Silver Nanowires Research Articles

MXene and AgNW based flexible transparent conductive films with sandwich structure for high-performance EMI shielding and electrical heaters

With the popularization of 5G technology and the development of science and technology, flexible and transparent conductive films (TCF) are increasingly used in the preparation of optoelectronic devices such as electromagnetic shielding devices, transparent flexible heaters, and solar cells. Silver nanowires (AgNW) are considered the best material for replacing indium tin oxide to prepare TCFs due to their excellent comprehensive properties. However, the loose overlap between AgNWs is a significant reason for the high resistance. This article investigates a sandwich structured conductive network composed of AgNW and Ti3C2Tx MXene for high-performance EMI shielding and transparent electrical heaters. Polyethylene pyrrolidone (PVP) solution was used to hydrophilic modify PET substrate, and then MXene, AgNW, and MXene were assembled layer by layer using spin coating method to form a TCF with a sandwich structure. One-dimensional AgNW is used to provide electron transfer channels and improve light penetration, while two-dimensional MXene nanosheets are used for welding AgNWs and adding additional conductive channels. The flexible TCF has excellent transmittance (85.1 % at 550 nm) and EMI shielding efficiency (27.1 dB). At the voltage of 5 V, the TCF used as a heater can reach 85.6 °C. This work offers an innovative approach to creating TCFs for the future generation.

Development of a wearable surface enhanced Raman scattering sensor chip based on silver nanowires for rapid detection of urea, lactate and pH in sweat

A wearable sweat sensor chip based on surface-enhanced Raman spectroscopy (SERS) is here presented. The plasmonic core of the chip, obtained by deposition of silver nanowires on a polytetrafluoroethylene (PTFE) porous membrane, permits the direct and label-free detection of urea and lactate at physiologic concentrations in combination with the pH measurement in the range between 5 and 9. Once integrated with commercial biocompatible and adhesive tape layers, the as produced SERS-active chip provides a low-cost, flexible and wearable sensing device for rapid and reliable human sweat analysis. The chip was finally tested on real sweat samples to estimate lactate and urea during medium-intense exertions.

GO/AgNW aided sustained release of ciprofloxacin loaded in Starch/PVA nanocomposite mats for wound dressings application

Compared to conventional bandages, which do not meet all wound care requirements, nanofiber wound dressings could provide a potentially excellent environment for healing. In the present research, nanocomposite membrane based on starch (St) - polyvinyl alcohol (PVA) nanofibers containing ciprofloxacin antibiotic drug loaded on graphene oxide‑silver nanowire (GO-AgNWs) hybrid nanoparticles is produced by electrospinning process. Morphological studies showed that the length and diameter of silver nanowires are 21 ± 9.17 μm and 82 ± 10.52 nm, respectively. The contact angle of 57.1° due to the hydrophilic nature of nanofibers, also the swelling degree of 679.51 % and, the water vapor permeability of 2627 ± 56 (g/m2.day) can be expressed as a confirmation of the ability of this wound dressing to manage secretions around the wound. In evaluating the antibacterial activity of these nanocomposite membranes against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria, the most potent antibacterial effect is in the case of nanofibers containing a high percentage of starch and nanoparticles carrying ciprofloxacin; with non-growth halos of 47.58 mm and 22.06 mm was recorded. The release of ciprofloxacin drug in vitro was reported to be 61.69 % during 24 h, and the final release rate was 82.17 %. Despite the biocompatibility and cell viability of 97.74 % and the biodegradability rate of 28.51 %, the StP-GOAgNWCip nanocomposite membrane can be introduced as a suitable candidate for wound dressing.

Uniform and welded networks of silver nanowires surface-embedded on cellulose yarns with PEDOT:PSS passivation for sustainable E-textiles

Electronic textiles are critical for wearable electronics and real-time health care monitoring. The use of cellulose fibers with conductive components to construct optimized materials for enhanced performance remains an ongoing mission. We report the use of continuous dip-coating of hydrogel fibers to fabricate conductive cellulose yarns (CCYs). Uniform, interwelded and compact silver nanowire (AgNW) networks are embedded on the surfaces of the cellulose yarns, after which a PEDOT:PSS passivation layer is applied to ensure the reliability and practicality of the CCYs. This unique AgNW network provids high electrical conductivity of the CCYs, high strain sensitivities and good Joule heating. Wearable fabric devices embroidered with CCYs exhibit superior performance in strain sensing and electrothermal insulation. This CCY realizes the organic combination of manufacturing, practicability and functionality in sustainable E-textiles. The CCY has the potential to enable scalable manufacturing of low-cost wearable sensors integrated into everyday clothes.

