Keon Jae Lee Ph.D
KAIST Institute for AI, Professor


Keon Jae Lee is a professor in Dept. of MSE at KAIST. He earned the Ph.D degree from UIUC in 2006. His current research interests are self-powered flexible electronic system for bio, energy and electronics. He has coauthored over 80 SCI papers in journal including Science, Nature Materials, Nature Comm. Nano Letters, Adv. Mater, Energy Environ. Sci, ACS Nano, Adv. Energy Mater. Adv. Func. Mater. He has filed ~150 patents and ~60 of these are licensed.


With the emergence of the internet of things (IoT) era, visual IoT platforms have attracted significant interest, which can offer sensing, collecting, and processing of optical information in hyperconnected society. Flexible displays are a potential candidate for bilateral visual communication, as they can be easily affixed anywhere, such as on the surfaces of human skin, clothes, automobiles and buildings. III-V Inorganic LEDs have superior characteristics, such as long-term stability, high efficiency, and strong brightness compared to OLED. However, due to the brittle property of inorganic materials, III-V LED limits its applications for the flexible electronics. This seminar introduces the flexible vertical GaAs/GaN microLED on plastic substrates using anisotropic conductive film (ACF), resulting high optical power density, The superb properties of the flexible inorganic LED enable the dramatic extension of flexible displays toward not only wearable devices of light source but also full color flexible micoLED displays for consumer TV.

MicroLED stimulation of specific neural populations of the brain is one of the facile and reliable methods used in neuroscience for deduction of functional movement, complex behavior and even long-range connectivity. Recent advanced biomedical tools now employ flexible optoelectronic devices combined with optogenetic mouse models to activate small functional regions using blue-light driven channelrhodopsin. Here we introduce flexible vertical light-emitting diodes (VLEDs) for 2D perturbation of specific functional areas of mouse cortex, capable of stimulating motor neurons deep below layer III from the brain surface. Selective operation of pulsed red light from f-VLEDs induces mouse body movements and synchronized electromyogram (EMG) signals. These results show that the III-V based flexible LED can be used as the future flexible implantable biomedical applications such as skin research and phototherapeutic tool.