Strain Sensors with a High Sensitivity and a Wide Sensing Range Based on a Ti3C2Tx (MXene) Nanoparticle–Nanosheet Hybrid Network

A high sensitivity and large stretchability are desirable for strain sensors in wearable applications. However, these two performance indicators are contradictory, since the former requires a conspicuous structural change under a tiny strain, whereas the latter demands morphological integrity upon a large deformation. Developing strain sensors with both a high sensitivity (gauge factor (GF) > 100) and a broad strain range (>50%) is a considerable challenge. Herein, a unique Ti₃C₂T_x MXene nanoparticle–nanosheet hybrid network is constructed. The migration of nanoparticles leads to a large resistance variation while the wrapping of nanosheet bridges the detached nanoparticles to maintain the connectivity of the conductive pathways in a large strain region. The synergetic motion of nanoparticles and nanosheets endows the hybrid network with splendid electrical–mechanical performance, which is reflected in its high sensitivity (GF > 178.4) over the entire broad range (53%), the super low detection limit (0.025%), and a good cycling durability (over 5000 cycles). Such high performance endows the strain sensor with the capability for full‐range human motion detection.     

A Flexible Microwave Shield with Tunable Frequency‐Transmission and Electromagnetic Compatibility

Wireless techniques have improved life quality for many. However, the drawbacks like instable signal and high loss in air of electromagnetic interference hinder its further development. One solution is to develop a smart material or device, which can selectively receive a specific frequency (f_s) of electromagnetic wave with less loss, and simultaneously show effective shielding against unwanted waves (frequency is denoted as f_p). A bottleneck has been reached, such that using materials alone is unable to achieve the above due to the limitation of the intrinsic physical properties of materials. Here, a strategy combining the material structure design with a voltage control is proposed to overcome the limitation of materials toward the aforementioned task. The efforts are focused on exploring a suitable electrically tunable material with a sensitive response to an external voltage and the flexibility to be engineered to the needed macrostructure. As a result, the f_s region can be fine‐tuned to 8–8.4, 8–9.3, and 8–10.3 GHz.     

Semitransparent,Flexible, and Self‐Powered Photodetectors Based on Ferroelectricity‐Assisted Perovskite Nanowire Arrays

Transparent and flexible photodetectors hold great promise in next‐generation portable and wearable optoelectronic devices. However, most of the previously reported devices need an external energy power source to drive its operation or require complex fabrication processes. Herein, designed is a semitransparent, flexible, and self‐powered photodetector based on the integrated ferroelectric poly(vinylidene‐fluoride‐trifluoroethylene) (P(VDF‐TrFE)) and perovskite nanowire arrays on the flexible polyethylene naphthalate substrate via a facile imprinting method. Through optimizing the treatment conditions, including polarization voltage, polarization time, and the concentration of P(VDF‐TrFE), the resulting device exhibits remarkable detectivity (7.3 × 10¹² Jones), fast response time (88/154 µs) at zero bias, as well as outstanding mechanical stability. The excellent performance is attributed to the efficient charge separation and transport originating from the highly oriented 1D transport pathway and the polarization‐induced internal electric field within P(VDF‐TrFE)/perovskite hybrid nanowire arrays.     

A Versatile Approach for Direct Patterning of Liquid Metal Using Magnetic Field

Patterning of liquid metal (LM) is usually an integral step toward its practical applications. However, the high surface tension along with surface oxide makes direct patterning of LM very challenging. Existing LM patterning techniques are designed for limited types of planar substrates, which require multiple‐step operation, delicate molds and masks, and expensive equipment. In this work, a simple, versatile, and equipment‐free approach for direct patterning of LM on various substrates using magnetic field is reported. To achieve this, magnetic microparticles are dispersed into LM by stirring. When a moving magnetic field is applied to the LM droplet, the aggregated magnetic microparticles deform the droplet to a continuous line. In addition, this approach is also applicable to supermetallophobic substrates since the applied magnetic field significantly enhances the contact between LM and substrate. Moreover, remote manipulation of the magnetic microparticles allows direct patterning of LM on nonplanar surfaces, even in a narrow and near closed space, which is impossible for the existing techniques. A few applications are also demonstrated using the proposed technique for flexible electronics and wearable sensors.     

Simultaneous Electrochemical Dual‐Electrode Exfoliation of Graphite toward Scalable Production of High‐Quality Graphene

Developing scalable methods to produce large quantities of high‐quality and solution‐processable graphene is essential to bridge the gap between laboratory study and commercial applications. Here an efficient electrochemical dual‐electrode exfoliation approach is developed, which combines simultaneous anodic and cathodic exfoliation of graphite. Newly designed sandwich‐structured graphite electrodes which are wrapped in a confined space with porous metal mesh serve as both electrodes, enabling a sufficient ionic intercalation. Mechanism studies reveal that the combination of electrochemical intercalation with subsequent thermal decomposition results in drastic expansion of graphite toward high‐efficiency production of graphene with high quality. By precisely controlling the intercalation chemistry, the two‐step approach leads to graphene with outstanding yields (85% and 48% for cathode and anode, respectively) comprising few‐layer graphene (1–3 layers, >70%), ultralow defects (I_D/I_G < 0.08), and high production rate (exceeding 25 g h^?1). Moreover, its excellent electrical conductivity (>3 × 10⁴ S m^?1) and great solution dispersibility in N‐methyl pyrrolidone (10 mg mL^?1) enable the fabrication of highly conductive (11 Ω sq^?1) and flexible graphene films by inkjet printing. This simple and efficient exfoliation approach will facilitate the development of large‐scale production of high‐quality graphene and holds great promise for its wide application.     

