Silver Nanowires Research Articles

Improved preparation of AgNW film and its application in flexible counter electrodes of dye-sensitized and perovskite solar cells

Silver nanowire (AgNW) has been wildly used to prepare flexible conducting substrate of electronic and optoelectronic devices. By coating a layer of carbon onto a polymer/AgNW substrate, a counter electrode (CE) was obtained and it offers the advantages of high flexibility, light weight, low cost, simple fabrication, and operating efficiently in dye-sensitized solar cells (DSSCs) and perovskite solar cells (PSCs). By modifying the traditional unidirectional roll-coating process of AgNW to cross-directional coating, the morphology and distribution of the AgNW network was improved, which led to increased transmittance and electroconductivity, and subsequently improved cell efficiency of DSSCs and PSCs. The performance of the CEs and solar cells was further promoted by optimized fabrication process of the carbon layer. The as-prepared flexible CEs achieved great enhancement of cell efficiencies, and maximum power conversion efficiencies of 5.17% and 14.32% were obtained by DSSCs and PSCs, respectively.

Highly sensitive volatile organic compounds monitoring enabling by silver-nanowire@metal–organic frameworks core-shell heterostructure

Metal–organic frameworks (MOFs) hold great promise as advanced chemical sensing materials due to their high surface area and tunable surface chemistry. However, due to the inherent conductivity, building a highly sensitive MOFs-based gas sensor for real-time monitoring hazardous gas operated at room temperature (RT) is still a huge challenge. Herein, an in-situ anchoring strategy is proposed to construct a 1D-0D core-shell heterostructure by integrating silver nanowires (AgNWs) with highly conductivity and Zn-MOF with high specific surface area. The incorporation of AgNWs establishes a highly conductive network architecture to facilitate rapid charge transport while preventing the Zn-MOF nanoparticles from agglomeration, ensuring an effective transmission highway for target gas molecules. Meanwhile, the Zn-MOF nanoparticles induce remarkable absorption capacity and contribute high gas response. By strategically amalgamating the inherent distinctive virtues of the individual components and capitalizing on the synergistic benefits arising from the composite, the sensors hinged upon the refined AgNWs@Zn-MOF (A@Z) heterostructure unveiled remarkable response value of 27 to 20 ppm ethanol at RT, accompanied by a low detection limit of 1 ppm. Moreover, the A@Z sensor further showcases superior selectivity and repeatability. This work offers a fresh standpoint for the fabrication of MOF-based heterostructures, fostering advancements in diverse applications.

Flexible Transparent Films of Oriented Silver Nanowires for a Stretchable Strain Sensor.

The potential applications of stretchable strain sensors in wearable electronics have garnered significant attention. However, developing susceptible stretchable strain sensors for practical applications still poses a considerable challenge. The present study introduces a stretchable strain sensor that utilizes silver nanowires (AgNWs) embedded into a polydimethylsiloxane (PDMS) substrate. The AgNWs have high flexibility and electrical conductivity. A stretchable AgNW/Pat-PDMS conductive film was prepared by arranging nanowires on the surface of PDMS using a simple rod coating method. Depending on the orientation angle, the overlap area between nanowires varies, resulting in different levels of separation under a given strain. Due to the separation of the nanowire and the change in current path geometry, the variation in strain resistance of the sensor can be primarily attributed to these factors. Therefore, precision in strain regulation can be adjusted by altering the angle θ (0°, 60°, or 90°) of the nanowire. At the same time, the stability of the AgNW/Pattern-PDMS (AgNW/Pat-PDMS) conductive film application was verified by preparing a sandwich structure PDMS/AgNW/Pat-PDMS stretchable strain sensor. The sensor exhibited high sensitivity within the operating sensing range (gauge factor (GF) of 15 within ~120% strain), superior durability (20,000 bending cycles and 5000 stretching cycles), and excellent response toward bending.

