Composition Of Nanowires Research Articles

GaN–MoS2 Composite Nanowires Grown on Graphite Paper as Battery-type Electrode Materials

GaN–MoS2 Composite Nanowires Grown on Graphite Paper as Battery-type Electrode Materials

Study of Graphene Oxide and Silver Nanowires Interactions and Its Association with Electromagnetic Shielding Effectiveness.

Technological development has led to the need for materials able to block electromagnetic waves (EMWs) emitted from various devices. EMWs could negatively affect the working performance and lifetime of multiple instruments and measuring devices. New EMW shielding materials are being developed, while among nanomaterials, graphene-based composites have shown promising features. Herein, we have produced graphene oxide (GO), silver nanowires (AgNWs) composites, by varying the mass ratios of each component. UV-Vis, infrared, Raman spectroscopies, and thermogravimetric analysis proved the establishment of the interactions between them. For the first time, the strength and the nature of the interaction between GO sheets with various levels of oxidation and AgNWs were investigated using density function theory (DFT). The interaction energy between ideal graphene and AgNWs was calculated to be -48.9 kcal/mol, while for AgNWs and GO, this energy is almost doubled at -81.9 kcal/mol. The DFT results confirmed the interfacial polarization at the heterointerface via charge transfer and accumulation at the interface, improving the efficacy of EMW shielding. Our results indicated that AgNWs create a compact complex with GO due to charge transfer between them. Charge redistributions in GO-AgNWs composites resulted in an improved ability of the composite to block EMWs compared to GO alone.

Seed Layer Effect on Electrodeposited 3D CoPt Alloy Nanowires for Magnetic Storage Application

Nanowires with modulated magnetic properties like perpendicular magnetic anisotropy (PMA) could be applicable for next-generation magnetic storage devices like Racetrack memory. The 3D nanowire structures in Racetrack memory can provides high-density storage, where digital bits are stored in a series of magnetic layers separated by domain wall (DW).1,2 Electric current-driven DW motion can be used to move digital bits through the nanowires. Compared to traditional information storage devices, 3D magnetic nanowires with many DW encoded into them offer high-density storage.Template-assisted electrodeposition technique in nanoporous membranes is one of the few processes allowing the formation of void-free nanowires with modulated composition.3,4 Among magnetic materials, CoPt alloys show large magnetic anisotropy and have been studied widely for magnetic storage devices.4,5,6 The crystal structure and composition of CoPt alloy nanowires play a vital role in getting strong PMA. The composition of CoPt alloy can be controlled by adjusting the applied potential during the electrodeposition process.3 In this study, we report the crystal structures and magnetic properties of CoPt alloy nanowires electrodeposited into a polycarbonate membrane template (PT) with 1% porosity and an average pore diameter of 100 nm. A Cu (400 nm) or a Pt (100 nm) seed layer sputtered at the back side of the PT. CoPt nanowires were produced using the standard three-electrode electrodeposition procedure, in which Ag/AgCl (sat. KCl) and Pt mesh were utilized as the reference and counter electrodes, respectively, while the seed layer coated PT served as the working electrode. The bath solution used for electrodeposition contained CoSO4.7H2O (0.1 M), Pt(NH3)2(NO2)2 (0.001 M), and H3BO3 (0.5 M). The solution has a pH of 5.2 and is stirred at 200 rpm at 40 °C. The applied potentials were -1000 mV vs Ag/AgCl (Sat. KCl) to form Co-rich CoPt alloy nanowires. The deposition time was adjusted to form a similar aspect ratio of CoPt alloy nanowires.The X-ray diffraction (XRD) patterns in Figure 1a showed that the CoPt alloy nanowires present a hcp structure on both seed layers. However, the Pt (111) seed layer favours the epitaxial growth along the hcp (002) direction while other orientations (hcp 100) are found with the Cu seed layer. As a result, the CoPt nanowires deposited with the Pt seed layer present better PMA than those deposited with the Cu seed layer. The magnetization curves M – H of CoPt nanowires on the Pt seed layer (vibrating-sample magnetometry, VSM) present a good squareness (M/M S = 0.64), a strong coercive field H C = 660 Oe and a saturation magnetization of 740 emu cm-3 (Figure 1b). These properties are suitable for 3D magnetic domain motion memory. In summary, our work may contribute to regulating the epitaxial growth of CoPt crystalline structure, enhancing the magnetic properties of 3D CoPt alloy nanowires for magnetic storage devices.AcknowledgementThis work was supported by JST, CREST Grant Number JPMJCR21C1, Japan.References S. P. Parkin, M. Hayashi, and L. Thomas, Science, 2008, 320, 190–194.M. Hung, T. Li, R. Hisatomi, Y. Shiota, T. Moriyama, and T. Ono, Journal of the Magnetics Society of Japan, 2021, 45, 6–11. M. Hasan, T. Huang, M. Saito, Y. Takamura, D. Oshima, T. Kato, and T. Homma, 2023 IEEE International Magnetic Conference (INTERMAG), 2023, 1-5. M. Hasan, T. Huang, M. Saito, Y. Takamura, D. Oshima, T. Kato, and T. Homma, 2023 IEEE International Magnetic Conference-Short Papers, 2023, 1-2. Huang, Y. Takamura, M. Saito, M. M. Hasan, S. Kasai, Y. Sonobe and S. Nakagawa, IEEE Transactions on Magnetics, 2023, 59(11), 1301005. Wodarz, T. Hasegawa, S. Ishio, T. Homma, Journal of Magnetism and Magnetic Materials, 2017, 430, 52-58. Figure 1