Biodegradable flexible conductive film based on sliver nanowires and PLA electrospun fibers

AbstractBiodegradable conductive films are crucial for the sustainable development of wearable electronics. In this work, a flexible and degradable conductive film was prepared based on a carefully designed interface of polylactic acid (PLA) electrospun fibers and silver nanowires (AgNWs). The amphiphilic triblock copolymer was added to PLA solution for electrospinning, followed by solvent posttreatment to induce the hydrophilic block of the amphiphilic triblock copolymer to migrate to the fiber surface. Dopamine can be uniformly polymerized on the surface of hydrophilic PLA fibers, and the prepared PLA@PDA fiber film can form a good interface combination with AgNWs. The electrical conductivity of AgNWs/PLA@PDA flexible film can reach 258.5 S cm−1, showing obvious Joule heating effect and good mechanical properties. Degradation experiments showed that in phosphate buffered saline, the PLA molecular chain showed a dynamic equilibrium due to the scission and rearrangement of the ester groups and degraded slowly, while AgNWs/PLA@PDA degraded rapidly under alkaline conditions. Our study provides a simple and controllable method to prepare flexible degradable electronic films, which is expected to be applied to flexible wearable bioelectrodes.

Flexible, hydrophobic, and robust composite films with sandwich structure for electromagnetic interference shielding and Joule heating

Electromagnetic interference (EMI) shielding materials with favorable flexibility, robustness, and multipurpose capabilities are urgently desired for smart wearable devices. Herein, flexible PDMS/cellulose nanofiber/Ag nanowire composite films with sandwich structures were successfully fabricated by a facile method. First, silver nanowires (AgNWs) were uniformly stacked in the upper part of the cellulose gel using a controlled two-step vacuum-assisted filtration; next, AgNWs were tightly embedded in the cellulose matrix by a hot-pressing strategy; finally, a hydrophobic protective layer, PDMS, was introduced. The water contact angle (WCA) of composite films could reach 121°. Compared with uniformly mixed films, AgNWs deposited only on the surface of the matrix allowed the conductivity to reach 381 S/cm at a low weight fraction of AgNWs (6 wt%). Thanks to such excellent conductivity, the composite films exhibited superior EMI shielding effectiveness (49 dB) at only 40 μm thickness, and Joule heating performance, i.e., the surface temperature reached 111.3 °C at 1.5 V driving voltage. It was worth noting that after bending and peeling damage, the WCA and EMI shielding effectiveness of composite films were not significantly impacted due to the hot-pressing strategy and hydrophobic surface protection. The robust composite films show huge application potential in the wearable electronics field.

Surface Embedded Metal Nanowire-Liquid Metal-Elastomer Hybrid Composites for Stretchable Electronics.

Both liquid metal (LM) and metallic filler-based conductive composites are promising stretchable conductors. LM alloys exhibit intrinsically high deformability but present challenges for patterning on polymeric substrates due to high surface tension. On the other hand, conductive composites comprising metallic fillers undergo considerable decrease in electrical conductivity under mechanical deformation. To address the challenges, we present silver nanowire (AgNW)-LM-elastomer hybrid composite films, where AgNWs and LM are embedded below the surface of an elastomeric matrix, using two fabrication approaches, sequential and mixed. We investigate and understand the process-structure-property relationship of the AgNW-LM-elastomer hybrid composites fabricated using two approaches. Different weight ratios of AgNWs and LM particles provide tunable electrical conductivity. The hybrid composites show more stable electromechanical performance than the composites with AgNWs alone. In particular, 1:2.4 (AgNW:LMP w/w) sequential hybrid composite shows electromechanical stability similar to that of the LM-elastomer composite, with a resistance increase of 2.04% at 90% strain. The sequential approach is found to form AgIn2 intermetallic compounds which along with Ga-In bonds, imparts large deformability to the sequential hybrid composite as well as mechanical robustness against scratching, cutting, peeling, and wiping. To demonstrate the application of the hybrid composite for stretchable electronics, a laser patterned stretchable heater on textile and a stretchable circuit including a light-emitting diode are fabricated.

