Ag Wire Research Articles

Electrocatalytic facets of a newly designed cobalt(III) complex towards sustainable hydrogen evolution

A hybrid cobalt complex (C7H10ON)[Co(L)2].CH3OH (Co-complex) bearing an organic cation and anionic cobalt complex has been designed, synthesized, and structurally characterized. The tridentate chelator, 2-((2-hydroxybenzylidene)amino)-4-methylphenol (H2L), was prepared by the condensation reaction between salicylaldehyde and 4-methyl-2-amino phenol. Crystal structure analysis reveals a slight distortion in the octahedral coordination geometry of the cobalt(III) centre. This complex was evaluated in the hydrogen evolution reaction (HER) using a glassy carbon working electrode in acetonitrile (ACN), using tBu4NClO4 as the supporting electrolyte. The catalyst exhibited heightened catalytic activity when acetic acid was introduced, leading to a significant elevation in the catalytic wave at −1.6 V (V vs. Ag wire). The most pronounced activity was observed by adding 15 mM acetic acid, with a turnover number (TON) of 10.1. The catalyst’s durability was confirmed through controlled potential electrolysis (CPE) at −1.6 V for 2 h, displaying a steady current for the initial 20 min, followed by a gradual increase over the subsequent 2 h. A negligible amount of deposited metallic cobalt on the surface of the glassy carbon electrode through a ligand dissociation was evident during the electrocatalytic studies, as ensured by X-ray Photoelectron Spectroscopy (XPS) analysis. Further, the presence of ligand-centric reduction wave in the complex signifies the synergistic effect of the M−L cooperation and offers a plausible ECEC mechanistic route for the release of molecular hydrogen.

Long-Term Performance of Ag/AgCl Reference Electrodes for Corrosion Potential Monitoring in Radioactive Tank Waste at the Hanford Site

This work studied the exposure effects of radioactive tank waste on the long-term performance of single junction Ag/AgCl reference electrodes for corrosion potential monitoring at the Hanford Site. Electrodes from three manufacturers with very different designs were studied using open-circuit potential and electrochemical impedance measurements in radioactive tank waste. Post-test analyses were conducted on some failed electrodes using destructive and nondestructive techniques. The intrusion of the aggressive and radioactive chemicals in tank waste through the porous frit materials was the primary mechanism that led to the clogging of frit, physical and chemical degradation of AgCl bonded to Ag wire, and alteration of the internal electrolyte. Radiolytic chemical species such as H2O2 and HNO3 may have also induced the degradation of the Ag wire. The extent of electrode degradation and failure probability highly depended on the electrode design and environmental conditions. Chemicals in tank waste had stronger effects than radiation on the long-term performance of the Ag/AgCl reference electrodes.

Silver Bonding Wire - an Alternative for Mechanical Sensitive Chip Configurations in Automotive Electronics Packaging

Silver (Ag) bond wires are mainly used in consumer products as a reliable low-cost alternative to gold (Au) bond wires. In previous investigations, we have shown that silver wires also have potential for use in the automotive sector (1, 2, 3, 4], where the materials are exposed to particularly harsh environmental conditions. In order to understand thc intluence of these conditions in the electronic package on the silver-aluminum material system, we carried out extensive studies on test packages built on laboratory level. For the future development of challenging automotive devices, it will be important to have a cooperation between semiconductor package developer and material supplier with an assist of characterization spccialists. In this project, we formed a threeparty project in which characterization specialists, package developer, and wire manufacturer collectivcly conduct a feasibility study of a new Ag wire material for automotive application. Two wire types (standard Ag wire and new type of Ag wire GX2s) were chosen for the investigation in direct comparison regarding long-term reliability. Samples were built under mass production conditions and then subjected to various reliability tests following AEC-Q006 requirements. Subsequently, mechanical characterizations by means of ball shear and pull tests as weil as high resolution SEM microstructure analyses on cross-section samples are applied. In the paper, results of the different tests will be summarized, but a more in-depth analysis will be given to the temperature cycle test (TCT), where the most significant differences between the sample variations occurred. Overall, the results show the importance of the knowledge for the material reliability upfront a device qualification process (robustness validation) and give further guidance for material selection.

