Ag Nanowires Research Articles

Biodegradable, Self‐Adhesive, Stretchable, Transparent, and Versatile Electronic Skins Based on Intrinsically Hydrophilic Poly(Caproactone‐Urethane) Elastomer

In biomedical sciences, there is a demand for electronic skins with highly sensitive tactile sensors that have applications in patient monitoring, human–machine interfaces, and on‐body sensors. Sensor fabrication requires high‐performance conductive surfaces that are transparent, breathable, flexible, and easy to fabricate. It is also preferable if the electrodes are easily processable as wastes, for example, are degradable. In this work, the design and fabrication of hydrophilic silanol/amine‐terminated poly(caprolactone‐urethane) (SA‐PCLU) elastomer‐based breathable, stretchable, and biodegradable electrodes are reported. Ag nanowires dispersed in water are sprayed onto the intrinsically hydrophilic electrospun SA‐PCLU that became embedded into the scaffold and formed conformal hydrophilic polyurethane‐based conductive networks (HPCN). The electrodes are used to fabricate capacitive, curvature, and strain sensors, all having monomaterial composition. In addition to displaying particularly good transparencies at low sheet resistances, stretchability, hydrophilicity, and tight and conformal bonding with the target surface, the electrodes also allow the evaporation of perspiration, making them suitable for epidermal sensors for long‐time use. The application of the HPCN electrodes in flexible electronics and bionic skin applications is demonstrated through gesture monitoring experiments and swelling sensors.

Quantifying Interface‐Performance Relationships in Electrochemical CO2 Reduction through Mixed‐Dimensional Assembly of Nanocrystal‐on‐Nanowire Superstructures

AbstractFine‐tuning the interfacial sites within heterogeneous catalysts is pivotal for unravelling the intricate structure–property relationship and optimizing their catalytic performance. Herein, a simple and versatile mixed‐dimensional assembly approach is proposed to create nanocrystal‐on‐nanowire superstructures with precisely adjustable numbers of biphasic interfaces. This method leverages an efficient self‐assembly process in which colloidal nanocrystals spontaneously organize onto Ag nanowires, driven by the solvophobic effect. Importantly, varying the ratio of the two components during assembly allows for accurate control over both the quantity and contact perimeter of biphasic interfaces. As a proof‐of‐concept demonstration, a series of Au‐on‐Ag superstructures with varying numbers of Au/Ag interfaces are constructed and employed as electrocatalysts for electrochemical CO2‐to‐CO conversion. Experimental results reveal a logarithmic linear relationship between catalytic activity and the number of Au/Ag interfaces per unit mass of Au‐on‐Ag superstructures. This work presents a straightforward approach for precise interface engineering, paving the way for systematic exploration of interface‐dependent catalytic behaviors in heterogeneous catalysts.

Laser-Induced Self-Limiting Welding of Ag Nanowires with High Mechanical and Electrical Performance.

The high-efficiency and high-precision welding technology of Ag nanowires is of great engineering significance for the integration of new-generation micro- and nanodevices, and the mechanical behavior of its interconnect joints is also essential for their reliable application, especially for some flexible device. In this paper, based on the nano-focusing and localized plasma enhancement properties of Ag nanowires under laser irradiation, Ag nanowire self-limiting joints with mechanical and electrical properties comparable to those of the base material are obtained. At the same time, the local plasma enhancement characteristics of Ag nanowire joints are scanned and analyzed with nanoscale resolution by using cathodoluminescence technology, and the local multi-physical field coupling regulation mechanism of Ag nanowire joints induced by different laser parameters is systematically investigated by combining theoretical simulations. Meanwhile, based on the in situ laser welding and nanomechanical tensile experiments, the mechanical properties of single Ag nanowires and their welded joints are systematically analyzed, and the characteristics of the interfacial atomic behaviors and the evolution process during the welding and tensile processes are investigated.

Dressing AgNWs with MXenes Nanosheets: Transparent Printed Electrodes Combining High-Conductivity and Tunable Work Function for High-Performance Opto-Electronics.

