Continuous Patterning of Silver Nanowire-Polyvinylpyrrolidone Composite Transparent Conductive Film by a Roll-to-Roll Selective Calendering Process

The roll-to-roll (R2R) continuous patterning of silver nanowire-polyvinylpyrrolidone (Ag NW-PVP) composite transparent conductive film (cTCF) is demonstrated in this work by means of slot-die coating followed by selective calendering. The Ag NWs were synthesized by the polyol method, and adequately washed to leave an appropriate amount of PVP to act as a capping agent and dispersant. The as-coated Ag NW-PVP composite film had low electronic conductivity due to the lack of percolation path, which was greatly improved by the calendering process. Moreover, the dispersion of Ag NWs was analyzed with addition of PVP in terms of density and molecular weight. The excellent dispersion led to uniform distribution of Ag NWs in a cTCF. The continuous patterning was conducted using an embossed pattern roll to perform selective calendering. To evaluate the capability of the calendering process, various line widths and spacing patterns were investigated. The minimum pattern dimensions achievable were determined to be a line width of 0.1 mm and a line spacing of 1 mm. Finally, continuous patterning using selective calendering was applied to the fabrication of a flexible heater and a resistive touch sensing panel as flexible electronic devices to demonstrate its versatility.

Superhydrophobicity and conductivity of polyester-conductive fabrics using alkaline hydrolysis

A superhydrophobic conductive fabric is developed to solve the problem of functional deterioration due to oxidation by air and water through alkaline hydrolysis and hydrophobic coating.

Preparation of a multifunctional silver nanoparticles polylactic acid food packaging film using mango peel extract

As high-efficiency, safe, and low-drug resistant antibacterial agents, silver nanoparticles (AgNPs) have been widely applied in food and biomedicine. AgNPs was prepared using mango peel extract (MPE) as green and cheap reducing agent and stabilizer. In addition, a novel of preservative film material was developed with polylactic acid (PLA) as protective and substrate. AgNPs was characterized by XPS, XRD and TEM, and the size of AgNPs were in the range of 2.5-6.5 nm. The addition of AgNPs improved the mechanical properties of the film and its barrier ability to water vapor and oxygen. The film exhibited excellent antibacterial properties, and the inhibition rate against Escherichia coli and Staphylococcus aureus were above 95%. Furthermore, in terms of safety, the silver migration and cytotoxicity of the film met the relevant standards, and the shelf life of strawberries was significantly extended.

Highly stabilized flexible transparent capacitive photodetector based on silver nanowire/graphene hybrid electrodes

The need for photodetectors in various fields has gradually emerged, and several studies in this area are therefore being conducted. For photodetectors to be used in various environments, their transparency, flexibility, and durability must be ensured. However, the development of flexible photodetectors based on the current measurement techniques of conventional photodetectors has been difficult owing to the limitations of semiconductor materials. In this study, a new type of flexible and transparent capacitive photodetector was fabricated to address the shortcomings of conventional photodetectors. In addition, by introducing graphene electrodes to a new type of manufactured photodetector, devices with excellent overall chemical, thermal, and mechanical durability have been developed. Compared to photodetectors based on pristine Ag nanowire (AgNW) electrodes, AgNW/graphene hybrid electrode-based photodetectors exhibit a 20% higher photosensitivity. Also, the hybrid AgNW/graphene electrode on the dielectric layer exhibited low sheet resistance (~ 8 Ω/sq) and relatively high transmittance (~ 45%).

Recycling silver nanoparticle debris from laser ablation of silver nanowire in liquid media toward minimum material waste

As silver nanowires (Ag NWs) are usually manufactured by chemical synthesis, a patterning process is needed to use them as functional devices. Pulsed laser ablation is a promising Ag NW patterning process because it is a simple and inexpensive procedure. However, this process has a disadvantage in that target materials are wasted owing to the subtractive nature of the process involving the removal of unnecessary materials, and large quantities of raw materials are required. In this study, we report a minimum-waste laser patterning process utilizing silver nanoparticle (Ag NP) debris obtained through laser ablation of Ag NWs in liquid media. Since the generated Ag NPs can be used for several applications, wastage of Ag NWs, which is inevitable in conventional laser patterning processes, is dramatically reduced. In addition, electrophoretic deposition of the recycled Ag NPs onto non-ablated Ag NWs allows easy fabrication of junction-enhanced Ag NWs from the deposited Ag NPs. The unique advantage of this method lies in using recycled Ag NPs as building materials, eliminating the additional cost of junction welding Ag NWs. These fabricated Ag NW substrates could be utilized as transparent heaters and stretchable TCEs, thereby validating the effectiveness of the proposed process.

