Resistance Of Nanowires Research Articles

Flexible, transparent, and low-temperature usable electromagnetic shielding film based on orthogonally arranged silver nanowire network/graphene oxide conductive network

With the increasing diversification of application environments of new electronic products, demands are being placed on flexibility, transparency, and stable operation capability even under harsh conditions of electromagnetic shielding films. Aiming at the issue of high contact resistance of simple silver nanowire (AgNWs) conducting network, this work utilizes orthogonally arranged AgNWs and graphene oxide (GO) to establish unique AgNWs/GO conductive network, achieving more conductive nodes and enhancing the stability of the conductive network. The resulting AgNWs/GO film exhibits a reduced resistance of 9.8 Ω/sq, an impressive light transmittance of 85.7 % (λ = 550 nm), and excellent electromagnetic interference shielding efficiency (EMI SE) reaching 30.3 dB in the X-band (8.2–12.4 GHz). Moreover, the AgNWs/GO film exhibits the potential for long-term operation in harsh environments. After undergoing numerous bending cycles (10,000 times), prolonged exposure (90 days), and repeated energization (800 times), the resistance of the AgNWs/GO film remains extremely stable. Furthermore, the film demonstrates remarkable electrothermal conversion capability in cold environments, rapidly heating to 73.3 ℃ under a 4 V voltage and maintaining stability thereafter. After 800 h of operation, there is negligible change in its electrothermal properties. The development of such a flexible electromagnetic shielding film holds significant implications for various applications.

Investigation on the electrical property of gold nanowire prepared by nanoskiving

The electrical signal plays a pivotal role in the functionality of nanowire-based sensors. The investigation on the electrical property of nanowire has thus drawn increasing attention. In this study, gold nanowires are prepared by nanoskiving approach and the electrical properties of Au nanowires are evaluated. It is found that the resistivity of Au nanowire is significantly higher than that of bulk Au. The influence of nanoskiving parameters on the electrical properties are also investigated. The resistivity of the nanowire increases with the decreasing cutting depth and the film thickness. The minimum resistivity of the nanowire is 2.8 × 10−8 Ω m. The investigation into the failure behavior of the nanowire reveals that it exhibits significant Joule heating and electromigration, ultimately resulting in its structural degradation due to high current-induced melting fracture. The research presented in this study provides a valuable technical framework for the application of nanowire-based sensors that prepared by nanoskiving technique.

Temperature-based energy changes in gold nanowire sensors for flow rate detection and failure prediction

This study delves into the dynamic operational states of nanowire sensors within microfluidic channels for flow velocity detection, classifying these states into decline, steady, and failure states. It conducts a comparative analysis of the steady-state operational characteristics of nanowire sensors across various voltages and inlet flow rates, alongside examining the interplay between nanowire resistivity and temperature. This investigation identifies an optimal working condition for the sensor at a 1 V operating voltage and a nanowire dimension of 150 × 150 nm. Employing both theoretical and experimental approaches, the research elucidates the convective heat transfer mechanism that underpins the functionality of the nanowire sensor for flow rate detection. It unveils the pattern of nanowire temperature changes during inlet flow rate measurement within a range from 10 to 50 μL/min range and establishes standard values of temperature and calorimetric differences for various flow velocities. Furthermore, the study achieves the prediction of the time to reach the steady and failure states under given operational conditions for the nanowire-based sensor. This advancement will enhance the reading precision of the signal output from the nanowire sensor, mitigate the risk of sensor failure, and contribute to prolonging the operational lifespan of equipment.

Enhanced efficiency and stability of dye-sensitized solar cells utilizing FeCo2S4 nanowires as Pt-free counter electrodes

