Research articles

Development of the classical lithium-ion technology based on liquid electrolytes has been limited to a certain extent by the intrinsic instability of liquid electrolytes and their mechanical properties. A multifunctional single-ion polymer electrolyte based on polyanionic block copolymers consisting of polystyrene segments is now shown to exhibit enhanced lithium-ion transport, mechanical properties and electrochemical stability window.

Macroscopically long, cell-encapsulating, core–shell hydrogel microfibres that can be assembled into macroscopic cellular constructs by weaving and reeling are shown to reconstitute intrinsic morphologies and functions of living tissues. When transplanted into the subrenal capsular space of diabetic mice, the microfibres normalize blood glucose concentrations for about two weeks and can later be removed.

Josephson plasma solitons are a kind of excitation predicted to occur in cuprate superconductors subject to strong electromagnetic fields. By using intense radiation from a free-electron laser, these modes are now demonstrated experimentally in the copper oxide material La_1.84Sr_0.16CuO₄.

The molecular alignment and order of conjugated polymers within organic electronic devices is an important consideration for the enhancement of device performance. Now, some design rules are revealed that promote the directed alignment of the polymers and result in the fabrication of well-aligned films with highly anisotropic carrier mobilities.

Adhesive interactions between stem cells and the extracellular matrix are known to regulate stem cell differentiation, yet the underlying mechanisms are not well understood. It is now shown that fate decisions of stem cells encapsulated in covalently crosslinked hydrogels are regulated, independently of matrix mechanics and cell morphology, by the cellular tension generated from cell-induced degradation of the hydrogels.

The optical and electronic performance of inorganic nanocrystal assemblies stabilized by organic ligands has been extensively investigated, whereas less attention has been paid to their thermal transport properties. It is now shown that the thermal conductivity of these composite systems is determined by the vibrational states of both inorganic and ligand regions, as well as by their relative volumes.

Although poly(vinylidene fluoride) is a well-known organic ferroelectric, its utilization in microelectronics has been hampered by the difficulty in obtaining uniform thin films. By exploiting a high-temperature deposition approach, smooth and thin films of the ferroelectric δ-phase polymorph of this material are now obtained, showing their potential for capacitors and non-volatile memories.

The dynamics of thin magnetic films revealed by ultrafast laser techniques cannot be explained by standard equilibrium descriptions. Diffraction experiments using an X-ray laser now allow the spin dynamics of the separate magnetic constituents of ferromagnetic GdFeCo alloys to be spatially resolved.

Much less exploited than the spectral and spatial properties of surface plasmons (SPs) are their local density of states (SP-LDOS), which rule a number of important nanoscale phenomena. Using two-photon luminescence microscopy, the SP-LDOS in ultrathin gold nanoprisms is now visualized directly, allowing for the SP modal distribution to be tuned.

Experimental realizations of topological insulators are relatively rare at present. Now, a structurally complex bismuth rhodium iodide is synthesized and shown to have a honeycomb-layered structure akin to that of graphene, but made up of bismuth and rhodium sheets.

Despite recent progress in the production of bendable thin-film transistors, their development is limited by leakage currents and fragile inorganic oxides. Combining graphene and single-walled carbon nanotube electrodes with a geometrically wrinkled inorganic layer, highly stretchable and transparent field-effect transistors have now been demonstrated.

Artificially grown superlattices consisting of iron pnictide materials offer a strategy for tailoring their superconducting properties. The fabrication of compositionally modulated oxygen- and cobalt-doped BaFe₂As₂ heterostructures yields vertically aligned defects that introduce strong vortex pinning sites and enhance the materials’ critical current density.

Measuring and characterizing dynamic charge density waves in cuprate superconductors is a challenging task. By using a method based on ultrafast spectroscopy, the problem is overcome and detecting the presence and lifetimes of these fluctuations is made possible.

The tunnelling electroresistance effect that occurs at ferroelectric tunnel junctions could form the basis for a class of potential memory applications. Now, an enhanced effect is observed in a complex oxide interface as a result of a ferroelectrically induced phase transition.

The application of three-photon excitation to biomedical imaging is demonstrated by combining the three-photon excitation properties of ZnS nanocrystals and the visible emission from Mn²⁺ dopants. The biocompatible, doped nanocrystals are used for high-resolution cellular imaging and in vivo tumour-targeting imaging under non-invasive conditions.

Supercapacitors are electrochemical energy-storage devices that take advantage of electrostatic interactions between high-surface-area nanoporous electrodes and electrolyte ions. Molecular mechanisms at work inside supercapacitor carbon electrodes are now clarified with solid-state nuclear magnetic resonance.

The fabrication of microchips with vertically stacked circuits is challenging because they require arrays of electrical interconnections between the circuits, where accessibility is limited. An approach to generate conductive, mechanically stable plug-and-socket interconnections through three-dimensional actin-filament self-organization and selective metallization offers a potential solution to this problem.

The control and manipulation of domain walls in perpendicularly magnetized nanowires by means of an electric current has gained attention for possible device applications. Now, the depinning of domain walls in Pt/Co/Pt nanowires is shown to be driven by the spin Hall effect.

The crystallization of many minerals from solution has been shown to involve disordered precursors that agglomerate into an amorphous intermediate phase, a pathway that seems to contradict classical nucleation theory. It is now found that the crystallization of magnetite—a magnetic iron oxide with many bio- and nanotechnological applications—occurs classically from the accretion of precursors in the absence of amorphous intermediates.

The use of colloidal quantum dots in optical applications is hampered by difficulties in optimizing their physical properties. The synthesis of high-quality quantum dots that simultaneously exhibit narrow emission linewidths and minimal blinking potentially overcomes this problem.