Tri-system integration in metal-oxide nanocomposites via in-situ solution-processed method for ultrathin flexible transparent electrodes

For stable operation of ultrathin flexible transparent electrodes (uFTEs), it is critical to implement effective risk management during concurrent multi-loading operation of electrical bias and mechanical folding cycles in high-humidity environments. Despite extensive efforts in preparing solution-processed uFTEs with cost-effective and high-throughput means, achieving in-situ nano-adhesion in heterogeneous metal-oxide nanocomposites remains challenging. In this work, we observed by serendipity liquid-like behaviour of transparent metal-oxide-semiconductor zinc oxide nanoparticles (ZnONPs) onto silver nanowires (AgNWs) developed by in-situ solution processed method (iSPM). This enabled us to address the long-standing issue of vulnerability in the nanocomposite caused by the interface of dissimilar materials between AgNWs and ZnONPs, resulting in a remarkably improved multi-loading operation. Importantly, substrate-integrated uFTEs constituted of the metal-oxide nanocomposite electrode semi-embedded in the polymer matrix of greatly thin <0.5 μm thickness is successfully demonstrated with the smooth surface topography, promoted by the tri-system integration including (i) AgNW-AgNW, (ii) ZnONP-ZnONP, and (iii) AgNW-ZnONP systems. Our finding unveils the complex interfacial dynamics associated with the heterogeneous interface system between AgNWs and ZnONPs and holds great promise in understanding the in-situ nano-adhesion process and increasing the design flexibility of next generation solution-processed uFTEs.

Stretch-Induced Conductivity Enhancement in Highly Conductive and Tough Hydrogels.

The resistance of gels and elastomers increases significantly with tensile strain, which reduces conductive stability and restricts their use in stable and reliable electronics. Here, highly conductive tough hydrogels composed of silver nanowires (AgNWs), liquid metal (LM), and poly(vinyl alcohol) (PVA) are fabricated. The stretch-induced orientations of AgNWs, deformable LM, and PVA nanocrystalline create conductive pathways, enhancing the mechanical properties of the hydrogels, including increased ultimate fracture stress (13-33MPa), strain (3000-5300%), and toughness (390.9-765.1MJ m-3 ). Notably, the electrical conductivity of the hydrogels is significantly improved from 4.05 × 10-3 to 24 S m-1 when stretched to 4200% strain, representing a 6000-fold enhancement. The incorporation of PVA nanocrystalline, deformable LM, and AgNWs effectively mitigates stress concentration at the crack tip, thereby conferring crack propagation insensitivity and fatigue resistance to the hydrogels. Moreover, the hydrogels are designed with a reversible crosslinking network, allowing for water-induced recycling.

Improved Coloration Efficiency and Stability of WO3 Electrochromic Devices by the Addition of Silver Nanowires

Improved Coloration Efficiency and Stability of WO3 Electrochromic Devices by the Addition of Silver Nanowires

Ionic Liquid-Enhanced Assembly of Nanomaterials for Highly Stable Flexible Transparent Electrodes

HighlightsWe present a method that utilizes ionic liquid-enhanced nanomaterial assembly to fabricate highly stable and large-area MXene-silver nanowire electrodes with ordered layered structures.This approach emphasizes the use of hydrophobic and nonvolatile ionic liquids, which form stable interfaces with water by reducing interface energy, preventing the sedimentation loss of nanomaterials during assembly.The prepared electrodes not only exhibit excellent optoelectronic properties (9.4 Ω sq−1 sheet resistance and 93% transmittance), but also have exceptional antioxidant capacity.

