-
- [Research] Prof. Sunkook Kim develops on-skin wearable multichannel electromyography sensor
- Prof. Sunkook Kim develops on-skin wearable multichannel electromyography sensor - Published online in IEEE Transaction on Industrial Electronics on May 10th, 2021 [Image 1] Prof. Sunkook Kim and Dr. Srinivas Gandla Prof. Sunkook Kim’s research team (Dr. Srinivas Gandla, First author) developed on-skin wearable multi-channel electromyography (EMG) sensor that enables controlling the robotic arm as smooth as human arm, even in long distance. Traditional PDMS was inconvenient for a long time usage due to the limited applicability and limitation in monitoring accurate EMG sensor values. Hence, the research team fabricated on-skin wearable multi-channel EMG sensor which can track human arm’s subtle EMG signal and built a system in which robot arms can move according to human gestures. The research team developed a high-sensitivity biosignal monitoring sensor featuring deformable EMG electrode design by applying Kirigami serpentine structures inspired by nature. To capture the wearer’s arm muscle movement in a stable manner, the sensor is equipped with a stretchable electrode structure exhibiting mechanical/electrical stability standing up to 150% of stress on x, y, and z-axis. ※ Kirigami : 'Kiri in Japanese means to cut, and 'gami', which means paper, when combined, refers to the form representing a stereoscopic shape when cut into a particular pattern or folded. Fig. 1. Large-area patched-based stretchable multichannel array sensor processed by laser ablation technique for robotic control. As control signal for digital devices by receiving human "gestures" through biosignals or EMG, this technology can be used in the contact-free industry, robot industry, and medical industry to connect people and digital devices. Dr. Gandla participated in this research with the support of Sungkyunkwan University's foreign researcher support initiative (해외우수신진연구자 사업). The findings, the stretchable electrode material technology, was applied to T&L’s (티앤엘(사)) Smart Thermometer in 2021. Fig. 2. Overview of the proposed multichannel sensor arrays for the robotic arm control system. “I hope the technology to be applied in an artificial EMG sensor system which can directly transmit user’s biosignals." Dr. Gandla stated. This work was supported by the National Research Foundation of Korea (2021R1A2B5B0200216 and 2018R1D1A1B0704 8232) and the SKKU Research Fellowship Program of Sungkyunkwan University. The paper was published online in one of the world-renowned journal, IEEE Transaction on Industrial Electronics, on May 10th, 2021 (Top 5% in electronics). https://www.skku.edu/skku/campus/skk_comm/news.do?mode=view&articleNo=89855&article.offset=0&articleLimit=10&srSearchVal=%EA%B9%80%EC%84%A0%EA%B5%AD
-
- 작성일 2022-01-26
- 조회수 1372
-
- [Research] Prof. Jeong Min Baik suggests a new approach for commercialization of sustainable energy harvesting
- Prof. Jeong Min Baik suggests a new approach for commercialization of sustainable energy harvesting technology - Development of non-contact mode triboelectric nanogenerator (TENG) applying C60-functionalized Polyimide - BiSbTe-based thermoelectric generators exhibit world's highest output through the triboelectrification field effect Contact electrification (CE), which occurs due to the coupling effect of two separate materials, is the foundation of triboelectric nanogenerators (TENG) that converts the ambient mechanical energy into electricity. TENGs have successfully demonstrated their excellence in charging small electronic devices and capturing momentary stimuli in devices like electronic skin, touch screens, healthcare devices, and habit-recognition security systems. Nevertheless, several drawbacks of contact electrification (CE) have been raised, such as the wear of materials, the need to replace the device, and noise resulting from its operation. In this regard, Prof. Baik’s research team, by fabricating C60-functionalized Polyimide, developed a non-contact mode nanogenerator, which shows 4.3 times higher output power and three times higher charge-retention characteristics. Non- contact mode TENG was applied in a keyless electronic door lock system and an automobile speed sensor for the first time in the world, demonstrating its stability and superiority in operation. Also, by pioneering the use of CE in thermoelectric harvesting, the research team suggested a