Science China Materials最新文献

Two-dimensional (2D) materials with large band gaps and strong and tunable second-harmonic generation (SHG) coefficients play an important role in the miniaturization of deep-ultraviolet (DUV) nonlinear optical (NLO) devices. Despite the existence of numerous experimentally synthesized 2D materials, none of them have been reported to meet DUV NLO requirements. Herein, an experimentally available graphene-like BeO monolayer created only by NLO-active [BeO₃] units is suggested as an excellent 2D DUV NLO material because of its ultrawideband gap (6.86 eV) and a strong SHG effect (χ₂₂⁽²⁾(2D) = 6.81 Å pm/V) based on first-principles calculations. By applying stacking, strain, and twist engineering methods, numerous 2D BeO sheets have been predicted, and their flexible structural characteristics provide them with tunable NLO propertie s. Remarkably, the extremely stress-sensitive out-of-plane χ₁₅⁽²⁾(2D) and χ₃₃⁽²⁾(2D) (with an exceptional 30% change) and robust in-plane χ₂₂⁽²⁾(2D) against large strains can be achieved together in AC- and ACE-stacked BeO sheets under in-plane biaxial strain, exhibiting emergent phenomena uniquely not observed in other known 2D NLO materials. Our results reveal that 2D BeO systems should be a new option for 2D DUV NLO materials.

Antifogging coatings show significant promise for transparency optical components, but existing antifogging coatings face challenges in achieving both durability and energy efficiency. We report an innovative printing technology for the scalable fabrication of uniform nanoparticle (NP) coatings featuring an Au@SiO₂ core-shell architecture. The Au core enables efficient photothermal conversion, while the SiO₂ shell ensures strong interfacial adhesion to diverse substrates and provides a hydrophilic surface. Leveraging the hydrophilicity and photothermal effect, the NP coatings restrain moisture condensation upon light exposure. The resulting coatings exhibit exceptional robust mechanical stability, maintaining their anti-fogging performance under harsh environmental conditions (soaking in water for 1 week or wiping with a glass cloth over 100 times), offering a sustainable and energy-efficient solution for long-term anti-fogging applications. This technology demonstrates significant potential for use in optical devices, automotive glass, and medical instruments. Our work not only provides a scalable platform for functional NP coating fabrication but also opens new avenues for the design of next-generation anti-fogging materials.

Macrophages play an indispensable role in infection resolution and tissue repair through dynamic M1-to-M2 phenotypic polarization. The polarization phenotype of macrophages can be regulated by different nano-biomaterials, but it still faces challenges in achieving sequential polarization of pro-inflammatory M1 and anti-inflammatory M2 through a single nanoformulation. In this study, we proposed an approach to regulate the M1–M2 sequential polarization of macrophages using transition metal carbide/nitride (MXene) nanosheets endocytosed by the cells as the only regulator. In vitro experiments demonstrated that endocytosed MXene nanosheets, leveraging their high electrical conductivity and magnetoelectric activity, generated electrical signals and produced reactive oxygen species (ROS) under a rotating magnetic field, thereby inducing M1 macrophage polarization. Upon magnetic field removal, the bioactivity of MXene nanosheets facilitated macrophage repolarization to the M2 phenotype. Furthermore, the mechanism underlying the regulation of macrophage polarization from M1 to M2 phenotype involves both inhibition of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway and activation of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway. In vivo experiments further proved that MXene nanosheets, under on-off rotating magnetic field stimulation, enabled sequential M1-to-M2 macrophage polarization, effectively promoting bacterial clearance and tissue regeneration. These findings highlight that this two-step sequential strategy targeting macrophages represents a promising approach for infected wound healing.