Replacing traditional Pt-based counter electrodes with low-cost and highly stable materials is crucial for the development of commercially viable dye-sensitized solar cells (DSSCs). In this study, we synthesized a ternary Pt-free FeCo2S4 nanowire (NW)-based sulfide electrocatalyst by a three-step solvothermal method. This material was then used as a counter electrode in DSSCs to facilitate the reduction of triiodide species. The formation of FeCo2S4 NW was confirmed by various characterization techniques such as X-ray diffraction, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Scanning electron microscopy analysis revealed the structure of the nanowires. Electrochemical studies, which included cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization methods, revealed the excellent stability, superior electrocatalytic activity and remarkable kinetics of FeCo2S4 NW in the reduction of triiodide to iodide. Photovoltaic measurements of the fabricated DSSCs yielded a power conversion efficiency (PCE) of 7.88 % for the FeCo2S4-based devices, outperforming the control device made of Pt (PCE=7.45 %). This improvement was primarily due to the increase in short-circuit current density (JSC), thanks to the lower charge transfer resistance (RCT) of FeCo2S4 NW (JSC=15.23 mA/cm2; RCT=5.54 Ω cm2) compared to Pt (JSC=14.12 mA/cm2; RCT=7.07 Ω cm2). In addition, the FeCo2S4 NW-based solar cells exhibited excellent stability and maintained their high PCE value even after 10 days of aging under ambient conditions, while Pt-based DSSCs showed a 3 % decrease from their initial PCE value. This FeCo2S4 NW counter electrode proves to be an excellent alternative to Pt, and the presented results provide valuable insights for the development of cost-effective and highly stable DSSCs.

Effects of ballistic transport on the thermal resistance and temperature profile in nanowires

Effects of ballistic transport on the temperature profiles and thermal resistance in nanowires are studied. Computer simulations of nanowires between a heat source and a heat sink have shown that in the middle of such wires the temperature gradient is reduced compared to Fourier’s law with steep gradients close to the heat source and sink. In this work, results from molecular dynamics and phonon Monte Carlo simulations of the heat transport in nanowires are compared to a radiator model which predicts a reduced gradient with discrete jumps at the wire ends. The comparison shows that for wires longer than the typical mean free path of phonons the radiator model is able to account for ballistic transport effects. The steep gradients at the wire ends are then continuous manifestations of the discrete jumps in the model.Graphical abstract

Modeling the Temporal Response of Gated ZnO Nanowire Field Emitter by Considering the Charging and Self-Heating Effect for Improving the Response Speed

ZnO nanowire is a promising candidate for large-area gated field emitter arrays. How to improve its temporal response is one of the key problems to be solved for applications. In this work, a device model for a gated ZnO nanowire field emitter with consideration of charging and self-heating effect has been established to investigate its temporal response. It is found that while the charging effect is responsible for the delay at the beginning of the pulse, the self-heating effect which induces delay due to the thermal conduction process can shorten the charging time because of its lowering of nanowire resistance. The response time can be minimized when these two effects are balanced at an optimal field which is below the critical field for thermal runaway. We further investigate the optimal response time of a nanowire with the same resistance but a different length, radius, and electrical properties. The results imply that a lower heat capacity and higher critical temperature for thermal runaway are in favor of a shorter response time, which must be taken into account in the reduction in nanowire resistance for improving response speed. All the above should be useful for the device design of a fast-response gated ZnO nanowire field emitter array.

Unraveling the electrical energy loss in silver nanowire electrodes for flexible and Large-Area organic solar cells

Although the transparency and sheet resistance of silver nanowire (AgNW) electrodes are comparable to those of rigid indium-tin-oxide electrodes, flexible organic solar cells (FOSCs) are still less efficient than their rigid counterparts. Herein, by recording the microscopic photocurrent images of AgNW-based FOSCs in operation, it has been revealed that the limited lateral charge collection range of AgNW leads to inevitable electrical energy loss. The regulation of carrier mobility and energy level of adjacent ZnO electron transport layer increases the effective collection range of AgNWs by 1.8 times and uniform the electrical potential distribution in FOSCs. The D18:Y6:PC71BM-based FOSCs achieve a power conversion efficiency of approaching 18%. Moreover, the performance drop of large-area FOSCs is significantly reduced due to the improved charge collection on large area scale. This work provides an intuitive insight into the electrical energy loss mechanism of AgNW electrodes and demonstrates an electric field regulation strategy in FOSCs.