Construction and Evaluation of Cheap and Robust Miniature Ag/AgCl Reference Electrodes for Aqueous and Organic Electrolytes

AbstractStable reference electrodes (REs) are crucial for reliable voltammetry, controlled potential electrosynthesis, or spectro‐electrochemistry. Yet, inferior pseudo‐REs, such as plain Ag wire are often used, because commercial REs are expensive, may degrade or contaminate under required conditions, or don't fit geometric restrictions of custom setups. Addressing such cases, we report construction, benchmarking and utilization of easy to make, cheap (<1 €), and robust miniature REs from pasteur pipettes, molecular sieve beads and Ag wire. Excellent potential precision and accuracy with at least 1 week device stability was obtained for aqueous Ag/AgCl REs with 3 M NaCl in H2O and anhydrous 0.1 M TBACl in MeCN inner‐electrolytes. Even in alkaline 1 M NaOH electrolyte, where initial Ag/AgCl REs quickly convert to Ag/Ag2O (1 M NaOH) REs, perfect potential precision, accuracy, and at least 1 week stability are demonstrated. According to experimental needs, miniature REs can be built with many organic and aqueous electrolytes. For these custom use‐cases, we report guidelines to calibrate absolute RE potential, and to assess device precision, accuracy and stability. Finally, electro‐hydrogenation of styrene on nickel electrodes exemplifies superiority of Ag/AgCl REs over Ag wire pseudo‐REs, affording more reliable electrolysis current, cell potential and potential dependent Faraday efficiency.

Purines recognition and quantitative analysis by surface-enhanced Raman spectroscopy

The common quantification methods of purines, including high-performance liquid chromatography, micellar electrokinetic chromatography, reverse phase ion pair chromatography, and capillary zone electrophoresis, have been used for the analysis of purines. These conventional techniques are limited by long operation times, large sample volumes, requirements for pretreatment and separation processes, or sophisticated, bulky and expensive equipment. Here, we have developed a simple method to prepare a probe for the quantitative analysis of purines using the surface-enhanced Raman scattering (SERS) method. The SERS probe is a rough Ag wire obtained with simple electrochemical treatment, which is optimized to reach the maximum SERS signal enhancement. The Raman enhancement factor (EF) of Ag wire after roughening can reach ∼106. Under optimized conditions, the rough Ag wire is capable of recognizing four purine bases (namely, guanine, adenine, hypoxanthine, and xanthine) in the range of 10−5 to 10−1 mg/mL with a linear relationship between SERS intensity of signature peak and purine concentration. The recovery rate of each purine base is higher than 80% in the mixture of four purines. The overall method was successfully applied to the monitoring of the level of purines in marketplace beer beverages. The novel wire-based SERS sensor used with portable Raman spectroscopy is prospective in diet safety and personalized point-of-care medical detection.

NO formation by N2/O2 plasma catalysis: The impact of surface reactions, gas-phase reactions, and mass transport

Pathways and timescales relevant to facilitate plasma-assisted N2-O2 reactions are assessed by measuring the consumption of plasma-derived N and the formation of NO in the gas phase and over Ag catalytic surfaces. These measurements are enabled by a setup that enables N2 activation in an atmospheric pressure RF plasma jet, enables O2 addition in the plasma afterglow, facilitates reactions over an Ag wire catalyst, and allows species density quantification by molecular beam mass spectrometry. Gas-phase reactions consume N but do not form NO with high selectivity. The presence of the non-porous Ag wire catalyst increases the rate of N conversion to NO, though mass transfer processes, not surface reactions, dictate the rate of N consumption. When O2 concentrations and the ratio of the surface area of the catalyst to the void volume of the reactor are high (3–5 mol% O2, 10900 m−1), N conversion to NO reaches 100 % selectivity. When both N2 and O2 are fed through the plasma jet, gas-phase NO production increases 10×, although plasma and gas-phase processes do not exclusively produce NO. Above a threshold NO density, N cannot diffuse to the catalyst surface faster than it is consumed in the gas phase by reactions with NO. Thus, the use of heterogeneous catalysts to enhance plasma-driven NxOy formation and control NxOy product selectivity is limited to cases where diffusive transport of N from the gas phase to the catalyst surface is faster than consumption of N from gas-phase reactions with NO.