Ultrathin and highly flexible layered silver nanowires/carboxymethyl cellulose nanofiber nanocomposite films for electromagnetic interference shielding

Lightweight, flexible, efficient and easy-to-manufacture electromagnetic interference (EMI) shielding materials are in urgent demand in the communications industry, artificial intelligence and wearable electronics. Based on the large size difference between one-dimensional carboxymethyl cellulose nanofibers (CMC) and large-diameter silver nanowires (AgNWs), layered AgNWs/CMC nanocomposite films with large effective thickness, and high conductivity were first prepared by a simple one-step vacuum filtration self-assembly technique. The unique layered structure of the AgNWs/CMC nanocomposite film significantly enhances the conductive pathways within the film, endowing it excellent EMI shielding performance. The results show that the conductivity of the ultra-thin film with a thickness of 20 μm is 3.72 × 106 S/m, and the EMI SE in the X-band is 87.7 dB, which can effectively shield electromagnetic signals in mobile communications. Furthermore, the AgNWs/CMCs nanocomposite films exhibit excellent thermal management performance, which can be heated to 100–180 °C within 10 s at a low voltage of 1.5 V. In particular, this nanocomposite film with a new layered structure provides a noval preparation idea for future EMI shielding materials and wearable heating devices.

Multifunctional porous soft composites for bimodal wearable cardiac monitors

AbstractWearable heart monitors are crucial for early diagnosis and treatment of heart diseases in non‐clinical settings. However, their long‐term applications require skin‐interfaced materials that are ultrasoft, breathable, antibacterial, and possess robust, enduring on‐skin adherence—features that remain elusive. Here, we have developed multifunctional porous soft composites that meet all these criteria for skin‐interfaced bimodal cardiac monitoring. The composite consists of a bilayer structure featuring phase‐separated porous elastomer and slot‐die‐coated biogel. The porous elastomer ensures ultrasoftness, breathability, ease of handling, and mechanical integrity, while the biogel enables long‐term on‐skin adherence. Additionally, we incorporated ε‐polylysine in the biogel to offer antibacterial properties. Also, the conductive biogel embedded with silver nanowires was developed for use in electrocardiogram sensors to reduce contact impedance and ensure high‐fidelity recordings. Furthermore, we assembled a bimodal wearable cardiac monitoring system that demonstrates high‐fidelity recordings of both cardiac electrical (electrocardiogram) and mechanical (seismocardiogram) signals over a 14‐day testing period.

Patterned flexible Silver Nanowire/2D MXene transparent conducting electrode for organic light-emitting diodes

With the advent of numerous flexible optoelectronic applications, the importance of flexible and stable transparent conducting electrodes (TCEs) has been considerable. The conventional silver nanowire (AgNW) is a promising candidate as TCEs due to its decent opto-electrical properties and solution processibility. However, AgNW's high surface root mean square (RMS) roughness, relatively high sheet resistance, and low work function (∼4.5 eV) limit the usage for display applications. In this work, we design and study the AgNW and MXene (Ti3C2Tx) hybrid TCEs for flexible organic light-emitting diodes (OLEDs) to enhance the optoelectrical properties and the hole injection within the device. Experiment investigation is carried out via an application of AgNW/MXene (AgMX) hybrid TCEs as a bottom electrode for OLEDs devices in which the photolithography process and lift-off technique are employed for such fabrication. The hybrid TCEs indicate high optical transparency (86.8 % at 550 nm) and low sheet resistance (24.1 Ω/cm2) as well as improved surface morphology, enabling the efficient OLEDs operation. The optimized OLEDs exhibit a clear and stable red electroluminescence (EL) peak with an improved maximum external quantum efficiency (EQE) and luminance of 5.25 % and 3421.7 cd/m2, respectively. Furthermore, the hybrid TCEs are readily formed on poly(ethylene terephthalate) (PET) substrate, showing high durability under the bending test up to 100,000 cycles. The results demonstrate that adopting AgMX TCEs is a reasonable strategy for obtaining proper flexible optoelectronic devices.

Fabrication of PHFPO Surface-Modified Conductive AgNWs/PNAGA Hydrogels with Enhanced Water Retention Capacity toward Highly Sensitive Strain Sensors.

