A Simple Strategy towards Highly Conductive Silver‐Nanowire Inks for Screen‐Printed Flexible Transparent Conductive Films and Wearable Energy‐Storage Devices

Abstract

As the most widely used TCFs, indium tin oxide (ITO) can support high transparency (>90%) and low film resistance (<25 Ω sq −1 ). However, the inherent brittleness makes ITO easy to cracking. Meanwhile, conventional sputtering techniques and the limited reserves of indium also result in high material and processing costs. Therefore, it is quite challenging for ITO to adapt to the low-cost, flexible, and wearable applications.Several emerging conductive materials, including metal nanowires, metal grids, graphene, carbon nanotubes, and conductive polymers, have become potential substituents for the fabrication of high-performance TCFs. [12][13][14] Among them, silver nanowires (Ag NWs) have been regarded as the most promising alternative for replacing ITO, because of their good conductivity, high transparency, and especially excellent mechanical flexibility. [15] Comparable or even superior photoelectric properties have been achieved for Ag NW-based TCFs as compared to ITO. [16,17] The commonly used film deposition methods associated with the use of Ag NWs involve spin-coating, rodcoating, dip-coating, spraying techniques, etc. [18][19][20] The limited throughput and abundant material waste are the major challenges toward low-cost and large-scale mass production. It is therefore urgently needed to develop scalable solution processing techniques compatible for manufacturing Ag NW-based TCFs with limited material waste and good cost-effectiveness.Screen printing, as a technique for creating 2D patterns, represents an important step forward for manufacturing highperformance TCFs. [21] However, there exist many crucial challenges for making up printable Ag NW inks, such as complex formulation, environmental hazard (e.g., the use of fluorosurfactant as the binder/additive), and insufficient length of Ag NWs, which would largely limit the practical mass production and the conductivity as well as the flexibility of the resulting TCFs. [22,23] In general, long Ag NWs are preferred for obtaining high-conductive patterns with good flexibility. A high bonding strength between Ag NW patterns and flexible substrates is also critical for achieving stable photoelectric properties under mechanical deformations. Thus, a new type of environmentally friendly printable Ag NW ink with simple formulation, high conductivity, and good compatibility with flexible substrates is highly demanded for manufacturing high-performance Printable silver-nanowire (Ag NW) inks with simple formulation, low cost, and high conductivity are developed and screen printed on flexible poly(ethylene terephthalate) substrates. By using ultralong Ag NWs (≈75 µm in length) as the conductor, the screen-printed Ag NW patterns exhibit exceptional conductivity (up to 8.32 × 10 3 S cm −1 ) and excellent mechanical robustness. Rheological behavior suitable for screen printing is achieved by adjusting the formulation of the inks, which assures neat and smooth screen-printed lines with resolution as high as 100 µm. Uniform and honeycomb-structured Ag NW transparent condu...

All‐Printed Green Micro‐Supercapacitors Based on a Natural‐derived Ionic Liquid for Flexible Transient Electronics

“…Conductive inks have been designed and developed for this purpose, usually based on viscous stable suspensions of conductive nanostructures, such as metallic nanoparticles or nanowires, graphene and conductive polymers. [57] Nevertheless, the conceptual simplicity of this approach encounters with some issues. The employed inks must simultaneously achieve high loading of the conductive species, suspension stability and suitable viscosity, so that the presence of stabilizers, thickeners and additives is often required.…”

Long-term electrically stable silver nanowire composite transparent electrode under high current density

“…Particularly, silver nanowire (AgNW) networks can be fabricated with easy solution process, and exhibit comparable or even better opto-electronic performance compared with traditional indium tin oxide (ITO), showing advantages to other candidates [1]. It has been e ciently integrated into various devices such as solar cells [2], organic light-emitting diodes (OLEDs) [3], lm heaters [4], touch screens [5], sensors [6], and energy electronics [7][8].…”

Fabrication of Screen Printing-Based AgNWs Flexible Transparent Conductive Film with High Stability

“…Zhou and co-workers reported the first fully screen-printed topgated thin-film transistors (TFTs) array on flexible substrates using silver-based conductive inks for source, drain, and gate electrodes [9]. Despite great success being realized in the field of flexible screen-printed electronics, few have successfully developed screen-printable inks with high stability and conductivity for wearable electronic applications [26][27][28]. Therefore, many eventful challenges still remain in the development of high-quality screen printable inks for TCFs.…”