Reliability evaluation of thick Ag wire bonding on Ni pad for power devices

In recent years, silicon carbide (SiC) semiconductors have gained traction in high-performance power devices due to their ability to operate at high temperatures (above 200 °C). However, traditional interconnection materials are not sufficiently reliable at such elevated temperatures. Typically, in power devices, thick Al wires with diameters of 200 μm or larger are commonly used to bond Al electrodes of semiconductor chips to their corresponding Cu leadframes or substrates. Nevertheless, the low melting point of Al can lead to recrystallization at high temperatures, thereby raising concerns about reliability and a decrease in wire strength and fatigue properties. Although thick Cu wires with higher melting points have been explored as potential solutions, their high hardness and susceptibility to work hardening during bonding can damage the chip beneath the bonding area, making them impractical. In response to these challenges, we investigated the use of thick Ag wires. However, direct bonding of thick Ag wires to Al pads can form intermetallic compounds (IMC) in the bonding area, leading to concerns about decreased reliability. To address this issue, we experimented with a bonding method that utilized thick Ag wires on Ni pads. In this study, we evaluated the reliability of thick Ag wire bonding under various stress conditions, including high-temperature storage tests (HTST) and temperature cycling tests (TCT). Our results showed that thick Ag wire bonding on Ni pads exhibited high bond strength and prevented IMC formation after HTST. Nonetheless, bond failure of the Ag wires could occur after TCT due to the mismatch in the coefficient of thermal expansion (CTE) between the Ag wire and SiC chip, particularly under extremely severe TCT conditions. We found this issue could be mitigated by introducing a soft metal layer, such as Al, between the Ni pad and the SiC chip. This reduced internal stress and enabled the device to pass TCT under harsher conditions with reliable performance.

Simulation of two nanoparticle melting to understand the conductivity drop of 3D-printed silver nanowires

The future flexible sensor technology will require low-temperature, fast processing 3D printing techniques that will rely heavily on the quality of nanoparticle (NP) Ink. Electrical conductivity has been found to decrease in majority of the 3D printed electronic wires. Herein we report a fundamental understanding in drop of electrical conductivity in processed silver (Ag) line wire, generally found in Ag-nanoparticle Ink, using large-scale atomistic molecular dynamics (MD) simulations of sintering of five different sizes of Ag NPs. To preserve the high conductivity of pure silver wires, the integrity of the pristine face-centered cubic (FCC) crystalline structure must be retained in the processed line wires. Simulations show that the pristine Ag FCC structures of the nanoparticles are not recovered after melting and resolidification, instead, the resolidified material is paracrystaline. The breakdown of pristine FCC structures might be the cause of the drop in conductivity of processed Ag wires. Simulation results suggest that the intermediate size nanoparticles retain highest percentage of the pristine silver face-centered cubic (FCC) structure after pulse treatments. Our results show that the most promising Ag-Ink should contain smaller to medium size silver NPs that can retain FCC structure after 3D printing of the Ag-Ink.

Comparison of size distributions of recovered particles generated from Ag wire in air by pulsed wire discharge and electric explosion of wire methods

Electric explosion of a wire (EEW) with discharge and pulsed wire discharge (PWD) are essential methods for producing nanosized and micronized metal particles. The study of Ag particle size distributions is important for Ag particle recovery from photovoltaic panel sheets using these methods performed in previous studies. In this study, we examined the size distributions of Ag particles generated from an Ag wire in air by EEW and PWD to clarify the difference between, and effects of these methods on particle generation. The particle size distribution generated in PWD was concentrated in a narrower range. The simulation results suggest that volume expansion occurred for a liquidized Ag wire in EEW and for a gasified Ag wire in PWD. Visualized images of processes and current waveforms in EEW and PWD indicated that after the wire explosion the restrike with plasma occurred in the expanding Ag particles in air in PWD. These results suggest that the narrower particle size distribution obtained in PWD may be attributable to monodisperse powderization by plasma evaporation of the gasified wire. These results show that PWD with plasma of an Ag wire in air effectively creates particles that are more monodispersed than those formed by EEW.

