February 3, 2017
Scalable and economical manufacturing of flexible transparent conducting films (TCF) is a key barrier to widespread adoption of low-cost flexible electronics. Here we demonstrate a simple, robust, and scalable method of flexible TCF formation using supersonic kinetic spraying. Silver nanowire (AgNW) suspensions were sprayed at supersonic speed to produce self-sintered films of AgNWs on flexible substrates. These films displayed remarkably low sheet resistance, < 10 Ω/sq, combined with high transmittance, > 90 %. These electrically-conducting, transparent and flexible coatings can be deposited over a 100 cm2 area in ~30 s. Theoretical analysis reveals the underlying physical mechanism behind self-sintering, showing that self-sintering is enabled by the high velocity of impact in supersonic spraying.
Dr. Sam S. Yoon is a Professor in the School of Mechanical Engineering at Korea University since 2005. He received a B.S. degree from Colorado School of Mines in 1997, a M.S. and Ph.D. degree in Aeronautics & Astronautics from Purdue University in 1999 and 2002, respectively. He was a post-doctoral fellow in the Department of Fire Science & Technology (9132) at Sandia National Lab from 2002 to 2005. He was a Visiting Professor at the NREL (National Renewable Energy Laboratory) in 2011. He has so far published over 145 peer-reviewed journal papers in the areas of electronics thermal management, heater, thermal barrier coating; supersonic cold spraying, inkjet printing, electrospraying, electrospinning, aerosol deposition; surface modification (superhydrophobic and superhydrophilic), self-cleaning, self-healing composite materials with focus in energy and environment applications.