Flexible highly-sensitive pressure sensor based on rGO/Fe nanowires composites for wearable human health detection.

Flexible pressure sensors applied in wearable detection often face challenges, such as low sensitivity, large device size, poor flexibility, and long response time. This study aims to design and develop high-performance pressure-sensitive materials for wearable human detection applications. Using a sensitive layer composite and microstructural design, rGO/Fe nanowires (NWs) composites were proposed as the pressure-sensitive material. This approach yields a compact sensor with high flexibility, good mechanical properties, and excellent sensing performance. Firstly, rGO/Fe NWs composites were prepared by the Hummers method and an in situ reduction technique under a magnetic field. Secondly, the structural design, component construction, and sensing mechanism of the sensors were thoroughly investigated. Finally, the performance of the flexible pressure sensor was tested, and its application in the wearable field was explored. The results demonstrate that the sensor exhibits excellent performance with a good response to both large and small pressures within the range of 0-30kPa, providing an effective method for wearable human health detection.

The optoelectronic device with high efficiency for the incidence photons based on silver iodide/poly-2-aminobenzenethiol-intercalated iodide ion nanowire composite

The optoelectronic device with high efficiency for the incidence photons based on silver iodide/poly-2-aminobenzenethiol-intercalated iodide ion nanowire composite

Self-Healing and Shear-Stiffening Electrodes for Wearable Biopotential Sensing and Gesture Recognition.

The achievement of flexible skin electrodes for dynamic monitoring of biopotential is one of the challenging issues in flexible electronics due to the interference of large acceleration and heavy sweat that influence the stability of skin-electrode interfaces. This work presents materials and techniques to achieve self-healing and shear-stiffening electrodes and an associated flexible system that can be used for multichannel biopotential measurement on the skin. The electrode that is based on a composite of silver (Ag) flakes, Ag nanowires, and polyborosiloxane offers an electrical conductivity of 9.71 × 104 S/m and a rheological characteristic that ensures stable and fully conformal contact with skin and easy removal under different shear rates. The electrode can maintain its conductivity even after being stretched by more than 60% and becomes self-healed after mechanical damage. The combination of the electrodes with a screen-printed multichannel flexible sensor allows stable monitoring of both static and dynamic electromyography signals, leading to the acquisition of high-quality multilead biopotential signals that can be readily extracted to yield gesture recognition results with over 97.42% accuracy. The conductive self-healing materials and flexible sensors may be utilized in various daily biopotential sensing applications, allowing highly stable dynamic measurement to facilitate artificial intelligence-enabled health condition diagnosis and human-computer interface.