Modulation Doping of Silicon Nanowires to Tune the Contact Properties of Nano‐Scale Schottky Barriers

AbstractDoping silicon on the nanoscale by the intentional introduction of impurities into the intrinsic semiconductor suffers from effects such as dopant deactivation, random dopant fluctuations, out‐diffusion, and mobility degradation. This paper presents the first experimental proof that doping of silicon nanowires can also be achieved via the purposeful addition of aluminium‐induced acceptor states to the SiO2 shell around a silicon nanowire channel. It is shown that modulation doping lowers the overall resistance of silicon nanowires with nickel silicide Schottky contacts by up to six orders of magnitude. The effect is consistently observed for various channel geometries and systematically studied as a function of Al2O3 content during fabrication. The transfer length method is used to separate the effects on the channel conductivity from that on the barriers. A silicon resistivity is achieved as low as 0.04–0.06 Ω ·cm in the nominal undoped material. In addition, the specific contact resistivity is also strongly influenced by the modulation doping and reduced down to 3.5E‐7 Ω · cm2, which relates to lowering the effective Schottky barrier to 0.09 eV. This alternative doping method has the potential to overcome the issues associated with doping and contact formation on the nanoscale.

Thermal shock behavior and oxidation resistance of novel SiC nanowires+Si/Yb2Si2O7-Si/Yb2Si2O7 environmental barrier coatings

The objective of this work is to design environmental barrier coatings with new structure to improve the thermal shock and oxidation resistance. A novel tri-layer SiC nanowires+Si/Yb2Si2O7-Si/Yb2Si2O7 coating was designed and fabricated on the surface of C/SiC composites by chemical vapor reaction route and combination of the method of atmospheric plasma spraying. All coated samples were subjected to thermal shock test at 1300 ℃. Results indicated that the interfacial bond among the layers in the coating system and C/SiC composites was still intact without delamination crack. The Si in the Yb2Si2O7-Si layer consumed the oxygen diffused into coating and then reacted with Yb2SiO5 to form Yb2Si2O7, which could decrease the release of tensile stress caused by thermal mismatch. The study also investigates the Yb2Si2O7 formation in the Yb2SiO5-Si system, and finds that the Yb2Si2O7 formation was controlled by the diffusion of Yb3+ and Si4+ ions through the Yb2Si2O7 layer.

A Platinum Nanowire Sensor for Ethylene in Air.

A single platinum nanowire (PtNW) chemiresistive sensor for ethylene gas is reported. In this application, the PtNW performs three functions: (1) Joule self-heating to a specified temperature, (2) in situ resistance-based temperature measurement, and (3) detection of ethylene in air as a resistance change. Ethylene gas in air is detected as a reduction in nanowire resistance by up to 4.5% for concentrations ranging from 1 to 30 ppm in an optimum NW temperature range from 630 to 660 K. This response is rapid (30-100 s), reversible, and reproducible for repetitive ethylene pulses. A threefold increase in signal amplitude is observed as the NW thickness is reduced from 60 to 20 nm, commensurate with a signal transduction mechanism involving surface electron scattering.

Percolation and electrical conduction in random systems of curved linear objects on a plane: Computer simulations along with a mean-field approach

Using computer simulations, we have studied the percolation and the electrical conductance of two-dimensional, random percolating networks of curved, zero-width metallic nanowires. We mimicked the curved nanowires using circular arcs. The percolation threshold decreased as the aspect ratio of the arcs increased. Comparison with published data on the percolation threshold of symmetric quadratic Bézier curves suggests that when the percolation of slightly curved wires is simulated, the particular choice of curve to mimic the shape of real-world wires is of little importance. Considering the electrical properties, we took into account both the nanowire resistance per unit length and the junction (nanowire/nanowire contact) resistance. Using mean-field approximation (MFA), we derived the total electrical conductance of nanowire-based networks as a function of their geometrical and physical parameters. The MFA predictions have been confirmed by our Monte Carlo numerical simulations. For our random homogeneous and isotropic systems of conductive curved wires, the electric conductance decreased as the wire shape changed from a stick to a ring when the wire length remained fixed.

The Study of Electrical Resistance of Silver Nanowires in Isopropanol for Heater Application

Silver nanowire is one of the most attractive materials for making devices. In this work, we are interested in using silver nanowires for heater application. To get a good heater, the electrical resistance of the device should be low in order to generate a high temperature. The media to disperse nanowires is also important and helps inter-connection between nanowires. Hence, we study the different amounts of isopropanol (IPA) in water as the media to disperse silver nanowires. The nanowire solutions were prepared under different percentages of isopropanol varying from 0% to 100%. Optical images showed the dispersity of nanowires after the media evaporated. The electrical resistances of spun silver nanowires on glass slides were conducted. The results show that the electrical resistance of nanowires in different amounts of IPA was separated into 2 groups. First, from 0% to 50% of IPA, the electrical resistances were lower than 15 Ohms. Second, for 75% to 100% of IPA, the electrical resistances show more than 85 Ohms. After heater testing of the first group, the temperature is stable and repeatable with a certain applied voltage and current.