Corrosion resistance multi-functional chemical conversion coating on Mg-Gd-Y-Zr alloy with high absorbance and electrical conductivity

In this work, a new design of phosphate chemical conversion coating with low electrical contact resistance and high light absorption (C-E-PCC) on Mg-Gd-Y-Zr (Mg-RE) alloy was proposed. The conversion coating was stained with black dye aiming to blacken PCC, and post-treated with silane loaded nano-Ag wire, achieving low electrical contact resistance (ECR) due to the overlapping network of Ag wires on the surface of PCC. The experimental results indicated that the hydrogen evolition volume of C-E-PCC was 2.54 ± 0.09 ml/cm2 immersion 3.5 % wt NaCl for 120 h. The absorption in the visible light range of C-E-PCC was 30%. Moreover, the ECR of C-E-PCC was 11.00 ± 0.47 Ω. The aforementioned results implied that the PCC not only with high absorbance and low ECR but also with high corrosion protection.

Differential aeration corrosion of silver in sulfate melts at 900 °C

The thermodynamic of the Ag/Ag2SO4 electrode, serving as reference for carrying electrochemical experiences of corrosion in sulfates at 900 °C, was investigated because of the observed limited operating lifetime. Its use led to the total degradation of the ∅1 mm Ag wire in ∼200 h. Half-immersion of Ag wires in sulfates mixes (selected for their acido-basicity) evidenced the homogeneous thinning of the immersed part of the wires and the precipitation of metallic Ag in the salt. The different steps governing the corrosion mechanism were proposed considering that the driving force was the differential aeration of the Ag wire.

Effects of Field Strength and Silver Nanowire Size on Plasmon-Enhanced N2 Dissociation.

Dissociation of the nitrogen molecule via plasmon-enhanced catalysis using noble metal nanoparticles has been investigated both experimentally and computationally in recent years. However, the mechanism of plasmon-enhanced nitrogen dissociation is still not very clear. In this work, we apply theoretical approaches to examine the dissociation of a nitrogen molecule on atomically thin Agn nanowires (n = 6, 8, 10, 12) and a Ag19+ nanorod. Ehrenfest dynamics provides information about the motion of nuclei during the dynamics process and real-time TDDFT calculations show the electronic transitions and population of electrons over the first 10 s of fs time scale. The activation and dissociation of nitrogen are typically enhanced when the electric field strength increases. However, the enhancement is not always monotonic with field strength. As the length of the Ag wire increases, nitrogen is typically easier to dissociate and thus requires lower field strengths, even though the plasmon frequency is lower. The Ag19+ nanorod leads to faster dissociation of N2 than the atomically thin nanowires. Overall, our detailed study yields insights into the mechanisms involved in plasmon-enhanced N2 dissociation, as well as provides information about factors that can be used to improve adsorbate activation.

Insulated, Passivated & Adhesively-Promoted Bond Wire Using All-in-One Al2O3 Coating

Insulated, Passivated & Adhesively-Promoted Bond Wire Using All-in-One Al2O3 Coating

Antibacterial activity of CuO-Ag Janus like nanoparticles against recombinant strain Escherichia coli.

The toxic action of CuO-Ag Janus particles and a bicomponent mixture of CuO and Ag particles have been studied against a recombinant strain Escherichia coli K12 TG1 with cloned luxCDABE genes of marine bacteria Photobacterium leiognathi 54D10. An original method was used for the preparation CuO-AgJanus like nanoparticles by simultaneous electrical explosion of twisted Cu and Ag wires in a mixture of argon and oxygen gases. The bioluminescence inhibition on recombinant strain E. coli shows that CuO-Ag Janus NPs were effective. The concentration by 50% (EC50) for CuO-Ag Janus NPs was 0.03 ± 0.001mg/ml (p < 0.05). The bioactivity of the bicomponent mixture of CuO and Ag NPs (EC50) was 0.25 ± 0.002mg/ml (p < 0.05). The effective concentration of CuO-Ag Janus NPs against E. coli was comparatively lower than those of bicomponent mixture CuO and Ag against which explains the higher activity of CuO-Ag Janus NPs. The toxicity values of CuO and Ag as monocomponent nanoparticles were 2-32 times lower compared with the bicomponent nanoparticles. A dose-dependent inhibition of bacterial luminescence developed over time was noted. The result of contact E. coli with CuO-Ag Janus particles was 100% suppression of bacterial luminescence from the first minutes of contact occured starting with a content of 2.0mg/ml and within the next 180min. The effect of bioactivity prolonged in the final concentration of nanopowder (EC100 = 0.0625 ± 0.002mg/ml) (p < 0.05). CuO-Ag Janus particles exhibited more pronounced antibacterial activity compared to CuO, Ag nanoparticles and their mechanical mixture.