Printed fabric heater based on Ag nanowire/carbon nanotube composites

The increasing demand for smart fabrics has inspired extensive research in the field of nanomaterial-based wearable heaters. However, existing stretchable heaters employ polymer substrates, and hence require additional substrate-fabric bonding that can result in high thermal contact resistance. Moreover, currently used stretchable fabric heaters suffer from high sheet resistance and require complex fabrication processes. In addition, conventional fabrication methods do not allow for patternability, thus hindering the fabrication of wearable heaters with diverse designs. Herein, we propose an improved spray coating method well suited for the preparation of patternable heaters on commercial fabrics, combining the structural stability of carbon nanotubes with the high electrical conductivity of Ag nanowires to fabricate a stretchable fabric heater with excellent mechanical (stretchability ≈ 50%) and electrical (sheet resistance ≈ 22 Ω sq^-1) properties. The fabricated wearable heater reaches typical operating temperatures of 35 °C-55 °C at a low driving voltage of 3-5 V with a proper surface power density of 26.6-72.2 [Formula: see text] (heater area: [Formula: see text]) and maintains a stable heating temperature for more than 30 h. This heater shows a stable performance even when folded or rolled, thus being well suited for the practical wearable applications.

Enhanced Efficiencies of Perovskite Solar Cells by Incorporating Silver Nanowires into the Hole Transport Layer

In this study, we incorporated silver nanowires (AgNWs) into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a hole transport layer (HTL) for inverted perovskite solar cells (PVSCs). The effect of AgNW incorporation on the perovskite crystallization, charge transfer, and power conversion efficiency (PCE) of PVSCs were analyzed and discussed. Compared with neat PEDOT:PSS HTL, incorporation of few AgNWs into PEDOT:PSS can significantly enhance the PCE by 25%. However, the AgNW incorporation may result in performance overestimation due to the lateral charge transfer. The corrosion of AgNWs with a perovskite layer was discussed. Too much AgNW incorporation may lead to defects on the interface between the HTL and the perovskite layer. An extra PEDOT:PSS layer over the pristine PEDOT:PSS-AgNW layer can prevent AgNWs from corrosion by iodide ions.

Highly oxidation-resistant silver nanowires by C x F y polymers using plasma treatment

We demonstrate plasma-treated Ag nanowires (NWs) as flexible transparent electrode materials with enhanced long-term stability against oxidation even in a high humidity environment (80% humidity, 20 °C). Through a simple fluorocarbon (C₄F₈ or C₄F₆) plasma treatment method, a C _x F _y protective polymer was sufficiently cross-linked and attached on the surface of the AgNWs strongly and uniformly. Even though C₄F₈ and C₄F₆ activate differently on the AgNW surface due to the different dissociated radicals formed in the plasma, it was found that the C _x F _y protective polymers obtained by both chemicals work similarly as a protective layer for transparent conductive electrodes; a nearly constant sheet resistance ratio (R _s/R _o) of 1.6 was found for AgNWs treated with C₄F₈ and C₄F₆ plasmas, while the AgNWs without the plasma treatment exhibited a ratio of 176.2 after 36 days in a harsh environment. It is believed that the fluorocarbon plasma treatment can be used as a key method for ensuring long-term oxidation stability in numerous electronic applications including flexible solar cells utilizing various types of metallic nanowires.

Coating-free, air-stable silver nanowires for high-performance transparent conductive film

Silver nanowire (Ag NW) based films are considered as a promising alternative for traditional indium tin oxide but still suffer from some limitations, including insufficient conductivity, transparency and environmental instability. We here report a novel etching synthesis strategy to improve the performance of Ag NW films. Different from the traditional methods to synthesize high aspect ratios of NWs or employ electrically conductive coatings, we find it effective to reduce the high-reactivity defects of NWs for optimizing the comprehensive performance of Ag NW films. In this strategy etching can suppress the generation of high-reactivity defects and meanwhile the etching growth of NWs can be accomplished in an uneven ligand distribution environment. The resulting Ag NWs are uniformly straight with a sharp-edged structure. The transparent conductive film obtained exhibits simultaneous improvements in electrical conductivity, transparency and air stability. Even after exposure in air for 200 days and no protective coatings, the film can still meet the highest requirement of practical applications, with a figure of merit 361 (i.e., FoM > 350). These results not only demonstrate the importance of defect control in the synthesis of Ag NWs, but also pave a way for further optimizing the performance of Ag NW-based films.

