#dgist

'No pumps, no batteries needed': Wearable semiconductor fabric monitors health through sweat

A research team led by Prof. Kim Bong-hoon from the Department of Robotics and Mechatronics Engineering at the Daegu Gyeongbuk Institute of Science and Technology has developed a semiconductor fiber-based wearable sweat sensor that can collect sweat automatically and analyze various biosignals simultaneously without an external power source. They have reported their achievement in Small Structures. Sweat is a useful indicator for real-time health monitoring because it contains various biological information, such as electrolytes and metabolites. However, conventional wearable sweat sensors use microchannel (minute tube) structures or forcefully induce sweating through external stimuli, resulting in unstable skin contact and difficulty reliably collecting the required amounts of sweat.

Key transistor for next-generation 3D stacked semiconductors operates without current leakage

A research team led by Professor Jae Eun Jang and Dr. Goeun Pyo from the Department of Electrical Engineering and Computer Science at DGIST has developed "dual-modulated vertically stacked transistors" that operate stably without current leakage even in two-dimensional nanoscale channel structures. A study on this work is published in the journal Advanced Science. In recent years, the semiconductor industry has faced physical limitations as the demand to integrate more devices within limited space continues to grow. To overcome these constraints, "vertically stacked transistors," in which current-carrying channels are vertically layered, have emerged as a promising alternative for next-generation 3D semiconductors. However, conventional vertically stacked transistors suffer from a critical drawback in which gate electric signals are not delivered uniformly into the channel interior due to their electrode structure, consequently leading to current leakage or unstable device operation as the channel length becomes shorter.

Magnetic interactions in new alloy catalyst enhance hydrogen fuel cell performance

A research team led by Professor Jong Sung Yu of the Department of Energy Science and Engineering at DGIST has developed a new alloy structure that can significantly enhance the performance of electrode catalysts, a key component of hydrogen fuel cells. This study enhanced the oxygen reduction reaction (ORR) at the cathode, a key factor in fuel cell efficiency, and is expected to contribute to the development of next-generation eco-friendly energy technologies. The findings are published in Advanced Materials. Hydrogen fuel cells are gaining attention as an eco-friendly technology that emits only water in the process of generating electricity. However, platinum (Pt), a precious metal, is primarily used as the catalyst required to improve performance and durability. As a result, efficiency enhancement and cost reduction have remained major research challenges.

Inkjet-style technique developed to produce high-sensitivity biosensors

A research team has successfully developed the technology to fabricate high-sensitive biosensors by simply spraying, like an inkjet printer. The technology enables the fabrication of sensitive and precise sensors without expensive and complex equipment, and is expected to contribute to improving the fabrication scale and speed of biosensors in the future. The work is published in the journal ACS Applied Materials & Interfaces. The team was led by Yoonhee Lee (Well Aging Research Center) in the Division of Biomedical Technology at the Daegu Gyeongbuk Institute of Science & Technology. Carbon nanotube (CNT)-based field-effect transistors (FET) have emerged as next-generation biosensors, as they have high electric conductivity and sensitive surfaces and can capture even very small substances. For optimal sensor performance, however, single CNTs should be aligned consistently between electrodes, which requires complex equipment and expensive processes.

A research team from DGIST's (President Kunwoo Lee) Division of Energy & Environmental Technology, led by Principal Researcher Kim Jae-hyun, has developed a lithium metal battery using a "triple-layer solid polymer electrolyte" that offers greatly enhanced fire safety and an extended lifespan. This research holds promise for diverse applications, including in electric vehicles and large-scale energy storage systems. Conventional solid polymer electrolyte batteries perform poorly due to structural limitations which hinder an optimal electrode contact. This could not eliminate the issue of "dendrites" either, where lithium grows in tree-like structures during repeated charging and discharging cycles. Dendrites are a critical issue, as an irregular lithium growth can disrupt battery connections, potentially causing fires and explosions.

Ferromagnetism achieved in pure vanadium oxide by tuning oxidation states

A research team has succeeded in inducing ferromagnetism, a key property of conventional magnets, in pure vanadium oxide, a compound not previously recognized for such magnetic behavior. Through a series of experiments, the team verified that by precisely adjusting the oxidation state of vanadium ions, they could induce the element to behave magnetically. The research is published in the journal Advanced Functional Materials. The team was led by Professor Chun-Yeol You from the Department of Physics and Chemistry at DGIST. Vanadium oxide (VO) is widely known for its metal-insulator transition (MIT), a phenomenon in which its electrical conductivity dramatically changes depending on temperature. While its electronic properties have been extensively studied, its magnetic properties—especially the possibility of ferromagnetism—remain largely unexplored. VO typically exhibits antiferromagnetic or paramagnetic behavior, which limits its application as a magnetic material.

Innovative doping technique boosts semiconductor nanocrystal performance

A research team has successfully developed a new technology to control doping at the nucleus (seed) phase to increase the performance of semiconductor nanocrystals. The study uncovered how the doping process and location differ depending on the type of doping element (dopant). The developed technology is expected to be widely utilized in advanced electronic devices, such as displays and transistors. With the rapid development of advanced technologies in recent years, such as displays and transistors, interest in technologies that can precisely control doping in nanoscale semiconductors is growing. In particular, II-VI semiconductor-based nanocrystals have been widely studied owing to their outstanding optical and electrical properties.