Reviews & Analysis

The surface areas of molecular organic cage solids now rival those of metal–organic frameworks. In this Review, the synthesis and structures of various porous organic cages are outlined together with a discussion of the characteristics — such as solubility, polymorphism and modular co-crystallization — that distinguish these cages from their inorganic or hybrid counterparts.

The fascinating wave phenomenon of ‘bound states in the continuum’ spans different material and wave systems, including electron, electromagnetic and mechanical waves. In this Review, we focus on the common physical mechanisms underlying these bound states, whilst also discussing recent experimental realizations, current applications and future opportunities for research.

With a dangling-bond-free surface, two dimensional layered materials (2DLMs) can enable the creation of diverse van der Waals heterostructures (vdWHs) without the conventional constraint of lattice matching or process compatibility. This Review discusses the recent advances in exploring 2DLM vdWHs for future electronics and optoelectronics.

Multiferroic materials exhibit magnetic and ferroelectric order at the same time and provide a way to control magnetism with electric fields. We discuss the mechanisms supporting multiferroicity, multiferroic thin films and heterostructures, the non-equilibrium dynamics of multiferroics, fundamental symmetry issues and the impact of multiferroics on other research areas.

Magnetic skyrmions are quasiparticles that hold promise for future spintronic devices. In this Review, the detection, creation, manipulation and deletion of individual skyrmions in ultrathin films and in multilayers are surveyed, and their control by currents and external fields is discussed.

Applications of liquid-phase transmission electron microscopy (TEM) and cryogenic TEM to investigations of dynamic processes in diverse materials systems — both inorganic and organic — are transforming our understanding of the mechanisms underlying the formation of materials in synthetic, biological and geochemical environments.

Complex mechanisms are responsible for the biomineralization of skeletal tissues and pathological calcification in the cardiovascular system. In this Review, the physiochemical and biomechanical properties of mineralized tissues, both physiologic and pathophysiologic, and analytical methods to elucidate their finer structure are discussed.

Thermomechanical treatments — cold and hot deformation — are established for polycrystalline metals. Their use on metallic glasses to obtain relaxed and rejuvenated states has just begun to be explored, and holds promise for extending the range of available glassy states and gaining access to improved properties.

The clinical translation of biomaterials for tissue engineering reveals their therapeutic performance and relevance, and thus enables the improvement of biomaterials design. In this Review, the design and translation of biomaterials, particularly cartilage and cornea repair, and a new understanding of the interaction between biomaterials and the host immune system are discussed.

To optimize the synthesis of functionally designed nanoparticles, a clear understanding of their formation mechanisms is needed. This Review presents the structural properties of nanoclusters and their role in the prenucleation period, and discusses nonclassical nucleation and growth models, as well as heterogeneous nucleation of multicomponent nanoparticles.

Graphene has now enabled the development of faster and more powerful batteries and supercapacitors. In this Review, we discuss the current status of graphene in energy storage, highlight ongoing research activities and present some solutions for existing challenges.

In this Review, the structure, bonding and defects of half-Heusler compounds are explained in terms of the framework of Zintl (or valence-precise) chemistry. This deeper understanding of the structure and electronic properties of half-Heusler compounds should aid the design of improved thermoelectric materials.

Piezotronics and piezo-phototronics offer new means of implementing adaptive electronics and optoelectronics, taking advantage of the coupling between piezoelectric polarization and semiconductor properties in piezoelectric semiconductor nanomaterials. This Review discusses the recent progress in piezotronics and piezo-phototronics, as well as future research directions.

Mesoporous materials are finding increasing uses in energy conversion and storage devices. This Review highlights recent developments in the synthesis of mesoporous materials and their applications as electrodes and/or catalysts in solar cells, solar fuel production, rechargeable batteries, supercapacitors and fuel cells.

Recent research into semiconductor nanowire lasers has resulted in the advent of new materials, a broader wavelength selection and effective electrical pumping schemes, thereby bringing these nanoscale lasers much closer to application in fields like communications, computing, sensing and imaging.

Assisted by rationally designed novel plasmonic nanostructures, surface-enhanced Raman spectroscopy has presented a new generation of analytical tools (that is, tip-enhanced Raman spectroscopy and shell-isolated nanoparticle-enhanced Raman spectroscopy) with an extremely high surface sensitivity, spatial resolution and broad application for materials science and technology.

This Perspective explores and explains the fundamental dogma of nanoparticle delivery to tumours and answers two central questions: ‘how many nanoparticles accumulate in a tumour?’ and ‘how does this number affect the clinical translation of nanomedicines?’

The polymer materials of the twenty-first century will be complex chemical systems that can respond and adapt to their environment. Such materials can be attained by synthesizing precision macromolecules with controlled architectures, and by mastering polymer interactions and self-organization.

Membranes have an increasingly important role in alleviating water scarcity and the pollution of aquatic environments. Promising molecular-level design approaches are reviewed for membrane materials, focusing on how these materials address the urgent requirements of water treatment applications.

Post-lithium-ion batteries are reviewed with a focus on their operating principles, advantages and the challenges that they face. The volumetric energy density of each battery is examined using a commercial pouch-cell configuration to evaluate its practical significance and identify appropriate research directions.