High-work function transparent electrodes (HWFTEs) are key for establishing Schottky and Ohmic contacts with n-type and p-type semiconductors, respectively. However, the development of printable materials that combine high transmittance, low sheet resistance, and tunable work function remains an outstanding challenge. This work reports a high-performance HWFTE composed of Ag nanowires enveloped conformally by Ti3C2Tx nanosheets (TA), forming a shell-core network structure. The printed TA HWFTEs display an ultrahigh transmittance (>94%) from the deep-ultraviolet (DUV) to the entire visible spectral region, a low sheet resistance (<15 Ωsq-1), and a tunable work function ranging from 4.7 to 6.0eV. The introduction of additional oxygen terminations on the Ti3C2Tx surface generates positive dipoles, which not only increases the work function of the TA HWFTEs but also elevates the TA/Ga2O3 Schottky barrier, resulting in a high self-powered responsivity of 18mAW-1 in Ga2O3 diode DUV photodetectors, as demonstrated via experimental characterizations and theoretical calculations. Furthermore, the TA HWFTEs-based organic light-emitting transistors exhibit exceptional emission brightness of 5020cd m-2, being four-fold greater than that in Au electrodes-based devices. The innovative nano-structure design, work function tuning, and the revealed mechanisms of electrode-semiconductor contact physics constitute a substantial advancement in high-performance optoelectronic technology.

Unique framework effect induced by uniform silk fibroin dynamic nanospheres enables multiscale hydrogel with outstanding elastic resilience and strain sensing performance

It is a significant challenge to obtain hydrogels simultaneously with low tensile energy dissipation, high compressive resilience and long durability. Herein, the uniform dynamic nanospheres (Sil-4H0.75) derived from 4-Hydroxybutyl acrylate glycidyl ether grafted silk fibroin is designed to overcome this issue. Due to its uniform and dynamic characteristic, Sil-4H0.75 could endow hydrogel with homogeneous multiscale structure and produce unique framework effect. Thus, transparent Sil-4H0.75 crosslinked acrylamide hydrogel doped with Ag nanowires APS3.75%/AgNW0.1 exhibits a high stretchability (1260 %) and outstanding elastic resilience. The tensile energy dissipation ratio maintains a low value of 9 % across a wide 800 % strain range. A high compression resilience ratio of 92.2 % is kept after ten compression cycles under 90 % compressive strain. The orderly AgNWs motion guided by framework effect also make it be used as both tensile and compressive sensors and exhibits high gauge factor of 7.35, outstanding compression sensitivity of 30.379 kPa−1 and excellent durability (up to 2000 cycles). The detection or other applications based on both two sensing modes are also demonstrated. In a word, this work affords a general strategy to achieve high-performance hydrogel based on uniform dynamic nanospheres which exhibits great potential in the applications of flexible wearable strain sensors.

Growth mechanism and SERS effect of Ag nanowire arrays prepared by solid-state ionics method

Solid-state ionic method has attracted more and more attention due to its simple operation and controllable preparation, but its growth mechanism is still uncertain. In this work, Ag nanowire (Ag NW) arrays prepared by solid-state ionics method at 5 μA impressed currents using fast ionic conductor RbAg4I5 films and different metal electrodes were reported. The conduction mode of Ag+ in RbAg4I5 films, the growth mechanism of Ag NW arrays prepared by solid-state ionics method and the effect of microscopic morphology on surface-enhance Raman scattering (SERS) performance were investigated. The results show that Ag nanoparticles (Ag NPs) with diameters from 40 nm to 70 nm were attached to the surface of Ag NW arrays with diameters of 80–150 nm prepared with different metal electrodes, which lead to Ag NW arrays have high surface roughness. The conduction velocity and stability of Ag+ in RbAg4I5 films are closely related to the morphology of Ag NW arrays. The irregular electrode interface and apical growth advantage resulted in the fractal dimension of Ag NW arrays prepared with Ag electrodes is 1.69 due to macroscopic dendritic structure. Ag NW arrays have excellent SERS performance due to the many Ag NPs attached to the surface of the closely aligned Ag NWs, the limit of detection (LOD) for Basic Fuchsin (BF) and Crystal Violet (CV) detected by Ag NW arrays SERS substrates prepared with Ag electrodes are as low as 10−11and 10−14mol/L, respectively. This paper provides a reference for the preparation method of metal nanostructures, Ag NW arrays have good potential for application in the field of trace analysis.