20.1: Invited Paper: Research on Oxide Thin Film Transistors for Wearable Sensors

With the rapid development of the Internet of Things, sensors as an important foundation in the era of smart interconnection, have a significant potential in the emerging fields of smart home, wearable devices, and smart mobile terminals. Flexible sensor has been attracting a great attention due to its portability, miniaturization and long endurance. The high consumption and signal crosstalk are urgent issues for the high‐integration sensing array. These issues could be effectively addressed by active‐matrix thin film transistors (TFT) backplane. In this work, the feasibility of oxide TFT for flexible sensor was discussed, in which high‐quality oxi de semiconductor films, oxide dielectric films, and printing Ag electrodes and wires were investigated, respectively. The device performance of flexible Si‐doped SnO2 TFT was optimized by modulating oxygen partial pressure, which could achieve a relative good electrical properties at room temperature. To implement low‐consumption application, high quality of high‐k ZrO2 dielectric film was investigated by solution‐processed method. The dielectric properties of ZrO2 film with the mircowave‐as sisted or deep ultraviolet irradiation‐assisted annealing process was similar to that of the thermal ann ealing process. The morphology and conductivity of Ag electrodes and wires printed by electrohydrodynamic (EHD) inkjet printing technology were studied. High conductivity of Ag electrodes and wires was achieved at a low curing temperature. These results imply that oxide TFT has a significant potential in the application of flexible sensor array.

Ambipolar Electrochemistry of Pre‐Intercalated Ti3C2Tx MXene in Ionic Liquid Electrolyte

AbstractCation intercalation with or without redox remains the dominant charge storage mechanism for two‐dimensional (2D) Ti3C2Tx MXene. Anion‐based charge storage remains unexplored due to intrinsic negative surface charge of MXenes preventing spontaneous intercalation of anions and irreversible oxidation of Ti at anodic potentials in aqueous electrolytes. In this work, we report on the ambipolar electrochemical behavior of the Ti3C2Tx in ionic liquid electrolyte over a 2.5 V electrochemically stable window. The experiments are conducted on a thin Ti3C2Tx film current collector coated with an electroactive layer of small flakes (∼150 nm) of Ti3C2Tx pre‐intercalated with 1‐ethyl‐3‐methylimidazolium bis‐(trifluoromethylsulfonyl)‐imide (EMIM‐TFSI) ionic liquid. Couples of redox peaks with a very small potential separation during the voltage sweep are observed at high negative (−0.75 V vs. Ag wire) and high positive (+0.75 V vs. Ag wire) potentials. Our experimental electrochemical data combined with density functional theory (DFT) calculations suggest feasibility of pseudo‐intercalation of TFSI anions between Ti3C2Tx flakes. This study provides a pathway for elucidating anion intercalation for different MXene chemistries in solvent‐free electrolytes, which can lead to development of MXene based energy storage devices with improved performance.