Effects of silver nanowires and their surface modification on electromagnetic interference, transport and mechanical properties of an aerospace grade epoxy

The aerospace industry has progressively grown its use of composites. Electrically conductive nanocomposites are among important modern materials for this sector. We report on a bulk composite containing silver nanowires (AgNW) and an aerospace grade epoxy for use in carbon fiber reinforced polymers (CFRPs). AgNWs’ surfaces were also modified to enhance their ability to be dispersed in epoxy. Composites were obtained by use of three-roll milling which is of major interest for industrial applications, especially for the aerospace sector, since the process is scalable and works for aerospace grade resins with high curing temperatures. Our main objective is to improve the electromagnetic interference (EMI) shielding performance of CFRPs via improving the properties of the resin material. The addition of AgNWs did not considerably alter the flexural strength of the epoxy, however the composite with surface-modified AgNWs has a 46 % higher flexural strength. Adding AgNWs over a low threshold concentration of 0.05 wt% significantly enhanced the electrical conductivity. Conductivities above the percolation threshold lie around 102 S/m. At a concentration of 5 wt% AgNW, the EMI shielding efficiency (SE) of epoxy increased from 3.49 to 12.31 dB. Moreover, the thermal stability of the epoxy was unaffected by AgNWs. As a result, it was discovered that (surface modified) AgNWs improved the (multifunctional) capabilities of the aerospace grade epoxy resin which might be used in CFRPs to further enhance properties of composites parts, demonstrating suitability of AgNWs’ as a reinforcement material in aerospace applications.

Impact of Hybrid Plasmonic and Temperature in Random Laser Tuning

This research explores the interaction between silver films and dispersed silver nanowires (Ag NWs) in the context of generating random laser emission. To achieve random lasing, we use a mixture of Rhoda mine B (RhB) dye and a polyvinyl alcohol (PVA) matrix as the gain medium. The combination of silver components plays a crucial role in trapping and controlling light. The surface characteristics of the film, including its roughness and the interplay between localized and extended surface plasmons significantly affect the performance of the random laser (RL). The laser’s threshold is closely linked to the thickness of the film, which is influenced by its surface roughness. Additionally, variations in film thickness lead to wavelength modulation, ranging from 597 nm to 606 nm, primarily due to the reabsorption of RhB. Moreover, this research demonstrates the intriguing capability to tune emission wavelengths in response to temperature changes, promising precise wavelength control for plasmonic devices and potential applications.

Multilayer ordered silver nanowire network films by self‐driven climbing for large‐area flexible optoelectronic devices

AbstractSilver nanowire (AgNW) networks hold great promises as next‐generation flexible transparent electrodes (FTEs) for high‐performance flexible optoelectronic devices. However, achieving large‐area flexible AgNW network electrodes with low sheet resistance, high optical transmittance, and a smooth surface remains a grand challenge. Here, we report a straightforward and cost‐effective roll‐to‐roll method that includes interface assembly/wetting‐induced climbing transfer, nanowelding, and washing processess to fabricate flexible ordered layered AgNW electrodes with high network uniformity. By manipulating the stacking number of the interfacially assembled AgNW monolayer, we can precisely tailor and balance the transparency and the conductivity of the electrodes, achieving an exceptional Figure of Merit (FoM) value of 862. Moreover, the ordered layered structure enhances surface smoothness, compared with randomly arranged structures. To highlight the potential of these ordered layered AgNW network electrodes in flexible optoelectronic devices, we successfully employ them as highly sensitive strain sensors, large‐area flexible touch screens, and flexible smart windows. Overall, this work represents a substantial advance toward high‐performance FTEs over large areas, opening up exciting opportunities for the development of advanced optoelectronic devices.image

Multilayered silver nanowires and graphene fluoride-based aramid nanofibers for excellent thermoconductive electromagnetic interference shielding materials with low-reflection

