Conductive Silver Nanowire Research Articles

Hydrogen Evolution Activity of Platinum Nanoparticles Decorated on Silver Nanowire Networks and Graphite Electrodes

The catalytic activity of graphite (C) and conductive silver nanowire (AgNW) networks coated on glass and graphite substrates with low platinum content towards hydrogen evolution reaction (HER) is reported. The results exhibit that the chronoamperometric electrodeposition of platinum on AgNW substrates results in the formation of spherically shaped nanoparticle agglomerates aligned on the nanowires. Also, platinum doped graphite electrodes with a rough surface showed an efficient distribution of platinum nanoparticles (PtNPs). Studies of the electrocatalytic HER activity as a function of platinum loading indicate that the optimum loading is in the range of 60 µg/cm2 and further loading results only in a minor reduction of the overpotential. At low Pt content, a synergistic effect of the AgNW network in terms of enhancement of the HER performance was observed. Tafel analysis showed that in the low overpotential region, the Volmer reaction was the rate determining step for the graphite based electrodes. The graphite substrate in conductive connection with the nanowires was shown to significantly boost the hydrogen formation rate.

Fabrication of Heat-generating Polyester through Formation of Conductive Silver Nanowire Network

Fabrication of Heat-generating Polyester through Formation of Conductive Silver Nanowire Network

Printed flexible solid-state microsupercapacitor with highly-stable aqueous cobalt-based inks

Cobalt-based nanomaterials are among the most noticed candidates for manufacturing supercapacitive electrodes. Inkjet-printing is an emerging technique for fabricating miniaturized devices. In this work, highly flexible microsupercapacitors (MSCs) are manufactured, using a pseudocapacitive (C = 900 F‌ g−1 at 1 A g−1) Co-oxide-hydroxide water-based and ultra-stable (up to 12 months) ink on paper. The synthesized capacitive active material consists of cobalt-oxide nanocubes and cobalt-hydroxide hexagonal nanoflakes. Conductive (Rs = 13 Ω/□) silver nanowire networks serve as current collectors, and the morphology of cobalt oxide-hydroxide structures and the developed ink features, allow for printing well-detailed and homogeneous patterns. The inkjet-printed symmetric and asymmetric devices show notable areal specific capacitances of 35.68 mF cm−2 and 23.60 mF cm−2 at a current density of 0.1 mA cm−2, respectively. The asymmetric devices deliver impressive energy and power densities of 2.76 μW h cm−2 (4.10 W h kg−1) and 646 μW cm−2 (959 W kg−1), respectively. A thorough study on the cyclic and mechanical stability of the flexible devices resulted in perfect capacitance maintenance of 94.3 % after 10,000 charge and discharge cycles and retention of over 80 % even after 1000 cycles of successive bending and folding. The extensive study of capacitance retention following folding under various obtuse and reflex angles, which can be regarded as an important step toward characterizing flexible devices suitable for being utilized in wearable electronics, is carried out for the first time to the best of our knowledge. The findings of this study clearly illustrate the prospects of using the inkjet-printing technique to fabricate high-performance MSC devices appropriate for integration with flexible and wearable electronics.

Ternary composites of poly(vinylidene fluoride-co-hexafluoropropylene) with silver nanowires and titanium dioxide nanoparticles as separator membranes for lithium-ion batteries

In the realm of polymer composites, there is growing interest in the use of more than one filler for achieving multifunctional properties. In this work, a composite separator membrane has been developed for lithium-ion battery application, by incorporating conductive silver nanowires (AgNWs) and titanium dioxide (TiO2) nanoparticles into a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer matrix. The composite membranes were manufactured by solvent casting and thermally induced phase separation, with total filler content varying up to 10 wt%. The ternary composites composites present improved mechanical characteristics, ionic conductivity and lithium transfer number compared to the neat polymer matrix. On the other hand, the filler type and content within the composite has little bearing on the morphology, polymer phase, or thermal stability. Once applied as a separator in lithium-ion batteries, the highest discharge capacity value was obtained for the 5 wt% AgNWs/5 wt% TiO2/PVDF-HFP membrane at different C-rates, benefiting from the synergetic effect from both fillers. This work demonstrates that higher battery performance can be achieved for next-generation lithium-ion batteries by using separator membranes based on ternary composites.

