Communications Materials最新文献

The scaling of Si transistor technology has resulted in a remarkable improvement in the performance of integrated circuits over the last decades. However, scaled transistors also require reduced electrical interconnect dimensions, which lead to greater losses and power dissipation at circuit level. This is mainly caused by enhanced surface scattering of charge carriers in copper interconnect wires at dimensions below 30 nm. A promising approach to mitigate this issue is to use directional conductors, i.e. materials with anisotropic Fermi surface, where proper alignment of crystalline orientation and transport direction can minimize surface scattering. In this work, we perform a resistivity scaling study of the anisotropic semimetal NbP as a function of crystalline orientation. We use here focused ion beam to pattern and scale down NbP crystallites to dimensions comparable to the electron scattering length at cryogenic temperatures. The experimental transport properties are correlated with the Fermi surface characteristics through a theoretical model, thus identifying the physical mechanisms that influence the resistivity scaling of anisotropic conductors. Our methodology provides an effective approach for early evaluation of anisotropic materials as future ultra-scalable interconnects, even when they are unavailable as epitaxial films.

Lithium-sulfur batteries offer high theoretical energy density for advanced energy storage, but practical deployment is hindered by the polysulfide shuttle effect and sluggish kinetics in conventional catholytes. Here, we develop a high-rate sulfur cathode by integrating Li₁₀GeP₂S₁₂, a highly ion-conductive solid-state electrolyte, directly into the positive electrode. We systematically investigate the influence of solvent systems and binders on electrochemical performance, while optimising the slurry casting process. Electrochemical tests demonstrate that the addition of Li₁₀GeP₂S₁₂ improved lithium-ion transport, reduced internal resistance, and enhanced reaction kinetics, leading to a high initial capacity of over 1400 mAh g^-1. We observe high-capacity retention at high current densities (1 C) with the positive electrode exhibiting a stable capacity of 800 mAh g^-1, significantly outperforming control samples fabricated without Li₁₀GeP₂S₁₂. This study confirms that the integration of Li₁₀GeP₂S₁₂ into the positive electrode enhances the performance of quasi-solid-state lithium-sulfur batteries, offering potential for future improvements based on the optimisation of lithium-ion conducting pathways in the positive electrode.

Metastable β Ti alloys have potential for vibration damping and actuation applications within the aerospace industry due to thermal and mechanical hysteresis. However, variations in transformation parameters, which are also seen to change following thermal or mechanical cycling, significantly limit industrial acceptance. There is a widespread belief that these variations are a consequence of ⍵ phase formation. However, here we provide evidence to show that this is not necessarily the case. Instead, we show how residual stresses and defect structures are crucial to the transformation of these alloys and present an understanding of the mechanism that governs their behaviour. Importantly, we highlight the consequences for the design of new transforming alloys and component geometries, and how current design theories may need to be employed in conjunction with other methods to effectively prevent longer-term changes in behaviour. To this end, we demonstrate how functional properties could be periodically recovered by introducing short intercycle heat treatments and suggest possible next steps for advancing our understanding of these materials.

Electrically conductive hydrogels can simulate the sensory capabilities of natural skin, such that they are well-suited for electronic skin. Unfortunately, currently available electronic skin cannot detect multiple stimuli in a selective manner. Inspired by the deep eutectic solvent chemistry of the frog Lithobates Sylvaticus, we introduce a double network granular organogel capable of simultaneously detecting mechanical deformation, structural damage, changes in ambient temperature, and humidity. The deep eutectic solvent chemistry adds an additional benefit: Thanks to strong hydrogen bonding, our sensor can recover 97% of the Young's modulus after being damaged. The sensing performance and self-healing capacity are maintained within a temperature range of -20 °C to 50 °C for at least 2 weeks. We exploit the granular nature of this system to direct ink to write a cm-sized frog and e-skin wearables. We realize selective tactile perception by training recurrent neural networks to achieve sensory stimulus classification between the temperature and strain with 98% accuracy.

Light-responsive materials with intrinsic negative feedback enable self-oscillation in non-equilibrium states. Conventional systems rely on self-shadowing in bending modes but fail when shadowing is constrained. Here, we demonstrate that external mechanical forces can bypass this limitation, enabling sustained oscillations without complete shadowing. Using a vertically suspended light-responsive liquid crystal network (LCN) strip under constant irradiation, a transition from static deformation to continuous oscillation arises when a critical load is applied. This system reveals two key phenomena: (1) oscillation amplitude scales with light intensity, reaching an angular displacement of 300°-significantly surpassing bending-mode oscillators; and (2) oscillation frequency decreases with increasing load, reflecting intrinsic mechanical sensitivity. This force-assisted self-oscillation principle generalizes across diverse deformation modes, including bending, twisting, contraction, and off-axis LCN strips. By mimicking biological mechanosensation based on dissipative mechanism, our findings provide a simplified design for non-equilibrium matter capable of dynamic adaptation to mechanical loads.