Superelastic Conductive Fibers with Fractal Helices for Flexible Electronic Applications

AbstractThe widespread application of flexible electronic devices places higher demands for stretchable conductors as crucial components owing to their stable and consistently high conductivity and high stretchability. In this study, a superelastic conductive fractal helix fiber (FHF) consisting of a thermoplastic polyurethane fiber and Ag wire is developed, which exhibits excellent waterproofing ability. The maximum strain of the FHF can be improved to 8300% by increasing the helical index C and Ag wire winding density. A high conductivity of 6.3 × 107 S m−1 and ultra‐high Q value of 3.37 × 104 at a strain of 5600% are realized for the conductive fiber owing to its fractal helical structure. The elastic limit point A of the FHF can be obtained by the relative resistance change (0.166%) to ensure that elastic deformation only occurs when stress is applied. In the elastic strain range, FHF demonstrates high electrical reliability under repeated deformation (over 10 000 cycles of stretching with a strain of 5600%) with a negligible increase in resistance. Moreover, the FHF can be easily integrated with the fabrics as an interconnection for wearable electronics. The newly developed twined FHF can also be used as a capacitive strain sensor to monitor human activity.

Investigation on corrosion behaviors of silver and LDB coated silver wires in 0.5 M NaCl

Silver (Ag) is used widely in the semiconductor industry for its good conductivity and stable corrosion behaviour in various environments. However, a chloride attack on Ag could change its properties and affect other sensitive behaviours of Ag. In the present work, the corrosion behaviours of Ag wire and Ag wire coated with black leather dye (LDB) through dip coating are examined in 0.5 M NaCl by electrochemical impedance spectroscopy (EIS), Tafel polarisation curves (TPC), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX). LDB structure is investigated through Fourier transform infrared spectroscopy (FTIR), and LDB is found to contain numerous functional groups. Based on this fact, it is assumed that LDB can significantly suppress Ag corrosion; however, the results have not supported this assumption, and only a slight improvement in the corrosion behaviour of Ag wire has been noticed. The corrosion study on Ag and LDB coated Ag wires is also performed after 1 and 3 h of immersion in NaCl; however, the degradation in corrosion behaviour is acknowledged. Based on results, it is found that LDB is protecting Ag, but for short time immersion.

Electrochemical detection of cholesterol in human biofluid using microneedle sensor.

The development of a straightforward, economical, portable, and highly sensitive sensing platform for the rapid detection of cholesterol is desirable for the early diagnosis of several pathologic conditions. In this work, we present a fascinating skin-worn microneedle sensor for monitoring cholesterol in interstitial fluid samples. The microneedle sensor was developed by incorporating platinum (Pt) and silver (Ag) wires within pyramidal microneedles containing a microcavity opening; cholesterol oxidase (ChOx) was coupled on the Pt transducer surface using bovine serum albumin and Nafion. Under optimal conditions, the enzymatic microneedle sensor exhibited high sensitivity (0.201 μA μM-1) towards cholesterol in buffer solution, with good linearity over the 1-20 μM range and a correlation coefficient of 0.9910. The analytical performance of the microneedle sensor was also investigated in artificial interstitial fluid and a skin-mimicking phantom gel; the sensor showed great potential for skin-worn/wearable applications with excellent linearity and a low detection limit. In addition, the developed microneedle sensor showed satisfactory stability and good selectivity towards cholesterol in the presence of potential interfering biomolecules, including glucose, lactic acid, uric acid, and ascorbic acid. This sensor exhibits enormous promise for straightforward, sensitive, and minimally invasive monitoring of cholesterol.

Effect of Au Coating on the Electrolytic Migration of Ag Bonding Wires for Electronic Packaging Applications

Ag-based bonding wires were generally accepted as the most promising material to substitute for Au bonding wires, however, the electrolytic migration concern of Ag limited its industrial application in electronic packaging, especially in ultra-fine pitch wire bonding. In the present study, the electrolytic migration behaviors of Au-coated Ag bonding wires and Ag wires were studied through water drop tests. The dendrites’ growth and morphology evolution were investigated by in-situ optical microscope observation and the microstructure of the cathodic and anodic bonding wires were characterized by scanning electron microscope test. It could be seen that when comparing Au-coated Ag bonding wires with Ag wires, the dendrite assembled by a large number of Ag nanoparticles grew much more slowly from cathode to anode. The Ag2O particle layer on the anodic wires was thinner, the dendrite contact time was delayed and the current densities at the dendrite contact time were much smaller when the Au coating layer exist. The above results show that Au coating could act as a barrier to inhibit electrolytic migration, which has contributed to electronic packaging applications of Au-coated Ag bonding wires.