Monolayer Vacancy-Induced MXene Memory for Write-Verify-Free Programming.

The fundamental logic states of 1 and 0 in Complementary Metal-Oxide-Semiconductor (CMOS) are essential for modern high-speed non-volatile solid-state memories. However, the accumulated storage signal in conventional physical components often leads to data distortion after multiple write operations. This necessitates a write-verify operation to ensure proper values within the 0/1 threshold ranges. In this work, a non-gradual switching memory with two distinct stable resistance levels is introduced, enabled by the asymmetric vertical structure of monolayer vacancy-induced oxidized Ti3C2Tx MXene for efficient carrier trapping and releasing. This non-cumulative resistance effect allows non-volatile memories to attain valid 0/1 logic levels through direct reprogramming, eliminating the need for a write-verify operation. The device exhibits superior performance characteristics, including short write/erase times (100 ns), a large switching ratio (≈3 × 104), long cyclic endurance (>104 cycles), extended retention (>4 × 106 s), and highly resistive stability (>104 continuous write operations). These findings present promising avenues for next-generation resistive memories, offering faster programming speed, exceptional write performance, and streamlined algorithms.

Fast-speed, Highly Sensitive, Flexible Humidity Sensors Based on a Printable Composite of Carbon Nanotubes and Hydrophilic Polymers.

Carbon nanotubes (CNTs) are a promising material for humidity sensors and wearable electronics due to their solution capability, good flexibility, and high conductivity. However, the performance of CNT-based humidity sensors is limited by their low sensitivity and slow response. Herein CNTs and hydrophilic polymers were mixed to form a composite. The hydrophilicity of the polymers and the network structure of the CNTs empowered the humidity sensors with a high response of 171% and a fast response/recovery time of 23 s/10 s. Owing to the sticky and flexible polymers, the humidity sensors showed strong adhesion to the PET substrate and exhibited outstanding bending durability. Furthermore, the flexible humidity sensor was applied to monitor human breathing and detect finger movements and handshaking.

Room-temperature nanojoining of silver nanowires by graphene oxide for highly conductive flexible transparent electrodes.

Flexible transparent electrodes for touch panels, solar cells, and wearable electronics are in great demand in recent years, and the silver nanowire (AgNW) flexible transparent electrode (FTE) is among the top candidates due to its excellent light transmittance and flexibility and the highest conductivity of silver among all metals. However, the conductivity of an AgNWs network has long been limited by the large contact resistance. Here we show a room-temperature solution process to tackle the challenge by nanojoining AgNWs with two-dimensional graphene oxide (GO). The conductivity of the AgNWs network is improved 18 times due to the enhanced junctions between AgNWs by the coated GOs, and the AgNW-GO FTE exhibits a low sheet resistance of 23 Ohm sq-1and 88% light transmittance. It is stable under high temperature and current and their flexibility is intact after 1000 cycles of bending. Measurements of a bifunctional electrochromic device shows the high performance of the AgNW-GO FTE as a FTE.

Layer-dependent anisotropic frictional behavior in two-dimensional monolayer hybrid perovskite/ITO layered heterojunctions.

Two-dimensional (2D) organic-inorganic hybrid perovskites, which possess outstanding optical and electrical properties, are promising semiconductor materials that have attracted significant interest in widespread applications. The frictional behavior of 2D perovskite materials with other transparent conductive materials, such as indium tin oxide (ITO), offers promising developments in optoelectronic devices. Therefore, the understanding of this frictional behavior is essential. Atomic force microscopy (AFM) is employed here to measure the frictional behavior between the (001) plane of the 2D organic-inorganic hybrid (C4H9NH3)2PbBr4 perovskite and the (111) plane of the ITO. The experimental analyses characterizing the nature of the friction in a single-crystalline heterojunction are reported. Based on the results of the analyses of interfaces between 2D monolayer perovskites and ITO, a strong anisotropy of friction is clearly demonstrated. The anisotropy of friction is observed as a four-fold symmetry with low a frictional coefficient, 0.035, in misaligned contacts, and, 0.015, in aligned contacts in the heterojunction configuration. In addition, atomistic simulations reveal underlying frictional mechanisms in the dynamical regimes. A new phenomenon discovered in the studies establishes that the measured frictional anisotropy surprisingly depends on the number of atomic layers in the 2D perovskite. The frictional anisotropy decreases significantly with the increase in the number of layers up to 16 layers, and then it becomes independent of the thickness. Our results are predicted to be of a general nature and should be applicable to other 2D hybrid perovskite heterojunction configurations, and thus, furthers the development of adaptive and stretchable optoelectronic nanodevices.

