Area-Selective Lift-Off Mechanism Based on Dual-Triggered Interfacial Adhesion Switching: Highly Facile Fabrication of Flexible Nanomesh Electrode

Abstract

With the recent emergence of flexible and wearable optoelectronic devices, the achievement of sufficient bendability and stretchability of transparent and conducting electrodes (TCEs) has become an important requirement. Although metal-mesh-based structures have been investigated for TCEs because of their excellent performances, the fabrication of mesh or grid structures with a submicron line width is still complex due to the requirements of laborious lithography and pattern transfer steps. Here, we introduce an extremely facile fabrication technique for metal patterns embedded in a flexible substrate based on submicron replication and an area-selective delamination (ASD) pattern. The high-yield, area-specific lift-off process is based on the principle of solvent-assisted delamination of deposited metal thin films and a mechanical triggering effect by soft wiping or ultrasonication. Our fabrication process is very simple, convenient, and cost-effective in that it does not require any lithography/etching steps or sophisticated facilities. Moreover, their outstanding optical and electrical properties (e.g., sheet resistances of 0.43 Ω sq at 94% transmittance), which are markedly superior to those of other flexible TCEs, are demonstrated. Furthermore, there is no significant change of resistance over 1000 repeated bending cycles, with a bending radius of 5 mm, and immersion in various solvents such as salt water and organic solvents. Finally, we demonstrate high-performance transparent heaters and flexible touch panels fabricated using the nanomesh electrode, confirming the long-range electrical conduction and reliability of the electrode.

Geometrically Structured Nanomaterials for Nanosensors, NEMS, and Nanosieves

“…High‐performance sensors having high sensitivity, flexibility, power efficiency, and stability are very important not only in conventional healthcare, safety diagnostics, mechanics, and security, but also in future electronics, such as wearables and bioimplantable devices 5,40,140–147. In this regard, nanomaterials have been conventionally studied as a sensing material for high‐performance sensors because their unique form factors, such as light weight, high aspect ratio, and large surface‐to‐volume ratio, are appropriate to produce performance‐enhanced sensor devices 1–9. More recently, researchers have further revealed that geometrically structured nanomaterials can improve device performance and functionality because of the unexpected superior physical and chemical characteristics due to the geometry of the nanomaterials 7,8,53,77–81.…”

“…Over recent decades, scientific exploration and engineering of nanomaterials have gained great attention in diverse fields from academia to industry thanks to extraordinary physical and chemical phenomena originating from their nanosize effects, which cannot be realized in the bulk materials 1–13. Indeed, superior mechanical strength, electrical resistivity or mobility, electrical quantum effects, thermal resistivity or mobility, chemical reaction, and optical light emission have been observed with diverse nanomaterials, such as various metallic and semiconductor nanoparticles and nanowires, carbon nanotubes (CNTs), quantum dots, graphene, and molybdenum disulfide (MoS 2 ) 14–34.…”

Desolvation‐Triggered Versatile Transfer‐Printing of Pure BN Films with Thermal–Optical Dual Functionality

“…The polar solvent (IPA) molecules interact with the hydroxyl edge‐functional groups of the f‐BN and effectively shields the f‐BN, weakening the interaction between the f‐BN and other interfacial surfaces. The solvent provides an interfacial screening effect, [ 37 ] and thus the adhesion strength between the substrate and the BN film can be negligible in the fully solvated state, resulting in the BN film remaining on the membrane. Although f‐BN is solvated, the BN film is still bound to the membrane surface because the generated fluid pressure from the vacuum filtration process causes f‐BN to be physically adsorbed on the membrane.…”

Sugar transfer of nanomaterials and flexible electrodes

“…Nanomaterials (e.g., nanowires, nanofilms, 2D materials and 3D nanostructures) have been widely used in the field of flexible electrodes, optoelectronics, and nanoelectronics, due to their exceptional optical and electrical properties [1][2][3][4][5][6]. Transfer of nanomaterials from its original substrate is one of the key components for the fabrication of the heterogeneously integrated functional systems [7].…”