Synthesis of Polyaniline/BiPr Composite Oxide Nanowires with Enhanced Electrochemical Sensing Performance

Background: Considerable interest has been devoted to electrochemical sensors for the detection of L-cysteine using BiPr-based oxide-modified electrodes due to high specific surface area and good electro-catalytic activity with several oxidation states. The combination of the BiPr composite oxide nanowires with polyaniline (PAn) can promote the electro-catalytic performance towards Lcysteine because PAn can facilitate the electro-catalytic process by enhancing the charge transfer. Methods: PAn/BiPr composite oxide nanowires were obtained via low temperature one-step hydrothermal route. The obtained composite oxide nanowires were analyzed by X-ray diffraction, electron microscopy, and electrochemical methods. Results: Characterization results indicate that amorphous PAn nanoparticles with a size of about 50 nm are homogeneously dispersed at the surface of the BiPr composite oxide nanowires. PAn/BiPr composite oxide nanowire-modified electrode shows an enhanced L-cysteine electro-catalytic activity. PAn promotes electro-catalytic activity of the BiPr composite oxide nanowires. A pair of quasi-reversible cyclic voltammetry (CV) peaks exist at +0.49 V, -0.19 V, respectively. PAn/BiPr composite oxide nanowire modified electrode possesses a linear response in L-cysteine concentration of 0.001-2 mM and detection limit of 0.095 μM, good repeatability, and stability. Conclusion: PAn/BiPr composite oxide nanowires act as effective electro-catalysts for L-cysteine oxidation resulting in the enhancement of the electro-catalytic activity relative to BiPr composite oxide nanowires.

Light-Driven Electrochemical Biosensing with DNA Origami-Assisted Hybrid Nanoantenna for Fumonisin B1 Monitoring.

The electrochemical detection of biosensors is largely governed by the changes in physical properties of redox probes, which are susceptible to electrode substrate effects, inhibiting sensor sensitivity. In this work, a light-driven electrochemical biosensor based on a hybrid nanoantenna was developed for the sensitive detection of fumonisin B1 (FB1). The hybrid nanoantenna sensing interface was constructed by coupling CdSe quantum dots (QDs)-DNA nanowire and graphdiyne oxide composites loaded with methylene blue and gold nanorods (GDYO-MB-Au NRs) using a tetrahedral DNA nanostructure, which acted as a light-driven unit and an amplification unit, respectively. The hybrid nanoantenna with light-driven properties facilitated the alteration in the chemical properties of MB at the sensing interface; that is, MB was degraded under light illumination. The stripping of the CdSe QDs-DNA nanowire triggered by the binding of FB1 could degrade the light-driven capability, thereby improving the electrochemical signal through depressing MB degradation. Taking advantage of the photodegradation of MB by the hybrid nanoantenna, the developed biosensor reduced the background signal and increased the detection sensitivity. The developed biosensor exhibited a linear detection range from 0.5 fg mL-1 to 10 pg mL-1 and a detection limit down to 0.45 fg mL-1. This strategy shows great promise for the fabrication of highly sensitive electrochemical biosensors.

A Layered Titanate Nanowire Helps Pt/TiO2 Photocatalyst for Solar Hydrogen Evolution from Water with High Quantum Efficiency

Abstract Research into TiO2 photocatalysts for solar H2 evolution from water is still growing for environmentally benign and economically valid H2 production. Herein, in contrast to many researches on the modification of TiO2 toward higher photocatalytic activities, we develop a photocatalytically inactive TiO2-based nanostructure and use it, like graphene, as a booster of a benchmark TiO2. A layered potassium titanate with two-dimensional plate-like particle morphology was converted to the corresponding one-dimensional nanowire form via a hydrothermal reaction, after which the layered potassium titanate nanowire was acid-treated to obtain a layered titanate nanowire. This nanowire was completely inactive toward H2 evolution from water containing methanol under solar simulator irradiation. However, when Pt nanoparticle-loaded P25 TiO2 (Pt/P25) was mixed with a considerably smaller amount of the layered titanate nanowire in water, a durable composite was obtained and the composite showed a good photocatalytic activity three times higher than Pt/P25. The apparent quantum efficiency of the reaction at wavelength of 350 nm was 56%, which was higher than or comparable to those of the state-of-the-art TiO2-based photocatalysts. The possible reason for the enhanced photocatalytic activity of the Pt/P25 and layered titanate nanowire composite involved the transfer of photogenerated holes from Pt/P25 to the nanowire to suppress charge recombination and/or disaggregation (improved dispersion) of Pt/P25 particles on the nanowire.