Silver nanowire bridged graphene framework for encapsulating phase change materials with high thermal conductivity and solar-to-heat conversion ability

To construct a high-efficiency thermally conductive graphene nanoplate (GNP) framework, ball-milling technique and silver nanowires (AgNW) bridging strategy were employed to improve the compatibility of GNP and the interfacial thermal resistance (ITR) in GNP skeletons, respectively. By using unidirectionally freeze casting technique, long range ordered GNP frameworks containing a small amount of AgNW as “bridge” were obtained, which were used to encapsulation phase change material (PCM). As a result, the honeycomb-like micropores of the framework with strong capillary effect give PCM anti-leakage and shape stability. The vertically aligned and AgNW bridged GNP skeletons form high-speed heat transfer paths endowith low ITR, thus significantly improve thermal conductivity to 7.24 W/mK. More importantly, GNP framework with strong light absorption ability endows PCM with well solar-to-heat conversion and storage ability. Therefore, AgNW bridged GNP framework endowing PCM with comprehensive thermal management ability exhibits a high potential in addressing the thermal problems of electronics.

Enhancing Conductivity of Silver Nanowire Networks through Surface Engineering Using Bidentate Rigid Ligands.

Solution processable metallic nanomaterials present a convenient way to fabricate conductive structures, which are necessary in all electronic devices. However, they tend to require post-treatments to remove the bulky ligands around them to achieve high conductivity. In this work, we present a method to formulate a post-treatment free conductive silver nanowire ink by controlling the type of ligands around the silver nanowires. We found that bidentate ligands with a rigid molecular structure were effective in improving the conductivity of the silver nanowire networks as they could maximize the number of linkages between neighboring nanowires. In addition, DFT calculations also revealed that ligands with good LUMO to silver energy alignment were more effective. Because of these reasons, fumaric acid was found to be the most effective ligand and achieved a large reduction in sheet resistance of 70% or higher depending on the nanowire network density. The concepts elucidated from this study would also be applicable to other solution processable nanomaterials systems such as quantum dots for photovoltaics or LEDs which also require good charge transport being neighboring nanoparticles.

Large-scale semi-embedded AgNW-based stretchable transparent electrodes via superwettability-induced transfer of AgNWs/ionic liquid onto gradient PDMS.

Stretchable transparent electrodes (STEs) composed of highly conductive silver nanowires (AgNWs) and mechanically stretchable polydimethylsiloxane (PDMS) are compelling materials for the development of flexible electronic devices. So far, the fabrication processes of the AgNWs/PDMS-based STEs suffer from low efficiency on a small scale, apart from the limitations and challenges posed by the continuous fabrication processes that are required to exploit these fascinating materials in an industrial context. Here, we have addressed these limitations by using gradient PDMS with a tunable modulus as the stretchable substrate, on which ionic liquid-mediated aligned semi-embedded AgNWs are formed via a scalable superwettability-induced transfer strategy. We have demonstrated the importance of the gradient PDMS in achieving STEs with improved optoelectrical properties, mechanical stretchability, and long-term stability. Furthermore, we have shown the applications of the designed STEs for electro-heating and electroluminescent devices. This promising fabrication process is an industrially relevant alternative to current processes that are either complicated and less effective (for example, stamping transfer) or not compatible with continuous, large-scale production (for example, spin-coating or electrospinning).

Hydrodynamic control of silicone elastomers on between porous media

Silicone elastomers, for example, polydimethylsiloxane (PDMS), have been widely used as cross-linkers for fabrication of flexible strain sensors. They not only lend strong adhesion to adjacent materials, for example, porous fabrics, but also tune their elastic property. Silicone elastomer precursors, which are typical non-Newtonian fluids, can easily penetrate into porous fabrics, driven by the capillary effects of fibers. Unfortunately, such a penetration has negative effects on both adhesion strength and elastic property of PDMS, thus limiting their applications. Here we report a facile method for preparing uniform silicone elastomer films, that is, PDMS, on between porous media via controlling the hydrodynamics of elastomer precursors. Our experiments show that the hydrodynamics of elastomer precursors can be easily controlled by modulating the pre-curing time of PDMS precursors to prevent them from penetration into porous media but keep their high adhesion. Based on this hydrodynamic modulation of PDMS precursors, we firmly adhere conductive silver nanowires (AgNWs) onto knitted fabrics, and further combine composites with common clothing from the point of view of ergonomics, showing the possibility of applying such a modulation to the fabrication of wearable strain sensors. Our findings not only present an understanding of liquid transport in porous media, but also provide a novel method of controlling the hydrodynamics of elastomer precursors in porous media for achieving the effective wearable sensors.

