Solution-Processed Flexible Transparent Electrodes for Printable Electronics

Abstract

Flexible transparent electrodes (FTEs) have been widely witnessed in various printable electronic devices, especially those involving light. So far, solution processes have demonstrated increasing advantages in preparing FTEs not only in their mild operation conditions and high-throughput but also in the diversity in micropatterning conductive nanomaterials into networks. For the FTEs, both high transparency and high conductivity are desirable, which therefore create requirements for the conductive network by considering the trade-off relationship between the coverage and the micropatterns of the network. In addition, the conductive networks also affect the flexibility of FTEs due to the deformation during bending/stretching. Consequently, solution processes capable of micropatterning conductive nanomaterials including nanoparticles, nanowires/polymers, and graphene/MXene play a crucial role in determining the performance of FTEs. Here, we reviewed recent research progress on solution-processed FTEs, including the solution processes, the solution-processable conductive nanomaterials and the substrates for making FTEs, and applications of FTEs in flexible electronics. Finally, we proposed several perspective outlooks of the FTEs, which aim at not only the enhanced performance but also the performances in extreme conditions and in integration. We believe that the review would offer inspiration for developing functional FTEs.

Functionalization of Natural-Derived Biogels for Soft Bioelectronics

“…6 For example, an interpenetrating network structure with two or more independent cross-linked and intertwined polymer networks in the gel matrix has been intensively studied for improving the mechanical properties of gels, because such an interpenetrating structure could implement the energy dissipation through the fracture or reversible cross-linking or domain transformation of sacrificial polymer chains, and maintain high elasticity by the long-chain networks. 7 Considering that a wide selection of natural biopolymers can provide domain transformation or reversible interaction for mechanical energy dissipation, strategies that interpenetrate such biopolymers with other long-chain polymer networks may be efficient to obtain tough biogels. And integrating multiple pairs of energy dissipation and elasticity maintaining mechanisms into a biogel, such as integration of fiber/mesh reinforcement, transformable domains, and hybrid cross-linkers, may provide another effective strategy for designing biogels with superior stretchability and toughness.…”

“…12 The conductivity of ion-conductive biogels is from freely moving ions that come from electrolytes, polyelectrolytes, or ionic liquids, and relies on the ion transportation in biogel matrix. 7 A well-designed porous structure and high ion concentration is conducive to improving the ion conductivity. Ion-conductive biogels permit the ionic conductivity like electrolytic tissue media and can possess other advantageous properties such as soft elastic nature, high stretchability, optical transparency, and electrochemical stability.…”

Self-Healing and Freeze-Resistant Boat-Fruited Sterculia Seed Polysaccharide/Silk Fiber Hydrogel for Wearable Strain Sensors

“…As the digital healthcare landscape continues to evolve, 1−3 wearable strain sensors 4−6 have garnered significant interest in the fields of motion monitoring, 7,8 health monitoring, 9,10 and human−computer interactions. 11,12 Their flexibility, 13,14 softness, 15,16 and adhesion 17,18 have made hydrogels a key class of materials for next-generation flexible electronic sensing devices. 19−21 For instance, wearable sensors leveraging hydrogel with conductivity based on an amylopectin/poly-(acrylamide−acrylic acid) polymer have been effectively utilized to monitor human movements.…”

Tunable Magnetic Domain Patterns in Thickness-Gradient Nickel Films on Flexible PDMS Substrates

“…Due to the stretchability, biocompatibility, lightweight, and low-cost properties, flexible electronics has great application prospects in bionic robots, electronic skins, tactile sensors, solar cells, and wearable devices. − As indispensable components of the flexible electronics family, flexible magnetoelectronic devices (based on magnetic films) have also received a great deal of attention in the past two decades. − They have many potential applications in the fields of information storages, magnetic sensors, microwave filters, and magnetic tunnel junctions.…”