ACS Materials Letters最新文献

Low resistance to fracture in two-dimensional covalent organic frameworks (2D COFs) limits their practical applications, especially in mechanically demanding fields, such as flexible electronics and sensing devices. We address this critical limitation by fabricating a sandwich-structured nanocomposite consisting of graphene layers sandwiched between 2D COF layers (2D COFs/graphene/2D COFs) via chemical vapor deposition. Our sandwich-structured nanocomposites exhibit a remarkable improvement in modulus E, fracture toughness K_IC, and critical energy release rate G_C compared to pure 2D COFs. This enhancement is likely due to the graphene layers as the backbone of the sandwich structure effectively carrying and redistributing mechanical stress within the nanocomposite. Our findings demonstrate that a sandwich structure can improve the mechanical robustness of a 2D COF so that it can preserve the functionality and mechanical integrity for applications in stretchable electronics.

Organic mixed ionic–electronic conductors (OMIECs) are promising materials for bioelectronics, neuromorphic computing, and energy storage due to their dual conductivity. However, the relationship between the film morphology and device performance in the OMIEC-based organic electrochemical transistors (OECTs) remains poorly understood. We investigate the carboxyl-alkyl-functionalized conjugated polymer poly[3-(4-carboxybutyl)thiophene] (P3CBT) and show that the ratio of pyridine (Py) to dimethyl sulfoxide (DMSO) in the precursor solution strongly influences the OECT performance. We find that varying the Py:DMSO ratio significantly alters the electronic mobility (μ), while the volumetric capacitance (C*) remains largely unchanged. Films cast from an 80:20 Py:DMSO mixture yield a μC* product of 110 ± 26 F cm^–1 V^–1 s^–1, a 5-fold enhancement compared to films processed from Py. UV–vis absorption and X-ray scattering measurements reveal that this improvement arises from increased polymer crystallinity and orientational order. These results demonstrate that precursor solvent is a key parameter for optimizing OECT performance.

Predicting dielectric failure in semicrystalline polymers, e.g., poly(vinylidene fluoride) (PVDF) under extreme electric fields (>300 MV/m) remains impeded by the disconnection from the spatial structure, which can be attributed to a fundamental schism where reciprocal-space band models fail to capture real-space aggregated states control of carrier dynamics. Herein, this dichotomy is resolved through an aggregation-state framework where crystalline spherulites and amorphous domains deterministically control electronic behavior. To address this, engineered spherulite dimensions directly modulate the entire field-dependent band models of carrier injection, trapping, detrapping, and enabling field-driven intertrap hopping via amorphous free-volume channels. Moreover, space-charge-limited current and thermally stimulated current measurements map carrier trapping to chain-end defects at spherulite edges, while electrical treeing visualization identifies these interfaces as breakdown initiation sites. As a consequence, by correlating band structure modification, and carrier kinetics, this paradigm transforms aggregation states into design variables for high-field insulation robustness in semicrystalline polymers.

This study explores the viscosity behavior of the Ge–Se chalcogenide glass-forming system. Four compositions containing 5, 10, 15, and 20 at. % germanium were examined. Viscosity measurements were performed over a broad range, spanning approximately 13 orders of magnitude, by combining the pressure-assisted melt filling technique with penetration and parallel-plate viscometry. The results demonstrate that no fragile-to-strong crossover occurs in any of the studied compositions.

Active particles consume energy from their environment and locally dissipate it to power their motion, assembly, or reconfiguration. While active particle research has been ongoing since the early 2000s, it has struggled to move beyond research laboratories and into real-world use. In this Perspective, we discuss three basic aspects of active particle design that can be improved to accelerate their translation to real-world settings, such as drug delivery, analyte detection, and pollution removal. First, we describe strategies for enhancing particle dexterity to operate in non-idealized environments. Then, we discuss the integration of application-relevant materials to move from basic proof-of-concept studies to field-testable systems. Finally, we discuss the need to balance the inherent trade-off between complexity and scale-up to promote large-scale manufacturing for applications that require it. Addressing these areas, coupled with increased commercial investment and strategic licensing, may help to catalyze the translation of active particles into the real world.