Effective resistance and transmittance of two-dimensional nanowire based networks: computational investigation to study the effect of filler length fraction

Effective resistance and transmittance of two-dimensional nanowire based networks: computational investigation to study the effect of filler length fraction

Electrical conductance of two-dimensional random percolating networks based on mixtures of nanowires and nanorings: A mean-field approach along with computer simulation.

We have studied the electrical conductance of two-dimensional (2D) random percolating networks of zero-width metallic nanowires (a mixture of rings and sticks). We took into account the nanowire resistance per unit length and the junction (nanowire-nanowire contact) resistance. Using a mean-field approximation (MFA) approach, we derived the total electrical conductance of these nanowire-based networks as a function of their geometrical and physical parameters. The MFA predictions have been confirmed by our Monte Carlo (MC) numerical simulations. The MC simulations were focused on the case when the circumferences of the rings and the lengths of the wires were equal. In this case, the electrical conductance of the network was found to be almost insensitive to the relative proportions of the rings and sticks, provided that the wire resistance and the junction resistance were equal. When the junction resistance dominated over the wire resistance, a linear dependency of the electrical conductance of the network on the proportions of the rings and sticks was observed.

Simulation of Copper Nanowire by Comparing its Volume and Alignment range using Composite Filament Simulation 3D to predict the Resistivity of the Nanowire

Aim: In this research work the simulation of electrical resistivity of copper nanowire by using a Novel Composite Filament Simulation Tool, and comparing the resistivity by its Volume and Alignment range. Materials and Methods: This review was done at the Simulation research lab, Saveetha School of Engineering, Chennai. The sample size computation was finished by past outcomes using clinical.com by keeping alpha error-threshold by 0.05, enrollment ratio as 0:1, 95% confidence interval, power at 80%. Group 1 and 2 are volume (N=20) and alignment range (N=20) of copper nanowire. The complete sample size was 50. Results: Comparison between these two parameters are done by independent sample test using SPSS software. There is a statistical indifference between volume and in alignment range. Copper nanowire based on its volume (55%) showed higher resistivity in comparison to its alignment range (50%). There appears to be a statistically significant difference (p=0.047, p<0.05) by using an independent sample T test. Copper nanowire having volume a high showed better results in comparison to its alignment range. Conclusion: Copper nanowire by volume appears to give better electrical resistivity than its alignment range.

Simulation of Resistivity in Silver and Copper Nanowire Composite Filament using Composite Filament Simulation 3D to predict the Resistivity of the Nanowire

Aim: The aim of this research work is to determine and compare the electrical resistivity of silver and copper nanowire by using the Novel Composite Filament Simulation Tool. Materials and Methods: This study was carried out at the Simulation laboratory, Saveetha School of Engineering, Chennai. The sample size calculation was done using clinical.com by keeping alpha error-threshold by 0.05, enrollment ratio as 0:1, 95% confidence interval, power at 80%. Group 1 was silver nanowire (N=20) and group 2 was copper nanowire (N=20). The total sample size was 40. Results: Comparison of electrical resistivity is done by independent sample test using SPSS software. There is a statistical indifference between silver and copper nanowire. Copper nanowire (55%) showed higher resistivity in comparison to silver nanowire (45%). There appears to be a statistically insignificant difference (p=0.269, p>0.05) by using an independent sample T test. Conclusion: Silver nanowire appears to give better electrical conductivity than in copper nanowire.