Anisotropic Thermal Conductive Composite by the Guided Assembly of Boron Nitride Nanosheets for Flexible and Stretchable Electronics

Owing to the growing demand for highly integrated electronics, anisotropic heat dissipation of thermal management material is a challenging and promising technique. Moreover, to satisfy the needs for advancing flexible and stretchable electronic devices, maintaining high thermal conductivity during the deformation of electronic materials is at issue. Presented here is an effective assembly technique to realize a continuous array of boron nitride (BN) nanosheets on tetrahedral structures, creating 3D thermal paths for anisotropic dissipation integrated with deformable electronics. The tetrahedral structures, with a fancy wavy shaped cross‐section, guarantee flexibility and stretchability, without the degradation of thermal conductivity during the deformation of the composite film. The structured BN layer in the composites induces a high thermal conductivity of 1.15 W m^?1 K^?1 in the through‐plane and 11.05 W m^?1 K^?1 in the in‐plane direction at the low BN fraction of 16 wt%, which represent 145% and 83% increases over the randomly mixing method, respectively. Furthermore, this structured BN composite maintains thermal dissipation property with 50% strain of the original length of composite. Various electronic device demonstrations provide exceptional heat dissipation capabilities, including thin film silicon transistor and light‐emitting diode on flexible and stretchable composite, respectively.     

Ultrafast Laser Pulses Enable One‐Step Graphene Patterning on Woods and Leaves for Green Electronics

Fast, simple, cost‐efficient, eco‐friendly, and design‐flexible patterning of high‐quality graphene from abundant natural resources is of immense interest for the mass production of next‐generation graphene‐based green electronics. Most electronic components have been manufactured by repetitive photolithography processes involving a large number of masks, photoresists, and toxic etchants; resulting in slow, complex, expensive, less‐flexible, and often corrosive electronics manufacturing processes to date. Here, a one‐step formation and patterning of highly conductive graphene on natural woods and leaves by programmable irradiation of ultrafast high‐photon‐energy laser pulses in ambient air is presented. Direct photoconversion of woods and leaves into graphene is realized at a low temperature by intense ultrafast light pulses with controlled fluences. Green graphene electronic components of electrical interconnects, flexible temperature sensors, and energy‐storing pseudocapacitors are fabricated from woods and leaves. This direct graphene synthesis is a breakthrough toward biocompatible, biodegradable, and eco‐friendlily manufactured green electronics for the sustainable earth.     

激光剥离技术在柔性电子制造领域的应用研究进展

激光剥离技术通过脉冲激光辐照致材料烧蚀实现器件向终端基底的转移,具有一定的材料适用性和工艺兼容性,已成为近年来柔性电子器件制造的新兴关键技术。从激光剥离技术的基本机制和工艺特点出发,对激光剥离技术在不同柔性电子器件制造中的研究现状进行调研和介绍,重点阐述激光剥离技术应用中的新工艺与新理论。对激光剥离技术今后的发展方向,特别是超快激光在技术中的应用可能性进行了总结和展望。     

电子装备生产调测线网络化测试技术研究

针对离散型制造车间电子装备生产调测线中存在的多品种批量测试压力大的问题,结合制造物联技术的应用重新定义当前测试过程,设计具有实时测试信息特征的工作模式和通信手段,以适应车间数字化改造升级的要求。以离散车间自动测试系统为研究对象,通过搭建面向实时测试过程的工业物联识别环境,构建自动测试系统信息化体系框架,详细分析了基于开关切换和自动化流水线的多被测件测试技术、现场设备在线互操作协同技术、基于实时跟踪的数据通信技术等关键技术,给出了基于浏览器/服务器结构的网络化柔性测试生产线实现方法,为提升制造车间的整体测试服务水平提供了基础。     

Progress in flexible perovskite solar cells with improved efficiency

Perovskite solar cell has emerged as a promising candidate in flexible electronics due to its high mechanical flexibil-ity,excellent optoelectronic properties,light weight and low cost.With the rapid development of the device structure and mater-ials processing,the flexible perovskite solar cells (FPSCs) deliver 21.1％ power conversion efficiency.This review introduces the latest developments in the efficiency and stability of FPSCs,including flexible substrates,carrier transport layers,perovskite films and electrodes.Some suggestions on how to further improve the efficiency,environmental and mechanical stability of FPSCs are provided.Specifically,we considered that to elevate the performance of FPSCs,it is crucial to substantially improve film quality of each functional layer,develop more boost encapsulation approach and explore flexible transparent electrodes with high conductivity,transmittance,low cost and expandable processability.