Science China Materials最新文献

Postoperative abdominal adhesion, coupled with adverse effects, threatens to patient’s life. However, most bioadhesives as anti-tissue adhesion barrier encounter unreliable adhesion towards slippery abdominal wall along with accidental mispositioning during use, even overlook the impact of frictional stimuli and inflammation on abdominal adhesion. Herein, inspired by lubricated peritoneum, a programmable adhesive dual-layer Janus patch (DJP) barrier with unilateral lubrication and anti-inflammation integrating lubricated layer and adhesive matrix is developed to prevent postoperative abdominal adhesion. Programmable adhesion of DJP rapidly establishes adhesion interface between barrier and tissue primarily through noncovalent interaction, then enhances the interfacial stability of 2.81-fold through covalent interaction. This timescale-dependent adhesion can also allow the mispositioned bioadhesive to be repositioned on tissue in short time, improving surgical fault tolerance. Hydration of micron-scale poly sulfobetaine methacrylamide brush on DJP surface imitates peritoneal lubrication with low coefficient of friction (0.06), diminishing frictional stimuli towards injured tissue. Meanwhile, anti-inflammation of DJP by the antioxidative catechol-containing copolymer is demonstrated in vitro. Further, a rat model indicates that DJP adhering to injured site reduces deposited collagen between abdominal wall and cecum, preventing abdominal adhesion and facilitating tissue healing compared with commercial barriers. Overall, this work provides a notable guiding reference in development of antiadhesive biomaterials.

Heteroatom occupancy plays a key role in the precise modulation of specific material regions by introducing foreign elements into the main material matrix, yet it urgently requires further understanding from a spatial perspective. Herein, we propose a “satellite atom-spinel crystal” concept by synthesizing model catalysts with Fe atoms strategically positioned at two different spatial positions of spinel Co₃O₄ (satellite-Fe at Co₃O₄ (Fe_(Sat)-Co₃O₄) and Fe-doped Co₃O₄ (Co₃Fe_(In)O₄)), through which a new catalytic phenomenon is found. Multidimensional in situ spectroscopies revealed that Fe_(Sat)-Co₃O₄ overcomes the crystal field potential energy (Fe_Sat–O > Fe_Sat–O–Co_Oh) and exhibits 1%_{(Fe atom)} lower impedance than that of Co₃Fe_(In)O₄ due to the resistance-free electron delocalization layer formed in Fe_(Sat)-Co₃O₄, which results in tens of times increase of the turnover frequency and mass activity and then a great reduction in the overpotential by 120 mV when used to catalyze the electrochemical oxygen evolution reaction compared to that of Co₃Fe_(In)O₄. Density functional theory calculations further dynamically reveal the mechanisms governing electron itinerancy modulation. This study not only provides valuable insights into the impact of heteroatomic spatial positioning on material properties but also significantly expands our understanding of atomic manipulation.

Water scarcity and the increasing demand for clean water have driven the development of efficient solar desalination technologies. Interfacial solar steam generation (ISSG) is promising, yet its practical deployment is hindered by insufficient light harvesting and salt crystallization on photothermal surfaces. Here, we report a Janus hydrogel evaporator in which tubular Co₉S₈ nanocrystals are uniformly embedded in a polyvinyl alcohol (PVA) matrix with a concave pyramid pattern, creating a broadband light-trapping architecture (200–2500 nm) with 96% solar absorption. The top surface is further coated with hydrophobic zeolitic imidazolate framework-8 (ZIF-8), while the bottom retains intrinsic hydrogel hydrophilicity, establishing asymmetric wettability that sustains rapid water supply yet suppresses salt deposition. Under one-sun illumination (1 kW m⁻²), the Janus evaporator achieves an evaporation rate of 2.69 kg m⁻² h⁻¹ and a solar-to-vapor efficiency of 98.15 %. Continuous operation in 3.5 wt% brine shows stable performance for 11 h without observable salt crystallization. This work offers an effective, durable pathway toward high-performance solar desalination and wastewater purification.

