Science China Materials最新文献

Conjugated polymers exhibit exceptional adaptability in flexible thin-film transistors, owing to their inherent flexibility and high charge mobility. Nonetheless, achieving conjugated polymers that demonstrate both high mobility and stability under mechanical stress, such as bending or stretching, remains a significant challenge. In this study, we synthesized an ethylene-bridged conjugated polymer, PDPPVIDT, derived from methyl-side diketopyrrolopyrrole (DPP) and indacenodithiophene (IDT) aldehydes, using an environmentally friendly Knoevenagel condensation reaction under mild conditions, resulting in a moderate yield with promising scalability. Conventional characterization techniques revealed enhanced backbone planarity with stable π-π stacking, while thin films of PDPPVIDT displayed a near-amorphous nature due to the conformational isomerism of the ethylene bond. This structure enables simultaneous charge transport and flexibility. Consequently, flexible organic thin-film transistor (OTFT) devices based on PDPPVIDT demonstrated excellent hole mobility (μ_h) reaching up to 1.70 cm² V⁻¹ s⁻¹, along with high mechanical bending resilience. This work underscores the potential of vinyl-bridged donor-acceptor conjugated polymers, highlighting the industrial adaptability of their production process and offering new insights for the design and synthesis of future flexible electronic materials.

Covalent organic frameworks (COFs) are garnering significant interest in photocatalytic CO₂ reduction. However, their limited efficiency in separating photogenerated carriers and the scarcity of catalytic sites lead to suboptimal photocatalytic performance. Here we develop a molecular engineering approach to design a pyrene-based COF (PyTa-H COF) confined cobalt single atoms photocatalyst (Co SACs) for CO₂ reduction. Pyrene moiety is introduced to enhance visible-light harvesting capability and improve charge separation in the COF. Subsequently, Co SACs enhance the photocatalytic activity by accelerating the migration of photo-induced carriers and reducing the reaction energy of the rate-determining step. Remarkably, PyTa-H@Co achieves a CO production rate of 18.36 mmol g⁻¹ h⁻¹ and a selectivity of 94% in 4 h under visible light irradiation, which is comparable to the reported best-performing COFs. Density functional theory calculations reveal that the Co SACs greatly stabilize *COOH and significantly reduce the energy of the decisive step, leading to outstanding photocatalytic performance. This work, through molecular engineering design, highlights the critical relationship between catalyst structure and function in enhancing photocatalytic efficiency.

Persistent luminescence nanomaterials can remain luminescence when the light source is turned off, which exhibits promise in biosensor and bioimaging fields since they have the ability to completely eradicate tissue autofluorescence. Although significant progress has been made in the persistent luminescence biosensing, there is still a dearth of long-afterglow detection platform with low limit of detection (LOD) and high sensitivity. Herein, Zn₂GeO₄:Mn, Cr persistently luminescent nanorods (PLNRs) with superior persistent luminescence and long afterglow time were developed. The addition of Cr³⁺ manifestly improves persistent luminescence intensity and afterglow duration through creating a deep defect trap. Then the biosensors were constructed by combining the Zn₂GeO₄:Mn,Cr PLNRs-antibody and Fe₃O₄ magnetic nanoparticles (MNPs)-antibody for nucleocapsid protein detection based on electrostatic attraction. The LOD value for nucleocapsid protein realizes as low as 39.82 ag/mL, which is much lower than the previously reported persistent luminescent-based biosensors. Accordingly, the low detection sensitivity is attributed to fluorescence resonance energy transfer. In addition, high specificity is also achieved. Therefore, the as-prepared Zn₂GeO₄:Mn,Cr persistently luminescent materials can act as the promising candidate in biosensors applications. This strategy provides effective guidance for the development of biosensing platforms with high sensitivity and specificity.

Inorganic-organic composite electrolyte is proved an effective way to enhance the overall performance of the electrolytes. However, simply combining powder fillers with polymers is not sufficient for the application of composite electrolytes. In this work, we designed an ultrathin organic-inorganic composite solid electrolyte with high mechanical strength and ionic conductivity, in which the inorganic Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) solid electrolyte is pre-fiberized into a three-dimensional nanofiber network to serve as a self-supporting skeleton for the polyethylene oxide (PEO) matrix. This continuous skeleton structure not only significantly improves the mechanical strength of the PEO-based electrolyte, but also forms a continuous lithium-ion conduction path, promoting the rapid migration of lithium ions. The fiber-reinforced composite electrolyte has an ionic conductivity of 8.27×10⁻⁴ S cm⁻¹ at 60°C and a tensile strength of up to 4.29 MPa. Besides, it exhibits a reduced overpotential and stable long-term cycling performance over 1700 h when used in Li/Li symmetric batteries. The LiFePO₄ (LFP)∣Li cell assembled with the fiber-reinforced composite electrolyte also delivers a specific capacity of about 142 mAh g⁻¹ over 300 cycles at 0.5 C and maintains good cycling stability. This work provides a novel idea for designing the next generation of safe and reliable organic-inorganic composite solid-state electrolyte membranes.

