Graphene Nanowires Research Articles

Review of: "CNT carbon nanotubes can conduct large amounts of electrical current, much more than graphene nanowires and nanoribbons generally self-assemble in "electron nanospins""

Review of: "CNT carbon nanotubes can conduct large amounts of electrical current, much more than graphene nanowires and nanoribbons generally self-assemble in "electron nanospins""

Optimization of Contact Pad Design for Silver Nanowire-Based Transparent Heater to Improve Heating Characteristics.

Transparent heaters are gaining significant attention for applications such as antifog glass, smart windows, and smart farm greenhouses. A transparent heater basically consists of transparent conducting materials that serve as a heating area and contact pad electrode to apply power. To fabricate a transparent heater, materials with excellent light transmittance and low sheet resistance are required. Among various transparent conducting materials, such as Indium Tin Oxide (ITO), carbon nanotube (CNT), graphene, and silver nanowires (AgNWs), AgNWs are particularly favored due to their good electrical, optical, and mechanical properties. However, in order to improve the heating characteristics of transparent heaters, research is essential not only on improving the properties of transparent conducting materials but also on the design of contact pad electrodes that can uniformly improve current distribution. Here, we explore various shapes of contact pad electrodes for AgNW-based transparent heaters to improve current distribution. Shapes such as line, spot, twisted, and parallel-type contact pad electrodes are designed and investigated to optimize overall heating characteristics. We analyze the heating properties of these transparent heaters with various contact pad electrodes, demonstrating how their specific shape and size affect heating characteristics and uniformity. We also investigate the optimal shape of the contact pad electrode to minimize transmission loss through UV-VIS spectroscopy. As a result, we confirm that the shape of the contact pad electrode was important for simultaneously achieving high heating characteristics of 120 °C, good heating uniformity, and over 80% transparency in an AgNW-based transparent heater.

Review of: "CNT carbon nanotubes can be large amounts transfer electric current, much more than graphene nanowires and nanoribbons generally self-aggregate in nanostructures, increasing nanoelectromagnetic interaction (nanoparticles) in conductive nanomaterials and semiconductors"

Review of: "CNT carbon nanotubes can be large amounts transfer electric current, much more than graphene nanowires and nanoribbons generally self-aggregate in nanostructures, increasing nanoelectromagnetic interaction (nanoparticles) in conductive nanomaterials and semiconductors"

Low-cost, reliable and flexible piezoresistive pressure sensors coated with single layer graphene and silver nanowires on three-dimensional polyurethane sponge

Flexible wearable sensors perform a significant role in practical applications such as medical monitoring, rehabilitation exercises, and artificial skin, as they can quantify and visualize external stress and strain. Polyurethane (PU) sponge stands out as a highly elastic and reproducible material frequently employed as a substrate in flexible electronic devices. Sponge materials with different pore sizes and densities exhibit varying degrees of deformation resistance under long-term cyclic pressure, thereby affecting the performance of sensors. Herein, piezoresistive pressure sensors based on PU with different pore diameters were successfully fabricated by dip-coating technology. By incorporating silver nanowires (AgNWs) and single layer graphene (SLG) into the sponge, both the low-density and high-density composite sponges can withstand over 70 % compressive strain, with stresses of 62.57 kPa and 31.79 kPa, respectively. Moreover, high-density composite sponge demonstrates a more stable conductive structure, more consistent relative resistance and better flame-retardant performance. The response and recovery time between 10 % and 40 % strains of the resulting pressure sensor based on high-density composite sponge (PU@AgNWs@SLG) are 110 ms and 106 ms and its gauge factor reaches 2.39. The pressure sensor exhibits a satisfactory reproducibility after over 3000 compression-release cycles, and performs during various applications, such as controlling brightness of LEDs, monitoring human activities, sensing finger movements.

Prediction of grain boundary strength and mechanical responses of high-entropy carbides reinforced by hybrid graphene and SiC nanowire

The excellent performance of high entropy ceramics (HECs) has attracted extreme attention in the most advanced functional applications and engineering structures, yet the poor toughness limits the application of HECs in many fields. As a consequence, advanced technology and new doping phases are urgently demanded to enhance the comprehensive mechanical properties of HEC composites. The microstructure model of 0.2 wt% graphene (G) and SiC nanowires (SiCnw) doped in (HfNbTaTiZr)C is established in Abaqus with Python language. The effects of HEC-HEC interface strength and HEC-G interface strength on crack propagation and mechanical properties of HEC composites were investigated. The improvement of mechanical properties of (HfNbTaTiZr)C with different content of SiCnw was predicted respectively. The composites obtain the optimal combination of mechanical properties at the content of 1.5 wt% SiCnw. The accuracy of the simulation is verified by the experimental data of mechanical properties changing trend and toughening mechanism, providing theoretical support for toughening HEC composites.

