Electrochemical Replication and Transfer for Low‐Cost, Sub‐100 nm Patterning of Materials on Flexible Substrates

Abstract

The fabrication of high‐resolution patterns on flexible substrates is an essential step in the development of flexible electronics. However, the patterning process on flexible substrates often requires expensive equipment and tedious lithographic processing. Here, a bottom‐up patterning technique, termed electrochemical replication and transfer (ERT) is reported, which fabricates multiscale patterns of a wide variety of materials by selective electrodeposition of target materials on a predefined template, and subsequent transfer of the electrodeposited materials to a flexible substrate, while leaving the undamaged template for reuse for over 100 times. The additive and parallel patterning attribute of ERT allows the fabrication of multiscale patterns with resolutions spanning from sub‐100 nm to many centimeters simultaneously, which overcomes the trade‐off between resolution and throughput of conventional patterning techniques. ERT is suitable for fabricating a wide variety of materials including metals, semiconductors, metal oxides, and polymers into arbitrary shapes on flexible substrates at a very low cost.

Metallic Micro‐Nano Network‐Based Soft Transparent Electrodes: Materials, Processes, and Applications

“…Imprint Lithography: Imprint lithography (IL) is a timesaving patterning technique that makes use of an existing mold, [129] Copyright 2023, Wiley-VCH GmbH. b) A fresh leaf (left) is etched to dry leaf venation network (middle); right: an SEM image of the network.…”

“…Figure 4. a) Schematic illustration of the templated lithography for fabricating Cu MMNNs. Reproduced with permission [129]. Copyright 2023, Wiley-VCH GmbH.…”

Optical Integration in Wearable, Implantable and Swallowable Healthcare Devices

“…By embracing diversity and exploring more possibilities, the field of optical system-supported wearable, implantable, and swallowable healthcare devices can venture into uncharted territories of innovation. For example, researchers can study various luminescent materials for light sources, such as quantum dots, organic semiconductors responsive to high-energy radiation, or rare earth-doped nanoparticles that are excitable by near- and mid-IR light. , In addition, it is essential to explore sensing methods beyond encoding changes in the polarization, spectrum, intensity, phase, and directional properties of light. A range of exciting sensing modalities, including distributed optical fibers, patterned optical cavities, structured light modulation, laser ranging, and stereovision, can revolutionize the capabilities of wearable, implantable, and swallowable optoelectronic devices.…”

“…Although most wearable optical sensors focus on monitoring biophysical or biochemical information, optoelectronic devices that can perform various functions on the skin surface are becoming increasingly popular. − These methods enable high-sensitivity recognition of parameters such as temperature, pressure, and mechanical deformation, with practical applications ranging from rehabilitation training to bionic machinery, intelligent control, and virtual reality. Flexible fibers demonstrate excellent performance in wearable electronic devices. − Optical fibers, with the ability to encode multiple parameters beyond intensity, offer significant advantages in multimodal distributed sensing. Bai et al have developed a sensor based on stretchable distributed fiber-optic sensors (DFOSs), which use elastomeric lightguides comprising continuum or discrete chromatic dyes (Figure B).…”

Highly Robust and Strain-Resilient Thin Film Conductors Featuring Brittle Materials

“…The practical implementation of flexible electronics has been hindered by a lack of stretchable electrodes that can maintain strain-insensitive electrical conductivity under deformations. Metal films have been commonly used as conductors/electrodes because of their intrinsically high conductivity (>10 5 S cm –1 ), cost-effectiveness, and well-developed processing techniques. − However, the nanocrystalline metal films on elastomer substrates often suffer from sudden crack initiation and rapid crack propagation due to the obvious mechanical incompatibility between metal films and polymer substrates, leading to electrical failure at a small strain.…”