One-step synthesis of ultra-long silver nanowires of over 100 μm and their application in flexible transparent conductive films

Silver nanowires (AgNWs) >100 μm and even 160 μm in length have been synthesized using a facile and rationally designed solvothermal method by heating preservation at 150 °C. The length of the as-synthesized AgNWs is over 4–5 times longer than those previously reported, while the diameter range is from 40 nm to 85 nm. A transparent conducting film (TCF) was fabricated using hydroxyethyl cellulose (HEC) as the adhesive polymer, and it achieved exceptional and stable optoelectronic properties. Its low sheet resistance of ∼19 Ω sq⁻¹ (on polyethylene terephthalate, PET) and high optical transmittance of ∼88% are superior to that of expensive indium tin oxide (ITO) films. More significantly, the AgNW network demonstrates excellent adhesion to PET substrates. This study indicates that ultra-long silver nanowires can serve as an alternative to ITO, which also demonstrates its potential application in flexible electronic devices.

Ultra-long silver nanowires (100–160 μm) were applied in flexible transparent conductive films showing low sheet resistance and high optical transmittance.

Cold Isostatic-Pressured Silver Nanowire Electrodes for Flexible Organic Solar Cells via Room-Temperature Processes

Transparent conducting electrodes (TCEs) are considered to be an essential structural component of flexible organic solar cells (FOSCs). Silver nanowire (AgNW) electrodes are widely used as TCEs owing to their excellent electrical and optical properties. The fabrication of AgNW electrodes has faced challenges in terms of forming large uniform interconnected networks so that high conductivity and reproducibility can be achieved. In this study, a simple method for creating an intimate contact between AgNWs that uses cold isostatic pressing (CIP) is demonstrated. This method increases the conductivity of the AgNW electrodes, which enables the fabrication of high-efficiency inverted FOSCs that have a power conversion efficiency of 8.75% on flexible polyethylene terephthalate with no short circuiting occurring as the CIP process minimizes the surface roughness of the AgNW electrode. This allows to achieve 100% manufacturing yield of FOSCs. Furthermore, these highly efficient FOSCs are proven to only be 2.4% less efficient even for an extreme bending radius of R ≈ 1.5 mm, compared with initial efficiency.

Flexible Transparent Conductive Films with High Performance and Reliability Using Hybrid Structures of Continuous Metal Nanofiber Networks for Flexible Optoelectronics

We report an Ag nanofiber-embedded glass-fabric reinforced hybrimer (AgNF-GFRHybrimer) composite film as a reliable and high-performance flexible transparent conducting film. The continuous AgNF network provides superior optoelectronic properties of the composite film by minimizing transmission loss and junction resistance. In addition, the excellent thermal/chemical stability and mechanical durability of the GFRHybrimer matrix provides enhanced mechanical durability and reliability of the final AgNF-GFRHybrimer composite film. To demonstrate the availability of our AgNF-GFRHybrimer composite as a transparent conducting film, we fabricated a flexible organic light-emitting diode (OLED) device on the AgNF-GFRHybrimer film; the OLED showed stable operation during a flexing.

Facile synthesis of Ag@Au core–sheath nanowires with greatly improved stability against oxidation

Ag@Au core–sheath nanowires showed identical morphology and optical properties to Ag nanowires, but with improved stability against oxidation.

Enhanced Optoelectronic Conversion Efficiency of CdSe/ZnS Quantum Dot/Graphene/Silver Nanowire Hybrid Thin Films

In this study, we prepared the reduced graphene oxide (rGO)-CdSe/ZnS quantum dots (QDs) hybrid films on a three-layer scaffold that the QD layer was sandwiched between the two rGO layers. The photocurrent was induced by virtue of the facts that the rGO quenched the photoluminescence of QDs and transferred the excited energy. The quenching mechanism was attributed to the surface energy transfer, supported in our experimental results. We found that the optoelectronic conversion efficiency of the hybrid films can be significantly improved by incorporating the silver nanowires (AgNWs) into the QD layer. Upon increasing AgNW content, the photocurrent density increased from 22.1 to 80.3 μA cm(-2), reaching a near 3.6-fold enhancement compared to the pristine rGO-QD hybrid films. According to the analyses of photoluminescence spectra, shape effect, and electrochemical impedance spectra, the enhancement on the optoelectronic conversion efficiency arise mainly from the strong quenching ability of silver and the rapid electron transfer of AgNWs.