Self-powered graphene/4H-SiC nanowire array-based ultraviolet photodetectors with fast response time and low dark current for promising wireless ultraviolet communication

Self-powered ultraviolet photodetectors (UV PDs) capable of detecting UV light signals without using an external power supply have become particularly attractive because of their high sensitivity, consistent optical response, ultra-small size, low energy consumption, and long-term robustness for the future. Here we reported a self-powered UV PDs coupling of two-dimensional (2D) single-layer graphene and one-dimensional (1D) 4H-SiC nanowire arrays. The fabricated PDs can feature an ultra-high on-off ratio of 6301 at 0 V and the 2D-1D architectural exhibits a low dark current of ∼4 pA, an ultra-fast response of 4.89 ms. The high performance was associated with the formed heterojunction between the 2D graphene and 1D 4H-SiC nanowire array and the high carrier mobility of the graphene. Moreover, the 2D-1D PDs with a large switching ratio and ultra-fast response time can be beneficial to achieve efficient, real-time, and accurate information transmission under 275 nm UV light, shedding some light on the development of high-performance wireless optical communication systems.

Water self-purification via electron donation effect of emerging contaminants arousing oxygen activation over ordered carbon-enhanced CoFe quantum dots

The release of emerging contaminants (ECs) into aquatic environments poses a significant risk to global water security. Advanced oxidation processes (AOPs), while effective in removing ECs, are often resource and energy-intensive. Here, we introduce a novel catalyst, CoFe quantum dots embedded in graphene nanowires (CoFeQds@GN-Nws), synthesized through anaerobic polymerization. It uniquely features electron-rich and electron-poor micro-regions on its surface, enabling a self-purification mechanism in wastewater. This is achieved by harnessing the internal energy of wastewater, particularly the bonding energy of pollutants and dissolved oxygen (DO). It demonstrates exceptional efficiency in removing ECs at ambient temperature and pressure without the need for external oxidants, achieving a removal rate of nearly 100.0%. The catalyst's structure-activity relationship reveals that CoFe quantum dots facilitate an unbalanced electron distribution, forming these micro-regions. This leads to a continuous electron-donation effect, where pollutants are effectively cleaved or oxidized. Concurrently, DO is activated into superoxide anions (O2•−), synergistically aiding in pollutant removal. This approach reduces resource and energy demands typically associated with AOPs, marking a sustainable advancement in wastewater treatment technologies.

SENSING MECHANISM AND APPLICATION OF MECHANICAL STRAIN SENSOR: A MINI-REVIEW

This study reviews the potential of flexible strain sensors based on nanomaterials such as carbon nanotubes (CNTs), graphene, and metal nanowires (NWs). These nanomaterials have excellent flexibility, conductivity, and mechanical properties, which enable them to be integrated into clothing or attached to the skin for the real-time monitoring of various activities. However, the main challenge is balancing high stretchability and sensitivity. This paper explains the basic concept of strain sensors that can convert mechanical deformation into electrical signals. Moreover, this paper focuses on simple, flexible, and stretchable resistive and capacitive sensors. It also discusses the important factors in choosing materials and fabrication methods, emphasizing the crucial role of suitable polymers in high-performance strain sensing. This study reviews the fabrication processes, mechanisms, performance, and applications of stretchable strain sensors in detail. It analyzes key aspects, such as sensitivity, stretchability, linearity, response time, and durability. This review provides useful insights into the current status and prospects of stretchable strain sensors in wearable technology and human–machine interfaces.

Integrated asymmetric cellulose aerogel membrane with triple thermal insulation and unidirectional liquid penetration for personal thermal management

With the rapid development of personal thermal management, there is an urgent need for an advanced material that can effectively integrate various thermal functions to keep body warm and cope with the cold outdoor environment. Herein, a multifunctional cellulose based asymmetric modification aerogel membrane (ACAM) encompassing thermal insulation, thermal radiation reflection, solar adsorption, and directional perspiration has been fabricated via bottom-up assembling biomass sisal fibers and pulp fibers into cellulose aerogel membrane, followed by spin-coating ionic liquid modified graphene (IGNs) and silver nanowires (AgNWs) on both sides of the cellulose aerogel membrane, respectively. The results showed that the temperature on the IGNs side is 14.2 °C higher than that of the cotton cloth after 30 s of sunlight exposure. Compared with pure cellulose aerogel membrane, the AgNWs side of ACAM has lower infrared emissivity and higher infrared reflectivity, and the temperature is reduced by 3.2 °C in indoor environment. In addition, the ACAM has asymmetric wettability, which facilitates the transfer of sweat from the hydrophobic side to the hydrophilic side and perspiration penetration was achieved in 10.6 s to obtain the comfort of wearing. The ACAM also exhibits excellent breathability, easy preparation and controllable functional structures. This work may provide a new idea for heat management and dynamic moisture to ensure maximum comfort in very harsh environments.