Dark Field X-ray Microscopy (DFXM) has advanced 3D non-destructive, high-resolution imaging of strain and orientation in crystalline materials, enabling the study of embedded structures in bulk. However, the photon-hungry nature of monochromatic DFXM limits its applicability for studying highly deformed or weakly crystalline structures, and constrains time-resolved studies in industrially relevant materials. Here, we present pink-beam DFXM (pDFXM) at the ID03 beamline of ESRF, achieving a 27-fold increase in diffracted intensity while maintaining 100 nm spatial resolution. We validate pDFXM by imaging a partially recrystallized aluminum grain, confirming sufficient angular resolution for microstructure mapping. The increased flux significantly enhances the diffracted signal, enabling the resolution of subgrain structures. Additionally, we image a highly deformed ferritic iron grain, previously inaccessible in monochromatic mode without focusing optics. Beyond static imaging, pDFXM enables real-time tracking of grain growth during annealing, achieving hundred-millisecond temporal resolution. By combining high photon flux with non-destructive, high-resolution 3D mapping, pDFXM expands diffraction-contrast imaging to poorly diffracting crystals, unlocking new opportunities for studying grain growth, fatigue, and corrosion in bulk materials.

The discovery of unconventional superconductivity often triggers significant interest in associated electronic and structural symmetry breaking phenomena. For the infinite-layer nickelates, structural allotropes are investigated intensively. Here, using high-energy grazing-incidence x-ray diffraction, we demonstrate how in-situ temperature annealing of the infinite-layer nickelate PrNiO_2+x (x ≈ 0) induces a giant superlattice structure. The annealing effect has a maximum well above room temperature. By covering a large scattering volume, we show a rare period-six in-plane (bi-axial) symmetry and a period-four symmetry in the out-of-plane direction. This giant unit-cell superstructure-likely stemming from ordering of diffusive oxygen-persists over a large temperature range and can be quenched. As such, the stability and controlled annealing process leading to the formation of this superlattice structure provides a pathway for novel nickelate chemistry.

Piezoelectric energy harvesting, i.e. the interconversion of electrical and mechanical energy, has the potential to revolutionise how we generate sustainable power for electronic devices. Currently the majority of research into maximising the electrical output of piezoelectrics focuses on the material itself i.e. modulating the electromechanical properties via stoichiometry, crystal engineering, deposition technique, etc. Here we take a different approach, demonstrating that for direct force harvesting the base layer onto which piezoelectrics are mounted has a huge impact on the voltage output of commercial piezoelectric transducers. We almost triple the open-circuit voltage output of a small piezoelectric array from 2.8 to 7.5 Volts by changing the flexibility of the material they are adhered to. As well as conventional base layer materials we use a variety of 3D-printed geometries, which offer a low-cost and efficient method for controlling the dynamics of a piezoelectric-based interface. The goal is that by demonstrating this phenomenon using widely used lead-based piezoelectrics, that it can be utilised for increasing the power output of sustainable alternatives.

Understanding polymer-surfactant interactions is essential for regulating phase transition and polymer aggregation, enabling the design of functional materials with tailored properties. Here, we introduce programmable dextran-based thermoresponsive polysaccharide condensates that exhibit reversible phase transitions with tunable lower critical solution temperatures. Photo-initiated radical polymerization permits hydrogel crosslinking, harnessing phase separation to generate hydrogels with distinct microstructures and mechanical heterogeneity. We systematically investigate the impact of anionic sodium dodecyl sulfate (SDS), cationic hexadecyltrimethylammonium bromide (CTAB), nonionic Pluronic F-127, and zwitterionic 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) surfactants on phase transition dynamics. Surfactant charge density, hydrophilic-lipophilic balance (HLB), and critical micelle concentrations (CMC) collectively govern temperature-triggered phase separation. The resulting photo-crosslinked gels demonstrate surfactant-specific microstructures, including core-shell domains, interconnected elongated micelles, and dual emulsions. Micromechanical characterization exhibits structurally coordinated stiffness and adhesion, where Pluronic forms core-shell structures with reduced adhesion, while CTAB presents elongated structures and lowered modulus. These findings provide a framework for tailoring surfactant-polysaccharide interactions to direct microstructure-property-performance relationships in biocomposite materials design.

Hydrogels are frequently used in regenerative medicine due to their hydrated, tissue-compatible nature, and tuneable mechanics. While many strategies enable bulk mechanical modulation, little attention is given to tuning surface tribology, and its impact on cellular behavior under mechanical stimuli. Here, we demonstrate that photocrosslinking hydrogels on hydrophobic substrates leads to significant, long-lasting reductions in surface friction, ideal for cartilage tissue regeneration. Gelatin methacryloyl and hyaluronic acid methacrylate hydrogels photocrosslinked on polytetrafluoroethylene possess more hydrated, lubricious surfaces, with lower friction coefficients and crosslinking densities than those crosslinked on glass. This facilitated self-lubrication via water exudation, limiting shear during biaxial stimulation. When subject to intermittent biaxial loading mimicking joint movement, low-friction chondrocyte-laden neo-tissues formed superior hyaline cartilage, confirming the benefits of reduced friction on tissue development. Finally, in situ photocrosslinking enabled precise hydrogel formation in a full-thickness cartilage defect, highlighting the clinical potential and emphasizing the importance of crosslinking substrate in regenerative medicine.