Multilayered films composed of alternating layers of graphene fluoride (GF) and silver nanowires (AgNWs) in an aramid nanofiber (ANF) matrix were fabricated. The films were prepared by sequential vacuum filtration of GF@ANF and AgNWs@ANF suspensions to obtain multilayered composite architectures. The multilayered GF@ANF/AgNWs@ANF films exhibited exceptional mechanical flexibility and strength, with tensile strength up to 130 MPa and 5000 bending cycles with negligible performance deterioration. The films displayed remarkably high electromagnetic interference (EMI) shielding effectiveness up to 54 dB in X-band frequencies, attributed to the multiple internal reflections in the multilayered structure. EMI shielding was dominated by absorption rather than reflection, enabling attenuation of incident microwaves without secondary pollution. The multilayered films also exhibited ultrahigh in-plane thermal conductivity of up to 45 W/mK, owing to the thermally conductive GF and AgNWs networks. The EMI shielding effectiveness and thermal conductivity were retained after temperature and bending cycling. The composite films also demonstrated excellent flame retardancy. This study provides an effective route toward concurrent enhancement of multi-functional properties through architectural engineering at the nanoscale. The combination of robust EMI shielding, mechanical flexibility, thermal management, and fire safety highlights the potential of rationally designed multilayered composites for practical applications in 5 G wearable electronics devices, communications systems, and radar technologies.

Highly Electroconductive Metal-Polymer Hybrid Foams Based on Silver Nanowires: Manufacturing and Characterization.

Due to their electroconductive properties, flexible open-cell polyurethane foam/silver nanowire (PUF/AgNW) structures can provide an alternative for the construction of cheap pressure transducers with limited lifetimes or used as filter media for air conditioning units, presenting bactericidal and antifungal properties. In this paper, highly electroconductive metal-polymer hybrid foams (MPHFs) based on AgNWs were manufactured and characterized. The electrical resistance of MPHFs with various degrees of AgNW coating was measured during repeated compression. For low degrees of AgNW coating, the decrease in electrical resistance during compression occurs in steps and is not reproducible with repeated compression cycles due to the reduced number of electroconductive zones involved in obtaining electrical conductivity. For high AgNW coating degrees, the decrease in resistance is quasi-linear and reproducible after the first compression cycle. However, after compression, cracks appear in the foam cell structure, which increases the electrical resistance and decreases the mechanical strength. It can be considered that PUFs coated with AgNWs have a compression memory effect and can be used as cheap solutions in industrial processes in which high precision is not required, such as exceeding a maximum admissible load or as ohmic seals for product security.

Highly aligned electrospun film with wave-like structure for multidirectional strain and visual sensing

Recently, flexible strain sensors have attracted great attention on account of the application potential in medical treatment, flexible prosthetics and human–machine interaction. Nevertheless, traditional uniaxial strain sensors cannot detect movement in different directions, limiting the applications in sensing technologies. In addition, it is still a significant challenge to simultaneously acquire visualized and high-performance strain sensors. Here, a highly flexible sensor with visual sensing function was fabricated by spraying silver nanowires (AgNWs)/carbon nanotubes (CNTs) ink on the aligned thermoplastic polyurethane (TPU) electrospun mat. The sensing performances of AgNWs/CNTs aligned TPU fluorescent mats (ACUM-F) are individually explored in vertical and parallel directions. Herein, the ACUM-F in vertical can exhibit high sensitivity (gauge factor (GF) up to 244.3), wide working range (0.1 ∼ 380 % strain), fast response/recovery time (80 ms/80 ms), good sensing durability and reproducibility (1000 stretching/releasing test cycles). Furthermore, ACUM-F is assembled as strain sensors to monitor various human body movements, which can achieve sign language interpretation through finger gesture monitoring, demonstrating its great potential in human–machine interaction. The direction-aware application of novel multidirectional sensors with visual sensing functions may bring inspiration for a new era of flexible electronics development.

Silver Nanowire-Based Transparent Electrodes for V2O5 Thin Films with Electrochromic Properties.

