High‐Performance Fluorescent Organic Light‐Emitting Diodes Utilizing an Asymmetric Anthracene Derivative as an Electron‐Transporting Material

Fluorescent organic light‐emitting diodes with thermally activated delayed fluorescent sensitizers (TSF‐OLEDs) have aroused wide attention, the power efficiencies of which, however, are limited by the mutual exclusion of high electron‐transport mobility and large triplet energy of electron‐transporting materials (ETMs). Here, an asymmetric anthracene derivative with electronic properties manipulated by different side groups is developed as an ETM to promote TSF‐OLED performances. Multiple intermolecular interactions are observed, leading to a kind of “cable‐like packing” in the crystal and favoring the simultaneous realization of high electron‐transporting mobility and good exciton‐confinement ability, albeit the low triplet energy of the ETM. The optimized TSF‐OLEDs exhibit a record‐high maximum external quantum efficiency/power efficiency of 24.6%/76.0 lm W^?1, which remain 23.8%/69.0 lm W^?1 at a high luminance of even 5000 cd m^?2 with an extremely low operation voltage of 3.14 V. This work opens a new paradigm for designing ETMs and also paves the way toward practical application of TSF‐OLEDs.     

Aligning Solution‐Derived Carbon Nanotube Film with Full Surface Coverage for High‐Performance Electronics Applications

The main challenge for application of solution‐derived carbon nanotubes (CNTs) in high performance field‐effect transistor (FET) is how to align CNTs into an array with high density and full surface coverage. A directional shrinking transfer method is developed to realize high density aligned array based on randomly orientated CNT network film. Through transferring a solution‐derived CNT network film onto a stretched retractable film followed by a shrinking process, alignment degree and density of CNT film increase with the shrinking multiple. The quadruply shrunk CNT films present well alignment, which is identified by the polarized Raman spectroscopy and electrical transport measurements. Based on the high quality and high density aligned CNT array, the fabricated FETs with channel length of 300 nm present ultrahigh performance including on‐state current I_on of 290 µA µm^?1 (V_ds = ?1.5 V and V_gs = ?2 V) and peak transconductance g_m of 150 µS µm^?1, which are, respectively, among the highest corresponding values in the reported CNT array FETs. High quality and high semiconducting purity CNT arrays with high density and full coverage obtained through this method promote the development of high performance CNT‐based electronics.     

Semimetal–Semiconductor Transitions for Monolayer Antimonene Nanosheets and Their Application in Perovskite Solar Cells

Antimonene‐based 2D materials are attracting increasing research interest due to their superior physicochemical properties and promising applications in next‐generation electronics and optoelectronics devices. However, the semiconductor properties of antimonene are still at the theoretical simulation stage and are not experimentally verified, significantly restricting its applications in specific areas. In this study, the semiconductor properties of monolayer antimonene nanosheets are experimentally verified. It is found that the obtained semiconductive antimonene nanosheets (SANs) exhibit indirect bandgap properties, with photoluminescence (PL) bandgap at about 2.33 eV and PL lifetime of 4.3 ns. Moreover, the obtained SANs are ideal for the hole extraction layer in planar inverted perovskite solar cells (PVSCs) and significantly enhance the device performance due to fast hole extraction and efficient hole transfer at the perovskite/hole transport layer interface. Overall, these findings look promising for the future prospects of antimonene in electronics and optoelectronics.     

Selectively Permeable Double Emulsions

Natural organisms are made of different types of microcompartments, many of which are enclosed by cell membranes. For these organisms to display a proper function, the microcompartments must be selectively permeable. For example, cell membranes are typically permeable toward small, uncharged molecules such as water, selected nutrients, and cell signaling molecules, but impermeable toward many larger biomolecules. Here, it is reported for the first time dynamic compartments, namely surfactant‐stabilized double emulsions, that display selective and tunable permeability. Selective permeability is imparted to double emulsions by stabilizing them with catechol‐functionalized surfactants that transport molecules across the oil shell of double emulsions only if they electrostatically or hydrophobically attract encapsulants. These double emulsions are employed as semipermeable picoliter‐sized vessels to controllably perform complexation reactions inside picoliter‐sized aqueous cores. This thus far unmet level of control over the transport of reagents across oil phases opens up new possibilities to use double emulsion drops as dynamic and selectively permeable microcompartments to initiate and maintain chemical and biochemical reactions in picoliter‐sized cell‐mimetic compartments.     