Conductive hydrogels, characterized by their unique features of flexibility, biocompatibility, electrical conductivity, and responsiveness to environmental stimuli, have emerged as promising materials for sensitive strain sensors. In this study, a facile strategy to prepare highly conductive hydrogels is reported. Through rational structural and synthetic design, silver nanowires (AgNWs) are incorporated into poly(N-acryloyl glycinamide) (PNAGA) hydrogels, achieving high electrical conductivity (up to 0.88 S m-1), significantly enhanced mechanical properties, and elevated deformative sensitivity. Furthermore, surface modification with polyhexafluoropropylene oxide (PHFPO) has substantially improved the water retention capacity and dressing comfort of this hydrogel material. Based on the above merits, these hydrogels are employed to fabricate highly sensitive wearable strain sensors which can detect and interpret subtle hand and finger movements and enable precise control of machine interfaces. The AgNWs/PNAGA based strain sensors can effectively sense finger motion, enabling the control of robotic fingers to replicate the human hand's gestures. In addition, the high deformative sensitivity and elevated water retention performance of the hydrogels makes them suitable for flow sensing. These conceptual applications demonstrate the potential of this conductive hydrogel in high-performance strain sensors in the future.

AC‐Driven Plasmon Waveguide Integrated Electroluminescent Device

AbstractPhotonic elements have greater information‐carrying capabilities compared to electronic components, making the development of high‐speed, chip‐integrated optical communication devices crucial for addressing interconnect bottlenecks in high‐speed computing systems. Significant progress has been made in studying light sources and their transmission. Despite these advancements, achieving a satisfactory integration of photonic circuits with both light source and optical waveguide functions has remained a challenge. Here, a silver nanowire (AgNW) waveguide‐integrated light source is demonstrated driven by alternating current (AC) voltage. AgNW functions as both the electrode and waveguide to simplify the device structure, and the 2D transition metal dichalcogenides (TMDs) monolayer acts as the gain media in device. The electroluminescence (EL) can be tunably modulated via adjusting the frequency and voltage of the AC in this device, and it is also successfully coupled into the waveguide with its transmission distance up to 25 µm. The experiments of electroluminescence and waveguide transmission of different materials and their interlayer excitons have made a preliminary exploration of multiple wavelength transmission. It provides a new research platform forward in the development of chip‐integrated optical communication devices, thereby hopefully addressing the interconnect bottleneck and unlocking the potential for enhanced performance and efficiency in high‐speed computing systems.

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

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

Experimental Proof of Concept for Using Hybrid Paper Based on Silver Nanowires, Cellulose and Poly(dimethylsiloxane) in Systems Dynamic Analysis and Healthcare Applications

The research results and evaluation of the applicability of the original composition of hybrid paper based on silver nanowires (AgNWs), cellulose pulp (CP), and carbon nanotubes (CNTs) are presented and discussed. The material tested was used to manufacture sensors for mechanical deformation resulting from external influences or related to human activity interactions. The sensors were fabricated using an AgNWs + CP suspension and additives by the vacuum filtration method. The substrate obtained was machined and then laminated with a layer of poly(dimethylsiloxane) (PDMS). The recorded responses to selected types of imposed mechanical interactions in the form of changes in the relative resistance of the sensor throughout the tests showed a close cause-and-effect relationship. The response of the tested systems when applying an alternating magnetic field was also observed. The results indicate that the proposed solutions can find application in the monitoring of mechanical interactions resulting from the dynamic behavior of physical objects, as well as derived from selected human vital functions.

Flexible piezo-resistive strain sensors based on silver nanowires and graphene nanoplatelets reinforced polydimethylsiloxane for human motion detection

In this work, flexible sensors consisting of silver nanowires (Ag NWs), graphene nanoplatelets (GNP), and polydimethylsiloxane (PDMS) are fabricated using a straightforward, affordable, and simple solution processing technique. The performance of the flexible devices with structure Ag NWs/GNP/PDMS has been studied, in which Ag NWs/GNP-based ternary conductive hybrid nanocomposites are used as acting sensing layers. The diameter of Ag NWs and flake size of GNPs were determined to be 80–160 nm and 30–190 nm, respectively. The Raman peaks of Ag NWs within the composite are appeared at 392.08, 482.12, 543.7, 679.42 and 854.87 cm−1. The peaks existing at 1317.68, 1565.36 and 2639.75 cm−1 represent the D, G and 2D bands of GNP, respectively. The gauge factor is determined to be 865 within the strain range of 0–71 %. The response and recovery time of the fabricated sensor are calculated to be 101 and 110 ms, respectively. The sensor exhibits a minimum detectable limit of 0.8 %. The sensor shows a highly reproducible response for more than 1150 bending and stretching cycles suggesting long-term durability which may be attributed to the Ag NWs/GNPs conductive networks for significant strengthening the hybridisation with PDMS. Different human activities, viz. finger bending, stretching, mouse/mobile screen scrolling, swallowing through the throat and drinking are monitored by the fabricated Ag NWs/GNP/PDMS-based flexible strain sensor, indicating promising applications in wearable electronics.

