Science China Materials最新文献

Photocatalytic synthesis has been considered a promising technology for solar-to-chemicals conversion. Here, a series of novel photocatalysts was synthesized by decorating uranyl sites on imine-based covalent organic frameworks (i-COF) and proved functioning for the uniformly boosted H₂O₂ production by 1.6–10.1 folds compared with the bare i-COFs in a wide pH range from 2 to 11. Typically, an optimal H₂O₂ production rate of 1435.9 µmol g⁻¹ h⁻¹, i.e., 28.72 mmol g_(U)⁻¹ h⁻¹, was realized over uranyl decorated TTa-COFs under visible light. Systematic investigations reveal that the universally and remarkably promoted performance is attributed to the outstanding electron-transfer ability, accelerated activation of molecular oxygen and favored formation of ·O₂⁻ and *OOH as the key intermediate by virtue of the decorated uranyl ions; thus the two-step single-electron oxygen reduction reaction (ORR) for H₂O₂ photo-generation is significantly facilitated. This work paves a new way for the uranyl-decorated COFs as a novel photocatalyst and provides in-depth insight to the reaction mechanism for photocatalytic H₂O₂ production.

Stretchable electronics have attracted significant attention owing to their unique mechanical flexibility, promising performance, and wear comfort. However, the reliance on single-layer architectures restricts their integration density, and mechanical incompatibility between rigid components and soft substrates limits their service life. To address these challenges, we developed a LEGO-like modular assembly strategy for constructing multilayer three-dimensional (3D) stretchable electronics. In this approach, electronic components (ECs) and self-healing polyurethane (SPU) substrates patterned with liquid metal (LM) circuits function as the LEGO blocks. This modular assembly design simplifies fabrication and enhances the 3D integration density. In addition, the combination of liquid metal circuits and self-healing elastic substrates allows the devices to withstand diverse deformation conditions and facilitates autonomous healing after mechanical damage. Notably, the fabricated devices can undergo multiple recycling and reuse cycles. The design concept and methodology presented here propose a new approach for developing advanced flexible electronics.

The urgent imperative for carbon-neutral chemical production has accelerated the development of solar-driven catalytic technologies that convert abundant C₁ feedstocks (CO₂ and CH₄) into value-added C₂₊ molecules. Standalone photocatalysis remains constrained by rapid charge-carrier recombination and poor C–C coupling selectivity. This review critically examines multi-field-coupled catalysis—a transformative paradigm synergistically integrating solar energy with auxiliary thermal, electric, and magnetic fields. Through mechanistic dissection of photothermal, photoelectrochemical, and photomagnetic field cooperativities, it is summarized that thermal gradients attenuate phonon scattering to enhance charge-carrier drift mobility while vi-brationally stabilizing reactive intermediates, electric potentials drive vectorial charge transport via Coulomb-force-directed separation and band alignment, and magnetic fields modulate spin-selective electron transfer through Zeeman splitting-mediated polarization to boost reaction specificity. This synergistic multi-field integration circumvents intrinsic limitations of single-mode photocatalysis by collectively reconfiguring reaction coordinates for selective C–C coupling. We further address persistent challenges in resolving ultrafast interfacial charge-transfer dynamics, scaling integrated field reactors for industrial deployment, and advancing in situ operando characterization of multiscale processes. Strategic research priorities are proposed to advance sustainable multi-field-coupled catalytic production of fuels and platform chemicals.

Though the rapid development of halogen-free solvent processed organic solar cells (OSCs) has been enabled by side chain modification on small molecular acceptors, the structure-property relationship on inner/outer chain lengths and device performance is unclear, which could inhibit further progress of this technology. In this study, five non-fullerene acceptors (NFAs) with different combinations of side chains are investigated through systematic variation of side-chain positions and architectures. The effects of inner versus outer side-chain modifications are clarified by a comprehensive study on energy level distribution, film morphology, and carrier dynamics. Notably, longer alkyl chains were not always superior, as excessive solubility was found to reduce molecular packing order. As a result, a power conversion efficiency (PCE) of 18.2% is achieved by PM6:BTP-TO12 blend. Furthermore, the optimized ternary OSCs incorporating BTP-TO12 achieved a remarkable PCE of 19.5%. The incorporation of BTP-TO12 as a guest material enhances the performance of L8-BO-based devices processed with green solvents, which represents state-of-the-art performance in the field. This improvement is attributed to the low energy loss and well-controlled aggregation behavior of BTP-TO12 in environmentally friendly processing solvents (toluene).