A superhydrophobic wearable rubber band with a synergistic dual conductive layer for monitoring human motions

Wearable and flexible electronics attract increasing attention due to their outstanding stretchability and human friendliness, while the significant parameters to evaluate sensor performance such as sensitivity and working range are the main challenge for better sensor design. Herein, an ultrasensitive and flexible strain sensor with synergistic dual conductive layers was successfully fabricated by designing a silk wrinkles structure to largely broaden the stretchable range for the conductive layer. The organic conductive polypyrrole and silver nanowire are combined to construct the conductive layer with high conductivity and better stretchability. The as-obtained sensor possesses a wide working range (0–126 %) and high sensitivity (a GF of 15710.75 at a strain of 120 %-126 %). The additional SiO2 layer is applied to the sensor to achieve a contact angle of 143.4°, which is close to super-hydrophobicity. The resultant sensor also possesses fast response and recovery speed due to the elastomeric rubber band substrate with the response and recovery time of 105 and 101 ms respectively, and still keeps high stability over 5000 cyclic stretching and releasing tests. The sensor is promising to be used in wearable applications potentially.

Stretchable and Self-Healable Fiber-Shaped Conductors Suitable for Harsh Environments.

Fiber-shaped conductors with high electrical conductivity, stretchability, and durability have attracted increasing attention due to their potential for integration into arbitrary wearable forms. However, these fiber conductors still suffer from low reliability and short life span, particularly in harsh environments. Herein, a conductive, environment-tolerant, stretchable, and healable fiber conductor (CESH), which consists of a self-healable and stretchable organohydrogel fiber core, a conductive and buckled silver nanowire coating, and a self-healable and waterproof protective sheath, is reported. Such a multilayer core-sheath design not only offers high stretchability (≈2400%), high electrical conductivity (1.0 × 106 S m-1 ), outstanding self-healing ability and durability, but also possesses unprecedented tolerance in harsh environments including wide working temperature (-60-20 °C), arid (≈10 % RH (RH: room humidity)), and underwater conditions. As proof-of-concept demonstrations, CESHs are integrated into various wearable formats as interconnectors to steadily perform the electric function under different mechanical deformations and harsh conditions. Such a new type of multifunctional fiber conductors can bridge the gap in stretchable and self-healing fiber technologies by providing ultrastable electrical conductance and excellent environmental tolerance, which can greatly expand the range of applications for fiber conductors.

Large scale fabrication of recyclable and multifunctional sandwich-structured electromagnetic interference shielding films based on waste Nylon-6 silk

Modern wearable electronics are being miniaturized with high integration and frequency, leading to excess electromagnetic radiation, heat storage, and fire risk. Besides overcoming these safety issues, realizing large-scale, low-cost and recyclable preparation of multifunctional films are urgently required for practical applications of electromagnetic interference (EMI) shielding. Herein, sandwich-structured films have been prepared using commercial nylon mesh (CNM) with a waste nylon-6 silk/ammonium polyphosphate (PA6/APP) porous flame-retardant outer layer and inner conductive ultra-long silver nanowires (AgNWs) network. Only 0.2 mg/cm2 of the conductive inner layer endows the films with excellent EMI shielding performance (53.7 dB), thermal diffusivity (5.206 ± 0.087 mm2/s) and antibacterial properties. In addition, the unique honeycomb structure of the PA6/APP outer layer produced during water bath treatment endows the films with superior printability. And such modified porous outer layer of the sandwich-structured films realizes a V0 rating during the UL-94 test. Even when these films are scrapped, they can still be recycled and reused. In summary, the methods described herein can be extended to realize the large-scale production of sandwich-structured films.