Coordinating the pore size of paper substrates and aspect ratio of silver nanowires to improve printed electronics

The internet of things is advancing toward a world of ubiquitous electronic devices, composed in large part of low-cost printed electronics (PE) such as sensors. PE typically use plastic substrates, such as polyethylene terephthalate (PET), but these materials are not biodegradable. The proliferation of PE devices and their degradation to form micro- and nanoplastics pose significant environmental hazards. Paper is a promising substrate to replace PET for greener PE due to its recyclability, affordability, and compatibility with many printing processes. However, the porous cellulosic structure of paper can be an obstacle when trying to print active inks due to wicking of the ink into the paper pores, which disperses the functional ink and negatively impacts electronic performance. Filling the pores of paper with a polymer to planarize the surface is a commonly used remedy, although this approach can compromise recyclability. Here, we present an approach to manage the dispersion of silver nanowires, a widely used and printable 1D nanomaterial ink, in paper substrates. We deposit solutions of short (20–30 μms) and long (100–200 μms) silver nanowires onto various graded filter papers that differ in pore size and examine the trends in wicking distance, wicking speed, and electrical properties. We show that with careful selection of AgNW length and the pore size of the paper, it is possible to control the lateral spreading of the ink and minimize the concentration of the AgNWs needed to achieve a specific electrical performance.

Highly Transmittance, Mechanical, Thermally Stable Silver Nanowires Network Using ZnO Nanoparticles.

This research addresses challenges with silver nanowires (Ag NWs) as transparent conductive electrodes (TCEs) and heaters in commercial devices. Here, zinc oxide nanoparticles (ZnO NPs) are first reported as a protective layer for Ag NWs. Multi-physics simulations confirm enhanced thermal stability due to improved heat dissipation, temperature distribution, and thermal conductivity from ZnO. When Ag NWs are surrounded by air, heat transfers mainly through convection and radiation because of air's low conduction coefficient. Encasing Ag NWs in ZnO enhances heat transfer to the ZnO surface, accelerating cooling and dissipating more heat into the atmosphere via convection. The results show composite's efficiency in the Joule effect, maintaining a consistent temperature of 78°C for 700s after 500 bending cycles, a significant improvement over Ag NWs operating for only 5s at 80°C. Additionally, the composite film exhibited exceptional performance, including a sheet resistance of 9.8Ωsq-1 and an optical transmittance of 96.96 %, outperforming Ag NWs, which have a sheet resistance of 12Ωsq-1 and a transmittance of 94.11%. The combination of enhanced electrical, thermal, and mechanical stability, along with impressive optical properties, makes Ag NWs/ZnO NPs a promising candidate for transparent conductive electrode materials in various applications.

Transparent, Bioelectronic, Natural Polymer AgNW Nanocomposites Inspired by Caviar

AbstractRecent breakthroughs in bioelectronic devices have stemmed from developments involving nanocomposites. Sepsis, preeclampsia, vascular dementia, and heart disease are serious conditions that will benefit from the continuous monitoring of pulse pressure (PP) and temperature (T) to improve medical insights and care. However, current clinical instruments are bulky, and lacking discreetness, while nanocomposites currently lack measurement accuracy. A thin (<1 mm) electronic skin (e‐skin) is developed utilizing nanocomposite micro‐caviar (MC), diameter (D) ≈290 µm, based on confined silver nanowire (AgNW) networks and food‐grade brown seaweed (BS). MCs are virtually invisible (transmittance >99%) and extremely electromechanically sensitive (gauge factor, G >200). In addition to a considerable temperature coefficient of resistance (TCR) of 4.58 ± 0.95% °C−1 and excellent signal stability, skin‐interfaced devices measured cuff‐less PP and skin T with an accuracy conducive to clinical instruments.