Two-dimensional planar pentagonal crystals, long pursued for their geometrically frustrated lattice configurations and emergent quantum phenomena, have remained challenging to realize due to the intrinsic incompatibility of regular pentagons with Euclidean tiling. Here, we unveil 37 dynamically stable binary planar pentagonal monolayers through high-throughput computational screening of 1470 stoichiometric candidates. These materials exhibit room-temperature magnetism, including ferromagnetic (Curie temperature (T_C) up to 521 K), antiferromagnetic (Néel temperature (T_N) up to 761 K), and altermagnetic (T_N = 984 K) ground states, alongside unprecedented electronic states: Dirac semimetals, Dirac half-metal, nodal-loop semimetal, nodal-loop half-metal, and altermagnetic semiconductors (Mn₄N₂) with giant spin splitting (0.78 eV). The latter achieves pure spin-polarized transport windows (−0.04 to 0.36 eV) and strain-tunable valley splitting (18.2 meV under 4% uniaxial strain). Intrinsic type-II multiferroicity emerges in Fe₄C₂ and Mn₄C₂, featuring in-plane electric polarization (1.4 and 1.6 pC/m), ferroelasticity (0.8% and 1.2% reversible strain), and reversal chirality. Topological band analysis identifies chiral edge states in Dirac semimetal pentagons, alongside a magnetic topological insulator with Chern number ∣C∣ = 2 in Mo₂S₄ and W₂Te₄. Temperature-driven structural transitions in Os₂S₄ and Tc₂S₄ from pentagonal to Lieb lattices accompany topological state switching and metal-to-semiconductor transitions. This work establishes pentagonal lattices as a platform for symmetry-driven multifunctionality, bridging geometric frustration with applications in spintronics, nanoelectronics, and quantum devices.

Inorganic perovskite solar cells (IPSCs) have garnered significant research interest in recent years owing to their excellent light and thermal stability, as well as their potential applications in tandem solar cells. However, the power conversion efficiency (PCE) and stability of IPSCs are often compromised by residual lattice stress and numerous defects at interfaces and within the bulk material, which lead to severe nonradiative recombination of photogenerated carriers. To address these challenges, we developed a zero-dimensional supramolecular complex, (ETP)₂SbCl₅, serving as both a dual interface and bulk modifier to regulate the growth of inorganic CsPbI₃ perovskite films. The (ETP)₂SbCl₅ modifier exhibits a unique spatial distribution: the ETP⁺ cations preferentially anchor at the buried interface, passivating defects on both TiO₂ and perovskite surfaces, while Sb³⁺ and Cl⁻ ions diffuse into the perovskite bulk during annealing, effectively relieving residual lattice stress. Moreover, Cl⁻ anions accumulate on the top surface of the CsPbI₃ film, passivating cation defects. Consequently, the (ETP)₂SbCl₅-modified CsPbI₃ IPSC achieves a high-quality active layer with significantly reduced defects and suppressed energy loss, an impressive PCE of 21.71% and a high open circuit voltage of 1.27 V, remaining 97.4% of their initial efficiency after 500 h of continuous maximum power point (MPP) tracking.

The development of advanced titanium alloys capable of operating above 600 °C remains a critical challenge for aerospace propulsion systems, where conventional Ti alloys suffer from insufficient high-temperature strength and microstructural instability. Here, we propose a computationally driven design strategy for titanium-based medium-entropy alloys (MEAs) that integrates thermodynamic phase prediction with mechanistically informed strength modeling, enabling systematic exploration of the Ti-Nb-Al-Cr quaternary system. The optimized Ti₇₀Nb₁₀Al₁₅Cr₅ MEA exhibits exceptional performance metrics: 18% room-temperature ductility (as-cast), a yield strength of 520.7 MPa at 650 °C (post-aging), and an ultralow density of 4.76 g/cm³ (45% lighter than Inconel 718). Microstructural characterization reveals a metastable single-phase BCC structure in the as-cast state, which transforms into a BCC/Ti₃Al dual-phase system upon aging, with temperature-dependent precipitate morphology and phase stability. The alloy demonstrates superior high-temperature strength retention up to 900 °C (>80 MPa yield strength), outperforming commercial titanium alloys (e.g., Ti-1100, TG6) and bridging the performance gap between conventional Ti alloys and nickel-based superalloys. This work establishes a multi-criteria design paradigm for entropy-engineered alloys, offering a viable pathway to lightweight, high-temperature structural materials for next-generation aerospace applications.

