Youn Sang Kim

We demonstrated a new water motion active transducer (WMAT) without any external bias-voltage sources or additional processes, which critically limit the use of conventional passive capacitive transducers that convert mechanical motion into electric energy. From a simple structure, we successfully turned on an LED using various kinds of natural water motion. The WMAT, which has wide applicability, has good potential to be a candidate for generating sustainable electric energy.

We have developed soft molding as a method for meso-scale-area fabrication of three-dimensional structures. The soft molding, which is a form of soft lithography, involves placing an elastomeric mold on the surface of a spin-coated polymer film with a slight pressure (<1 N/cm2), allowing the mold to absorb solvent, releasing the pressure, and then letting the mold and the substrate remain undisturbed for a period of time. The three-dimensional structure thus formed is robust in that the p

Solution-processed and alkali metals, such as Li and Na, are introduced in doped amorphous zinc tin oxide (ZTO) semiconductor TFTs, which show better electrical performance, such as improved field effect mobility, than intrinsic amorphous ZTO semiconductor TFTs. Furthermore, by using spectroscopic UV-visible analysis we propose a comprehensive technique for monitoring the improved electrical performance induced by alkali metal doping in terms of the change in optical properties. The change in th

Evaporation-induced electricity generation, harnessing natural vaporization of water, is spotlighted as a promising energy conversion system with showing off remarkable characteristics such as continuous generation without artificial water motions. However, the vague origin and mechanism of this phenomenon are obstacles for practical application. Herein, the origin of the evaporation-induced electricity generation was verified in terms of the "ionovoltaic" effect, ionic motion-induced charge car

A super-hydrophobic and highly transparent nanostructured film was fabricated via imprinting and conformally uniform chemical anchoring of poly(dimethylsiloxane) on a controlled nanoscopic dimension.

Oxidation-resistant copper nanowires (Cu NWs) are synthesized by a polyol reduction method. These Cu NWs show excellent oxidation resistance, good dispersibility, and have a low sintering temperature. A Cu NW-based flexible, foldable, and free-standing electrode is fabricated by filtration and a sintering process. The electrode also exhibits high electrical conductivity even bending, folding, and free-standing.

In this work, a whole manufacturing process of the curved copper nanowires (CCNs) based flexible transparent conductive electrode (FTCE) is reported with all solution processes, including synthesis, coating, and networking. The CCNs with high purity and good quality are designed and synthesized by a binary polyol coreduction method. In this reaction, volume ratio and reaction time are the significant factors for the successful synthesis. These nanowires have an average 50 nm in width and 25-40 μ

Here we present an alternative, new, unconventional lithographic technique developed to create dense and multilevel nanostructure pattern transfer using a highly accurate polyurethane acrylate (PU, MINS101m, Minuta Tech.) mold and a polyelectrolyte multilayer as the adhesion promotion layer. Specifically, we demonstrate the pattern transfer of periodic 80 nm lines with 400 nm height and complex and multilevel nanostructures to a polymer layer on various substrates, such as Si or SiO2 wafers, gla

We verified the origin of water-infiltration-induced electricity generation by an ionovoltaic effect, specifically, ion–surface interaction induced potential asymmetry in a porous CuO nanowire film.

Solution-processed high-K dielectrics for oxide thin-film transistors (TFTs) have been widely studied with the objective of achieving high performance and low-cost TFTs for next-generation displays. In this study, we introduce an amorphous hafnium-lanthanum oxide (HfLaOx) gate insulator with high electrical permittivity which was fabricated by the simple spin-coating method. In particular, the solution-processed HfLaOx dielectric layer, which was achieved by a mixture of two Hf and La metal hydr

A solution-processed ionic amorphous Al2O3 dielectric with a low temperature annealing process at 350 °C shows good compatibility and high performance in metal oxide semiconductor thin film transitors (TFTs) such as Li–ZnO TFTs and In–ZnO TFTs. The Li–ZnO/Al2O3 and In–ZnO/Al2O3 TFTs, with solution-processability and low temperature annealing at a maximum of 350 °C, exhibited field-effect mobilities of 46.9 cm2 V−1 s−1 in crystalline Li–ZnO/Al2O3 TFTs and 44.2 cm2 V−1 s−1 in amorphous In–ZnO/Al2O

A transparent thin film transistor (TTFT), including zinc oxide (ZnO), has come into the spotlight as an innovative TFT that has the potential to drive the future of the information technology industry. Herein, we developed a new direct patterning method, drop-casting with a new developing method, through the combination of an aqueous ammonia–ZnO process with the doping of Na ions and surface engineering for high n-type semiconducting performance with good operational stability at low temperatur

A novel lightweight three-dimensional (3D) composite anode for a fast-charging/discharging Li-ion battery (LIB) was fabricated entirely using one-dimensional (1D) nanomaterials, i.e., Cu nanowires (CuNWs) and multi-walled C nanotubes (MWCNTs). Because of the excellent electrical conductivity, high-aspect ratio structures, and large surface areas of these nanomaterials, the CuNW-MWCNT composite (CNMC) with 3D structure provides significant advantages regarding the transport pathways for both elec

General purpose patterning based on selective dewetting with an elastomeric mold is described. Several well‐defined nanostructures obtained by this method are presented (see Figure for an example). Unlike other patterning techniques, the same mold can be used to generate features ranging in size from the nanometer to the micrometer, simply by changing the duration of dewetting.