Preparation of Conductive Screen-Printing Ink for High-Performance Bendable and Wearable ECG Electrodes on Fabric Substrates

Monitoring of vital signs is a necessary tool to diagnose the symptoms of illness. This work developed screen-printing inks for conductive nanomaterials to fabricate electrocardiogram (ECG)-compatible fabric electrodes. The contents of the polymer matrix, calcium carbonate additive filler, and conductive nanomaterials (silver nanoparticles and copper nanowires) on the resistivity of the composite inks were optimized. A facile process of screen printing was applied to fabricate the electrodes on fabric to create an efficient conductor with high stability in conduction. The fabricated electrodes exhibited flexible and bendable behavior over 0.7% bending strain for wearable components. The results showed that the fabricated electrode based on copper nanowires resistivity was 40.01 ± 1.94 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{k}\Omega $ </tex-math></inline-formula> /cm, and the proposed signal-to-noise ratio (SNR) was approximately 27.16 ± 9.37 dB. Therefore, these fabricated electrodes can be applied in wearable vital biosignal detection devices that perform with high sensitivity during movement, thereby providing health monitoring opportunities. Moreover, the fabricated electrodes can be used without excessive pressure or an electrolyte gel layer, thus overcoming the challenges of developing a portable device.

Enhanced oxidization and corrosion resistance of silver nanowire based transparent conductor by nickel electroplating to obtain power conversion efficiency > 18 % in perovskite solar cells

Silver nanowire based transparent conductor is expected to be widely used in optoelectronic devices. However, when used in perovskite solar cells, it suffers from heavy corrosion caused by the lead halide hybrid perovskite. To solve the problem, nickel electroplating is used to modify the transparent conductor in this study. It is observed that nickel electroplating not only improves the conductance, but also upgrades the corrosion resistance and the oxidization resistance of the transparent conductor. In addition, SnO2 quantum dots are applied to flatten the conductor surface, while ITO sputtering is used to further improve the film conductance. After that, perovskite solar cells are fabricated on the modified transparent conductors. Current-voltage curves scanning under simulated irradiation shows that, power conversion efficiency of 18.37 % is achieved. Transient photocurrent / photovoltage decay curves and impedance spectroscopy tests show that, nickel treated transparent conductors could ensure efficient charge-extraction process, while retard charge recombination. Storage-stability of the devices is monitored, 80 % of initial performance is reserved after storage in dark for 432 h. The study paves the way for the application of silver nanowire basing transparent conductor in devices when heavy corrosion is involved.

Random 2D nanowire networks: Finite-size effect and the effect of busbar/nanowire contact resistance on their electrical conductivity

We have studied the resistance of two-dimensional random percolating networks of zero-width metallic nanowires (rings or sticks). We took into account the nanowire resistance per unit length, the junction (nanowire/nanowire contact) resistance, and the busbar/nanowire contact resistance. Using a mean-field approximation (MFA), we derived the total resistance of the nanoring-based networks as a function of their geometrical and physical parameters. We have proposed a way of accounting for the contribution of the busbar/nanowire contact resistance toward the network resistance. The MFA predictions have been confirmed by our Monte Carlo numerical simulations. Our study evidenced that the busbar/nanowire contact resistance has a significant effect on the electrical conductivity when the junction resistance dominates over the wire resistance.

Performance Enhancement of Silver Nanowire-Based Transparent Electrodes by Ultraviolet Irradiation.

Silver nanowires (AgNWs) are used as transparent electrodes (TE) in many devices. However, the contact mode between the nanowires is the biggest reason why the sheet resistance of silver nanowires is limited. Here, simple and effective ultraviolet (UV) irradiation welding is chosen to solve this problem. The influence of the power density of the UV irradiation on welding of the silver nanowires is studied and the fixed irradiation time is chosen as one minute. The range of the UV (380 nm) irradiation power is chosen from 30 mW/cm2 to 150 mW/cm2. First of all, the transmittance of the silver nanowire film is not found to be affected by the UV welding (400–11,000 nm). The sheet resistance of the silver nanowires decreases to 73.9% at 60 mW/cm2 and increases to 127.6% at 120 mW/cm2. The investigations on the UV irradiation time reveal that the sheet resistance of the AgNWs decreases continuously when the UV irradiation time is varied from 0 to 3 min, and drops to 57.3% of the initial value at 3 min. From 3–6 min of the continuous irradiation time, the change of the sheet resistance is not obvious, which reflects the self-limiting and self-termination of AgNWs welding. By changing the wavelength of the UV irradiation from 350–400 nm, it is found that the welding effect is best when the UV wavelength is 380 nm. The average transmittance, square resistance, and the figure of merit of the welded AgNWs at 400–780 nm are 95.98%, 56.5 Ω/sq, and 117.42 × 10−4 Ω−1, respectively. The UV-welded AgNWs are also used in silicon-based photodetectors, and the quantum efficiency of the device is improved obviously.