Metal assisted chemical etching derived reusable and scalable production of large-area Ag nanowire-based flexible transparent electrodes for electrochromic Zn-ion battery

To advance polydimethylsiloxane (PDMS)-supported silver nanowires (Ag NWs) based flexible and transparent electrodes (AgNWs/PDMS), innovative patterning techniques are essential for enabling large-area fabrication with cost-effective reusability features. Here, we introduce a metal assisted chemical etching (MACE) protocol for patterning Si wafers, allowing the repetitive fabrication of large-sized AgNWs/PDMS electrodes with controlled penetration depth for the first time. To the best of our knowledge, MACE technology has not previously been employed for fabricating AgNWs/PDMS electrodes. Through the careful selection of etchant, etching time, and suitably doped Si wafers (n-type and p-type), the resulting AgNWs/PDMS electrodes offer favorable optical, electrical and flexiblity characteristics. The electrodes deliver a sheet resistance of 18 Ω‧sq−1 at 88 % transmittance (550 nm) while retaining 93.18 % transmittance with only a 7 Ω‧sq−1 resistance increase after 10,000 bending cycles (3 mm). The penetration depth control offered by this method ensures impressive mechanical durability without additional post-processing. Moreover, the etched Si wafers can be reused multiple times, reducing overall costs. The sizes of AgNWs/PDMS electrodes produced using this method depend entirely on the Si wafer size, allowing scalability by employing larger wafers. As a proof-of-concept, we also demonstrate the fabrication of a robust, flexible, electrochromic zinc ion battery utilizing the AgNWs/PDMS electrodes developed in this study.

Enhancing Thermal Conductivity of Phase Change Materials Using Nanomaterials and its Effectiveness in Cooling Solar Cells

The latent heat storage system is considered the most promising technology in thermal energy storage (TES) because of its many advantages. This technique uses phase change material (PCM) as a TES medium. However, the low thermal conductivity (TC) of PCM is the major drawback of the system. Previous studies have shown that the addition of nanomaterials to PCM generally increases its TC. On the other hand, researchers tend to study the possibility of using enhanced PCM to cool solar cells. In fact, raising the solar cell’s operating temperature negatively impacts its efficiency. This problem is considered one of the biggest problems in solar energy systems, and researchers are still working to solve it. This paper focused on the possibility of enhancing the TC of paraffin by adding different shapes of silver nanomaterials to it (silver nanoparticles, silver nanowires and nanohybrid with silver nanoparticles and silver nanowires). Nanomaterials were added at volume fractions of 0.5% and 1%. Then, the study examined the ability to use this improved material to reduce the temperature of solar cells. We used the “Solidworks” program to create a 3D system, and then we used the “Ansys Fluent” software to simulate five cases; PV without PCM, PV with PCM, PV with PCM enhanced by nanoparticles, PV with PCM enhanced by nanowires, PV with PCM enhanced by nanohybrid (a mixture of nanoparticles and nanowires). The results show that using PCM enhanced by nanowire at a volume fraction of 0.5% gave the best results in decreasing the temperature of PV. The average temperature of PV declined by 14.9[Formula: see text]. In addition, the efficiency of PV rose by about 7.6%. Followed by using PCM enhanced by nanoparticles at a volume fraction of 1%. The average temperature of PV declined by 12.9[Formula: see text]. Moreover, the efficiency of PV rose by about 6.6%.

A method for batch modification of neural microelectrodes via removable electrical interconnection

The modification on the surface of neural electrodes is critical for improving the signal-to-noise ratio (SNR) and prolonging the recording time. Electrodeposition is a simple and practical modification technique that has been applied to a wide range of materials. However, the traditional electrodeposition becomes increasingly inefficient as the electrode channels dramatically increase since it is performed one by one. Short-circuiting multiple electrode sites and then modifying them together can significantly improve efficiency. But it remains a significant challenge to reliably connect hundreds or thousands of electrodes before the electrodeposition and to safely and easily disconnect them afterward. An approach of removable electrical connection was adopted to solve this problem. A kind of silver nanowire (AgNW) conductive ink with water as the dispersion was chosen to connect all the electrodes for simultaneous electrodeposition temporarily electrically. This approach makes the electrodeposition process convenient and reliable. Above all, the proposed approach is compatible with a wide range of Multi-electrode arrays (MEAs) fabricated from different materials.