Size-dependent Young's modulus in ZnO nanowires with strong surface atomic bonds.

The mechanical properties of size-dependent nanowires are important in nano-electro-mechanical systems (NEMSs), and have attracted much research interest. Characterization of the size effect of nanowires in atmosphere directly to broaden their practical application instead of just in high vacuum situations, as reported previously, is desperately needed. In this study, we systematically studied the Young's modulus of vertical ZnO nanowires in atmosphere. The diameters ranged from 48 nm to 239 nm with a resonance method using non-contact atomic force microscopy. The values of Young's modulus in atmosphere present extremely strong increasing tendency with decreasing diameter of nanowire due to stronger surface atomic bonds compared with that in vacuum. A core-shell model for nanowires is proposed to explore the Young's modulus enhancement in atmosphere, which is correlated with atoms of oxygen occurring near the nanowire surface. The modified model is more accurate for analyzing the mechanical behavior of nanowires in atmosphere compared with the model in vacuum. Furthermore, it is possible to use this characterization method to measure the size-related elastic properties of similar wire-sharp nanomaterials in atmosphere and estimate the corresponding mechanical behavior. The study of the size-dependent Young's modulus in ZnO nanowires in atmosphere will improve the understanding of the mechanical properties of nanomaterials as well as providing guidance for applications in NEMSs, nanogenerators, biosensors and other related areas.

Tactics analysis and evaluation of women football team based on convolutional neural network.

In order to realize the process of player feature extraction and classification from multi-frequency frame-changing football match images more quickly, and complete the tactical plan that is more conducive to the game, this paper puts forward a method for analyzing and judging the tactics of women's football team based on Convolutional Neural Network (CNN). By extracting the players' performance in recent training and competition from continuous video frame data, a multi-dimensional vector input data sample is formed, and CNN is used to analyze the players' hidden ability before the game and the players' mistakes in different positions on the field to cope with different football schedules. Before the formal test, 10 games of 2021-2022 UEFA Women's Champions League were randomly selected and intercepted to train the CNN model. The model showed excellent accuracy in the classification of image features of various football moves and goal angles, and the overall classification accuracy of each category exceeded 95%. The accuracy of classifying a single match is above 88%, which highlights the reliability and stability of the model in identifying and classifying women's football matches. On this basis, the test results show that: according to the analysis of players' personal recessive ability before the game, after model image recognition and comparison, the difference between the four scores of players' personal recessive ability with CNN mode and the manual score of professional coaches was smaller, and the numerical difference was within the minimum unit value, and the numerical calculation results were basically the same. According to the analysis of players' mistakes in different positions on the field, CNN was used to monitor the real-time mistakes. It was found that the two players in the forward position made the highest mistakes, and they were replaced by substitute players at 73.44 min and 65.28 min after the team scored and kept the ball, respectively. After the substitute players played, the team's forward position mistake rate decreased obviously. The above results show that CNN technology can help players get personal recessive ability evaluation closer to professional evaluation in a shorter time, and help the coaching team to analyze the real-time events better. The purpose of this paper is to help the women's football team complete the pre-match tactical training, reduce the analysis time of players' mistakes in the game, deal with different opponents in the game and improve the winning rate of the game.

Trapezoidal Cantilever-Structure Triboelectric Nanogenerator Integrated with a Power Management Module for Low-Frequency Vibration Energy Harvesting.