novel approach by developing a brand new technology that profoundly enhanced output power without raising the necessity of thermoelectric material modification. Thermoelectric energy harvesting generated valuable energy utilizing the temperature difference on the material’s outside when heat is applied on both ends of the material. So far, the focus was on the modification of thermoelectric materials’ (Bi2Te3, SnSe, PbTe, etc.) Seebeck coefficient, electrical conductivity, and thermal conductivity to improve energy conversion efficiency; however, there were difficulties in commercialization due to low output voltage. To solve such problems, the research team attached a Kapton layer with a negative charge on the cold side of BiSbTe-based thermoelectric materials, which has the highest ZT value. It doubled output power and enabled setting a world record of 50% higher output voltage. “This research set the tone by attesting stable energy production capability by leveraging CE; The findings illuminated the unlimited potential in the field of energy harvesting.” Prof. Baik noted. The corresponding research was published in Energy & Environmental Science (IF 30.287) and ACS Energy Letters (IF: 19.003), respectively. https://www.skku.edu/skku/research/industry/researchStory_view.do?mode=view&articleNo=89863
-
- 작성일 2022-01-26
- 조회수 1355
-
- [Faculty] Prof. Miso Kim wins Prime Minister’s Commendation at Science, Information and Communication Day
- Prof. Miso Kim wins Prime Minister’s Commendation at Science, Information and Communication Day [Image] Professor Miso Kim (School of Advanced Materials Science and Engineering) Professor Miso Kim of AMSE won a Prime Minister's Commendation at 2021 Science, Information and Communication Day. Prof. Kim received the PM’s commendation in the science and technology promotion sector for her contribution of securing a leading international position in the field by successfully implementing the “Meta Energy Harvesting System,” an unmatched convergence research technology that created synergy between meta materials and energy harvesting technology. “I think the PM’s commendation is a generous award for me. I believe that I was given the award to make further achievements. I will do my best to contribute not only to the science community but also to the society on the whole. In addition, I personally feel very grateful because it is the first award I won since I was appointed to Sungkyunkwan University,” says Prof. Kim. https://www.skku.edu/skku/campus/skk_comm/news.do?mode=view&articleNo=89529&article.offset=0&articleLimit=10
-
- 작성일 2022-01-26
- 조회수 854
-
- [Research] Prof. Hyoungsub Kim’ s research team in collaboration with Samsung Advanced Institute of Technology (SAIT) revealed dime
- Prof. Hyoungsub Kim’ s research team in collaboration with Samsung Advanced Institute of Technology (SAIT) revealed dimension-breaking reconstruction process during conversion of MoO2 to MoS2 [Figure 1] Professor Hyoungsub Kim (AMSE, co-corresponding author), Dr. Eunha Lee (SAIT, co-corresponding author) The joint research team led by Prof. Hyoungsub Kim (AMSE) and Dr. Eunha Lee (SAIT) first discovered the appearance of highly ordered arrays of 1D intermediate crystals during the chemical transformation of MoO2 to 2D layer-structured MoS2. Recently, for application to next-generation semiconductor and energy devices, numerous researches have been actively conducted to synthesize various 2D layer-structured materials (transition-metal dichalcogenides) via a thermal sulfidation- or selenization-based conversion process of metal oxides. Ideally, such a synthesis process follows sequential layer-by-layer phase transformation characteristics of an atomic layer-level thickness. During the sulfidation process of MoO2, the joint research team directly observed the appearance of highly ordered arrays of 1D intermediate crystals at the MoO2/MoS2 interface using STEM with an atomic-scale resolution. They also developed a comprehensive structural model and energetics of the intermediate crystals during the dimension-breaking transformation process (3D→1D→2D) based on the first-principles DFT calculations. [Figure 2] (left) Schematic illustration of chemical phase transformation, (right) STEM images Furthermore, by collaborating with a Prof. Mann-Ho Cho’s team (department of physics at Yonsei University), they proved possible modulation of the metal-contact type (from p- to