The development of electrochromic systems, known for the modulation of their optical properties under an applied voltage, depends on the replacement of the state-of-the-art ITO (In2O3:Sn) transparent electrode (TE) as well as the improvement of electrochromic films. This study presents an innovative ITO-free electrochromic film architecture utilizing oxide-coated silver nanowire (AgNW) networks as a TE and V2O5 as an electrochromic oxide layer. The TE was prepared by simple spray deposition of AgNWs that allowed for tuning different densities of the network and hence the resistance and transparency of the film. The conformal oxide coating (SnO2 or ZnO) on AgNWs was deposited by atmospheric-pressure spatial atomic layer deposition, an open-air fast and scalable process yielding a highly stable electrode. V2O5 thin films were then deposited by radio frequency magnetron sputtering on the AgNW-based TE. Independent of the oxide's nature, a 20 nm protective layer thickness was insufficient to prevent the deterioration of the AgNW network during V2O5 deposition. On the contrary, crystalline V2O5 films were grown on 30 nm thick ZnO or SnO2-coated AgNWs, exhibiting a typical orange color. Electrochromic characterization demonstrated that only V2O5 films deposited on 30 nm thick SnO2-coated AgNW showed characteristic oxidation-reduction peaks in the Li+-based liquid electrolyte associated with a reversible orange-to-blue color switch for at least 500 cycles. The electrochromic key properties of AgNW/SnO2 (30 nm)/V2O5 films are discussed in terms of structural and morphological changes due to the AgNW network and the nature and thickness of the two protective oxide coatings.

Silver Nanowires Cascaded Layered Double Hydroxides Nanocages with Enhanced Directional Electron Transport for Efficient Electrocatalytic Oxygen Evolution.

Designing and fabricating highly efficient oxygen evolution reaction (OER) electrocatalytic materials for water splitting is a promising and practical approach to green and sustainable low-carbon energy systems. Herein, a facile in situ growth self-template strategy by using ZIF-67 as a consumable layered double hydroxides (LDHs) template and silver nanowires (AgNWs) as 1D conductive cascaded substrate to controllably synthesize the target AgNWs@CoFe-LDH composites with unique hollow shell sugar gourd-like structure and enhanced directional electron transport effect is reported. The AgNWs exhibit the key functions of the close connection of CoFe-LDH nanocages and the support of the directional electron transport effect in the composite catalyst inducing electrons directionally moving from CoFe-LDH to AgNWs. Meanwhile, the CoFe-LDH nanocages with ultrathin nanosheets and hollow structural properties show abundant active sites for electrocatalytic oxygen generation. The versatile AgNWs@CoFe-LDH catalyst with optimized components, enhanced directional electron transport, and synergistic effect achieves high OER performance with the overpotential of 207 mV and long-term 50 h stability at 10 mA cm-2 in an alkaline medium. Moreover, in-depth insights into the microstructure, structure-activity relationships, identification of key intermediate species, and a proton-coupled four-electron OER mechanism based on experimental discovery and theoretical calculation are also demonstrated.

Durable and sustainable CoFe2O4@MXene-silver nanowires/cellulose nanofibers composite films with controllable electric–magnetic gradient towards high-efficiency electromagnetic interference shielding and Joule heating capacity

Exploring electromagnetic waves (EMW) absorption-dominated high-performance electromagnetic interference (EMI) shielding materials with robust mechanical properties and remarkable Joule heating capability is highly desired but remains a daunting challenge for the development of modern electronic equipment. Herein, durable and multifunctional cellulose nanofiber-based composite films with elaborate electric–magnetic dual gradient structure were successfully fabricated through highly controllable vacuum-assisted filtration technology. The electric–magnetic dual gradient network consists of CoFe2O4@MXene hybrids with electric–magnetic cooperative loss concentrated on the top region as impedance matching layer and silver nanowires (AgNWs) with high conductivity placed on the bottom as high-efficiency shielding layer. Benefiting from the construction of dual gradient network with rational arrangement of the impedance matching layer and conductive shielding layer, the synergy of electric–magnetic loss, polarization loss induced by the numerous heterointerfaces and “absorption-reflection-reabsorption” shielding mechanism, the resultant composite films simultaneously reveal ultraefficient EMI shielding effectiveness (SE) and low EMW reflectivity. The prepared composite films (0.1 mm in thickness) achieve an extraordinary EMI SE of 84.3 dB and a satisfactory reflection coefficient of 0.42, realizing EMW absorption-dominated shielding feature. Moreover, the mechanical properties and Joule heating capacity of the prepared composite films are outstanding, which mainly benefits from the construction of hierarchically layered structure. This work paves a novel route for designing and fabricating absorption-dominated high-performance EMI shielding composite films with durable mechanical performance and outstanding Joule heating capability, which are potentially suitable for new-generation advanced electronics.