- 건국대학교

	Wi Hyoung Lee's team Develops Super-sensitive Transparent Graphene Tactile Sensor
	관리자		568		2020.04.27

Professor Wi Hyoung Lee of the Department of Chemical Engineering, Konkuk University, announced on the 17th that in collaboration with Professor Do-Hwan Kim of the Department of Chemical Engineering, Hanyang University, they developed an ultra-sensitive transparent graphene tactile sensor using the phenomenon of liquid droplets sticking and falling. <img style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11786130" />This research paper written by Prof. Wi Hyoung Lee of Konkuk University (corresponding author), Seung Chul Lee of Department of Organic and Nano System Engineering(first author, graduated from master's course), Joo Sung Kim, Ph.D. student from Hanyang University (first author), and Prof. Do Hwan Kim(corresponding author) and the paper was published in the latest issue of the international journal titled “Advanced Functional Materials (IF = 15.621),” in the April issue of Inside Front Cover. (Title of paper: “Enhanced Sensitivity of Iontronic Graphene Tactile Sensors Facilitated by Spreading of Ionic Liquid Pinned on Graphene Grid” ) With the increasing importance of wearable sensors, the importance of smart interfaces and electronic skin technologies that recognize users' surroundings in real time is increasing. The most important technology among electronic skin is a tactile sensor technology that can sensitively recognize even small pressure stimuli.
Prof. Wi Hyoung Lee's research team at Konkuk University has developed an ionic tactile sensor with the world's best sensitivity in the Gentle touch area by using the phenomenon that the ionic liquid is immobilized between the intaglio graphene grid layers and spreads as the upper electrode made of graphene contacts the ionic liquid.
Furthermore, by using this technology, a tactile sensor array in which crosstalk between devices and devices is completely blocked was manufactured. This excellent characteristic is that an ionic liquid having a large dielectric constant has an air capacitance when it does not come into contact with the upper electrode and then uses a phenomenon in which the capacitance increases rapidly when it touches the upper electrode. This study presented for the first time the paradigm that a tactile sensor with excellent sensitivity / fast recovery speed can be manufactured by using the phenomenon of sticking and dropping of liquid, and was selected as a cover paper in the latest issue of Advanced Functional Materials. Figure. Tactile sensor mechanism proposed in this study: A schematic diagram of sensing pressure from the change in capacitance as the ionic liquid immobilized on the graphene grid contacts the upper graphene electrode.
<img style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11785697" width="589" height="391" /> 
The ionic tactile sensor developed in this study is expected to be applicable to various fields such as flexible displays and healthcare devices. In addition, when manufacturing this tactile sensor as a large-area array, it will be possible to minimize errors when touching with low crosstalk between devices. In addition, since the graphene electrode / ionic liquid active layer is transparent and flexible, it is expected to be used as a wearable tactile sensor that can provide various visual effects and body adhesion.
Researcher Seung Chul Lee, the first author of this research paper, graduated from the Department of Organic and Nano System Engineering at Konkuk University, is currently a researcher at LG Display. This research was carried out with the support of the Global Frontier Project (Nano-based Soft Electronics Research Group) and the Basic Research Project (Mid-sized Research) by the Ministry of Science and ICT.
  ☞ <a style="color: #0000ff;" href="https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201908993" target="_blank">Click to see the paper online </a> <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201908993" target="_blank"><img style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11785695" width="610" height="801" /></a>

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