Semiconductor-based surface-enhanced Raman scattering (SERS) substrates have garnered significant attention due to high uniformity, reproducibility, stability, and cost-effectiveness. However, the Raman enhancement in semiconductors primarily relies on the chemical mechanism (CM), which typically results in a lower enhancement capability compared to traditional noble metals. In this study, we developed a novel two-dimensional (2D) SERS substrate, Ag₂Te nanosheets (NSs), synthesized through a simple one-step redox reaction utilizing 2D Te NSs as the template. The 2D Ag₂Te NSs not only exhibit strong interfacial interactions with molecules, thereby supporting the CM, but also possess quasi-metallic properties with low resistivity (2.8 × 10⁻⁴ Ω cm) and high density of free electrons (4.15 × 10²² cm⁻³), giving rise to a significant visible-region surface plasmon resonance (SPR) band and contributing to enormous electromagnetic mechanism (EM). By synergizing CM and EM, the 2D Ag₂Te NSs SERS substrate achieved an ultra-low limit of detection (LOD) of 10⁻¹⁰ M with an enhancement factor (EF) of 2.6 × 10⁷ for methylene blue (MB), outperforming most semiconductors, even rivaling noble metals. The quasi-metallic properties of 2D Ag₂Te NSs also benefit their sensitivity to multiple molecules. The accuracy and reliability were demonstrated in real-sample detections with recoveries of 91.5%–108.3% for various target molecules. These excellent performances, combined with remarkable cost-effectiveness, demonstrate the potential of 2D Ag₂Te NSs as a practical SERS substrate with broad applicability. Furthermore, the inherent structural simplicity of these nanosheets creates significant opportunities for further sophisticated nanostructural engineering to advance the SERS performance in the future.

Organic field-effect transistors (OFETs) offer significant potential for flexible electronics owing to their low-cost processing and mechanical adaptability. This study systematically enhanced electrical performance in N2200-based top-gate bottom-contact OFETs through parametric optimization, demonstrating that shorter channel lengths (150 µm) boosted current density (with leakage control), while optimized N2200/poly(methyl methacrylate) (PMMA) concentration ratios (7/100 mg/mL) and annealing (80 °C, 3 h) improved crystallinity and interfacial properties, achieving stable electrical performance. Crucially, fabrication-parameter-driven performance prediction was established using 719 experimental data (superior to prevalent TCAD-generated datasets) via convolutional neural network (CNN), back propagation neural network (BPNN), and random forest (RF) models—further refined by our innovatively developed CNN-particle swarm optimization (PSO)-BP based hybrid architecture. These architectures autonomously extracted physical characteristics without predefined formulas, with CNN achieving R²>0.9 for all metrics (notably ({R^2}_{{V_{{rm{th}}}}} = 0.95), ({R^2}_{SS} = 0.96)), and with CNN-PSO-BP based hybrid architecture delivering significant error reductions: 15.7% mean absolute error (MAE)/14.9% root mean square error (RMSE) for V_th, 10% MAE/9% RMSE for lg(I_on/I_off), and 13.5% MAE/9.5% RMSE for SS, and enhanced μ_sat stability via outlier fitting. Leveraging PSO demonstrates superior navigation of OFET performance prediction, establishing machine learning-driven frameworks as a critical value for intelligent performance forecasting and accelerated high-throughput device performance tuning.

Enhancing the light olefin selectivity and extending the catalytic durability remain critical challenges for ZSM-5 zeolites in the methanol to olefins (MTO) conversion, while the inherent diffusion restriction along the MFI b-axis direction and poor coke accommodation are the main limiting factors. In this work, we developed a hierarchically single-crystalline ZSM-5 sheet architecture that features an interconnected multiscale porosity and a remarkably reduced b-axis thickness (<50 nm), as quantitatively verified by three-dimensional (3D) electron tomography. Real-time confocal laser scanning microscopy (CLSM) tracking demonstrated a significant enhancement in molecular diffusivity compared to conventional micron-sized ZSM-5 counterparts (Micro-ZSM-5). This engineered structure allows abundant aluminum sites to be distributed on the highly accessible diffusion pathways, and displays an enlarged coke accommodation of 16.31 wt% with a coke deposition rate of 0.59 mg g⁻¹ h⁻¹, which was only one third of that in the Micro-ZSM-5. In a continuous MTO process, this novel hierarchical ZSM-5 sheet (Hier-ZSM-5-S) kept an average selectivity to ethylene and propene of 63.5% on stream for 22.2 h (WHSV = 3.6 h⁻¹, T = 480°C), which was 19% higher and 6.5 times longer than those of Micro-ZSM-5, respectively. This hierarchically shortened b-axis structure establishes a generalizable paradigm for enhanced diffusion and coke accommodation in a precisely designed pore system, which is expected to be adjusted and applied for varying reactions.