Effectively morphology-controlled NiMn layered double hydroxide microflowers by conductive silver nanowires for supercapacitor electrodes

Effective ion and electron transport pathways provide an effective method to further improve the energy storage performance of layered double hydroxide (LDH) for supercapacitors. Here, microflower-like NiMn LDH/silver nanowires (Ag NWs) composites for high-performance supercapacitors are constructed by a convenient hydrothermal method, in which silver nanowires are found to not only ensure excellent electron conductivity but also have a positive effect on the growth of LDH nanosheets to form the unique three-dimensional open pore structure. In addition, the significantly increased interlayer spacing of the composite enables fast ion transport. In particular, NiMn LDH/Ag NWs exhibits higher specific capacitance (1436.30 F·g−1 at 2 A·g−1) in a three-electrode system, which is 121.29% of the specific capacitance of pure NiMn LDH. The asymmetric supercapacitor assembled with NiMn LDH/Ag NWs and AC electrode exhibits high specific capacitance of 215.63 F·g−1 at 2 A·g−1, superior energy density of 71.95 Wh·kg−1 and excellent cycling stability, illustrating that the NiMn LDH/Ag NWs composite is the promising material for supercapacitor applications.

Enhancing and Understanding the High Stretchability of Printable, Conductive Silver Nanowire Ink

Enhancing and Understanding the High Stretchability of Printable, Conductive Silver Nanowire Ink

Ultralight and Highly Conductive Silver Nanowire Aerogels for High-Performance Electromagnetic Interference Shielding.

Metal-based materials possess superior electromagnetic interference (EMI) shielding performance because of their extraordinary electrical conductivity. Nevertheless, the high density and structural rigidity of metals seriously limit their applicability in portable and wearable electronic equipment. A common method for reducing the density of metal-based materials is to prepare metal nanowire aerogels by freeze-drying, but the weak connection among the nanowires results in poor mechanical and electrical properties. Herein, a facile approach is developed for the one-step synthesis of silver nanowire (AgNW) aerogels with ultralow density, good flexibility, high electrical conductivity, and a robust structure. The gel is directly formed by in situ assembly of AgNWs. The end-to-end nanojoining of AgNWs contributes to constructing an interconnected three-dimensional (3D) network, resulting in improved mechanical and electrical properties. The AgNW aerogel with an ultralow density of 4.87 mg cm-3 demonstrates a high electrical conductivity of 4584 S m-1. Moreover, the porous structure of the AgNW aerogel provides numerous interfaces for multiple reflections and scattering of EM waves, allowing them to be continuously absorbed and dissipated within the aerogel. Thus, the AgNW aerogel exhibits a superb EMI shielding effectiveness (SE) of 109.3 dB and a normalized surface specific SE (SSE/t, calculated as the SE divided by the density and thickness) of 353 183 dB cm2 g-1, significantly above that of previously known shielding materials. This work provides a new route for preparing high-performance metal nanowire aerogels and their great potential in EMI shielding.

Flexible breathable photothermal-therapy epidermic sensor with MXene for ultrasensitive wearable human-machine interaction

Multifunctional flexible wearable epidermic sensors have gained enormous attention for their promising potential applications in personal health management, electronic skins and intelligent human-machine interaction. However, it remains a critical challenge to realize a flexible breathable sensing device with reliable sensing performances for comfortably wearable human motion detection and ultrasensitive human-machine interfacing with the integrated functional capability of disease diagnosis and subsequent photothermal therapy simultaneously. Herein, a flexible breathable epidermic sensor is fabricated by delicately assembling conductive MXene nanosheets and silver nanowires (AgNWs) onto electrospun elastomeric substrates for ultrasensitive sensing and on-demand photothermal therapy. The as-prepared flexible breathable electronic sensor presents a broad sensing range (up to ∼120 %), ultrahigh sensitivity (gauge factor (GF) up to 4720), extremely low detection limit, remarkable reliability, and robust biocompatibility for serving as the electronic skin to monitor human physiological signals and wearable human-machine interaction. Moreover, it exhibits brilliant photothermal properties for enhanced antibacterial effect and timely photothermal therapy after healthcare monitoring and disease diagnosis. This work provides a facile way of developing flexible breathable multifunctional electronic sensors featured with excellent sensing ability, brilliant breathability and reliable photothermal properties for long-term healthcare monitoring, ultrasensitive wearable human-machine interfacing, smart disease diagnosis and treatment.

Intense Pulsed Light Welding Process with Mechanical Roll-Pressing for Highly Conductive Silver Nanowire Transparent Electrode

Intense Pulsed Light Welding Process with Mechanical Roll-Pressing for Highly Conductive Silver Nanowire Transparent Electrode

Stable, highly conductive and orthogonal silver nanowire networks via zwitterionic treatment

A high-performance AgNW electrode was developed via zwitterionic treatment, where the anions electrostatically adsorb on AgNWs and the cations enhance the electrostatic repulsion, resulting in orthogonally aligned AgNW electrode.