Synergistically enhancing the electrical conductivity of carbon fibre reinforced polymers by vertical graphene and silver nanowires

Increasing the electrical conductivity of carbon fibre reinforced polymers (CFRPs) holds great promises for a range of applications, such as removing the need for metallic meshes in the protection against electromagnetic interference and lightning strikes. Herein, a hybrid method of improving the electrical conductivity of CFRPs by functionalizing carbon fibres with vertical graphene (VG) and modifying the matrix with silver nanowires (AgNWs) is introduced. The results revealed that the hybrid method increased the through-thickness and the in-plane electrical conductivities by almost 38 times and 39%, respectively, without adversely affecting mechanical properties. Finite element modelling revealed that the unprecedented synergy is due to the significant reduction in the contact resistance between carbon fibres by the combination of VGs on the fibres and the AgNWs in the matrix. Computational modelling showed that the electrical conductivity increase can reduce the joule heat density by around one thousand times under simplified lightning strike conditions.

Carbon nanomaterials: Types, synthesis strategies and their application as drug delivery system for cancer therapy

Inorganic and organic nanoparticles are used for abundant number of applications due to their novelty, surface charge, alloys, and oxides. Among the different types of nanoparticles, carbon nanomaterials (CNM) are gaining constant attention for biomedical applications. Their unique physical and chemical characteristics, like electrical, thermal, structural, and optical diversity, make them suitable materials. Selecting CNM for the treatment and diagnosis of disease and infection will provide controlled, predictable, low cytotoxic, and target-specific delivery of drugs for biomedical applications. Different types of CNM, like graphene oxide (GO), carbon nanotubes, nanorods, nanowires, and graphene quantum dots (GQDs), need to be investigated for application in Cancer treatment. Therefore, this review focuses on the different types of synthesis, drug loading, surface coating, and application of CNM as a drug delivery agent for cancer diagnosis and treatment.

Investigation of graphene/InN nanowire based mixed dimensional barristors with widely tunable Schottky barrier for highly sensitive multimodal gas sensing applications

In this work, an electrically tunable mixed dimensional heterojunction of graphene and planar InN nanowires (NW) has been investigated as a potential candidate for highly sensitive gas sensing applications. The high surface carrier concentration of InN, which prevents it from forming good rectifying contact with graphene, has been effectively suppressed through controlled partial surface oxidation in a plasma reactor. The resulting surface modified InN NWs were found to form excellent Schottky junction with graphene, with a barrier height that is widely tunable by the gate voltage, turning it into a mixed dimensional barristor device. When utilized as a multimodal molecular sensor, utilizing both capacitive and conductive modes, it exhibited very high sensitivity, with detection limits reaching down to sub-ppb range for NO2 and low ppb range for NH3 and CO, tested in both N2 and dry air environments. Additionally, surface functionalization, using hemin/benzoic acid, of this non-conventional barristor device yielded excellent selectivity for specific analytes while maintaining the high sensitivity. The responses of the sensor were found to be minimally affected with long term exposure to atmospheric humidity, which underscores the potential of this barristor device as a highly sensitive gas sensor for practical applications.

Highly conductive supercapacitor based on laser-induced graphene and silver nanowires

Highly conductive supercapacitor based on laser-induced graphene and silver nanowires

Plasmonic hybrid terahertz photomixer of graphene nanoantenna and nanowires

Due to their attractive properties, silver nanowires (Ag-NWs) are newly used as nanoelectrodes in continuous wave (CW) THz photomixer. However, since these nanowires have small contact area, the nanowires fill factor in the photomixer active region is low, which leads to reduce the nanowires conductivity. In this work, we proposed to add graphene nanoantenna array as nanoelectrodes to the silver nanowires-based photomixer to improve the conductivity. In addition, the graphene nanoantenna array and the silver nanowires form new hybrid nanoelectrodes for the CW-THz photomixer leading to improve the device conversion efficiency by the plasmonic effect. Two types of graphene nanoantenna array are proposed in two separate photomixer configurations. These are the graphene nanodisk (GND) array and the graphene bow-tie nanoantenna (GNA) array. The photomixer active region is simulated using the computer simulation technology (CST) Studio Suite<sup>®</sup> for three optical wavelengths: 780 nm, 810 nm, and 850 nm. From the results, we found that the electric field in the active region is enhanced by 4.2 and 4.8 times for the aforementioned configurations, respectively. We also showed that the THz output power can be enhanced by 310 and 530 times, respectively.