Extremely Stable, Multidirectional, All‐in‐One Piezoelectric Bending Sensor with Cycle up to Million Level

AbstractFlexible bending sensors are crucial components of flexible/wearable electronics. However, their broad application is restricted by their difficulty in sensing different bending directions and, more importantly, their significant output attenuation after long cycles. Herein, a new design of an All‐in‐One piezoelectric bending sensor is proposed, in which double‐deck, cross‐over 3D interdigital microelectrodes (silver nanowires (Ag NWs)) are embedded in a piezoelectric polymer film (poly(vinylidene fluoride‐trifluoroethylene (P(VDF‐TrFE))). The piezoelectric film with the embedded 3D microelectrodes exhibits a high anisotropy coefficient ( > 1) based on dual piezoelectric modes (d31 and d33), which renders it more sensitive to different bending directions. More importantly, the homogeneous interconnected interface and heterogeneous microinterlocked interface formed inside the sensor significantly enhance its interface mechanical properties, with at least a tensile strength of 51 MPa, a shear strength of 28 MPa, and an interfacial toughness of 300 J m−2, which are nearly two orders of magnitude greater than those of conventional sandwich architectures. The prepared All‐in‐One sensor shows an extremely stable piezoelectric output over as many as 16 00 000 bending cycles, which represents a remarkable breakthrough. Furthermore, a single sensor can be used to remotely control the multidirectional motion of a smart car, demonstrating enormous potential in practical applications.

Fabrication of Flexible Transparent Conductive Films via an Energy-Efficient In Situ Chemical Welding and Reinforcement Strategy.

Recently, flexible transparent conductive films composed of metal nanowires have received significant interest, particularly for flexible electronics. However, the high contact resistance among metal nanowires and the weak bonding effect between metal nanowires and substrates often result in films whose conductivity, adhesion, and flexibility fall short of the stringent requirements demanded by real-world uses. We developed a simple method to fabricate high-performance flexible transparent conductive films via successively spin-coating silver nanowires (AgNWs) and acidic silica sol onto the surface of the substrate. Under the capillary force of ethanol and the etching effect of hydrochloric acid, the adjacent AgNWs are induced to chemically weld in situ to form a stable network. The resulting composite film exhibits a sheet resistance of only 8.5 Ω/sq, marking an impressive 80% decrease compared with the pristine AgNW film. Meanwhile, the silica sol acts as a filler, improving light transmittance while further reinforcing the network structure and firmly bonding it to the substrate. Thus, the delamination of the nanowires under bending motion is effectively inhibited, and the resulting film was endowed with resistance remaining below 15 Ω/sq after 3000 bending and 200 tape peeling. The energy-efficient in situ chemical welding and reinforcement method for nanowires provides an innovative strategy for the batch preparation of flexible transparent conductive films.

Ultratough and self‐healable electromagnetic interference shielding materials with sandwiched silver nanowires in polyurethane composite films

AbstractThis study presents a facile self‐healing electromagnetic interference (EMI) shielding composite by sandwiching a layer of silver nanowires (AgNWs) between two layers of self‐healing polyurethane (SPU). The AgNWs layer forms an interconnected conductive network that effectively reflects and absorbs electromagnetic radiation, providing efficient EMI shielding. The SPU layers contribute autonomous healing of mechanical damages and restoring structural integrity and conductive pathways. The composite films exhibit remarkable EMI shielding effectiveness (SE) (up to 64.6 dB), exceptional mechanical toughness (106.4 MJ/m3), and self‐healing capabilities, outperforming conventional shielding materials. The synergy between AgNWs and SPU layers offers lightweight, flexible, tough, and self‐healing properties, making this material highly promising for applications in wearable electronics, aerospace, and automotive industries where durability and long‐term reliability are critical.Highlights Facile fabrication of sandwiched AgNWs layer between SPU films. Sandwiched AgNWs/SPU films with exceptional EMI shielding. AgNWs form conductive networks for efficient EMI shielding. Remarkable mechanical toughness of 106.4 MJ/m3 and self‐healing capability. Potential shielding materials for lightweight, wearable electronics, aerospace.