한승용 교수

A facile fast laser nanoscale welding process uses the plasmonic effect at a nanowire (NW) junction to suppress oxidation and successfully fabricate a Cu-NW-based percolation-network conductor. The "nanowelding" process does not require an inert or vacuum environment. Due to the low-temperature and fast-process nature, plasmonic laser nanowelding may form Cu-nanowire networks on heat-sensitive, flexible or even stretchable substrates.

Thin, soft, skin-like sensors capable of precise, continuous measurements of physiological health have broad potential relevance to clinical health care. Use of sensors distributed over a wide area for full-body, spatiotemporal mapping of physiological processes would be a considerable advance for this field. We introduce materials, device designs, wireless power delivery and communication strategies, and overall system architectures for skin-like, battery-free sensors of temperature and pressur

Laser induced selective photothermochemical reduction is demonstrated to locally and reversibly control the oxidation state of Cu and Cu oxide nanowires in ambient conditions without any inert gas environment. This new concept of "nanorecycling" can monolithically integrate Cu and Cu oxide nanowires by restoring oxidized Cu, considered unusable for the electrode, back to a metallic state for repetitive reuse.

Mechanically reinforced skin-electronics are presented by exploiting networked nanocomposite elastomers where high quality metal nanowires serve as conducting paths. Theoretical and experimental studies show that the established skin-electronics exhibit superior mechanical enhancements against crack and delamination phenomena. Device applications include a class of biomedical devices that offers the ability of thermotherapeutic stimulation and electrophysiological monitoring, all via the skin.

Research on sustainable and high-efficiency energy devices has recently emerged as an important global issue. These devices are now moving beyond the form of a bulk, rigid platform to a portable, flexible/stretchable format that is easily available in our daily lives. Similar to the development of an active layer for the production of next-generation energy devices, the fabrication of flexible/stretchable electrodes for the easy flow of electrons is also very important. Silver nanowire electrode

Soft grippers that incorporate functional materials are important in the development of mechanically compliant and multifunctional interfaces for both sensing and stimulating soft objects and organisms. In particular, the capability for firm and delicate grasping of soft cells and organs without mechanical damage is essential to identify the condition of and monitor meaningful biosignals from objects. Here, we report a millimeter-scale soft gripper based on a shape memory polymer that enables ma

Anode-free sodium metal batteries (AF-SMBs) can deliver high energy and enormous power, but their cycle lives are still insufficient for them to be practical as a power source in modern electronic devices and/or grid systems. In this study, a nanohybrid template based on high aspect-ratio silver nanofibers and nitrogen-rich carbon thin layers as a core-shell structure is designed to improve the Coulombic efficiency (CE) and cycling performance of AF-SMBs. The catalytic nanohybrid templates drama

Abstract Copper nanowires are widely utilized for flexible electronics applications due to their excellent electrical conductivity, mechanical flexibility, and optical transparency with very low material cost. While many previous studies are dedicated to developing effective synthesis routes for copper nanowires, most of them have focused on the control of the morphology including length and diameter rather than synthesis yields. Although many postprocessing methods have been established to make

Copper nanowires (Cu NWs) are suitable material as an electrode for flexible, stretchable and wearable devices due to their excellent mechanical properties, high transparency, good conductivity, and low cost, but oxidation problem limits their practical use and application. In order to use Cu NWs as an electrode for advanced flexible, stretchable and wearable devices attached directly to the skin, the influence of the body temperature on the oxidation of Cu NWs needs to be investigated. In this

Abstract In spite of its excellent electrical, mechanical, and low‐cost characteristics, copper nanowire has fatal issues in the oxidation problem and the lack of biological compatibility, which occasionally outweighs its advantages and limits its usage as electronics or biodevice applications. In this study, a novel wet chemical synthesis method is developed for the oxidation‐free Cu–Au core–shell nanowire based on the prepared Cu nanowire with alkylamine‐mediated synthesis and ligand exchange.

Abstract Soft robotics, an emerging field that focuses on the development of robots utilizing soft, flexible, and deformable materials, is revolutionizing traditional robotics (reliant on rigid materials and motors) and broadening its range of applications and potential uses. In addition, by emulating the structure, function, and characteristics of biological systems, bioinspired materials are facilitating significant progress in a diverse array of soft robotic applications. This review offers a

A substantial amount of attention has been paid to the development of transparent electrodes based on graphene and carbon nanotubes (CNTs), owing to their exceptional characteristics, such as mechanical and chemical stability, high carrier mobility, high optical transmittance, and high conductivity. This review highlights the latest works on semitransparent solar cells (SSCs) that exploit graphene- and CNT-based electrodes. Their prominent optoelectronic properties and various fabrication method

Abstract Copper nanowires (Cu NWs) have gained attention as an alternative to noble metal nanowires due to their affordable price, but their susceptibility to rapid oxidization in ambient conditions has remained a critical limitation for their practical usage. Many studies have been conducted to address this disadvantage but have been successful only in terms of oxidation prevention at certain temperatures, leaving the matter of oxidation at high temperatures unresolved. In this article, a simpl

Among many attempts to make a decent human motion detector in various engineering fields, a mechanical crack-based sensor that deliberately generates and uses nano-scale cracks on a metal deposited thin film is gaining attention for its high sensitivity. While the metal layer of the sensor must be responsible for its high performance, its effects have not received much academic interest. In this paper, we studied the relationship between the thickness of the metal layer and the characteristics o

In this Letter, we report the development of a continuously tunable color filter based on a self-assembled isotropically stretchable microbead monolayer. Spreading equidistantly upon the application of lateral strain, the isotropically stretchable monolayer serves as a dynamic diffraction grating whose diffraction angle can be mechanically modulated. Combined with a simple spatial filtering scheme, the spectra of the filtered light are solely controlled by external strain (up to 32% radial strai