Search

In situ transmission electron microscopy is used to analyze the phase transition of Ag2Se nanoparticles with different size. The result provides a potential design toward a low-temperature range of thermoelectric materials through nanoengineering.

This review introduces thein situelectrical transmission electron microscope technologies that apply various electrical stimuli to resistive random access memory (RRAM) devices exploring the microscopic process of RRAM in different working modes.

The study and replication of human sensory abilities, such as visual, auditory, and tactile perception, depends on the availability of integrating electronics into flexible materials. Much previous research on pressure sensing films has a lack of flexibilities in its products and cannot be well applied to wearable device. In this letter, we first prepare Graphene-VSe2-Ecoflex sponge, and then fabricate highly compressible Graphene-VSe2-Ecoflex pressure sensors using this sponge, and finally construct an innovative glove with this highly compressible pressure sensor array. The Graphene-VSe2-Ecoflex pressure sensor sustains high strain up to 85%. The sensor retains a good linearity performance under the cycling test. Moreover, the glove can identify and manipulate subjects at an over 89% recognition rate after trained by neural networks. The realization of the smart object identification glove may provide a new strategy for applying flexible devices to intelligent sensing systems.

Intelligent systems have brought convenience to contemporary society. However, latency and poor-efficiency have been urgent problems for intelligence systems. Here, an infrared (IR) intelligent system fusing a non-contact IR thermopile sensor array fabricated by microelectromechanical system technology and an artificial neural network (ANN) algorithm is proposed, with the characteristics of high-efficiency and low-latency. The system is based on a designed near-sensor computing architecture, which can realize computing directly on edge devices without sending data to the cloud, resulting in reduced redundant data and decreased latency. The responsivity of the sensors affects the weight accuracy and computing speed of the ANN algorithm and further influences the accuracy and efficiency of the system. Transfer of graphene oxide (GO) material to the IR thermopile sensors with a proposed location transfer method is suggested to enhance the responsivity. The responsivity of the IR thermopiles with GO is up to 705.1 V/W, which is enhanced by 85.9% compared to that without GO. The system is applied to gesture recognition to study practicality. The recognition accuracy of the system with GO is 100%. This work provides an effective idea for studying a high-accuracy IR intelligent sensing system.

The robustness of electrostatic sensitive devices is important in state-of-the-art silicon technology. However, the electrical breakdown-induced microstructure evolution remains unclear. In this work, we performed the physical failure analysis of breakdown in an enhanced modified lateral silicon-controlled rectifier-based electrostatic discharge (ESD) device. Direct visualization of the conductive metal filaments in the doped silicon substrate has been achieved by high-resolution transmission electron microscopy. The locations of these metal filaments induced by breakdown are found near the cathode. The evolution of these microstructural changes and chemical properties provides guide to the failure analysis of ESD devices.

Paper, as a foldable, pollution-free, and low-cost material, has become a suitable support substrate for producing flexible thermoelectric (TE) generators to realize waste heat recycling and the application of human-powered electronic devices. We propose a facile fabrication method to modify cellulose paper with inorganic TE powders via vacuum filtration, making a modified paper that possesses good thermoelectric properties. By connecting the modified paper to copper foils, flexible paper-based TE generators (PTGs) are fabricated. The obtained PTG with three units of P–N modules can generate an output voltage of ∼41.2 mV at a temperature difference of 50 K. Based on this modified paper, a thermal sensor that responds to heat sources, such as fingers, is proposed with a rapid response time of 0.25 s. This work offers a promising strategy for the simple fabrication of PTGs, paving the way for achieving the commercial application of self-powered wearable electronics.

China has actively promoted electronic toll collection (ETC), increasing the proportion of ETC vehicles, and the number of ETC lanes at mainline toll stations has exceeded that of manual toll collection (MTC) lanes. To investigate the effects of ETC and MTC vehicles as guidance objects on the lane-changing behaviors of drivers, we designed three guidance signal plans, including the original sign plan (OR), a complete MTC sign plan (CMS), and a complete MTC sign plan with voice warnings (VW&CMS), for expressway mainline toll lanes. A driving simulator experiment with 40 participants was conducted to evaluate the efficacy of the plans. Generalized estimating equations were used to analyze the characteristics of lane-changing behaviors in different guidance plans, and an entropy weight model using the technique of ranking the order of preference by its similarity to the ideal solution (TOPSIS) was constructed to evaluate the guidance effects of different plans. The results showed that the CMS and VW&CMS plans significantly improved lane-changing behaviors. This improvement is demonstrated by a higher lane-changing ratio, shorter response time, earlier initiation of lane-changing location, higher speed, lower deceleration rate, and longer lane-changing duration distance. These findings can help expressway designers to optimize the guidance-sign system for mainline toll stations.

In daily life, individuals need to recognize and update emotional information from others' changing body expressions. However, whether emotional bodies can enhance working memory (WM) remains unknown. In the present study, participants completed a modified n-back task, in which they were required to indicate whether a presented image of an emotional body matched that of an item displayed before each block (0-back) or two positions previously (2-back). Each block comprised only fear, happiness, or neutral. We found that in the 0-back trials, when compared with neutral body expressions, the participants took less time and showed comparable ceiling effects for accuracy in happy bodies followed by fearful bodies. When WM load increased to 2-back, both fearful and happy bodies significantly facilitated WM performance (i.e., faster reaction time and higher accuracy) relative to neutral conditions. In summary, the current findings reveal the enhancement effect of emotional body expressions on WM and highlight the importance of emotional action information in WM.

Sublimation as the motion behavior of surface atoms plays a vital role in tailoring the structure and properties of materials for atomic-scale manufacturing. Revealing the thermodynamics of sublima...