Organic electrochemical transistors (OECTs) have significant potential in bioelectronics due to their strong signal amplification, low-voltage operation, and inherent biocompatibility. Complementary inverters, essential for electrophysiological signal amplification, require both p-type and n-type OECTs. Ambipolar OECTs offer advantages in simplifying fabrication and reducing costs. However, achieving balanced ambipolar OECTs remains challenging due to the contradictory molecular design requirements for optimizing both hole and electron transport. This requires sophisticated molecular engineering strategies. In this study, we develop high-performance ambipolar OECTs by blending an n-type glycolated naphthalenediimide (NDI)-dialkoxybithiazole (2Tz) copolymer (P-7O) with a p-type bithiophene-thienothiophene polymer (P(g2T-TT)). The resulting devices exhibit a low threshold voltage of 0.45 V and −0.56 V, exceptional operational stability (over 10 h in water), and switching ratios greater than 10³ in both operating modes. These devices enable inverters with high voltage gains (254 V/V at positive bias and 71 V/V at negative bias).

It is well established that semiconductor materials are crucial in modern technologies. Technological breakthroughs are achievable mainly through alteration of the properties of semiconducting materials by doping. Doping in semiconductors can be accomplished by multiple techniques. Every method possesses its own merits and drawbacks. Typically, most doping techniques affect the structure of the semiconducting material due to the impact of the doping atom during the doping procedure. This profoundly affects the characteristics of the semiconducting material. To tackle these issues, an innovative approach has recently been employed for doping semiconducting materials based on the differences in the work function among these materials. This technique is commonly referred to as “surface transfer doping”. This Review begins with a discussion of the theory underlying the surface transfer doping process, followed by an examination of its significant impact on the properties of semiconductors.

Quantum dot light-emitting diodes (QLEDs), as an emergent display technology, have garnered considerable interest due to their outstanding luminescent characteristics. Among various strategies to improve device performance, the localized surface plasmon resonance (LSPR) effect has been demonstrated as a promising approach. However, previously reported LSPR-enhanced green QLEDs rely on heavy-metal-based quantum dots (QDs), which pose a significant barrier to their future commercialization. Herein we present the first LSPR-enhanced eco-friendly green ZnSeTe-based QLEDs by incorporating Au nanoparticles into the ZnMgO electron transport layer (ETL) and optimizing their concentration to maximize the LSPR effect. As a result, the optimal plasmonic devices exhibited a significant improvement in performance, with the maximum external quantum efficiency (EQE) substantially increased from 7.15% to 11.75% and the extrapolated T₅₀ lifetime at 1000 cd m^–2 markedly extended from 107.63 to 150.41 h. Consequently, this work provides an efficient strategy toward developing high-performance, eco-friendly green QLEDs.

Photocatalytic H₂O₂ production coupled with uranyl ion complexation to form UO₂(O₂) precipitates provides an energy-efficient solution for uranium recovery. However, the currently used photocatalysts often require sacrificial agents and lack stability. Herein, a porphyrin-based conjugated microporous polymer, Bpy-Por-CMP, was synthesized via a one-step method utilizing pyrrole- and aldehyde-based ligands. Bpy-Por-CMP exhibited a high uranium extraction rate of 95.4% under simulated sunlight without sacrificial agents, maintaining over 94.0% efficiency across a pH range of 3–9. In contrast with biphenyl ligands, bipyridine ligands were found to construct a donor–acceptor structure with the porphyrins. This unique structure enhances photoinduced charge separation, facilitating effective photocatalytic H₂O₂ production and uranium extraction. This work demonstrates the application of a bipyridyl porphyrin-based conjugated microporous polymer for uranium extraction via the UO₂(O₂)-based approach under non-sacrificial and ambient conditions. The chemical stability and high uranium extraction performance of this material highlight its practical application in nuclear wastewater treatment.

Capacitive Deionization (CDI) has become a viable and energy-efficient desalination process nowadays. Conventional electrodes for CDI application possessed low ion adsorption capability. Recent advancements focus on faradaic electrodes, which exploit redox reactions to produce improved ion storage through pseudocapacitive and intercalation effects. Advanced materials offer improved desalination efficiency, operating adaptability, and charge storage properties. Advanced CDI electrode efficiency improved due to faradaic ion storage, such as cathodic oxygen reduction and intercalation reactions which resulted through the development of electrode functionality and design. This review thoroughly examines recent developments in capacitive and faradaic materials-based electrodes for CDI, focusing on material synthesis and performance optimization. The review outlines limitations such as parameter optimization, electrode deterioration, and integration into scalable CDI systems. Emerging materials offer effective desalination efficacy by tackling these limitations. This review critically analyzes the drawbacks of traditional carbon-based CDI electrodes and their physiochemical advancements, and assesses their economic viability.