Production of Ag nanowires with high yield and narrow size distribution by promoting nucleation through hot injection and their application to disposable paper electrodes

The polyol method has been the most commonly used technique for fabricating silver nanowires (Ag NWs), wherein additive reagents facilitate precise control over their morphology. In this work, we introduced a straightforward approach to synthesize Ag NWs with minimal impurities and uniform diameter by using hot injection method. The underlying mechanism and final product are evaluated, and the scalable process was optimized to achieve a high yield (∼87.8 %). It was found that the hot injection of a Ag precursor at 170 °C significantly accelerated the reduction of Ag ions. The issue of the uniformity of Ag NWs was addressed by adding an organic halide to control the nucleation rate of Ag. The resulting Ag NWs solution was used to impregnated cellulose paper, forming an enhanced electrical network compared to other substrates. Given the low commercial cost of paper, this approach holds significant potential for widespread use in disposable electrodes. Furthermore, after subjecting the fabricated paper electrodes to various forms of damage, the connected LED bulbs consistently maintained their brightness. This demonstrates the network stability and suitability of these electrodes for flexible applications.

A Flexible Multifunctional Sensor Based on an AgNW@ZnONR Composite Material.

A multifunctional sensor comprising flexible and transparent ultraviolet (UV) photodetectors (PDs) with strain gauges based on Ag nanowire (AgNW)@ZnO nanorods (ZnONRs) was fabricated using a cost-effective, simple, and efficient method. High-aspect ratio silver nanowires were synthesized using the polyol method. An AgNW@ZnONR composite was formed via the hydrothermal method to ensure the multifunctional capability of the flexible sensors. After refining the process parameters, the size of the ZnO nanorods was decreased to fabricate pliable multifunctional sensors using AgNW@ZnONRs. At a deposition of 0.207 g of AgNW@ZnONRs, the sensor achieves its maximum switching ratio and fastest response time under conditions of 2000 μW/cm2 UV optical power density. With a ton (rise time) of 2.7 s and a toff (fall time) of 2.3 s, the ratio of Ion to Ioff current is 1151. Additionally, the sensor's maximum optical current value correlates linearly with UV light's power density. The maximum response current increased from 222.5 pA to 588.1 pA, an increase of 164.3%, when the bending angle was increased from 15° to 90° for the sensor with a deposition of 0.276 g of AgNW@ZnONRs. There was no degradation in the response of the sensors after 10,000 bending cycles, as they have excellent stability and repeatability, which means they can meet the requirements of wearable sensor applications. Therefore, there is great potential for the practical application of multifunctional AgNW@ZnONRs in flexible sensors.

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.

Simultaneous Triboelectric and Mechanoluminescence Sensing Toward Self‐Powered Applications

AbstractSimultaneous phenomena of triboelectricity and mechanoluminescence (ML) acquire vital insights into the mechanics of charge separation and recombination, as well as the relationship between mechanical stress and light emission. In the present work, polydimethylsiloxane (PDMS) and ZnS:Cu particle‐based composites are fabricated, which have good ML characteristics and can generate electricity via contact electrification. ML, in conjunction with a triboelectric nanogenerator (TENG), contributes by producing power from mechanical operations while also giving vital visual input in the form of light emission. This dual capability improves user awareness and efficiency in a variety of applications, making mechanical systems and wearable devices easier to monitor and optimize. To accomplish this, a single‐electrode mode silver (Ag) nanowires embedded PDMS‐ZnS: Cu‐based TENG device is developed and achieved an electrical output of 60 V, 395 nA, and 15 nC by using a linear motor. Furthermore, the combined ML and TENG device is employed in various cases of safety monitoring. This integration provides self‐powered devices that detect mechanical stress, delivering real‐time warnings and illumination signals for increased safety and communication in demanding conditions such as SOS signaling, underwater driving, deep mining, and sports.