The ballistic and diffusive thermal transport in low-dimensional structures

The thermal transport property in low-dimensional structures has been studied theoretically taking into account the effect of temperature on phonon–phonon coupling. New thermal-transport equations are developed to discriminatively treat the ballistic and diffusive thermal transport in quantum structures. Using the new thermal transport equations, the thermal transport properties in GaAs nanowire and zigzag graphene nanoribbon are investigated to demonstrate the crossover from ballistic to diffusive thermal transport.

Effectiveness of Human Machine Interaction (HMI) for Development of Communication and Interaction between a Human and a Machine to Control Machines

This study is based on the human-machine interaction that is the way of communication between automatic systems and people. The HMI process allows humans to control the machine through initiatives behaviours and natural. Those factors also lead to building the established communication process with the technology and digital system as well. From this study, it has been seen that H2M devices include a sensor for measuring the comments signal such as voice, touch, and gestures for constructing an updated system to control and a measurement system to measure the electrophysiological signals. This study has also focused on the Sensor HMI that can help to detect the temperature and strain pressure. It can provide the opportunity to monitor and mimic human senses and it also can improve machine control by graphene, carbon nanotubes, hydrogel composites, and Ag nanowires. These kinds of elements give the provision to build a stretchable sensor for developing the structure's stretchability. Accordingly, it can be said that the mechanical sensor process assists to apply the attachment of the enabling strain sensors in the finger joints for measuring the movements of the figure and using the pressure sensor for improving the analysis of grasping activities. This study has also shed light on the Actuators of HMI that helps to deliver all kinds of human output and also have the ability to mimic the sense of people or individual for the desired outcome of human and machine interaction. It can help to stimulate the senses of humans mechanically. In this context, it can be said that wearable gloves use the benefits of soft actuators for rehabilitation. It helps to support the force of grasping. On the other hand, the mechanical vibration process helps to stimulate the human sense that helps to provide certain information as well. Intelligence-aided devices usage is one of the other critical parts of this study and from this portion, it has been seen that the advancement of actuators and sensors in machine intelligence help to get higher detectability in soft sensors, coping with chronic problems, and decoupling unwanted stimuli in sensor process. This factor helps human hands to provide the highest degree of freedom in the body for performing a range of tasks with the development of detecting hand motions. This study has chosen a secondary process to get the data for the study and it also helps to make a proper conclusion for the study. At last, it can be said that HMI is a blessing for the world population and future generations. Keywords : Ag nanowires, carbon nanotubes, human-machine interaction (HMI), and hydrogel compos PDMS.

Toughening in low-dimensional nanomaterials high-entropy ceramic nanocomposite

Very recently, high entropy concept has evolved from metal to the ceramic community, named as high entropy ceramics (HEC). The configurational entropy endowed the system with unique structure, performances as well as application potentials such as aerospace, high-speed machining tools, and nuclear reactors. However, the poor densification together with low fracture toughness of HEC significantly limited the practical applications of HEC. Herein, we report for the first time the employment of low-dimensional nanomaterials including multilayer graphene (MLG), carbon nanotube (CNT) and SiC nanowire (SiC nw ) to improve the densification coupled with fracture toughness of HEC through two-step spark plasms sintering. HEC-MLG and HEC-SiC nw exhibited flexural strength of 671.3 MPa and 626.5 MPa, with fracture toughness of 7.1 MPa m 1/2 and 6.2 MPa m 1/2 , respectively. The strength and toughness of HEC nanocomposites were both greater than those of the reported values for high entropy ceramics. The reinforcing mechanisms were discussed in detail for all the three HEC nanocomposites. Overall, this paper demonstrated that the toughening methods for normal ceramics were also feasible for HEC matrix, significantly increasing the freedom to tailor the properties and applications of HEC. • Low-dimensional nanomaterials were proposed for reinforcing high entropy ceramic. • Two-step spark plasms sintering was employed to densify high entropy ceramic. • The compromise between strength and toughness occurred to high entropy ceramic. Graphene and SiC nw performed better roles than CNT in toughening high entropy ceramic.