Cohesively improved conductivity, transparency, and stability of Ag NW flexible transparent conductive thin films by covering Al2O3 layer

Developing feasible Ag nanowire (NW) transparent conductive thin films (TCFs) with good conductivity, transparency, mechanical durability, strong adhesion, and high stability is a great challenge. Herein, novel TCFs composed of Ag NWs/Al2O3 on polyethylene terephthalate (PET) substrates with synchronously improved conductivity, transparency, mechanical durability, adhesion, and stability, are prepared. The corresponding values (before coating Al2O3: 13.0 Ω/sq. at 86.1 %, after coating Al2O3: 11.7 Ω/sq. at 87.7 %) indicate that the deposition of Al2O3 enhances the transparency and conductivity of Ag NW networks. Moreover, the resistance does not change significantly after 50 taping cycles and 2000 bending cycles with a bending radius of 5.0 mm, indicating the strong adhesion and good mechanical flexibility of Al2O3/Ag NWs composites. In addition, Al2O3/Ag NWs composites possess excellent stability to resist strong oxidizing, hot and humid environments. As a proof of concept, the flexible transparent heater prepared by Al2O3/Ag NWs composites is successfully demonstrated, verifying the practicability.

Stretchable Tissue-Like Gold Nanowire Composites with Long-Term Stability for Neural Interfaces.

Soft and stretchable nanocomposites can match the mechanical properties of neural tissue, therebyminimizing foreign body reactions to provide optimal stimulation and recording specificity. Soft materials for neural interfaces should simultaneously fulfill a wide range of requirements, including low Young's modulus (<<1MPa), stretchability (≥30%), high conductivity (>> 1000 Scm-1), biocompatibility, and chronic stability (>> 1 year). Current nanocomposites do not fulfill the above requirements, in particular not the combination of softness and high conductivity. Here, this challenge is addressed by developing a scalable and robust synthesis route based on polymeric reducing agents for smooth, high-aspect ratio gold nanowires (AuNWs) of controllable dimensions with excellent biocompatibility. AuNW-silicone composites show outstanding performance with nerve-like softness (250kPa), high conductivity (16000 Scm-1), and reversible stretchability. Soft multielectrode cuffs based on the composite achieve selective functional stimulation, recordings of sensory stimuli in rat sciatic nerves, and show an accelerated lifetime stability of >3 years. The scalable synthesis method provides a chemically stable alternative to the widely used AgNWs, thereby enabling new applications within electronics, biomedical devices, and electrochemistry.

Polymer-composite triboelectric nanogenerators with hook-shaped electrode for wind energy harvesting

Triboelectric nanogenerators (TENGs) based on the composite of polystyrene (PS) and silver nanowires (Ag-nWs) have been investigated. With open-circuit voltage, short-circuit current and power density of ∼200 V, ∼15 μA and ∼395 mW/m2 respectively in the contact separation mode, these TENGs exhibit highly reliable performance. To harvest the wind energy, a novel hook-shape geometry of the top fluttering electrode is demonstrated which is constructed using light-weight rectangular aluminum foil and is fixed at both ends. With PS:Ag-nW composite film, the hook-shaped-electrode TENG (HSE-TENG) provided an average VOC of 15 V, ISC of 0.75 μA and a power density of 18.33 mW/m2 at a wind speed of 5.5 m/s. Under high outdoor temperature and humidity levels, HSE-TENG demonstrated a high degree of response stability. In addition, the proposed TENG is affixed on the top surface of a moving vehicle, where it has been demonstrated to scavenge the energy from the experienced wind force. This study indicates that material strategies and device design approaches can be amalgamated to achieve high performance and operational robustness together for a specific application regime.

Predicting Stress–Strain Characteristics of Hot Deformed Cu-Zr Metallic Glass Alloy Composite Nanowires Using Supervised Machine Learning Algorithms

Predicting Stress–Strain Characteristics of Hot Deformed Cu-Zr Metallic Glass Alloy Composite Nanowires Using Supervised Machine Learning Algorithms

Silver nanowires/waterborne polyurethane composite film based piezoresistive pressure sensor for ultrasensitive human motion monitoring