Synthesis and physical characterization of novel Ag2S-CdS /Ag /GNP ternary nanocomposite

A new type of Ag2S-CdS/Ag/GNP nanocomposite material was successfully synthesized in the presented work. The structural and physical properties of compounds were studied separately and together. Ag2S-CdS/Ag/GNP nanocomposite materials were studied by Xray diffraction (XRD), Ultraviolet-Visible (UV-Vis), Fourier Transform Infrared (FTIR), Raman spectroscopy and Scanning Electron Microscopy (SEM). Based on the results, Ag nanowires (NWs) were successfully synthesized, and then it was determined that during the hybridization process, two phases of acanthite Ag2S and the cubic crystal system of Ag2O were formed. Then, Ag2S-CdS NWs were formed from mixed monoclinic Ag2S and hexagonal CdS. In the absorption spectrum of Ag NWs, the main absorbance peaks were observed at 357.3 nm and 380.2 nm. The energy gap (Eg) values of the Ag sample are 3.8 eV. The band gap value of Ag2S (2.5, 3.8, 4.6 eV) and Ag2S-CdS (2.5, 3.8, 4.8 eV) have a triple value due to the formation of a hybrid structure. The Raman spectrum of Ag2S-CdS belongs to longitudinal-optical (LO) phonon modes of zinc-blende phase CdS and for the 1, 2, and 3 times spin-coated samples on the surface of GNP/PVA have observed all characteristic Raman peaks, which belong to NWs at 485.13 cm-1, and 960.22 cm-1.

Quantifying Interface-Performance Relationships in Electrochemical CO2 Reduction through Mixed-Dimensional Assembly of Nanocrystal-on-Nanowire Superstructures.

Fine-tuning the interfacial sites within heterogeneous catalysts is pivotal for unravelling the intricate structure-property relationship and optimizing their catalytic performance. Herein, a simple and versatile mixed-dimensional assembly approach is proposed to create nanocrystal-on-nanowire superstructures with precisely adjustable numbers of biphasic interfaces. This method leverages an efficient self-assembly process in which colloidal nanocrystals spontaneously organize onto Ag nanowires, driven by the solvophobic effect. Importantly, varying the ratio of the two components during assembly allows for accurate control over both the quantity and contact perimeter of biphasic interfaces. As a proof-of-concept demonstration, a series of Au-on-Ag superstructures with varying numbers of Au/Ag interfaces are constructed and employed as electrocatalysts for electrochemical CO2-to-CO conversion. Experimental results reveal a logarithmic linear relationship between catalytic activity and the number of Au/Ag interfaces per unit mass of Au-on-Ag superstructures. This work presents a straightforward approach for precise interface engineering, paving the way for systematic exploration of interface-dependent catalytic behaviors in heterogeneous catalysts.

CoNi layered double hydroxides grown on Ag nanowires for high-efficient nitrate-to-ammonia conversion

Electrocatalytic reduction of nitrate to ammonia is a promising technology. The sluggish rate of the nitrate-to-nitrite reduction is the core issue. By reducing the energy barrier of this step, the reactivity can be greatly promoted. Here, we have documented Co2Ni1 layered double hydroxide (LDH) on Ag nanowire (NW) that demonstrates efficient catalytic activity in electro-reducing nitrate to ammonia under a diverse set of application conditions. It achieves a high ammonia yield (2.50 mmol h−l cm−2) and Faradaic efficiency (99.6 %) at −0.7 V versus a reversible hydrogen electrode (VRHE). Through comparative experiments, it has been proven that the selective reduction of nitrate to nitrite on Ag NW is the key. This series of Ag NW heterostructure electrodes provides new insights into the design principles of high-performance and high-durability nitrate reduction electrodes under environmentally relevant wastewater conditions.

