Self-Toughened 2D Moiré Superlattice Membranes with Extreme Thermal Shock Tolerance.

Excellent mechanical strength and toughness are demanded for two-dimensional material (2DM) membranes in various applications to withstand extreme strain and temperature changes and resist crack propagation. However, the trade-off between strength and toughness poses significant challenges in meeting these requirements. This study presents a self-toughened 2D moiré superlattice membrane composed of vertically stacked hexagonal boron nitride and graphene (hBN/Gr) that exhibits high mechanical strength.

Flexible high-entropy functional ceramics.

Functional ceramics, once integrated with flexibility, hold great promise for cutting-edge electronic devices. Unfortunately, functionality and flexibility are inherently exclusive in ceramics: the long-range order of ionic lattices bestows polarization-like properties that accompany brittleness, whereas disorder tolerates bond rotation to generate flexibility with significant loss of performance. Implanting ordered functional motifs within amorphous ceramics, though challenging, may balance this trade-off.

Unprecedented Superelasticity in MoO/MoS Core-Shell Nanowires.

Inorganic materials are usually known with high modulus and brittleness. Here the finding of a [001]-oriented MoO nanowires (NWs) material is reported with a thin MoS shell that exhibits superelastic deformability superior to the reported inorganic NWs. Three-point bending tests reveal that the elastic modulus of MoO crystals in the [001] direction is 103 GPa, consistent with the density functional theory (DFT)-predicted results.

An analytical model for customizing reinforcement plasticity to address the strength-ductility trade-off in staggered composites.

Plastic metals and low-dimensional materials are extensively utilized as reinforcements in fabricating bio-inspired staggered composites. Here, we introduce a comprehensive analytical model to investigate the influence of reinforcement plasticity on the mechanical properties of staggered composites while preserving the non-linear plastic characteristics of the matrix. Competitive plastic deformation in both the reinforcement and the matrix leads to two distinct deformation modes: reinforcement-first yield or matrix-first yield.

Selective Regulation of ray tissue for achieving ultrastable Zero-Poisson's-ratio material out of wood.

Introduction: Materials exhibiting a Poisson's ratio of zero have attracted considerable interest due to their unique properties and potential applications in various fields, including aerospace, athletic footwear, and sporting equipment. However, the high costs associated with their structural fabrication and the dependence on synthetic chemical materials for most zero Poisson's ratio materials complicate the preparation processes of current elastic materials, resulting in negative environmental impacts.

Objectives: This study presents a sustainable treatment strategy that utilizes the inherent cellular structure of wood to achieve a zero Poisson's ratio, thereby enhancing its elasticity.

Strong and Fatigue-Resistant Carbon Nanotube Composites Enabled by Amorphous/Crystalline Heterophase Shell.

Lightweight materials with high strength and long cyclic lifespan are greatly demanded in practical applications, yet these properties are usually mutually exclusive. Here, we present a strong, lightweight, highly deformation-tolerant, and fatigue-resistant carbon nanotube (CNT) composite enabled by an amorphous/crystalline heterophase carbon shell. In particular, we obtain nanocrystallites with CNT-induced crystalline orientation uniformly embedded within an amorphous matrix by controlled thermal annealing.

Amorphous alloys surpass E/10 strength limit at extreme strain rates.

Theoretical predictions of the ideal strength of materials range from E/30 to E/10 (E is Young's modulus). However, despite intense interest over the last decade, the value of the ideal strength achievable through experiments for metals remains a mystery. This study showcases the remarkable spall strength of CuZr amorphous alloy that exceeds the E/10 limit at strain rates greater than 10 s through laser-induced shock experiments.

Reinforcement hybridization in staggered composites enhances wave attenuation performance.

Advanced composites with superior wave attenuation or vibration isolation capacity are in high demand in engineering practice. In this study, we develop the hybrid dynamic shear-lag model with Bloch's theorem to investigate the hybrid effect of reinforcement on wave attenuation in bioinspired staggered composites. We present for the first time the relationship between macroscopic wave filtering and hybridization of building blocks in staggered composites.

