Professor of Department of Printed Electronics Engineering, Sunchon National University, Sunchon, Korea
Chair of Regional Innovation Center in Sunchon National University
R2R gravure as an additive manufacturing technology for the fabrication of large area, flexible and inexpensive devices
Department of Printed Electronics Engineering, Sunchon National University, Sunchon, Korea
Over the last decade, roll-to-roll (R2R) printing has been pursued with the expectation of developing a commercially viable, high throughput technology to manufacture flexible, disposable and inexpensive printed electronics. However, in recent years, pessimism has emerged due to the barriers faced when attempting to fabricate and integrate thin film transistors (TFT) using R2R printing. In this presentation, for the first time, I will report a way of manufacturing TFT based large area, flexible and inexpensive devices via a fully R2R gravure printing process with Ag nanoparticle based conducting ink, BaTiO3 nanoparticle based dielectric ink and single walled carbon nanotubes (SWCNT) based semiconducting ink. Using R2R gravure system including those inks and poly(ethylene terephthalate) (PET) as the substrate, we obtained about a 92 % device yield in 15 x 0.25 m2 of PET roll with the printing speed of 6 m/min and extracted the scalability factors needed for a feasible manufacturing process. The R2R gravure printing process addresses several barriers in the fabrication and integration of printed TFTs, circumventing or surmounting challenges associated with the alignment of source-drain and gate electrodes, threshold voltage (Vth) shift, stability and overall device yield, proving that R2R printing is indeed a viable advanced manufacturing technology that can enable high throughput production of inexpensive smart packaging
Gyoujin Cho received a Ph.D. degree from the University of Oklahoma, Norman, in 1995. In 1996, he joined the faculty of the Department of Chemical Engineering, Sunchon National University, Korea, and currently he is a faculty member in the Department of Printed Electronics Engineering, World Class University Program at Sunchon National University. Since 2002, he has focused his research on printed electronics and successfully demonstrated all-gravure printed 13.56 MHz RFID tags (4, 16, 32, and 96 bit). Based on printed RFID technology, fully printed electrochemistry (CV) based NFC sensor tags as a platform for RF e-sensor has been first demonstrated in the world. During the last 10 years to lead printed electronics, he was a PI of two government R&D projects (20 million dollar) and Associate Secretary of International Standardization (IEC-TC-119: Printed Electronics). He also has served as Associate Editor in Flexible and Printed Electronics, IOP, and Editorial Board in Scientific Reports, Nature Publishing. Recently. In 2017, he demonstrated the fully R2R gravure printed TFT-active matrix based flexible e-paper for the first time in the world.
Department of Printed Electronics Engineering and Regional Innovation Center (RIC) in Sunchon National University was respectively founded in 2008 and 2005 by Korean Government supports for leading the innovation in IoT and consumer electronics via Printed Electronics. Especially, technologies and services in R2R gravure printed electronics devices are the world best.