Multifunctional and high-performance electrothermal films based on carbon black/Ag nanowires/graphene composites

Fabricating high-conductive composites and constructing highly conductive networks are crucial for high-performance electrothermal film. In this study, an Ag nanowires/graphene (Ag/G) composite synthesized by liquid-phase exfoliation and in-situ photoreduction is mixed with carbon black (CB) to form a composite conductive ink, and a CB/Ag/G composite electrothermal film with a point-line-plane three-dimensional microstructure is obtained via blade coating process. Both the addition of Ag nanowires and a subsequent compression rolling treatment induce the establishment of the effective conductive network in the film, endowing it with an outstanding conductivity of 399.4 S cm−1. The film reaches a Ts of 204 °C with an input voltage of 3.0 V, and is successfully applied in water heating and de-icing, demonstrating its extraordinary electrothermal performance and vast potential for practical applications. The film is also used as an electromagnetic shielding film and heat dissipation substrate, showing exceptional electromagnetic shielding (42.5 dB) and heat dissipation properties.

Synthesis of Ag nanowires with high aspect ratio for highly sensitive flexible strain sensor

Flexible sensors, being a vital component of flexible devices, determine the functionalities and performance capabilities of the devices., especially, are widely used in flexible sensors in past research due to their great advantages in flexibility and sensitivity. In this work ， silver nanowires with aspect ratios of 600, 1000, and 1400 were synthesized by adjusting the synergy of Br– and Cl–, along with other process parameters, leading to an improved production efficiency of silver nanowires. The stability of the conductive network is enhanced when the aspect ratio of silver nanowires is 1000 and 1400.The sensor demonstrated high sensitivity at high strain, along with an extended strain range. Moreover, it was observed that increasing the aspect ratio of silver nanowires led to a more stable conductive network, thus enhancing the sensor's stability with over 10000 stretching cycles. under the appropriate deposition density, silver nanowires with aspect ratio of 600 have high sensitivity to low strain, and silver nanowires with aspect ratio of 1400 have high sensitivity to high strain, up to 247.3. Introducing microstructures on the surface of PDMS resulted in an increased maximum sensitivity of the sensor with decreasing microstructure size, reaching a maximum sensitivity of 322.2.

Ag nanowires modified expanded graphite based composite phase change materials with enhanced thermal conductivity, light/electro-to-thermal performances

Phase change materials with excellent thermal energy storage property displayed great potential application in many fields, such as lithium battery thermal management, energy saving building and waste heat utilization. In this paper, a novel composite phase change material of Ag nanowires modified expanded graphite/lauric-myristic-palmitic acid (AgNWs@EG/LMP) with the function of photo/electro-thermal conversion property was prepared which the AgNWs@EG was acted as the matrix material and LMP was the phase change material. The composite exhibited high latent heat of 118.42 J/g at the phase change temperature of 33.62 °C with the LMP supporting ratio of 76.18%. The thermal conductivity of AgNWs@EG/LMP reached 4.23 W/(m∙K) which enhanced 1914% than that of LMP. The photo-thermal conversion efficiency reached 88.01% and the electro-thermal conversion efficiency was 65.4% with an input voltage of 1.5 V. Further results showed the composite AgNWs@EG/LMP possessed good chemical compatibility, good thermal stability and reliability. Therefore, the novel composite of AgNWs@EG/LMP with good thermal property and multi-energy conversion functions will process potential application in energy storage system and thermal management fields.

Surface Plasmon Resonance Modulation by Complexation of Platinum on the Surface of Silver Nanocubes.

The use of plasmonic particles, specifically, localized surface plasmonic resonance (LSPR), may lead to a significant improvement in the electrical, electrochemical, and optical properties of materials. Chemical modification of the dielectric constant near the plasmonic surface should lead to a shift of the optical resonance and, therefore, the basis for color tuning and sensing. In this research, we investigated the variation of the LSPR by modifying the chemical environment of Ag nanoparticles (NPs) through the complexation of Pt(IV) metal cations near the plasmonic surface. This study is carried out by measuring the shift of the plasmon dipole resonance of Ag nanocubes (NCs) and nanowires (NWs) of differing sizes upon coating the Ag surface with a layer of polydopamine (PDA) as a coordinating matrix for Pt(IV) complexes. The red shift of up to 45 nm depends linearly on the thickness of the PDA/Pt(IV) layer and the Pt(IV) content. Additionally, we calculated the dielectric constant of the surrounding medium using a numerical method.