Wide-band vibration is abundant in various industrial equipment, but extracting low frequency energy is challenging. Here, we demonstrated a trapezoidal cantilever-structure triboelectric nanogenerator (C-TENG) that can efficiently harvest energy from vibration in the range of 1-22 Hz. The C-TENG is fabricated with a flexible film electrode, and its mechanical model is analyzed with structural mechanics for the optimal performance of the device. The C-TENG can harvest the vibration source with a frequency as low as 1 Hz, and its output power density reaches 62.2 W/m3 at a vibration frequency of 5 Hz. Furthermore, a power management module is developed, and its integration with TENG arrays enables the self-powered timing and wireless transmitting systems. This work proposes an effective strategy to harvest ubiquitously distributed but usually neglected vibration sources, which would contribute to the development of self-powered electronic systems and Internet of Things.

Constructing Heterogeneous Photocatalysts Based on Carbon Nitride Nanosheets and Graphene Quantum Dots for Highly Efficient Photocatalytic Hydrogen Generation.

Although graphitic carbon nitride nanosheets (CNs) with atomic thickness are considered as promising materials for hydrogen production, the wide band gap (3.06 eV) and rapid recombination of the photogenerated electron-hole pairs impede their applications. To address the above challenges, we synergized atomically thin CNs and graphene quantum dots (GQDs), which were fabricated as 2D/0D Van der Waals heterojunctions, for H2 generation in this study. The experimental characterizations indicated that the addition of GQDs to the π-conjugated system of CNs can expand the visible light absorption band. Additionally, the surface photovoltage spectroscopy (SPV) confirmed that introducing GQDs into CNs can facilitate the transport of photoinduced carriers in the melon chain, thus suppressing the recombination of charge carriers in body. As a result, the H2 production activity of the Van der Waals heterojunctions was 9.62 times higher than CNs. This study provides an effective strategy for designing metal-free Van der Waals hetero-structured photocatalysts with high photocatalytic activity.

Recent advances in MXene-based force sensors: a mini-review.

As an emerging two-dimensional (2D) material, MXene has excellent conductivity and abundant surface functional groups. Its unique layered structure, large surface area, and prominent hydrophilicity show remarkable performances, which allow abundant possibilities to work as the sensing element alone or combined with other auxiliary materials. As a senior member of MXenes, Ti3C2T x has shown great potential in the development of force sensors. The research development of force sensors based on Ti3C2T x MXene is reviewed in this paper, presenting the advanced development of force sensors in various forms and summaring their current preparation strategies and characteristics. In addition, the corresponding challenges and prospects of the MXene-based sensors are also discussed for future research.

Dynamic photonic perovskite light-emitting diodes with post-treatment-enhanced crystallization as writable and wipeable inscribers.

Controllable photonic patterns have attracted great attention for various applications in displays, smart sensors, and communications. Conventional patterned light-emitting-diode (LED) systems require complicated design, complex procedure, and advanced equipment. Moreover, permanent properties of the fabricated patterns on LED restrict it from various important applications. Herein, we present an innovative writable and wipeable perovskite light-emitting-diode (WWPeLED) device, which tactfully utilizes the large variation of turn-on voltage originating from the external quantum efficiency (EQE) difference under controllable thermal treatment. The turn-on voltages with/without thermal-treatment devices exhibit a large gap of over 5 V, and the thermal-treatment electroluminescence intensity is more than 10 times higher than that of non-thermal-treatment devices. The new phenomena open up an effective way of controlling illumination with desired pattern designs. Additionally, the distinct handwriting fonts and habits as well as printing patterns with illumination WWPeLED are also realized. Furthermore, these written and printed features can be totally wiped out with an 11 V cleaning voltage, turning the devices as a regular fully bright PeLED. The stability and repeatability tests prove the robustness of WWPeLED in both mechanical and electroluminescence performance after a long period of operations. The innovative WWPeLED devices may find prospective applications in various optoelectronic devices and flexible integrated systems.