Graphene sandwich-based biological specimen preparation for cryo-EM analysis.

High-quality specimen preparation plays a crucial role in cryo-electron microscopy (cryo-EM) structural analysis. In this study, we have developed a reliable and convenient technique called the graphene sandwich method for preparing cryo-EM specimens. This method involves using two layers of graphene films that enclose macromolecules on both sides, allowing for an appropriate ice thickness for cryo-EM analysis.

Large-scale assembly of isotropic nanofiber aerogels based on columnar-equiaxed crystal transition.

Ice-templating technology holds great potential to construct industrial porous materials from nanometers to the macroscopic scale for tailoring thermal, electronic, or acoustic transport. Herein, we describe a general ice-templating technology through freezing the material on a rotating cryogenic drum surface, crushing it, and then re-casting the nanofiber slurry. Through decoupling the ice nucleation and growth processes, we achieved the columnar-equiaxed crystal transition in the freezing procedure.

A High-Rigidity Organic-Inorganic Metal Halide Hybrid Enabling Reversible and Enhanced Self-Trapped Exciton Emission under High Pressure.

Zero-dimensional organic-inorganic metal halide hybrids provide ideal bulk-crystal platforms for exploring the pressure engineering of electron-phonon coupling (EPC) and self-trapped exciton (STE) emission at the molecular level. However, the low stiffness of inorganic clusters hinders the reversible tuning of these physical properties. Herein, we designed a Sb-doped metal halide with a high emission yield (89.

Probing Anisotropic Deformation and Near-Infrared Emission Tuning in Thin-Layered InSe Crystal under High Pressure.

Indium selenide (InSe) exhibits high lattice compressibility and an extraordinary capability of tailoring the optical band gap under pressure beyond other 2D materials. Herein, by applying hydrostatic pressure via a diamond anvil cell, we revealed an anisotropic deformation dynamic and efficient manipulation of near-infrared light emission in thin-layered InSe strongly correlated to layer numbers ( = 5-30). As > 20, the InSe lattice is compressed in all directions, and the intralayer compression leads to widening of the band gap, resulting in an emission blue shift (∼120 meV at 1.

Uniform thin ice on ultraflat graphene for high-resolution cryo-EM.

Cryo-electron microscopy (cryo-EM) visualizes the atomic structure of macromolecules that are embedded in vitrified thin ice at their close-to-native state. However, the homogeneity of ice thickness, a key factor to ensure high image quality, is poorly controlled during specimen preparation and has become one of the main challenges for high-resolution cryo-EM. Here we found that the uniformity of thin ice relies on the surface flatness of the supporting film, and developed a method to use ultraflat graphene (UFG) as the support for cryo-EM specimen preparation to achieve better control of vitreous ice thickness.

Thermal-Switchable, Trifunctional Ceramic-Hydrogel Nanocomposites Enable Full-Lifecycle Security in Practical Battery Systems.

Thermal runaway (TR) failures of large-format lithium-ion battery systems related to fires and explosions have become a growing concern. Here, we design a smart ceramic-hydrogel nanocomposite that provides integrated thermal management, cooling, and fire insulation functionalities and enables full-lifecycle security. The glass-ceramic nanobelt sponges exhibit high mechanical flexibility with 80% reversible compressibility and high fatigue resistance, which can firmly couple with the polymer-nanoparticle hydrogels and form thermal-switchable nanocomposites.

Enhancing strength and ductility via crystalline-amorphous nanoarchitectures in TiZr-based alloys.

Crystalline-amorphous composite have the potential to achieve high strength and high ductility through manipulation of their microstructures. Here, we fabricate a TiZr-based alloy with micrometer-size equiaxed grains that are made up of three-dimensional bicontinuous crystalline-amorphous nanoarchitectures (3D-BCANs). In situ tension and compression tests reveal that the BCANs exhibit enhanced ductility and strain hardening capability compared to both amorphous and crystalline phases, which impart ultra-high yield strength (~1.