n-type) with the number of atomic MoS2 layers via X-ray photoelectron spectroscopy, which can be used for innovative device applications. In this paper, Dr. Hyangsook Lee (SAIT) and Dr. Yeonchoo Cho (SAIT) contributed as co-first authors, and the results were published online in ‘Materials Today (Impact Factor = 26.416, JCR Ranking Top 2.7%)' on March 17, 2021. ※ Paper title: “3D-to-2D phase transformation through highly ordered 1D crystals from transition-metal oxides to dichalcogenides” ※ Paper source: https://www.sciencedirect.com/science/article/abs/pii/S1369702121000560 https://www.skku.edu/skku/campus/skk_comm/news.do?mode=view&articleNo=89231&article.offset=20&articleLimit=10
-
- 작성일 2022-01-26
- 조회수 1390
-
- [Research] Prof. Jeong Min Baik’s Research Team Suggest a New Paradigm of Study on Thermoelectric Energy-harvesting
- Prof. Jeong Min Baik’s Research Team Suggest a New Paradigm of Study on Thermoelectric Energy-harvesting - highest output voltage of BisbTe-based thermoelectric generator - published in ACS Energy Letters on February 2021 [Image] Prof. Jeong Min Baik (School of Advanced Materials Science and Engineering, SKKU) and Prof. Jae Sung Son (School of Materials Science and Engineering, UNIST) Prof. Baik’s research team and Prof. Son’s research team developed a new technique to increase the output voltage of a thermoelectric generator that does not involve material modification. Thermoelectric energy-harvesting is a technology that produces useful energy by utilizing temperature differences at both ends of the material when heat is applied from the outside. It has attracted a great deal of research interest due to its simplicity, minimal maintenance requirements, low cost, and reliability. It provides a good solution for sustainable energy generation from ambient heat sources. So far, various types of TE materials, including Bi2Te3, SnTe, PbTe, SnSe, etc., have been developed, and most research has been devoted to enhancing the materials’ ZT values using various methods such as nanostructuring, band structure engineering, etc. However, despite recent enhancements in efficiency, major issues with TE power generation technology remain, such as ultralow output voltages and consequent low-energy conversion efficiency, which are rooted in the intrinsic properties of TE materials. As a solution to these challenges, they created negative charges on the dielectric surface on the low temperature which caused the electric potential difference across the two electrodes to increase and achieved the highest output voltage. In addition, the team successfully demonstrated that the wind increased the output voltage without a significant decrease in wind speed through the pinwheel. Prof. Baik said “This research is a new method of energy convergence research that can present a new direction to overcome the limitations of thermoelectric energy-harvesting.” The research team has already applied for two related patents and is developing technologies that reach commercialization through study on non-contact thermoelectric energy-harvesting. This work was supported by the Mid-Career Researcher Program through a National Research Foundation of Korea (NRF) grant funded by the Korean government (NRF2019R1A2C2009822), by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (2019R1A4A1029237), and by the Ministry of Trade, Industry and Energy (MOTIE, 2005721, Korea). It was published in ACS Energy Letters (IF: 19.003, JCR Ranking: 1.852 %), a world-renowned energy journal on February 2021. ※ Paper: Triboelectric Charge-Driven Enhancement of the Output Voltage of BiSbTe-Based Thermoelectric Generators ※ https://doi.org/10.1021/acsenergylett.0c02483 https://www.skku.ac.kr/eng/About/media/news.do?mode=view&articleNo=88733&article.offset=0&articleLimit=10
-
- 작성일 2022-01-26
- 조회수 1315
-
- [Student] AMSE research team led by Prof. Hyung Koun Cho (Young-Been Kim Ph.D.) suggests photocurrent generation enhancement and p