High-Performance and Reliable Silver Nanotube Networks for Efficient and Large-Scale Transparent Electromagnetic Interference Shielding.

The development of flexible and transparent electromagnetic interference (EMI) shielding materials with excellent comprehensive properties is urgently demanded as visual windows and display devices in aeronautic, industry, medical, and research facilities. However, the method of how to obtain highly efficient and reliable transparent EMI shielding devices is still facing lots of obstacles. Here, a high-performance silver nanotube (AgNT) network with stable and integrated interconnects is prepared by physical depositing technology, based on a uniform and large-scale nanofiber skeleton. This unique structure enables the AgNT network to achieve one order higher conductivity (∼1.0 Ω/sq at >90% transmittance) than previous research studies and keeps <10% variation with random deformations (>5000 times). Moreover, the manufactured AgNT shielding film with a thickness of less than 1 mm can be easily transferred to arbitrary surfaces as a transparent and flexible EMI shielding film at commercial ∼35 dB EMI shielding effectiveness, with large-scale, low-cost, and simple preparation processes. These excellent properties endow the AgNT shielding film to achieve great potential for future flexible and transparent scenarios.

Single-Layer MoS2 Mechanical Resonant Piezo-Sensors with High Mass Sensitivity.

Thin-film resonators and scanning probe microscopies (SPM) are usually used on low-frequency mechanical systems at the nanoscale or larger. Generally, off-chip approaches are applied to detect mechanical vibrations in these systems, but these methods are not much appropriate for atomic-thin-layer devices with ultrahigh characteristic frequencies and ultrathin thickness. Primarily, those mechanical devices based on atomic-layers provide highly improved properties, which are inapproachable with conventional nanoelectromechanical systems (NEMS). In this report, the assembly and manipulation of single-atomic-layer piezo-resonators as mass sensors with eigen mechanical resonances up to gigahertz are described. The resonators utilize electronic vibration transducers based on piezo-electric polarization charges, allowing direct and optimal atomic-layer sensor exports. This direct detection affords practical applications with the previously inapproachable Q-factor and sensitivity rather than photoelectric conversion. Exploration of a 2406.26 MHz membrane vibration is indicated with a thermo-noise-limited mass resolution of ∼3.0 zg (10-21 g) in room temperature. The fabricated mass sensors are contactless and fast and can afford a method for precision measurements of the ultrasmall mass with two-dimentional materials.

Photo-Triggered Logic Circuits Assembled on Integrated Illuminants and Resonant Nanowires.

High-performance photo-triggered electronic devices have already become an abiding target of optoelectronics. Current results, involving high-sensitivity phototransistors with the enhancement of material properties or the modification of electrical field, need an independent external light-source system. Nevertheless, few research studies inform of circuits in which the logic channel can be directly light controlled by a fully integrated photogate. In this paper, nanowire-based photon-effect transistors (PETs) combined with organic light-emitting diode (OLED) gates, and the photo-triggered nanowire circuits (PTNCs) are exhibited. The nanowire channels are manifested as high-quality optical cavities coupled by reflective electrodes for forming standing wave resonance. With the function of resonance, the nanowire channel under the illumination of the OLED gate can reach a high on/off ratio of ∼107, and under the different interconnected configuration of OLED gates, the functions of PETs can separately be realized as P-type and N-type of CMOS-like transistors. Then, a PTNC inverter that includes two nanowire channels with the respective OLED gates is operated utilizing electrical input voltage and logic opposite output signal. NAND and NOR gates as PTNC have also been demonstrated and indicate their corresponding outstanding arithmetic logic operation. PTNCs can effectively represent an innovative step toward multipurpose photonic circuits as to programmable logic components and photo-triggered computing.

Ultra-High-Responsivity Vertical Nanowire-based Phototransistor under Standing-Wave Plasmon Mode Interaction Induced by Near-Field Circular OLED.