Atomically Thin Bilayer Janus Membranes for Cryo-electron Microscopy.

Cryo-electron microscopy (cryo-EM) has emerged as a vital tool to reveal the native structure of beam-sensitive biomolecules and materials. Yet high-resolution cryo-EM analysis is still limited by the poorly controlled specimen preparation and urgently demands a robust supporting film material to prepare desirable samples. Here, we developed a bilayer Janus graphene membrane with the top-layer graphene being functionalized to interact with target molecules on the surface, while the bottom layer being kept intact to reinforce its mechanical steadiness.

Zone-Folded Longitudinal Acoustic Phonons Driving Self-Trapped State Emission in Colloidal CdSe Nanoplatelet Superlattices.

Colloidal CdSe nanoplatelets (NPLs) have substantial potential in light-emitting applications because of their quantum-well-like characteristics. The self-trapped state (STS), originating from strong electron-phonon coupling (EPC), is promising in white light luminance because of its broadband emission. However, achieving STS in CdSe NPLs is extremely challenging because of their intrinsic weak EPC nature.

Growth of Ultraflat Graphene with Greatly Enhanced Mechanical Properties.

Graphene grown on Cu by chemical vapor deposition is rough due to the surface roughening of Cu for releasing interfacial thermal stress and/or graphene bending energy. The roughness degrades the electrical conductance and mechanical strength of graphene. Here, by using vicinal Cu(111) and flat Cu(111) as model substrates, we investigated the critical role of original surface topography on the surface deformation of Cu covered by graphene.

Highly compressible and anisotropic lamellar ceramic sponges with superior thermal insulation and acoustic absorption performances.

Advanced ceramic sponge materials with temperature-invariant high compressibility are urgently needed as thermal insulators, energy absorbers, catalyst carriers, and high temperature air filters. However, the application of ceramic sponge materials is severely limited due to their complex preparation process. Here, we present a facile method for large-scale fabrication of highly compressible, temperature resistant SiO-AlO composite ceramic sponges by blow spinning and subsequent calcination.

Robust ultraclean atomically thin membranes for atomic-resolution electron microscopy.

The fast development of high-resolution electron microscopy (EM) demands a background-noise-free substrate to support the specimens, where atomically thin graphene membranes can serve as an ideal candidate. Yet the preparation of robust and ultraclean graphene EM grids remains challenging. Here we present a polymer- and transfer-free direct-etching method for batch fabrication of robust ultraclean graphene grids through membrane tension modulation.

Kirigami-Inspired Deformable 3D Structures Conformable to Curved Biological Surface.

By introducing stretchability and/or deformability to planar electronics, devices can conformably attach to 3D curved surfaces with minimal invasiveness, which is of great interest for next-generation wearables in clinical and biological applications. Here, a feasible route is demonstrated to generate deformable 3D structures as a robust platform to construct electronic systems by utilizing silver nanowires/parylene hybrid films in a way analogous to the art of kirigami. The hybrid films exhibit outstanding electrical conductivity along with decent optical transparency, flexibility, and long-term stability.

Dynamic shear-lag model for understanding the role of matrix in energy dissipation in fiber-reinforced composites.

Unlabelled: Lightweight and high impact performance composite design is a big challenge for scientists and engineers. Inspired from well-known biological materials, e.g.

Engineering the Mechanical Properties of Monolayer Graphene Oxide at the Atomic Level.

The mechanical properties of graphene oxide (GO) are of great importance for applications in materials engineering. Previous mechanochemical studies of GO typically focused on the influence of the degree of oxidation on the mechanical behavior. In this study, using density functional-based tight binding simulations, validated using density functional theory simulations, we reveal that the deformation and failure of GO are strongly dependent on the relative concentrations of epoxide (-O-) and hydroxyl (-OH) functional groups.