High densification temperature is usually required for high-entropy carbonitride ultra-high temperature ceramics (HECN-UHTCs), which contributes to grain coarsening and deterioration of mechanical properties. Thus, the quest to decrease the densification temperature and simultaneously enhance the mechanical properties of HECN-UHTCs is a crucial issue of wide concern. To achieve this goal, herein, we introduce CrSi₂ as a sintering additive for (Ti, Zr, Hf, Nb, Ta)(C, N), which effectively reduces the densification temperature of (Ti, Zr, Hf, Nb, Ta)(C, N) by 200 °C. Intriguingly, (Ti, Zr, Nb)₂Cr₄Si₅ with orthorhombic structure is formed within the framework of (Ti, Zr, Hf, Nb, Ta)(C, N) due to interdiffusion or cation exchange. Apart from high hardness (24.65 ± 0.23 GPa), the dual phase (Ti, Zr, Hf, Nb, Ta)(C, N)/(Ti, Zr, Nb)₂Cr₄Si₅ ceramic exhibits a high fracture toughness of 6.03 ± 0.48 MPa m^1/2, significantly exceeding the values of most reported HECN-UHTCs. The mechanisms for the enhanced mechanical properties include: crack deflection, increase in localized lattice strain, and Cr grain boundary segregation. Furthermore, this liquid phase-assisted low-temperature sintering strategy can be widely applied to other UHTCs.

In this work, we introduce a new generation of porphyrin-based photosensitizers (PSs), PoTA1–PoTA3, each strategically engineered with dual anchoring groups—4-ethynylbenzoic acid, 3-ethynylbenzoic acid, or 5-ethynylthiophene-2-carboxylic acid—at the meso-position of the porphyrin macrocycle, and further functionalized with long-chain alkyloxy substituents. This dual-modification strategy not only suppresses undesirable charge recombination but also reduces aggregation on TiO₂ surfaces. Notably, PoTA3, featuring the 5-ethynylthiophene-2-carboxylic acid moiety, exhibits a dramatically redshifted and broadened absorption profile, enabling superior solar spectrum utilization. Under blue light irradiation, the PoTA3-based system achieves a remarkable apparent quantum yield (AQY) of 8.3%, an initial hydrogen evolution rate of 485 mmol g⁻¹ h⁻¹, and an exceptional turnover number (TON) of 27,858 in aqueous media—substantially outperforming both PoTA1 and PoTA2. More notably, both PoTA1 and PoTA3 exhibit remarkable performance under white light irradiation (AQY% = 5.5% and 6.8%, respectively), significantly outperforming the benchmark YD2-o-C8 (AQY% = 4.07%) under identical operating conditions. The synergistic effect of enhanced light harvesting, minimized aggregation, and optimized HOMO and LUMO electron density distributions in PoTA1 and PoTA3 translates to both high efficiency and robust operational stability. These findings create a flexible molecular engineering platform for the next generation of solar-to-hydrogen conversion systems. Our approach opens the door to designing better photosensitizers, which could lead to major improvements in producing hydrogen from water using sunlight.

Perovskite solar cells have attracted considerable attention due to their remarkable efficiency and potential for low-cost production. However, their performance is still impeded by defect states and non-radiative recombination. To mitigate this issue, pyromellitic diimide (PD) is employed as an additive to passivate bulk defects in perovskite materials, effectively inhibiting non-radiative recombination and minimizing energy loss within the system. Experimental investigations demonstrate that PD forms hydrogen bonds with formamidinium (FA⁺) ions and coordinates with Pb²⁺ ions, thereby effectively passivating defects. After being treated with PD, the perovskite film exhibits enhanced crystallinity and improved uniformity. As a result of suppressed non-radiative recombination, the solar cell achieves a high open-circuit voltage of 1.193 V along with a power conversion efficiency of 25.79% in 1.55 eV perovskite solar cells. Furthermore, the PD-treated unpackaged device shows improved stability, retaining 96% of its initial efficiency after 2000 h under a nitrogen atmosphere. This study offers valuable insights into developing effective passivation strategies that address defects in perovskite materials.