Developing polymer-based multicolor afterglow materials with tunable phosphorescent colors and applicability across diverse scenarios remains a significant challenge in optical anti-counterfeiting. This paper presents a novel method for preparing phosphorescent polymer anti-counterfeiting labels by coupling triplet-to-singlet Förster resonance energy transfer (TS-FRET) with ultraviolet (UV) laser direct writing technology. Using poly(acrylamide-co-4′-vinyl-[1,1′-biphenyl]-3,5-dicarboxylic acid) (BCA2PAM) as the donor and rhodamine 6G (R6G) as the acceptor, precise color tuning was achieved. Furthermore, time-resolved multicolor displays were realized by loading multicolor afterglow materials onto filter paper, while luminescent elastomers were synthesized through a facile integration with polydimethylsiloxane (PDMS). Inscribing “disappear” on R6G-doped BCA2PAM films with varying laser powers resulted in exclusive visibility of “appear” under UV irradiation. Upon UV off, “disappear” emerges, followed by the reappearance of “appear” after 1 s, demonstrating encryption efficacy. High-power laser-inscribed QR codes are imperceptible under UV illumination yet become visible after simulated breath exposure and subsequent UV activation. When integrated with polyethylene terephthalate (PET) adhesive tapes, the films constitute tamper-evident labels with customizable branding features. Laser-written patterns visible under UV irradiation can be erased under ambient humidity and re-encrypted with new motifs, exhibiting rewritable capability. These results provide a new method based on ultraviolet light and multicolor time-resolved coupling in the field of optical encryption, demonstrating the industrial production potential for high-end anti-counterfeiting label applications.

Organic photothermal cocrystals have garnered considerable attention owing to their diverse applications in photoacoustic imaging, seawater desalination, and photothermoelectric conversion. Herein, we synthesize an organic cocrystal, Tri-F₄TCNQ, which consists of a donor triphenylene and an acceptor F₄TCNQ with a wide absorption wavelength range from visible light to 1800 nm. Furthermore, the Tri-F₄TCNQ cocrystal has superior photothermal properties, making it highly promising for photothermal imaging applications. When illuminated with a laser of 1064 nm, the Tri-F₄TCNQ cocrystal achieves a high photothermal conversion efficiency (PCE) of 63.6%, which is attributed to the dominant nonradiative pathways and suppressed radiative decay channels. Notably, the Tri-F₄TCNQ crystals exhibit magnetism, and a magnetic field can effectively promote photothermal conversion. This is a highly uncommon report about magnetic-responsive photothermal effects in organic cocrystals. Moreover, the Tri-F₄TCNQ cocrystal demonstrates remarkable structural stability, photosensitivity, and magnetic field responsiveness, laying a solid foundation for future applications.

Polymeric carbon nitride (PCN) is identified as a promising photocatalyst for H₂O₂ production due to its visible-light response, low cost, and high selectivity of 2e⁻ oxygen reduction reaction (ORR). However, the H₂O₂ yield of carbon nitride is still restricted by narrow light absorption, low charge separation efficiency, and insufficient active sites. Herein, crystalline poly(heptazine imide) (PHI)-based carbon nitride with highly dispersed In sites and N defects was prepared through the ionothermal method using LiCl/KCl as molten salts. The large π-conjugated system and the existence of N defects greatly enhance the visible-light harvesting ability. The remaining K⁺ ions in the nitrogen cavities of PHI serve as interlayer electron channels, and the incorporation of N defects triggers asymmetric distribution of charges on the heptazine network, promoting interlayer and in-plane charge separation and transfer, respectively. The In sites accelerate charge transfer dynamics and act as active sites for ORR. The synergistic effect of metal modification and defect engineering boosts the electron delocalization within the photocatalyst and thus significantly improves the photocatalytic activity. The H₂O₂ production rate of 10InPHI reaches 15.3 mmol g⁻¹ h⁻¹ through a two-step single-electron ORR pathway, underscoring the great potential of modified carbon nitride materials in efficient H₂O₂ photosynthesis.