Black Phosphorus Quantum Dots with Renal Clearance Property for Efficient Photodynamic Therapy

Black phosphorus (BP) nanomaterials have emerged as rapidly rising stars in the field of nanomedicine. In this work, BP quantum dots (BPQDs) are synthesized and their potential as photosensitizers is investigated for the first time. The BPQDs present good stability in physiological medium and no appreciable cytotoxicity. More importantly, the BPQDs can be rapidly eliminated from the body in their intact form via renal clearance due to their ultrasmall hydrodynamic diameter (5.4 nm). Both in vitro and in vivo studies indicate that the BPQDs have excellent photodynamic effect under light irradiation that can effectively generate reactive oxygen species to kill cancer cells. The BPQDs thus can serve as biocompatible and powerful photosensitizers for efficient photodynamic therapy.     

A state-of-the-art review on passivation and biofouling of Ti and its alloys in marine environments

High strength-to-weight ratio, commendable biocompatibility and excellent corrosion resistance make Ti alloys widely applicable in aerospace, medical and marine industries. However, these alloys suffer from serious biofouling, and may become vulnerable to corrosion attack under some extreme marine conditions. The passivating and biofouling performance of Ti alloys can be attributed to their compact, stable and protective films. This paper comprehensively reviews the passivating and biofouling behavior, as well as their mechanisms, for typical Ti alloys in various marine environments. This review aims to help extend applications of Ti alloys in extremely harsh marine conditions.     

自修复聚合物的制备与应用研究进展

聚合物暴露于外部环境(光照、紫外线、热)之中会受到破坏,降低材料的性能以及使用寿命。自修复是人们模仿生物体损伤愈合的概念,解决材料损伤、延长材料使用寿命的新方法。针对近年来自修复聚合物材料的研究情况,文中根据自修复机理将其分为共价键自修复材料、超分子自修复材料两类,分别阐述了它们的化学原理与制备方法。在此基础上,对自修复性质的多样性,如形状自修复、导电性自修复、疏水性自修复、顺磁性自修复等应用性质进行综述。最后,展望了自修复聚合物材料的发展方向,指出纳米粒子、石墨烯等新颖的自修复方法已经崭露头角,有望从材料的堆积结构层次上完善并提高聚合物的自修复性能。     

Carbon‐Coated Na3.32Fe2.34(P2O7)2 Cathode Material for High‐Rate and Long‐Life Sodium‐Ion Batteries

Rechargeable sodium‐ion batteries are proposed as the most appropriate alternative to lithium batteries due to the fast consumption of the limited lithium resources. Due to their improved safety, polyanion framework compounds have recently gained attention as potential candidates. With the earth‐abundant element Fe being the redox center, the uniform carbon‐coated Na_3.32Fe_2.34(P₂O₇)₂/C composite represents a promising alternative for sodium‐ion batteries. The electrochemical results show that the as‐prepared Na_3.32Fe_2.34(P₂O₇)₂/C composite can deliver capacity of ≈100 mA h g^?1 at 0.1 C (1 C = 120 mA g^?1), with capacity retention of 92.3% at 0.5 C after 300 cycles. After adding fluoroethylene carbonate additive to the electrolyte, 89.6% of the initial capacity is maintained, even after 1100 cycles at 5 C. The electrochemical mechanism is systematically investigated via both in situ synchrotron X‐ray diffraction and density functional theory calculations. The results show that the sodiation and desodiation are single‐phase‐transition processes with two 1D sodium paths, which facilitates fast ionic diffusion. A small volume change, nearly 100% first‐cycle Coulombic efficiency, and a pseudocapacitance contribution are also demonstrated. This research indicates that this new compound could be a potential competitor for other iron‐based cathode electrodes for application in large‐scale Na rechargeable batteries.     

铝合金表面Ti-Zr转化膜的制备及腐蚀行为研究

为进一步提高铝合金的耐蚀性,以H2TiF6和H2ZrF6为主成膜剂,六偏磷酸钠为辅助成膜剂,在LY12铝合金表面制备了Ti-Zr转化膜,系统地研究了转化液pH值和转化时间对转化膜耐蚀性的影响.通过SEM、EDX、电化学测试、全浸试验等研究了转化膜表面形貌-成分-耐蚀性之间的关系.结果 表明:转化温度为40 ℃时,最佳转化液pH值为4.5,最佳转化时间为15 min;转化膜层中主要含有Ti、Al、O元素,另含有少量Zr元素,推测转化膜的主要成分为TiO2、ZrO2、Al2O3,生成的连续致密氧化膜能明显抵御Cl-的侵蚀,显著提高其耐蚀性.