Nickel cobalt sulfide (NiCo2S4) is a promising battery-type material for electrochemical energy storage. However, the slow charge transfer kinetics and ion diffusion as well as the deficiency of electrochemically active sites hinder the practical application of NiCo2S4. Defect engineering at the atomic level is adopted to improve charge storage kinetics, through the incorporation of P dopants and S vacancies onto the surface of a NiCo2S4 nanotube (P-NiCo2S4−x). Experimental results reveal that the introduction of these defects effectively increases the electrical conductivity and induces the formation of low oxidation state Ni and Co species, accelerating the charge transfer kinetics and enabling rich faradaic redox chemistry. Moreover, the partial substitution of S sites with P improves the covalent nature of P-NiCo2S4−x, facilitating surface electroactivity. The as-prepared P-NiCo2S4−x shows a high specific capacity of 1806.4 C g−1 at 1 A g−1 and a 95.5% capacity retention after 5000 cycles at a high current density of 30 A g−1. Flexible solid-state asymmetric supercapacitors with P-NiCo2S4−x and activated carbon as the positive and negative electrodes, respectively, deliver a high energy density of 68.2 W h kg−1 at 800 W kg−1 and excellent cycling stability. Moreover, the device exhibits good mechanical flexibility with negligible capacitance decay under different bending states.

Controllable tailoring and understanding the phase-structure relationship of the 1T phase two-dimensional (2D) materials are critical for their applications in nanodevices. The

Advanced electronic materials are the fundamental building blocks of integrated circuits (ICs). The microscale properties of electronic materials (e.g., crystal structures, defects, and chemical properties) can have a considerable impact on the performance of ICs. Comprehensive characterization and analysis of the material in real time with high-spatial resolution are indispensable. In situ transmission electron microscope (TEM) with atomic resolution and external field can be applied as a physical simulation platform to study the evolution of electronic material in working conditions. The high-speed camera of the in situ TEM generates a high frame rate video, resulting in a large dataset that is beyond the data processing ability of researchers using the traditional method. To overcome this challenge, many works on automated TEM analysis by using machine-learning algorithm have been proposed. In this review, we introduce the technical evolution of TEM data acquisition, including analysis, and we summarize the application of machine learning to TEM data analysis in the aspects of morphology, defect, structure, and spectra. Some of the challenges of automated TEM analysis are given in the conclusion.

Super long perovskite microwires (PMWs) are in a great demand in many fields such as low-loss microcables and integrated optical waveguide. Despite decades of research into PMWs, single crystal PMWs with several centimeters long have not been obtained. Here, ultralong (up to 7.6 centimeters) monoclinic crystal structure CH3NH3PbI3·DMF PMWs have been synthesized. The high-quality microwire exhibits long carrier lifetime of 1775.7 ns. The as-prepared free-standing PMWs can be integrated to any arbitrary substrate and 808 nm near-infrared photodetectors have been successfully demonstrated. The fabricated device shows a high light on/off ratio of 1.79×106 and an extremely low dark current of 2.5 fA at 1 V bias. This work provides a strategy for the solution growth of ultralong microwires.

The ultrastable metal electrodes that can withstand the mechanical deformations of the soft substrates are always essential for the development of flexible supercapacitors. However, the metal electrode physically deposited on the flexible substrate is rigid and delaminated, and the contact interface is easily degraded under the mechanical cycling. The highly flexible and conductive composites with the intermixed metal–polymer structure as electrodes are key to solving the contact problem. In this work, a universal and facile method for flexible micro-supercapacitors (MSCs) with combination of nickel electroless plating (EN) and reduced graphene oxide (rGO) electrodeposition was presented. The so-called surface exchange and ion exchange (SMIE) technique has been employed to prepare the seed layer, and the electroless plating was conducted to deposit the Ni–P layer. The rGO-coated (GC) layer was then electrodeposited onto the Ni–P layer to form an EN/GC composite structure. EN/GC electrodes with symmetric i...

Graphene with excellent electrical properties has a wide range of applications in electronic devices. Graphene-based planar resistance random access memory (RRAM) has received much attention due to its simple preparation methods and unique working mechanisms. However, the thermal reliability of graphene-based planar RRAM has rarely been reported. Here, we explore the reliability of the graphene-based RRAM at different temperatures, especially at high temperatures. The result shows that graphene-based planar RRAM could work in the temperature range from 100 K to 570 K.

Flexible chemical sensor with high sensitivity and reliability is important for health monitoring applications. A typical sodium-ion detection sensor based on ion selection is made of a reference electrode and a working electrode. The reliability of the electrodes is still challenging to achieve accurate and continuous measurements. Here we use the polydopamine-printed technology and chemical annealing method to prepare the flexible sodium-ion detection sensor that presents enhanced reliability. A sensitivity of 54 mV per decade is achieved for the sensor. In the best case, the reliabilities of the working and the reference electrodes are increased up to 95.3% and 93.9%, respectively for the detection of the sodium-ion concentration. This work provides a method to improve the stability of the flexible ion detection sensors.

Metallic two-dimensional (2D) 1T-VSe2 with high conductivity and a large specific surface area is a promising electrode material for supercapacitors. Here, we use a facile chemical vapor deposition (CVD) method to prepare thin VSe2 nanosheets. A flexible in-plane solid-state supercapacitor is fabricated using the high-quality VSe2 nanosheets as the electrode material. The prepared supercapacitor presents an electrical double-layer capacitive behavior, and it has a high power density that is comparable with that of advanced graphene-based supercapacitors. The flexible supercapacitor also shows good mechanical stability to both bending and fatigue tests up to 10 000 cycles. This work provides a novel method for the fabrication of high-performance thin-film power sources, and paves the way for their application in soft thin-geometry devices.