- AMSE research team led by Prof. Hyung Koun Cho (Young-Been Kim Ph.D.) suggests photocurrent generation enhancement and pulse-driven system by developing water-splitting Hydrogen producing-purpose Interleaved biphasic p–n blended copper indium selenide (Cu-In-Se) photoelectrode material [Figure1] Researcher Young-Been Kim AMSE Young-Been Kim under the Ph.D. program in Prof. Hyung Koun Cho‘s research team fabricated a high-efficient solar energy water splitting system that operates in alternating current (AC) voltage. By designing an electrochemical deposition-based precursor synthesis process in order to micro-control based on thermodynamic morphology of Cu-In-Se (CIS), the research team developed a semiconductor structure where secondary phases coexist through the selenization process. Based on that, the team built the pulse-driven system in which enables high hydrogen evolution. The multiphasic structure has improved the charge transport efficiency due to the expansion of the depletion region formed inside and on the surface of semiconductor electrodes. It can also generate photocurrent at reduction under negative (-) voltage and oxidation under positive (+) voltage due to the presence of multiphase. Consequently, the pulse-driven system is the new mechanism that can fully leverage the entire photocurrent generated out of AC output. Pulse-driven photoelectrochemical (PEC) water splitting has been introduced to improve Hydrogen evolution efficiency by destroying the charge accumulation and electrical double layer (ionic layer) of the electrode surface causing the loss. Herein, the research team demonstrated first significant performance in the field of photoelectrochemical water-splitting employing semiconductor electrodes. Furthermore, efficient hydrogen evolution was confirmed by suppressing the formation of large-size cluster bubbles and facilitating hydrogen ion adsorption. Specifically, Through a 156% improvement in hydrogen evolution over the DC voltage system, Researcher Kim attested the superior performance of pulse-driven PEC water splitting system. Along with public attention on hydrogen energy in which shows high efficiency as renewable energy to replace petroleum, water-splitting research using light to generate hydrogen is increasingly being active. Thus, research has been conducted on photoactive materials that can generate high current under sunlight. However, it was limited to single conductivity types in which shows very low efficiency of photo-generated charge transport due to the neutrality of the inner area of absorbers. Consequently, the researchers, by focusing on the development of multi-phase chalcogenide materials that enhance charge transport efficiency, enabled utilizing both photocathode and photoanode by controlling the precursor synthesis and selenization process. This research was supported by Samsung Research Funding &Incubation Center of Samsung Electronics [grant number SRFC-MA170206]. The paper was published online in January 2021 in Applied Catalogis B: Environmental (IF 16.683), a SCI journal within the top 1.94% in materials and environmental engineering category. [Figure 2] The photo-generated minority carriers effectively flow into interleaved depletion regions and transport along the externally induced built-in field at 0 V vs RHE. [Figure 3] (a) Sequential steps illustrating one-cycle of current behavior in chronoamperometry result under pulse bias of 0 and 0.8 V vs RHE under light illumination (b) schematic diagrams for charge transport mechanism under constant light illumination from p-n interleaved CIS photoelectrode, where (Steps 1 and 3 ) the high-density charge transport through interleaved depletion regions; and (Steps 2 and 4 ) charge accumulation at the surface region and equilibrium state indicating a saturated steady state. (c) CA results and hydrogen evolution rate of the CIS/AZO/TiO2/Pt photoelectrode at pulse bias of 0 and 0.8 V vs RHE with alternating frequency of 150 cpm (1 M Na2SO4 electrolyte buffered at pH 5 with potassium borate solution) under constant 1 sun light illumination. [Figure 4] (a) Electrical double layer (EDL) formation under negative biased electrode (b) Hydrogen generation mechanisms through the reduction reaction in the electrolyte (c) Active area loss due to gas agglomeration produced when DC power has driven https://www.skku.ac.kr/skku/campus/skk_comm/news.do?mode=view&articleNo=88237&article.offset=0&articleLimit=10
-
- 작성일 2022-01-26
- 조회수 1364
-
- [Student] Minsu Choi of AMSE wins a Silver award at the 27th HumanTech Paper Award