The development of low-cost, highly active platinum (Pt)-based electrocatalysts for oxygen reduction reaction (ORR) is crucial for widespread applications of fuel cells. An effective approach lies in alloying Pt with non-noble transition metals to modulate the physicochemical state of the Pt surface. However, fundamental challenges remain in understanding the structure-performance relationship due to the complexity of composition, crystal type, and surface structure during the alloying process. In this study, we synthesized a series of PtCo bimetallic solid solutions with varying ratios using a liquid-phase synthesis method. By exploiting the characteristics of solid solutions, the resulting PtCo bimetallic alloy maintains the face-centered cubic crystal structure of pure platinum, minimizing the complexities introduced during alloying and facilitating mechanism analysis. Furthermore, under controlled alloy composition and crystal structure, we investigated the dependence of the electrocatalytic activity for the oxygen reduction reaction on the surface strain of the platinum catalyst. The S-PtCo-SNPs cathode designed accordingly endows both proton exchange membrane fuel cell (PEMFC) (2.08 W cm⁻² at 4 A cm⁻²) and Zn-air battery (ZAB) (143.1 mW cm⁻² at 214.5 mA cm⁻²) with outstanding performance.

Compared with the inherent brittleness of bulk silicon (Si) at ambient temperature, the nanosized Si materials with very high strength, plasticity, and anelasticity due to size effect, are all well-documented. However, the ultimate stretchability of Si nanostructure has not yet been demonstrated due to the difficulties in experimental design. Herein, directly performing in-situ tensile tests in a scanning electron microscope after developing a protocol for sample transfer, shaping and straining, we report the customized nanosized Si mechanical metamaterial which overcomes brittle limitations and achieves an ultra-large tensile strain of up to 95% using the maskless focused ion beam (FIB) technology. The unprecedented characteristic is achieved synergistically through FIB-induced size-softening effect and engineering modification of mechanical metamaterials, revealed through analyses of finite element analysis, atomic-scale transmission electron microscope characterization and molecular dynamics simulations. This work is not only instructive for tailoring the strength and deformation behavior of nanosized Si mechanical metamaterials or other bulk materials, but also of practical relevance to the application of Si nanomaterials in nanoelectromechanical system and nanoscale strain engineering.

Anthraquinone (AQ), an effective hydrogen atom transfer catalyst, is limited in photocatalytic applications due to its dimerization. In this study, a simple 3-(3-(dimethylamino) propyl)-1-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide (EDC/HNS) assisted linking strategy was developed to covalently graft AQ–COOH onto C₃N₄ (CN). Using this method, we successfully synthesized amide-bonded CN–AQ ultrathin nanosheets. The amide covalent bond formed between C₃N₄ and AQ facilitates efficient electron migration from C₃N₄ to AQ. As a result, charge carrier recombination is prevented and the hydrogen atom transfer capacity of AQ is enhanced. The CN–AQ photocatalyst exhibits high activity and selectivity with a toluene conversion rate of 10274 (mol g⁻¹ h⁻¹ and 85% selectivity for benzaldehyde, which is 31 times and 1.7 times higher than those of pristine C₃N₄ and AQ–COOH, respectively. Owing to the strong covalent bond in CN–AQ composite, the stability of AQ–COOH was greatly enhanced. This approach provides a new pathway to improve catalytic efficiency and solve the dimerization problem of AQ.

The conversion of carbon dioxide (CO₂) to the reduced chemical compounds offers substantial environmental benefits through minimizing the emission of greenhouse gas and fostering sustainable practices. Recently, the unique properties of metal-organic frameworks (MOFs) make them attractive candidates for electrocatalytic CO₂ reduction reaction (CO₂RR), providing many opportunities to develop efficient, selective, and environmentally sustainable processes for mitigating CO₂ emissions and utilizing CO₂ as a valuable raw material for the synthesis of fuels and chemicals. Here, the recent advances in MOFs as efficient catalysts for electrocatalytic CO₂RR are summarized. The detailed characteristics, electrocatalytic mechanisms, and practical approaches for improving the electrocatalytic efficiency, selectivity, and durability of MOFs under realistic reaction conditions are also clarified. Furthermore, the outlooks on the prospects of MOF-based electrocatalysts in CO₂RR are provided.

We report a novel benzoxazole derivative, 1,4-bis(benzo[d]oxazol-2-yl)naphthalene (BBON), exhibiting exceptional multifunctional properties for advanced optoelectronic applications. BBON crystals demonstrate remarkable multidirectional bending and twisting at room temperature and retain elasticity under extreme conditions, such as exposure to liquid nitrogen, showcasing their durability. These crystals can be crafted into complex mesh and lantern shapes, highlighting their versatility for flexible and wearable technologies. Under high pressure, BBON exhibits significant piezochromic shifts, with the emission wavelength shifting from 477 to 545 nm upon pressure increase. BBON crystals, with a high quantum yield of 72.26%, exhibit excellent optical waveguide performance: 0.38 dB/cm when straight and 0.56 dB/cm when bent. These properties make them ideal for smart sensors and flexible electronic devices. Single-crystal analyses reveal that molecular stacking and intermolecular interactions are crucial to their elastic and piezochromic properties, providing insights for the design of future responsive materials.