High-sensitivity piezoelectric ceramics with high piezoelectric constants (d₃₃) values are of significant research value, because they facilitate the miniaturization, low-power, and high-efficiency characteristics of transducer devices. However, the development of traditional piezoelectric ceramics relies on the modulation of intrinsic parameters with both limited and blind performance enhancements. In contrast, a performance-driven metamaterials creation model provides new ideas for the development of structure-function-integrated high-performance piezoelectric materials. In this study, the effects of the d₃₃ were systematically investigated in species ranging from two-dimensional straight rod (SR) structures to 3D dot-matrix (Octa) structures, and from simple dot-matrix structures to complex triply periodic minimal surface (TPMS) structures and hybrid structures (Octa&SR). It was found that the metastructure design, characterized by both a high polarization charge conversion rate and a low compression modulus (stiffness), constituted an effective means for enhancing d₃₃. The SR structure demonstrated the optimal polarization charge conversion rate, the Fks-Shellular (FksS) structure in the TPMS structures exhibited low stiffness values, and the Octa&SR structure exhibited both properties. Notably, all three structures exhibited exceptional piezoelectric properties. Moreover, the FksS structure demonstrated a substantial d₃₃ (194 pC/N) enhancement of 24% compared with that of the conventional solid structure, while exhibiting isotropic and stress-insensitive properties with optimal structure-function integration. Overall, this study elucidates a mechanism for the design of structures exhibiting desirable piezoelectric properties, thereby providing a novel concept for the future development of high-performance and high-failure-strength piezoelectric materials.

Anisotropic hydrogels have garnered significant attention for their potential applications in actuators, soft robotics, and artificial muscles, owing to their ability to perform shape morphing and generate anisotropic responses under external stimuli. Herein, we present a novel strategy for fabricating anisotropic hydrogels with the aid of liquid crystal polymers (LCPs). A series of liquid crystal polyester-polyethylene glycol (LCP-PEG) multiblock copolymers with varying molecular weights of the PEG block is synthesized via one-pot melt-polycondensation. Upon stretching, LCP-PEG forms a stable, oriented microphase-separated lamellar structure, which endows LCP-PEG with reversible shape change from melting-induced contraction and crystallization-induced expansion of the oriented PEG crystals. This unique structure imparts anisotropic swelling behavior to the films when exposed to water or humidity. Thanks to the oriented microphase separated lamellar structure, the anisotropic liquid crystalline hydrogels have high fracture strength (11.2–14.7 MPa), fracture strain (1600%–2100%), fracture energy (1.7–2.8 MJ m⁻²), and Young’s modulus (51.2–139.9 MPa). Furthermore, the anisotropic LCP-PEG hydrogel actuators exhibit a range of versatile locomotion modes, including object grabbing and transfer between water and air, object gripping in rainy conditions, walking and somersaulting on ratchet-patterned bases under humidity stimuli, and slope climbing through somersault locomotion under salty water stimuli.

Flexible and perceptive sensors represent the pinnacle of wearable technology; nevertheless, most of the current hydrogel-based sensors encounter difficulties in concurrently achieving mechanical durability, biocompatibility, high sensitivity, and scalability. This work introduces an innovative multimodal hydrogel–textile composite sensor (WPU–ChCl hydrogel) developed using the free radical polymerization of acrylamide, integrating choline chloride (ChCl), EMIM TFSI ionic liquid, and waterborne polyurethane (WPU) to overcome existing constraints. The resultant hydrogel demonstrates a synergistic network of covalent and dynamic non-covalent connections, with remarkable stretchability (∼900%), mechanical toughness (>250 kJ/m³), and ionic conductivity (9.2 mS/cm at 600% strain). Comprehensive morphological and chemical analysis validated uniform structure, increased segmental ordering, and improved heat stability. The hydrogel exhibited swift strain responsiveness (gauge factor = 7.23), quick response/recovery times (∼108/114 ms), exceptional durability over 500 cycles, and enhanced self-healing and adherence to various surfaces. Into textiles, the composite demonstrated exceptional real-time touch and motion detection capabilities and retained sensing accuracy after 20 wash cycles. Code transmission and machine learning-based high-accuracy gesture recognition (93.65%) were examples of advanced uses. The wireless-enabled system demonstrated efficacy in IoT-based health monitoring, soft robotics, and human–machine interactions, representing a substantial advancement in next-generation wearable electronics.