transistors. The scaling constraints require an evolution from planar III–V metal oxide semiconductor field-effect transistors (MOSFETs) toward transistor channels with a three-dimensional structure, such as nanowire FETs, to achieve future performance needs for complementary metal oxide semiconductor (CMOS) nodes beyond 10 nm. Further device innovations are required to increase energy efficiency. This could be addressed by tunnel FETs (TFETs), which rely on interband tunneling and thus require advanced III–V heterostructures for optimized performance. This article describes the challenges and recent progress toward the development of III–V MOSFETs and heterostructure TFETs—from planar to nanowire devices—integrated on a silicon platform to make these technologies suitable for future CMOS applications.

Fast and significant progress has been achieved in the development of new biomarkers in recent years providing promising approaches for the reliable detection of diseases at an early stage. Yet, the disadvantages of commonly used markers, including photobleaching, autofluorescence, phototoxicity, and scattering, when ultraviolet or visible light is used for excitation, need to be overcome. Lanthanide-doped host materials are well known for their excellent optical properties, such as their ability to (up)convert near-infrared excitation to higher energies spanning the ultraviolet, visible, and near-infrared regions or to undergo strong near-infrared luminescence following near-infrared excitation. Their application as biomarkers may overcome the aforementioned drawbacks of conventional dyes. Thus, lanthanide-based nanostructures are highly promising candidates for cellular and small animal imaging, while the assessment of their cytotoxicity remains a crucial issue. Recent developments in the field of upconversion and near-infrared bioimaging focusing on some of the latest results obtained in in vitro and in vivo studies assessing the toxicity of lanthanide-based nanophosphors are highlighted in this review.

Research in nanotechnology-based molecular imaging and targeted drug delivery has resulted in a noticeable progress in cancer theranosis, the simultaneous application of cancer therapy and diagnosis. Theranostic nanoparticles (NPs) have been developed using diverse base materials, and organic materials are of major interest in the synthesis and preparation of these NPs. A variety of organic NPs have their own advantages, depending on the physiochemical and biological properties of the base materials. This article reviews recent developments in organic NPs, which are grouped into four major kinds of base materials: lipids, polysaccharides, peptides/proteins, and synthetic polymers. The advantageous properties of frequently used base materials and practical performance of the various organic NPs in vivo are discussed. These theranostic NPs offer new opportunities for effective cancer treatment.

The need for reducing the operating temperature of solid-oxide fuel cells (SOFCs) imposed by cost reduction has pushed significant progress in fundamental understanding of the individual components, as well as materials innovation and device engineering. Proton-conducting oxides have emerged as potential alternative electrolyte materials to oxygen-ion conducting oxides for operation at low and intermediate temperatures. This article describes major recent developments in electrolytes, electrodes, and complete fuel cell performance for SOFCs based on proton-conducting electrolytes. Although the performance of such fuel cells is still relatively modest, significant improvements in the power density output have been made during the last couple of years, and this trend is expected to continue.

Considering the need for designing better batteries to meet the rapidly growing demand for large-scale energy storage applications, an aspect of primary importance for battery materials is elemental abundance. To achieve sustainable energy development, we must reconsider the feasibility of a sustainable lithium supply, which is essential for lithium(-ion) batteries. Lithium is widely distributed in the Earth, but is not regarded as an abundant element. Therefore, widespread use of large-scale lithium batteries would be inevitably restricted. Sodium(-ion) batteries are thus promising candidates for large-scale applications because sodium is the most advantageous next to lithium considering its atomic weight, standard potential, and natural abundance. Rechargeable sodium-ion batteries consist of two different sodium insertion materials similar to Li-ion batteries. Sodium insertion materials, especially layered oxides, have been studied since the early 1980s, but not extensively for energy storage devices due to the expanded interest in lithium insertion materials in the 1990s. In recent years, materials researchers have again been extensively exploring new sodium insertion materials to enhance battery performance. This article reviews recent advancements and trends in layered sodium transition metal oxides as positive electrode materials for Na-ion batteries.

Interfacial water is believed to determine practical outcomes in systems of interest to biology, materials science, geology, and many other disciplines. In this article, recent progress in understanding interfacial water achieved using molecular simulations is reviewed. After the reliability of recent approaches is discussed, three possible research directions are described. These future developments promise to have a large impact on both fundamental science and applications of societal importance.