Highly Conductive and Compliant Silver Nanowire Nanocomposites by Direct Spray Deposition

The silver nanowire (Ag NW)/elastomer nanocomposite represents a prototypical form of a compliant conductor for flexible and stretchable electronic devices. The widespread implementations are currently hindered by the complicated procedures to effectively disperse Ag NWs into elastomer matrices. In this study, we report a facile and scalable coating process to create Ag NW nanocomposites on various flexible/stretchable substrates. As-synthesized Ag NWs from the high-yield polyol-reduction approach are homogeneously dispersed into a variety of dilute elastomer solutions, thereby enabling direct spray deposition into highly compliant conductors. The as-prepared nanocomposite exhibits excellent conductivity (∼11,000 S/cm) and high deformability to 100% strain. The stable electrical properties are largely retained under repetitive mechanical manipulations including stretching, bending, and folding. The patterned features of conductive nanocomposites are conveniently accessed using shadow masks or selective laser ablation. The practical suitability is demonstrated by the successful implementations of a stretchable sensing patch and a flexible light-emitting diode display.

Semi-transparent fullerene-based tandem solar cells with excellent light utilization efficiency enabled by careful selection of sub-cells

Semi-transparent (ST) tandem organic solar cells (OSCs) are typically exhibiting a trade-off between efficiency and average visible transmittance (AVT), which can be minimized by the appropriate selection of transparent contacts and absorbing materials in the sub-cells. Herein, we demonstrate efficient and highly transparent hetero-tandem OSCs constructed by stacking PBDT[2F]T:PC 71 BM and PCE10:PC 61 BM active layers as front-cell and back-cell, respectively. Optical and electrical simulations show that the PBDT[2F]T and PCE10-based sub-cells possess potential as ST and reflective tandem OSCs. With the aid of the simulations, we could fabricate reflective tandem OSCs with an efficiency of up to 8.3%. Furthermore, a ST tandem OSC, employing conductive silver nanowire top contact, achieved an AVT of 49.2%, efficiency of 5.3%, and high light utilization efficiency (LUE) of 2.61% under 1 sun, AM1.5G spectral illumination. This study demonstrates the importance of the sub-cells choices for developing ST tandem solar cells with a good balance of AVT and PCE, paving the way for solar windows of high performance. • Optical and electrical simulations performed to aid reflective and semi-transparent tandem OSCs fabrication. • Fabrication of tandem based on PBDT[2F]T:PC 71 BM and PCE10:PC 61 BM blends with PCE higher than their single-cells (8.2%). • Semi-transparent tandem device with a very high AVT of nearly 50%, in agreement with optical simulation. • The semi-transparent tandem based on PBDT[2F]T:PC 71 BM and PCE10:PC 61 BM blends achieved high PCE of 5.3% and LUE of 2.61%.

Multifunctional CoFe2O4@MXene-AgNWs/Cellulose Nanofiber Composite Films with Asymmetric Layered Architecture for High-Efficiency Electromagnetic Interference Shielding and Remarkable Thermal Management Capability.

Developing high-efficiency electromagnetic interference (EMI) shielding composite films with outstanding flexibility and excellent thermal management capability is vital but challenging for modern integrated electronic devices. Herein, a facile two-step vacuum filtration method was used to fabricate ultrathin, flexible, and multifunctional cellulose nanofiber (CNF)-based composite films with an asymmetric layered architecture. The asymmetric layered structure is composed of a low-conductivity CoFe2O4@MXene/CNF layer and a highly conductive silver nanowires (AgNWs)/CNF layer. Benefiting from the rational placement of the impedance matching layer and shielding layer, as well as the synergistic effect of electric and magnetic losses, the resultant composite film exhibits an extremely high EMI shielding effectiveness (SE) of 73.3 dB and an average EMI SE of 70.9 dB with low reflected efficiency of 4.9 dB at only 0.1 mm thickness. Sufficiently reliable EMI SE (over 95% reservation) is attained even after suffering from continuous physical deformations and long-term chemical attacks. Moreover, the prepared films exhibit extraordinary flexibility, strong mechanical properties, and satisfactory thermal management capability. This work offers a viable strategy for exploiting high performance EMI shielding films with attractive thermal management capacity, and the resultant films present extensive application potential in aerospace, artificial intelligence, advanced electronics, stealth technology, and the national defense industry, even under harsh environments.