Enhanced thermoelectric performance based on special micro-configuration of graphene-ZnO induced by high-pressure and high-temperature

Zinc oxide (ZnO) is a promising high-temperature thermoelectric material. Graphene is typically a two-dimensional material, and its development and application have attracted wide attention due to its excellent thermal stability and mechanical properties. To the best of our knowledge, the graphene-ZnO (C–ZnO) composite has never been studied in the field of thermoelectric conversion. The high-pressure and high-temperature (HPHT) technique has unique advantages in improving the thermoelectric properties of ZnO. In this study, for the first time, C–ZnO bulk energy materials with novel micro-configuration were prepared by rapid sintering using the HPHT method. Observation under a microscope revealed that as the doping amount of graphene increased, a large number of graphene nanowires formed connected between the ZnO grains, and with the excess amount of graphene introduced the morphology of the ZnO grains changed and their size became smaller. This novel micro-configuration of the 0.1C–ZnO sample showed an ultrahigh electrical conductivity of 2.8 × 104 S/m with a significantly lower lattice thermal conductivity of 4.3 Wm−1K−1 at 973 K. Ultimately, at 973 K, the zT value of the 0.1C–ZnO sample was 129 times higher than that of pure ZnO. Therefore, the high-temperature thermoelectric material C–ZnO prepared by the HPHT method can be used in automobile exhaust systems and industrial boilers to effectively recover and reuse the waste heat.

Electrically or chemically tunable photodetector with ultra high responsivity using graphene/InN nanowire based mixed dimensional barristors

In this work, an electrically/chemically tunable highly sensitive photodetector based on mixed dimensional heterojunction of graphene and planar InN nanowires (NW) is presented. Controlled partial oxidation of InN has been employed to effectively reduce the high surface carrier concentration of InN, which normally prevents it from forming good rectifying contact with graphene. The resulting surface modified InN NWs have been found to form excellent Schottky junction with graphene, with an increase in effective Schottky barrier height (SBH) by over 1.1 eV and a ratio of forward and reverse bias currents exceeding 4 orders of magnitude. Moreover, very strong barristor (gate tunable heterojunction) action has been observed, with I on/I off ≈ 4 orders of magnitude, and SBH increase by >0.3 eV. The barristor has been demonstrated to be highly sensitive to light, especially in the ultra-voilet, visible and near IR spectra. Responsivity was found to be widely tunable by gate voltage, with the highest value exceeding 1000 A W−1. Rise and fall times being in the range of hundreds of ms are indicative of photoconductive gain, which can be attributed to the ultra high responsivity. A method of semi-permanent molecular doping has been demonstrated to realize a two-terminal version of the photodetector, where the desired responsivity can still be achieved without requiring a back gate terminal, enabling the device to be realized on insulating substrates. The effect of encapsulation has been studied as a function of time, which has showed the long term stability of the dopant-induced enhancement and ultra high responsivity of the barristor photodetector.

Two‐Dimensional‐Germanium Phosphide‐Reinforced Conductive and Biodegradable Hydrogel Scaffolds Enhance Spinal Cord Injury Repair

AbstractDeveloping biodegradable conductive hydrogels is of great importance for the repair of electroactive tissues, such as myocardium, skeletal muscle, and nerves. However, conventional conductive phase incorporation in composite hydrogels, such as polypyrrole, polyaniline, carbon nanotubes, graphene, and gold nanowires, which are non‐degradable materials, will exist in the body as foreign matter. Herein, an injectable hydrogel based on the integration of conductive and biodegradable germanium phosphide (GeP) nanosheets into an adhesive hyaluronic acid‐graft‐dopamine (HA‐DA) hydrogel matrix is explored, and the successful application of this biohybrid hydrogel in spinal cord injury (SCI) repair is demonstrated. The incorporation of polydopamine (PDA)‐modified GeP nanosheets (GeP@PDA) into HA‐DA hydrogel matrix significantly improves the conductivity of HA‐DA/GeP@PDA hydrogels. The conductive HA‐DA/GeP@PDA hydrogels can accelerate the differentiation of neural stem cells (NSC) into neurons in vitro. In a rat SCI complete transection model, the in vivo implanted HA‐DA/GeP@PDA hydrogel is found to improve the recovery of locomotor function significantly. The immunohistofluorescence investigation suggests that the HA‐DA/GeP@PDA hydrogels promote immune regulation, endogenous angiogenesis, and endogenous NSC neurogenesis in the lesion area. The strategy of integrating conductive and biodegradable GeP nanomaterials into an injectable hydrogel provides new insight into designing advanced biomaterials for SCI repair.