High-responsivity photodevices are strongly desired for various demanding applications, such as optical communications, logic circuits, and sensors. The use of quantum and photon confinement has enabled a true revolution in the development of high-performance devices. Unfortunately, many practical optoelectronic devices exhibit intermediate sizes where resonant enhancement effects seem to be insignificant. Here we design and fabricate an ultra-high-responsivity organic-light-emitting-diode-induced nanowire resonance phototransistor (ONRPT) based on standing-wave resonance in the nanoscale cavity, subjected to a near-field light. Observations of the ONRPT in standing-wave resonance mode indicate a >104 enhancement in the on/off ratio and a six times higher subthreshold slope when compared with the ONRPT in non-resonance mode. The ONRPT, which leads itself to outstanding electrical and favorably stable performance, opens up a plethora of opportunities for high-efficiency energy devices and allows for nanowire applications in the solar cell, piezo-photonic detectors, and optical modulators.

High Performance and Efficiency Resonant Photo-Effect-Transistor by Near-Field Nano-Strip-Controlled Organic Light Emitting Diode Gate.

Phototriggered devices have attracted attention due to their exceptional characteristics, advanced multifunctionalities and unprecedented applications in optoelectronic systems. Here, we report a pioneer structural device, a resonant photoeffect-transistor (RPET) with a functionalized nanowire (NW) charge transport channel, modulated by a near-field nanostrip organic light emitting diode (OLED) and controlled by a gate bias to realize exceptional photoelectric properties. The RPET presents high-quality nanowire channel characteristics due to tunable optical cavities manifesting strong standing wave resonance under controlled light emission. To enhance performance, methodical analyses were carried out to determine the effects of the structural design, electric field distribution and charge carrier generation on photoresponsivity when light traverses a single or multiple nanoslit masks. The developed RPET yields stable photocurrents in the 105 range and generates current on/off ratios upward of 106 under the influence of intense electromagnetic distribution, effectively lending itself to promising opportunities in fully integrated optoelectronic devices.

Paper-like Foldable Nanowave Circuit with Ultralarge Curvature and Ultrahigh Stability.

Highly foldable conducting interconnects are fundamental elements for multipurpose flexible electronic circuits, including wearable electronics and biomedical devices. Traditional metalized thin-film interconnects demonstrate stable electronic performances in rigid devices but low deformation tolerance in flexibility. Recently, several remarkable research studies on flexible electronics have been carried out, as interconnect structures of serpentine, wavy, and nanowire networks. However, all of the reported flexible interconnects possess either mechanical instability or fabrication difficulty, which restrict their practical applications. Here, we report a new flexible circuit system, which consists of nanowave structure metal interconnects with highly foldable and large-scale manufactured features. This kind of nanowave interconnects presents both stable and prominent electrical performances under mechanical deformation (down to 0.2 mm bending radius with interconnecting resistance variation less than 10%). Further, a highly flexible paper-like wireless accelerometer based on the nanowave interconnects is fabricated and characterized under several extreme strain situations. Our approach affords a comprehensive direction for constitutional realization of new flexible designs and implements the assembly of next-generation foldable electronic equipment.

High Performance Vertical Resonant Photo-Effect-Transistor with an All-Around OLED-Gate for Ultra-Electromagnetic Stability.

The utilization of three-dimensional (3D) structures in next-generation nanodevices has been attractive due to the exceptional features they offer. These 3D structures can reduce component space and improve device properties compared to thin-film electronic components. The type of transistor applied in 3D nanodevices is one of the most widely studied components due to its rich physics and ubiquitous application. In this paper, we report a complete functionalized component, a 3D vertical resonant photo-effect-transistor (VRPET), which is realized with the functionalized nanowire current channel, asymmetric ohmic/Schottky contacts, and an ultraviolet photogate with an organic light emission diode (OLED) excitation. To enhance the VRPET performance, analyses of the design and fabrication parameters were carried out, where the focus was specifically on the relationship between light resonance and absorption. The transistor developed here can operate up to a high voltage of 16.5 V and control currents up to 50 µA with an ultrastable performance under a strong electromagnetic interference. The VRPET with excellent properties is a step toward achieving integrated photoelectric devices and corresponding applications.