Highly Conductive, Air-Stable Silver Nanowire@Iongel Composite Films toward Flexible Transparent Electrodes

A new type of flexible transparent electrode is designed, by employing wettability-induced selective electroless-welding of silver nanowire (AgNW) networks, together with a thin conductive iongel as the protective layer. The obtained electrode exhibits high optical transmittance, and excellent air-stability without sacrificing conductivity.

Flexible conducting electrodes based on an embedded double-layer structure of gold ribbons and silver nanowires

A hierarchical double-layer structure of gold ribbons and silver nanowires is fabricated for a flexible electronic conductor that can sensitively detect various deformation modes.

Graphene oxide/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate layers on silver nanowire working electrodes enhance the power conversion efficiencies of dye-sensitized solar cells in a low temperature process

Graphene oxide/PEDOT:PSS hybrid isolates silver nanowires to makes the silver nanowire working electrodes feasible for dye-sensitized solar cells.

Influence of polyvinylpyrrolidone (PVP) capping layer on silver nanowire networks: theoretical and experimental studies

By adjusting the polyvinylpyrrolidone (PVP) capping layer thickness on silver nanowire networks, improved electrical and optical properties were obtained, which was confirmed both experimentally and theoretically (Molecular dynamics and Monte Carlo simulations).

Highly Reliable Silver Nanowire Transparent Electrode Employing Selectively Patterned Barrier Shaped by Self-Masked Photolithography

The transparent electrode based on silver nanowire (AgNW) networks is one promising alternative of indium tin oxide film in particular for advanced flexible and printable electronics. However, the widespread application of AgNW electrode is hindered by its poor long-term reliability. Although the reliability can be improved by applying traditional overcoating layer or the core-shell structure, the transmittance or conductivity is inevitably undermined. In this paper, a novel patterned barrier of photoresist in situ assembled on the nanowire surface realized the reliability enhancement by simply employing AgNWs themselves as the mask in the photolithography process. The patterned barrier selectively covered the nanowires, while keeping the high transmittance and conductivity unchanged and improving the adhesion of AgNW networks on substrate. After 720 h storage in 85 °C/85% relative humidity (RH) environment, the resistance of electrode with patterned barrier only increased by 0.72 times. This study proposes a new way, i.e., the in situ patterned barrier containing light-sensitive substance, to selectively protect AgNW networks, which can be expanded to various metallic networks including nanowires, nanorods, nanocables, electrospun nanofibers, and so on.

Functionalization of Silver Nanowires Surface using Ag-C Bonds in a Sequential Reductive Method

Silver nanowires (Ag-NW) assembled in interdigitated webs have shown an applicative potential as transparent and conducting electrodes. However, upon integration in practical device designs, the presence of silver oxide, which instantaneously forms on the Ag-NW surfaces in ambient conditions, is unwanted. Here, we report on the functionalization of Ag-NWs with 4-nitrophenyl moieties through A-C bonds using a versatile two step reduction process, i.e., ascorbate reduction combined electrografting. We show that 40% of the Ag atop sites were terminated and provide high surface stability toward oxidation for more than 2 months while keeping the same intrinsic conductivity as in bulk silver.

Direct printed silver nanowire thin film patterns for flexible transparent heaters with temperature gradients

Silver nanowire thin film patterns are printed precisely to form transparent heaters with uniform or gradient temperature distributions.

Salt-mediated polyol synthesis of silver nanowires in a continuous-flow tubular reactor

Silver nanowires were successfully synthesized by a polyol reduction method in a continuous-flow reactor with a yield of 2 g h⁻¹.

Synthesis of Ag–Ni core–shell nanowires and their application in anisotropic transparent conductive films

Transparent conductive films with high anisotropic conductivity ratio (>10⁵) were prepared from Ag–Ni core–shell nanowires by applying a magnetic field.