Materials Horizons最新文献

Ionic conduction in solids that exceeds 1 mS cm^-1 is predicted to involve coupled phonon-ion interactions in the crystal lattice. Here, we use theory and experiment to measure the possible contribution of coupled phonon-ion hopping modes which enhance Li⁺ migration in Li_0.5La_0.5TiO₃ (LLTO). The ab initio calculations predict that the targeted excitation of individual TiO₆ rocking modes greatly increases the Li⁺ jump rate as compared to the excitation of vibrational modes associated with heating. Experimentally, coherently driving TiO₆ rocking modes via terahertz (THz) illumination leads to a ten-fold decrease in the differential impedance compared to the excitation of acoustic and optical phonons. Additionally, we differentiate the ultrafast responses of LLTO due to ultrafast heating and THz-range vibrations using laser-driven spectroscopy (LUIS), finding a unique long-lived response for the THz-range excitation. These findings provide new insights into coupled ion migration mechanisms, indicating the important role of THz-range coupled phonon-ion hopping modes in enabling fast ion conduction at room temperature.

Simultaneously optimizing the piezoelectric coefficient (d₃₃) and mechanical quality factor (Q_m) presents a fundamental challenge in developing high-performance piezoceramics for high-power applications. While conventional hardening approaches, like acceptor doping, can improve Q_m, they typically sacrifice d_33-an inherent trade-off that limits material performance. In this study, we propose an innovative strategy utilizing ion-conductive K₂Ti₆O₁₃ (KT) rod-shaped secondary phase as functional ionic channels to create spatially graded acceptor distribution in potassium sodium niobate (KNN)-based lead-free ceramics. This strategy achieves unprecedented property synergy, yielding simultaneous enhancements of 36% in d₃₃ and 64% in Q_m. Through multiscale characterization combining aberration transmission electron microscopy and phase-field simulations, we reveal that the KT-mediated gradient distribution of Cu ions induces localized domain activation in certain regions while enhancing pinning effects in others. This unique microstructure establishes a dynamic balance between domain wall mobility and stabilization, ultimately optimizing the overall piezoelectric response. This ion-channel-assisted heterogeneous doping strategy establishes a new design paradigm for overcoming the traditional d₃₃-Q_m compromise, opening avenues for next-generation lead-free piezoelectrics in high-power electromechanical systems.

Lattice materials with negative Poisson's ratios (NPR) exhibit exceptional mechanical properties, but their design has largely been limited to periodic cell structures, constraining their anisotropic potential. Irregular lattice cell architecture offers superior tunability, yet the complex relationship between its non-cyclic geometries and metamaterial properties has posed significant design challenges. Here, we introduce an AI-driven framework combining deep neural networks and genetic algorithms to parametrically optimize the anisotropic NPR and energy absorption of irregular 3D lattice cells. Through microscale and macroscale 3D printing, coupled with in situ and quasi-static compression tests, we experimentally validate the programmable NPR effects across varied materials and scales. Micro-DIC analysis reveals the strain localization patterns governing microscale deformation and pinpoints the critical buckling instabilities in compressed architectures. Our approach enables the inverse design of 3D lattice metamaterials composed of irregular unit cells with tailored mechanical properties, unlocking new possibilities for applications in lightweight structures, energy absorption, and beyond.

