신소재공학과

Research Highlight

A Korea Advanced Institute of Science and Technology (KAIST) research team led by Professor Keon Jae Lee from the Department of Materials Science and Engineering and Professor Daesoo Kim from the Department of Biological Sciences has developed flexible vertical micro LEDs (f-VLEDs) using anisotropic conductive film (ACF)-based transfer and interconnection technology. The team also succeeded in controlling animal behavior via optogenetic stimulation of the f-VLEDs.


                           


Flexible micro LEDs have become a strong candidate for the next-generation display due to their ultra-low power consumption, fast response speed, and excellent flexibility. However, the previous micro LED technology had critical issues such as poor device efficiency, low thermal reliability, and the lack of interconnection technology for high-resolution micro LED displays.

The research team has designed new transfer equipment and fabricated a f-VLED array (50x50) using simultaneous transfer and interconnection through the precise alignment of ACF bonding process. These f-VLEDs achieved optical power density (30 mW/mm2) three times higher than that of lateral micro LEDs, improving thermal reliability and lifetime by reducing heat generation within the thin film LEDs.
These f-VLEDs (thickness: 5 micrometre, size: below 80 micrometre) can be applied to optogenetics for controlling the behavior of neuron cells and brains. In contrast to the electrical stimulation that activates all of the neurons in brain, optogenetics can stimulate specific excitatory or inhibitory neurons within the localized cortical areas of the brain, which facilitates precise analysis, high-resolution mapping, and neuron modulation of animal brains. (Refer to the author's previous ACS Nano paper "Optogenetic Mapping of Functional Connectivity in Freely Moving Mice via Insertable Wrapping Electrode Array Beneath the Skull")

In this work, they inserted the innovative f-VLEDs into the narrow space between the skull and the brain surface and succeeded in controlling mouse behavior by illuminating motor neurons on two-dimensional cortical areas located deep below the brain surface.


                              이건재 교수 기사 4.jpg


Comparison of micro-LEDs Technology. (IMage: KAIST)


Professor Lee said, "The flexible vertical micro LED can be used in low-power smart watches, mobile displays, and wearable lighting. In addition, these flexible optoelectronic devices are suitable for biomedical applications such as brain science, phototherapeutic treatment, and contact lens biosensors."
He recently established a startup company (FRONICS Inc.) based on micro LED technology and is looking for global partnerships for commercialization. This result was published in the February 2018 issue of Nano Energy ("Optogenetic Control of Body Movements via Flexible Vertical Light-Emitting Diodes on Brain Surface").

No. Subject Author Date Views
Notice New Anisotropic Conductive Film for Ultra-Fine Pitch Assembly Applications ADMINI 2018.11.30 42
Notice KAIST Introduces Faster and More Powerful Aqueous Hybrid Capacitor ADMINI 2018.11.13 84
Notice Crystal size of organic semiconductors can be controlled using inorganic polymer micropillar-based solution shearing system ADMINI 2018.11.06 227
Notice Mussel-Inspired Defect Engineering Enhances the Mechanical Strength of Graphene Fibers ADMINI 2018.11.06 132
Notice Flexible Piezoelectric Acoustic Sensors for Speaker Recognition ADMINI 2018.10.04 248
Notice Spray Coated Tactile Sensor on a 3-D Surface for Robotic Skin ADMINI 2018.10.04 237
51 “Nature Materials” News & Views wrote by Prof. Sang Ouk Kim file admin 2015.02.17 11709
50 Hyper-stretchable elastic piezoelectric energy harvester file ADMINI 2015.04.29 9707
49 The Way towards Commercialization of Highly Efficient Nanogenerator file admin 2015.02.17 9229
48 Academic Achievements & Related Awards file admin 2015.02.17 9228
47 Best Paper Award at 2014 Pan Pacific Microelectronic Symposium file admin 2015.02.17 9050
46 The First Demonstration of Self-powered Cardiac Pacemaker file admin 2015.02.17 8972
45 Equipment Development: “Hu:u” -New Concept Indoor Environmental Gauge file admin 2015.02.17 5698
44 Making Graphene Using Laser-induced Phase Separation file ADMINI 2016.12.07 4564
43 Mobile Sensor Array Platform & its Circuit Development. file admin 2015.02.17 4069
42 Intel Best Paper Award at Electronic Components and Technology Conference file admin 2015.02.17 4049
41 Excellent Paper Award at the 2014 Conference on Next Generation Lithography file admin 2015.02.17 4047
40 Seon-Jin Choi, Jinsup Lee Prize Winner at the “9th 1nside” Edge International Thesis Competition from Samsung Electro-mechanics. file admin 2015.02.17 4001
39 One of 2013 KAIST Top 10 Representative R&D Outcomes. file admin 2015.02.17 3963
38 Grand Prize at the Dow Chemical Korea Award 2014 file admin 2015.02.17 3958
37 3D Free Standing Structure Made of Graphene. file admin 2015.02.17 3940
36 The Convergence New Technology Fair Silver Award file admin 2015.02.17 3931
35 Prize Winner at 20th SAMSUNG Human Tech Paper award (2013) file admin 2015.02.17 3841
34 Review article from Prof. Sang Ouk, Kim group was published in 25th anniversary of Advanced Materials. file admin 2015.02.17 3808
33 Excellent paper Award at the Optical Society of Korea. file admin 2015.02.17 3645
32 New Nanocomposite Catalyst applied for Li-O2 Batteries with improved High-capacity and Long-cycle file admin 2015.02.17 3625