Fabrication of Ag nanowires and Ag-graphite nanocomposite conductive adhesives by one-step hydrothermal method

Fabrication of Ag nanowires and Ag-graphite nanocomposite conductive adhesives by one-step hydrothermal method

Modulating the Electrocatalytic CO2-CO Performance by Ag Morphology

Highly selective conversion of CO2 into CO molecules remains a major challenge in electrocatalytic CO2 reduction reactions, and metallic silver-based materials have great potential. However, the selectivity and activity of traditional silver (Ag)-based materials cannot reach the desired level, and the development of new Ag-based materials has become a hot research topic. Here, novel ag-glomerated spore-shaped Ag nanomaterials are reported for the efficient reduction of CO2 to CO. The unique nanostructures endowed with larger specific surface area, and the spore-like dispersed Ag nanoparticles (NPs) have more unsaturated Ag sites, which endowed the catalysts with higher intrinsic activity. Electrochemical tests show that spore-like Ag can obtain a Faraday efficiency (FE) of 95.6% at −1 V vs RHE, which is much higher than that of Ag nanowires (NWs) (73%) and ordinary Ag NPs (83%) synthesized in the same period. By using the three different morphologies of Ag synthesized as a research platform and statistically comparing the FE in the corresponding voltage interval, we obtained the influence of morphology effect on the selectivity of CO product production by electrocatalytic CO2 production over Ag-based catalysts, which can be further used as a guideline for catalyst development.

Silver nanowires/WO3 quantum dots electrode with enhanced vertical electric field gradient for Al3+/Li+ dual-functional electrochromic supercapacitor

Dual-functional electrochromic supercapacitors (DECSs), which demonstrate the substantial potential for reversible changes in optical properties and energy storage capabilities, hold considerable promise for a wide range of applications in areas such as smart windows, displays, and wearable electronics. Nevertheless, challenges still exist in effectively optimizing their capacitance, ensuring cycling stability, and achieving cost-effective fabrication. Herein, this study explores an approach by integrating Al3+ and Li+ ions as hybrid electrolyte to enhance electrochemical activity. Utilizing WO3 quantum dots (WQDs) embedded within Ag nanowires (Ag NWs) grids offers a promising strategy to augment the vertical electric field gradient and prevent the self-agglomeration of WQDs. In addition, the integration of hybrid electrolyte comprising Al3+ and Li+ ions not only enhance electrochemical activity but also serves to mitigate the high-cost lithium sources. The resulting Ag NWs/WQDs electrode exhibits an impressive specific capacitance of 681.6 F g−1 at 0.25 mA cm−2 in Al3+/Li+ hybrid electrolyte, a notable 5-fold increase compared to the pristine WQDs electrode in Li+ electrolyte (139.3 F g−1). Simultaneously, this dual-function electrode demonstrates a large optical modulation (81.8 % at 700 nm), a fast switching-speed (tbleaching=7 s, tcoloring=5 s), and a long cycling life (maintaining 84.6 % of its original capacitance after 5000 cycles). Noteworthy insights from COMSOL simulations highlight the Ag NWs grid's "conductive bridge" function, which shows a positive attribution in optimizing the vertical electric field gradient. As a demonstration of proof-of-concept, a large-size flexible dual-functional electrochromic supercapacitor (DECS, 15 cm×10 cm) confirms energy-saving and storage dual-functionality device. Typically, the DECS-equipped inner room experiences a temperature 10°C lower than that of a room with a blank PET within 10 min, indicating the significant irradiation shielding. In addition, this device exhibits a remarkable specific capacitance of 9.25 mF cm−2 at 5 mV s−1, accompanied by an exceptional stability under simulated solar irradiation. The innovation of 0D/1D hierarchical structure of the electrodes together with the hybrid electrolyte not only reduce costs but also enhance the capacitance and cycle stability of DECSs, offering new insights for the development of next-generation flexible electronic wearables.