Wound healing remains a complex clinical challenge due to excessive exudate accumulation, bacterial infection, sustained inflammation, and impaired tissue regeneration, highlighting the urgent need for multifunctional therapeutic dressings. Although medicinal plants such as aloe vera have long been used for skin wound treatment, the isolated use of its rind or gel limits their ability to address the dynamic and stage-specific requirements of wound healing. Here, we report a supramolecular and plant-inspired engineering strategy to construct aloe vera-mimicking sponges (AMSs) that integrate nanoscale therapeutic functionality with a macroscopic porous scaffold to enable stepwise wound healing. Exosome-like nanovesicles are first derived from aloe vera peels via an extrusion process and further loaded with nanoenzymes, yielding mimetic peel nanovesicles (NAPNs) with controllable photothermal behavior and nitric oxide (NO) generation capability. These NAPNs are subsequently incorporated into porous sponge scaffolds obtained from freeze-dried aloe vera gel, forming bioinspired AMSs with precisely controllable pore structures. Owing to their interconnected porous architecture and excellent water retention capacity, the AMSs efficiently manage wound exudates and facilitate bacterial adsorption. Under near-infrared irradiation, the synergistic photothermal-NO effects enable potent antibacterial activity through strong, localized hyperthermia, while mild and controllable photothermal regulation further alleviates inflammation and promotes cellular proliferation and migration, thereby accelerating skin tissue regeneration. Overall, this work presents a biomimetic, nanomedicine-integrated, and structurally programmable dressing platform that bridges plant-inspired materials engineering with wound surface nanotherapy, offering a stepwise and synergistic strategy for enhanced skin wound healing.

The low carrier density in organic semiconductors leads to high resistivity and contact resistance in electronic devices. Doping has been implemented to solve these issues. We describe herein a molecular modification approach to increase the carrier density. A representative p-type organic semiconductor, dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT), was modified with a pinacolborane (Bpin) group, a reactive functional group in the Suzuki-Miyaura cross-coupling reaction. The resulting Bpin-modified DNTT (Bpin-DNTT) has a low-lying HOMO energy level at the single molecular level (5.4 eV below the vacuum level) and excellent transistor characteristics with mobility of greater than 2 cm² V^-1 s^-1. However, the Bpin-DNTT solid was easily oxidized upon exposure to ambient air, generating hole carriers. To clarify this unprecedented behavior, we investigated Bpin-DNTT in detail through single-crystal field-effect transistor (SC-FET), electron spin resonance (ESR) spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and theoretical calculations. The SC-FET and ESR spectra demonstrated that the surface of the Bpin-DNTT solid in air was readily oxidized, which was due to the significantly decreased ionization energy of 4.58 eV, confirmed by UPS. These results reveal the potential of the Bpin group to increase the carrier density in p-type organic semiconductors.

Adhesive hydrogels have great potential for application in the biomedical field. Currently, for clinical applications, adhesive hydrogels need to have the following characteristics: good biocompatibility, strong tissue adhesion, highly adaptable tissue specificity and multifunctionality, which are also included in the design principles of current adhesive hydrogels. When targeting different types of diseases in different tissues, adhesive hydrogels need different degrees of attention to these four key properties according to the characteristics of the pathological microenvironment of the tissue. In this regard, this article reviews the clinical disease characteristics of different tissues, and correspondingly introduces the considerations in the design process of adhesive hydrogels for this type of disease and application, in order to deepen the understanding of the design principles of adhesive hydrogels in biomedical applications.

Vacuum brazing with an innovative filler alloy is critical for manufacturing high-precision aerospace components requiring exceptional comprehensive performance, yet achieving superior strength in Ti₂AlNb/GH4169 brazed joints remains challenging. This study proposes a (TiZrHf)₅₀(NiCu)₄₅Al₅/(TiZrHf)₃₀(NiCu)₆₅Al₅ high-entropy gradient filler metal (HGFM) to join the Ti₂AlNb alloy and the GH4169 superalloy, which relieved the stress concentration and elevated microstructure stability, achieving a maximum shear strength of 335 MPa. The lower thermodynamic inclination and high entropy characteristics synergistically contributed to the solid solution mainly composed of (Ni,Cr,Fe)_ss and (Ni,Cu,Fe,Cr)_ss phases, replacing the intermetallic compounds dominated by (Ti,Zr,Hf)(Ni,Cu)₃ and (Ti,Zr,Hf)₂(Ni,Cu) phases. The corresponding lattice misfits between (Ni,Cr,Fe)_ss and (Ni,Cu,Fe,Cr)_ss phases were 3.72%, 13.24% and 20.14%, which enabled coherent and semi-coherent relationships, facilitating the dynamic equilibrium of dislocation motion without termination. A higher activation energy at the interface (393 kJ mol^-1) indicated that slow atomic diffusion controlled the excessive reaction at the interface. The remarkable drop in elastic modulus discrepancies in the customized solid solution region enhanced the synergistic deformation capacities, which drove the fracture locations to transform to the Ti₂AlNb dissolved with Ni and Cu phases, exhibiting a more tortuous fracture path and higher fracture toughness. Molecular dynamics simulations indicated that the solid solution interface enhanced the peak tensile strength to 10.36 GPa, demonstrating favorable high-temperature stability. The current work offers a directly transferable approach for developing a tailored filler metal for other dissimilar metal systems.