- Minsu Choi of AMSE wins a Silver award at the 27th HumanTech Paper Award Sungkyunkwan University is pleased to announce that it has received 2 Silvers, 4 Bronzes, 1 Special awards at the 27th Samsung Humantech Paper Award. At the award ceremony, Minsu Choi (Advisor: Prof. Jae-Chan Lee) in the Department of Advanced Materials Science Engineering was presented with Silver award within the category of ‘Material Science & Engineering’. The Humantech Paper Award was established in 1994 with the aim of discovering challenging and creative young researchers who would lead the future. It is a driving force for their academic enthusiasm to cultivate creativity and expression and further promote the desire for research. https://www.skku.ac.kr/eng/About/media/news.do?mode=view&articleNo=88226
-
- 작성일 2022-01-26
- 조회수 1408
-
- [Research] The joint research team led by Professor Sang-Woo Kim developed the world’s first perovskite-based direct current triboe
- The joint research team led by Professor Sang-Woo Kim developed the world’s first perovskite-based direct current triboelectric nanogenerator -The research team succeeded in the development of the world’s first direct current triboelectric nanogenerator by applying dynamic perovskite/CTL heterojunction -The findings can be applied to the charging mechanism for mobile electronic devices and skin wound treatment, etc. in near future [Figure 1] Prof. Sang-Woo Kim of AMSE and Prof. Nam Gyu Park of ChemE Prof. Sang-woo Kim, as the corresponding author, and a Ph.D. candidate Bosung Kim (co-first author) developed the world’s first perovskite-based direct current (DC) triboelectric nanogenerator (TENG) in collaboration with Prof.Park Nam Gyu (corresponding author) of ChemE, Dr. Chunqing Ma (lead author). The TENG converts mechanical energy from external sources into electrical energy through the contact-separation processes. Using micro-movement techniques in which generates electrical output, the TENG can be employed as an energy source for portable electronic devices and as a technology to treat skin wounds leveraging human body movements. Conventional triboelectrification entailed AC (alternating current) signals, which demands an external circuit that leads to the reduction of energy conversion efficiency with bulk system size. Free electrons and holes generated by triboelectrification from the sliding motion can be transferred by the heterojunction, forming DC power output. The phenomenon was first identified by the joint research team led by Prof. Sang-Woo Kim and Prof. Nam Gyu Park. Upon the contact and separating (Sliding) processes, the spiro’s organic hole conductor film placed on the perovskite semiconductor film produces negative and positive charges on the mutual interfaces. The charges migrate to form stable energy levels thermodynamically, resulting in electric current. [Figure 2] Schematic device structure and output analysis. (a) Schematic illustration of the dynamic perovskite/hole transport layer (HTL) heterojunction device. (b) IV curves obtained from the dynamic sliding contact between the FAPbI3 perovskite and the spiro layers, along with static (no sliding movement) condition, measured in the dark (c) voltage and (d) current output of the dynamic perovskite/spiro heterojunction device under continuous sliding movements. Conventional triboelectricity generates AC as the electric current changes along with the contact-separation direction. On the contrary, this triboelectricity follows the principle of charge separation in P/N junction; DC can be generated regardless of the direction of the contact-separation process. Furthermore, the research team demonstrated that light illumination and physical pressure act as stimuli to current output to a large extent. “Dynamic halide perovskite heterojunction that generates DC doesn’t require rectifier to convert AC to DC; thus it can reduce the device size”, said Prof. Nam Gyu Park. “The dynamic halide perovskite heterojunction will perform better than conventional AC triboelectricity when applied to wound treatment that requires micro-electric fields.”, Prof. Sang-woo Kim noted. This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Ministry of Science and ICT (MSIT) of Korea under contracts NRF-2016M3D1A1027663 and NRF-2016M3D1A1027664 (Future Materials Discovery Program) and NRF-2018R1A2A1A19021947 (the Basic Science Research Program). This research was in part supported by Energy Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), funded by the Ministry of Trade, Industry & Energy (No. 20193091010310). ※ Paper title: Dynamic halide perovskite heterojunction generates direct current https://www.skku.edu/skku/campus/skk_comm/news.do?mode=view&articleNo=88053&article.offset=0&articleLimit=10
-
- 작성일 2022-01-26
- 조회수 1290