Flexible piezoresistive pressure sensors are gaining significant attention, particularly in the realm of flexible wearable electronic skin. Here, a flexible piezoresistive pressure sensor was developed with a broad sensing range and high sensitivity. We achieved this by curing polydimethylsiloxane (PDMS) on sandpaper, creating a PDMS film as the template with a micro-protrusion structure. The core sensing layer was formed using a composite of silver nanowires (AgNWs) and waterborne polyurethane (WPU) with a similar micro-protrusion structure. The sensor stands out with its exceptional sensitivity, showing a value of 1.04 × 106 kPa−1 with a wide linear range from 0 to 27 kPa. It also boasts a swift response and recovery time of 160 ms, coupled with a low detection threshold of 17 Pa. Even after undergoing more than 1000 cycles, the sensor continues to deliver stable performance. The flexible piezoresistive pressure sensor based on AgNWs/WPU composite film (AWCF) can detect small pressure changes such as pulse, swallowing, etc, which indicates that the sensor has great application potential in monitoring human movement and flexible wearable electronic skin.

Optimizing preparation conditions and characterizing for CoxPt1-x alloy cylindrical nanowires fabricated by electrodeposition on nanoporous polycarbonate membranes

This study investigated the influence of the preparation conditions on the Co composition, crystal structure, and magnetic and electric conduction properties of cylindrical CoxPt1-x alloy nanowires having 0.08 ≤ x ≤ 0.90, which were electrodeposited on nanoporous templates. When prepared with an optimal concentration ratio of Co and Pt aqueous solutions and electrodeposition potentials, highly oriented crystal structures of fcc Co-Pt (111) was obtained in CoxPt1-x nanowires (0.58 ≤ x ≤ 0.80). Nanowires with (111)-oriented fcc Co-Pt crystals exhibited average lengths and diameters of 5.8–10.8 μm and 130 nm, respectively, and showed an easy axis of magnetocrystalline anisotropy in the longitudinal direction of the nanowire. These results indicate a direct correlation between the crystal structure and magnetic properties. The concentration ratio of Co and Pt in the electrolytes and the electrodeposition potentials for fabricating CoxPt1-x alloy nanowires using the diluted Co composition (0.08 ≤ x ≤ 0.25) were determined. These nanowires were polycrystalline and had a small saturation magnetization. Furthermore, the anisotropic magnetoresistance (AMR) for a single CoxPt1-x nanowire was measured to estimate the domain wall (DW) width in the single CoxPt1-x nanowire. The value of the magnetoresistance (MR) ratio for the single nanowire (0.58 ≤ x ≤ 0.80) with highly (111)-oriented fcc Co-Pt crystal was 0.082–0.23 %, and the estimated value of DW width was 17–25 nm. These findings provide valuable information for constructing three-dimensional magnetic memory devices.

Highly uniform organic nanowire synaptic arrays with excellent performance for associative memory

Synaptic devices of optoelectronic nature, which combine light-detection and data-storage capabilities, hold significant promise in the realm of neuromorphic computing. They are especially beneficial for the processing of visual data and the execution of intricate cognitive functions akin to learning, memory retention, and logical reasoning. However, current research is mostly confined to the level of individual devices, with corresponding studies on synaptic arrays being relatively scarce. Type II heterojunctions are widely used in optoelectronics. Bandgap engineering enables efficient separation and trapping of photogenerated excitons in selected materials, reducing carrier recombination. This prolongs carrier retention in the channel, delaying photocurrent decay, crucial for artificial optoelectronic synapses. We designed an organic nanowire/perovskite Type II heterojunction where CsPbBr3 perovskite films and TIPS nanowires serve as the photosensitive and channel layers, respectively. The composite synaptic array was successfully fabricated by in-situ growth of TIPS nanowires on the surface of perovskite thin films. It was further used to fabricate a photonic synapse array that exhibits characteristic photocurrent and stable optical response. Achieving high-performance photonic synapses was facilitated by characteristics such as high mobility and high on/off ratios, stemming from the formation of complete single-crystal nanowires on the perovskite films. Exhibiting synaptic behaviors such as photo-induced enhancements and paired-pulse facilitation, the device enabled a visual sensing system with a 5 × 5 pixel array for simulating memory processes and restoring associative memories. A novel photocurrent model was established for understanding device characteristics. This work provides valuable insights for future utilization of composite organic nanowire arrays in simulating brain-like computations and realizing large-scale intelligent visual sensing systems.

Highly Conductive PEDOT:PSS: Ag Nanowire-Based Nanofibers for Transparent Flexible Electronics.