Polyoxometalates (POMs) represent a class of nanomaterials distinguished by their exceptional catalytic performance and broad-spectrum antibacterial potential. However, their non-specific targeting capability often leads to collateral damage to mammalian cells, significantly constraining the precise biomedical application of POMs. Herein, employing a chiral engineering strategy, we designed and constructed chiral polyoxometalate nanozymes (D/L-POMs), which function as "POM-Lock" molecular agents capable of achieving precise targeting of bacterial membranes through a stereospecific recognition mechanism. Specifically, they were synthesized via a straightforward one-pot method and demonstrated superior catalytic activity, exhibiting antibacterial efficiencies exceeding 99% against both E. coli and S. aureus, significantly outperforming their achiral POM counterparts. This enhancement is attributed to the optimized W⁵⁺/W⁶⁺ redox cycling and the highly efficient membrane penetration enabled by chiral matching. Crucially, the "lock-and-key" mechanism allows L-POM to selectively disrupt bacterial membrane integrity while promoting fibroblast migration. In an infected wound model, wounds treated with L-POM achieved near-complete closure by day 10. Comprehensive biosafety evaluations revealed negligible hemolytic activity and organ toxicity. This work not only overcomes the limitation of insufficient targeting specificity in conventional POM materials but also establishes a paradigm for developing chiral nanozymes with precision antibacterial functionality.

Electro-active conjugated polymers have shown prominent advantages in the field of electrochromic energy storage materials (EESMs) in recent years. However, achieving highly air-stable n-type conjugated polymer EESMs in aqueous electrolytes remains an enormous challenge. The present study reports the first investigation of benzoimidazoisoindolone-based n-type fully conjugated ladder polymers (BBL-EC and BAL-EC) for EESMs, featuring high electron affinity, efficient and reversible electrochemical redox activity, high electron/ion conductivity, and an extended conjugated backbone structure. These polymers demonstrate enhanced electrochromic performance using aqueous sodium ions as an electrolyte under air atmosphere, alongside high optical contrast and exceptional cycling stability. The optical contrast of BAL-EC was 53.8% at 740 nm, which remained unchanged after 1200 cycles owing to the extended π-conjugated structure. Furthermore, BAL-EC exhibited a high specific capacitance of 257.22 mAh g^-1. The electrochromic energy storage mechanism of benzoimidazoisoindolone-based conjugated polymers involves sequential electron transfer with preferential carbonyl reduction, followed by imidazole ring reduction, which enables synergistic regulation of color switching and energy storage. Benzoimidazoisoindolone-based n-type fully conjugated ladder polymers demonstrate promising potential for highly air-stable aqueous sodium-ion electrochromic energy storage systems.

In this work, we report two rod-shaped Au₂₀ clusters with distinct core configurations and 14 free electrons, offering an important atomically precise model to probe structure-property relationships. A key finding is that ligand-tuned shortening of Au-Au bonds and a slight structure distortion within the cluster core decisively enhance photothermal conversion efficiency and tune NIR-II emission. The most compact Au₂₀ architecture achieves a photothermal conversion efficiency of 25% and extends emission into the NIR-II window at 1190 nm. These results establish bond-length engineering as a powerful and generalizable design principle for tuning the functional properties of atomically precise metal nanoclusters, opening new avenues for the development of high-performance photothermal and luminescent materials.