Metallic Nanowire‐Based Transparent Electrodes for Next Generation Flexible Devices: a Review

Abstract

Transparent electrodes attract intense attention in many technological fields, including optoelectronic devices, transparent film heaters and electromagnetic applications. New generation transparent electrodes are expected to have three main physical properties: high electrical conductivity, high transparency and mechanical flexibility. The most efficient and widely used transparent conducting material is currently indium tin oxide (ITO). However the scarcity of indium associated with ITO's lack of flexibility and the relatively high manufacturing costs have a prompted search into alternative materials. With their outstanding physical properties, metallic nanowire (MNW)-based percolating networks appear to be one of the most promising alternatives to ITO. They also have several other advantages, such as solution-based processing, and are compatible with large area deposition techniques. Estimations of cost of the technology are lower, in particular thanks to the small quantities of nanomaterials needed to reach industrial performance criteria. The present review investigates recent progress on the main applications reported for MNW networks of any sort (silver, copper, gold, core-shell nanowires) and points out some of the most impressive outcomes. Insights into processing MNW into high-performance transparent conducting thin films are also discussed according to each specific application. Finally, strategies for improving both their stability and integration into real devices are presented.

Degradation mechanisms of silver nanowire electrodes under ultraviolet irradiation and heat treatment

“…Ag NW electrodes have been attracting a great deal of concerns due to their having high flexibility, transparency, electrical conductivity, and low cost among the various alternative flexible electrodes 11–15 . While almost all candidates for alternative transparent electrodes show excellent flexibility in comparison with the most widely used indium-tin-oxide (ITO) electrodes, their sheet resistances, transmittances, and production costs still do not match those of ITO films 16, 17 . Some mobile phones that use rigid plastic substrates have already been released, and electronic devices based on flexible substrates are expected to be commercialized in the near future 18 .…”

Switchable Liquid Crystal Contact Lenses for the Correction of Presbyopia

“…Furthermore, their conductive properties are dependent upon registration with respect to one another. This is less of a problem when depositing them on a flat surface, but imperfections will appear when depositing them on to a curved substrate and need careful consideration for use in contact lenses [73].…”

Deformable and Transparent Ionic and Electronic Conductors for Soft Energy Devices

“…Therefore, using metal NW networks as STECs has been considered attractive for stretchable transparent supercapacitors as well as other stretchable and/or transparent electronics. [30,186,187] Gong et al fabricated Au NWs thin films as STECs for stretchable transparent supercapacitors using ultrathin Au NWs of 2 nm diameter with an aspect ratio of 10 000 (Figure 11a). [188] The electrodes accommodated 50% tensile strain with small resistance change (50%) and maintained the resistance value after a 500 cycle stretching test with 30% strain.…”

“…There are ongoing studies on the toxicity of the nanomaterials themselves [233][234][235][236] and potential exposure to nanomaterials as a result of them being released from products has been very recently investigated. [187] STICs can be promising candidates because most of the hydrogels are biocompatible and are conformal to human body parts, cells, and tissues down to the molecular scale. Many biological organisms use ionic conductors for the transfer of information via electrical signals.…”