With the rapid development of the Internet of Things and smart sensing technologies, triboelectric nanogenerators (TENGs) offer new efficient energy harvesting solutions for self-powered sensors. However, traditional TENG materials exhibit limited mechanical durability, environmental stability, and sensing performance under extreme conditions. Therefore, this study develops a novel eutectogel based on a deep eutectic solvent (DES) and poly(itaconic acid-co-2-hydroxyethyl acrylate) (P(IA-co-HEA)) polymer network. The careful molecular design and microstructural modification of this system result in a eutectogel with low hysteresis, excellent resilience (97.8%), high conductivity (48.02 mS m⁻¹), and strong adhesive strength. Owing to the low freezing point and low volatility of the DES, the P(IA-co-HEA) eutectogel maintains 75.7% and 69.4% tensile and compressive resilience, respectively, at −40 °C. Moreover, no significant change in resilience is observed after 24 h of storage under a −0.1 MPa vacuum environment. A self-powered TENG pressure sensor containing the developed eutectogel demonstrates a fast response time (16 ms) and stable signal output over 16000 contact-separation cycles. In addition, the sensor operates reliably at −60 °C and vacuum (−0.1 MPa) conditions. The high resilience of the flexible self-powered sensor makes it suitable for use in extreme environments, supporting long-term, reliable pressure monitoring.

Nanomaterial-based optical biomedicine and devices have garnered significant attention for their potential in tumor diagnosis and treatment. However, their application in tumor ablation is often hindered by limited functional integration and concerns over excessive radiation exposure. In this study, we address these challenges by developing a multifunctional fiber probe based on lanthanide-doped nanoparticles, featuring decoupled modules for localized heating and optical thermometry. This design enables synergistic therapy under near-infrared (NIR) laser irradiation. Beyond achieving precise photothermal ablation and real-time temperature monitoring, we uncovered a unique phenomenon: the generation of reactive oxygen species (ROS) by these na-noparticles under NIR laser excitation, even in the absence of traditional photosensitizers. Through a combination of experimental and computational approaches, we elucidated the physical mechanisms underlying ROS generation in wide-bandgap lanthanide nanoparticles. Leveraging these insights, we constructed an all-optical fiber system capable of simultaneous precise thermal control and photodynamic therapy. Our findings offer valuable guidance for the development of advanced optical nanomaterials and devices for effective tumor treatment, both in vivo and in vitro.

Sluggish water dissociation kinetics in the alkaline hydrogen evolution reaction (HER) continue to hamper its practical production. Herein, a class of heterojunction electrocatalyst featuring Ru-Ni(OH)₂ interfaces on nickel foam (NF) with self-engineered built-in electric fields (BIEF) has been synthesized via a simple in situ galvanic replacement reaction. The as-made hierarchical architecture of Ru-Ni (OH)₂/NF exhibits a record overpotential of 9.6 mV at a current density of 10 mA cm⁻² for alkaline HER, surpassing most reported catalysts and the commercial Pt/C benchmark. Furthermore, it also reveals exceptional catalytic activity towards hydrazine oxidation reaction (HzOR) at 100 mA cm⁻² with a remarkably low potential of ca. 0.015 V vs. RHE (reversible hydrogen electrode). The assembled overall hydrazine splitting (OHzS) system integrating HER and HzOR requires a cell voltage of about 0.09 V to reach 50 mA cm⁻², which is 1.637 V lower than the corresponding overall water splitting (OWS) device. Systematic analysis and calculation reveal that the BIEF induces the redistribution of interfacial electrons for Ru, facilitating H₂O dissociation and intermediates conversion to deliver the ultra-high electrocatalytic performance. This work provides an avenue for the design and preparation of electric field-mediated catalysts towards sustainable energy conversion.