Highly conductive, transparent, and easily available materials are needed in a wide range of devices, such as sensors, solar cells, and touch screens, as alternatives to expensive and unsustainable materials such as indium tin oxide. Herein, electrospinning was employed to develop fibers of PEDOT:PSS/silver nanowire (AgNW) composites on various substrates, including poly(caprolactone) (PCL), cotton fabric, and Kapton. The influence of AgNWs, as well as the applied voltage of electrospinning on the conductivity of fibers, was thoroughly investigated. The developed fibers showed a sheet resistance of 7 Ω/sq, a conductivity of 354 S/cm, and a transmittance value of 77%, providing excellent optoelectrical properties. Further, the effect of bending on the fibers' electrical properties was analyzed. The sheet resistance of fibers on the PCL substrate increased slightly from 7 to 8 Ω/sq, after 1000 bending cycles. Subsequently, as a proof of concept, the nanofibers were evaluated as electrode material in a triboelectric nanogenerator (TENG)-based energy harvester, and they were observed to enhance the performance of the TENG device (78.83 V and 7 μA output voltage and current, respectively), as compared to the same device using copper electrodes. These experiments highlight the untapped potential of conductive electrospun fibers for flexible and transparent electronics.

Self-Assembled BiGaSeAs Composite Superlattice-Structured Nanowire for Broad-Band Photodetection.

Photodetectors with a broad-band response range are widely used in many fields and are regarded as pivotal components of the modern miniaturized electronics industry. However, commercial broad-band photodetectors composed of traditional bulk semiconductor materials are still limited by complex preparation techniques, high costs, and a lack of mechanical strength and flexibility, which are difficult to satisfy the increasing demand for flexible and wearable optoelectronics. Therefore, researchers have been devoted to finding new strategies to obtain flexible, stable, and high-performance broad-band photodetectors. In this work, a novel self-assembled BiGaSeAs composite superlattice-structured nanowire was developed with a simple chemical vapor deposition method for easy fabrication. After the device assembling, the photodetector showed outstanding performance in terms of obvious Ion/Ioff (13.9), broad-band photoresponse (365-940 nm), excellent responsivity (1007.67 A/W), high detectivity (9.38 × 109 Jones), and rapid response (21 and 23 ms). The formation of microheterojunctions among various materials inside the nanowires also contributed to their extended broad-spectrum response and outstanding detection ability. These results indicate that the BiGaSeAs nanowires have potential applications in the field of flexible and wearable electronics.

Enhanced Transport Kinetics of Electrochromic Devices by W18O49 NW/Ti3C2Tx Composite Films

AbstractElectrochromic devices can facilitate the realization of a wide set of future applications, ranging from energy‐saving windows to smart wearables and stealth. Historically, tungsten oxides have been the most studied materials for electrochromism, albeit with bottlenecks like limited conductivity, high charge transport barrier, and low ion diffusivity. Here, inspired by the recent MXene materials, the study has engineered an electrochromic composite of MXene nanosheets (Ti3C2Tx) and W18O49 nanowires (NWs). A transparent conductive electrode is fabricated by co‐assembly of Ag and W18O49NWs, followed by depositing W18O49 NW/Ti3C2Tx layers for the fabrication of the electrochromic device. The incorporation of Ti3C2Tx nanosheets enhances the transport of electrons and ions within the electrochromic layer, leading to a significant improvement in the electrochromic performance. Noteworthily, the film structure comprising 15 layers of W18O49 NW/Ti3C2Tx composite reveals enhanced transmittance modulation (61%), rapid response time (4.5 s coloration, 6.5 s bleaching), and high coloration efficiency (139.1 cm2 C−1). Moreover, the electrode also presents a high diffusion coefficient of Li+ and good cycling stability (96.66% after 250 switching cycles). Finally, a large‐scale (15 × 20 cm2) flexible electrochromic device with a solid electrolyte is successfully fabricated and utilized as a smart window and a flexible stealth patch.

Investigating the influence of varying cobalt doping on the cross-sectional widths and surface composition of MnOx nanowires in the context of battery–supercapacitor systems

Investigating the influence of varying cobalt doping on the cross-sectional widths and surface composition of MnOx nanowires in the context of battery–supercapacitor systems