Choi, In-Suk

Researchers have recently discovered ultrastrong and ductile behavior of Au nanowires (NWs) through long-ranged coherent-twin-propagation. An elusive but fundamentally important question arises whether the size and surface effects impact the twin propagation behavior with a decreasing diameter. In this work, we demonstrate size-dependent strength behavior of ultrastrong and ductile metallic NWs. For Au, Pd, and AuPd NWs, high ductility of about 50% is observed through coherent twin propagation,

In this study, we developed a novel nanostructured polymer nanofiber/TiO2 nanoparticle composite photoelectrode with high bendability by a spray-assisted electrospinning method. The composite film is used as the photoelectrode in plastic dye-sensitized solar cells (DSCs). The polymer/TiO2 composite photoelectrode has a structure similar to that of a fiber-reinforced composite; the matrix of the composite photoelectrode contains TiO2 nanoparticles, and PVDF nanofibers are embedded in this matrix.

Abstract It remains a fundamental challenge in the development of stretchable electronics to understand how mechanical strain changes the electrical properties of materials. Although the piezoresistive behavior of poly(3,4‐ethylene‐ dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been observed, its intrinsic origin is not yet fully understood because there are many extrinsic contributing factors and an experimental platform with which to assess such behavior has not been established. Here

This study starts from the counterintuitive question of how we can render conventional stiff, nonstretchable, and even brittle materials sufficiently conformable to fully wrap curved surfaces, such as spheres, without failure. Here, we extend the geometrical design method of computational origami to wrapping. Our computational wrapping approach provides a robust and reliable method for fabricating conformal devices for arbitrary curved surfaces with a computationally designed nonpolyhedral devel

Design and fabrication of reliable electrodes is one of the most important challenges in flexible devices, which undergo repeated deformation. In conventional approaches, mechanical and electrical properties of continuous metal films degrade gradually because of the fatigue damage. The designed incorporation of nanoholes into Cu electrodes can enhance the reliability. In this study, the electrode shows extremely low electrical resistance change during bending fatigue because the nanoholes suppre

While cracks are usually considered detrimental, crack generation can be harnessed for various applications, for example in ceramic materials, via directing crack propagation and crack opening. Here, we find that electron beam irradiation prompts a crack suppression phenomenon in a copper (Cu) thin film on a polyimide substrate, allowing for the control of crack formation in terms of both location and shape. Under tensile strain, cracks form on the unirradiated region of the Cu film whereas crac

Nanostructured flexible electrodes with biological compatibility and intimate electrochemical coupling provide attractive solutions for various emerging bioelectronics and biosensor applications. Here, we develop all-inkjet-printed flexible nanobio-devices with excellent electrochemical coupling by employing amphiphilic biomaterial, an M13 phage, numerical simulation of single-drop formulation, and rational formulations of nanobio-ink. Inkjet-printed nanonetwork-structured electrodes of single-w

A direct integration scheme for a Li-ion battery on a polymer substrate is successfully implemented. As a proof of concept, the bendable Li-ion battery is fabricated using a nano-hairy Si anode, which exhibits a much longer cycle life and a higher capacity on various C-rates compared to a Si thin film electrode on a pristine PI. In the cyclic bending test, with a bending radius of 16 mm, over 3000 cycles are measured without a voltage drop. As a service to our authors and readers, this journal p

Abstract With increasingly diverse functionalities of electronic skins (E‐skins), components and structures for the E‐skin have also become more diverse and complex. It is extremely challenging to make all the components and devices required for additional functionalities stretchable and breathable to ensure skin comfort. Herein, we report a facile strategy to realize a versatile hybrid E‐skin patch with great skin comfort by developing a breathable and stretchable metastructure to serve as the