High‐Performance Flexible Transparent Electrode with an Embedded Metal Mesh Fabricated by Cost‐Effective Solution Process

Abstract

A new structure of flexible transparent electrodes is reported, featuring a metal mesh fully embedded and mechanically anchored in a flexible substrate, and a cost-effective solution-based fabrication strategy for this new transparent electrode. The embedded nature of the metal-mesh electrodes provides a series of advantages, including surface smoothness that is crucial for device fabrication, mechanical stability under high bending stress, strong adhesion to the substrate with excellent flexibility, and favorable resistance against moisture, oxygen, and chemicals. The novel fabrication process replaces vacuum-based metal deposition with an electrodeposition process and is potentially suitable for high-throughput, large-volume, and low-cost production. In particular, this strategy enables fabrication of a high-aspect-ratio (thickness to linewidth) metal mesh, substantially improving conductivity without considerably sacrificing transparency. Various prototype flexible transparent electrodes are demonstrated with transmittance higher than 90% and sheet resistance below 1 ohm sq(-1) , as well as extremely high figures of merit up to 1.5 × 10(4) , which are among the highest reported values in recent studies. Finally using our embedded metal-mesh electrode, a flexible transparent thin-film heater is demonstrated with a low power density requirement, rapid response time, and a low operating voltage.

A three-dimensional metal grid mesh as a practical alternative to ITO

“…Recently, uniform metal mesh structures prepared with nano-patterning lithography techniques such as photolithography, 29 nano-imprint lithography, [30][31][32] grain boundary lithography, 33 colloid sphere lithography, 34,35 AAO template lithography, 36 and electroplating lithography 37 have also attracted great interest as another alternative to ITO because their optical transmittance and electrical conductivity can easily be tuned by controlling the line width, line pitch, and film thickness. However, these approaches produce classical two-dimensional metal mesh structures with the typical trade-off between optical transmittance and electrical conductivity: wider and denser structures have high electrical conductivity, but at the price of reduced optical transmittance and vice versa.…”

Ultra-Smooth, Fully Solution-Processed Large-Area Transparent Conducting Electrodes for Organic Devices

“…Metal micro- and nano-mesh electrodes have attracted considerable attention recently because the thickness, spacing, and line-widths of metal patterns can be easily modified to obtain desirable optical and electrical properties with the benefit of air-processable conditions. These metal meshes have been fabricated by various methods such as pattern-masked evaporation2021, nanoimprint lithography172223, inkjet24, flexographic25, transfer2627 and gravure-offset printing1228. However, these electrodes also suffer from high surface roughness, resulting in the possibility of electrical short-circuits between the TCEs and the top electrode.…”

Printable High‐Aspect Ratio and High‐Resolution Cu Grid Flexible Transparent Conductive Film with Figure of Merit over 80 000

“…The transmittance of fully filled Cu metal-mesh including polyethylene terephthalate (PET) substrate is about 88.1% while 90% for only a Ag seed layer. [14,18,29] Although Cu metal-mesh TCF has a reddish color, which has some disadvantages for practical device applications, a thin nickel layer of about 10-20 nm on top of copper would be electroplated to eliminate the reddish color, as shown in Figure S11 (Supporting Information). In parallel, sheet resistance from only a seed layer to fully filling Cu in the microgrooves varied from 50.8 to 0.29 Ω □ −1 .…”

“…The relationship between the sheet resistance and transparency was calculated by using the equation below [10,29,30] The relationship between the sheet resistance and transparency was calculated by using the equation below [10,29,30] …”