ChEMS Seminar: New Materials & Printing Processes for Flexible Electronics
Department of Chemical Engineering and Materials Science
University of Minnesota, Minneapolis, MN
Abstract: Currently there is great interest in developing manufacturing methods for integrating electronic circuitry into flexible and stretchable substrates for a spectrum of applications including roll-up displays, wearable biosensors, smart labels, and electronic skins (e-skins) for robotics, for example. One fabrication strategy that has captured imaginations involves the use of digital or analog printing techniques to pattern electronically functional inks onto paper, plastic, rubber or metal foils. However, printed electronics has a number of significant challenges, including spatial resolution, pattern registration and printed circuit performance. In this talk, I will describe a multipronged approach to address these challenges that may bring roll-to-roll printed electronics closer to reality. To begin, I will show that innovations in materials allow the fabrication of printable, low-voltage thin film transistors (TFTs), the key building blocks of flexible circuits and that these can be incorporated into simple printed circuit demonstrations involving two dozen TFTs and an equivalent number of printed resistors and capacitors. The second half of the talk will describe a novel liquid-based fabrication approach that we term SCALE, or Self-Aligned Capillarity-Assisted Lithography for Electronics. The SCALE process employs a combination of digital printing and in-substrate capillary flow to produce self-aligned devices with feature sizes that are currently as small as 1 mm. The talk will finish with a discussion of the new opportunities in flexible microelectronics afforded by liquid-based processing.
Bio: C. Daniel Frisbie is Distinguished McKnight University Professor and head of chemical engineering and materials science at the University of Minnesota. He obtained a doctorate in physical chemistry at MIT in 1993 and was an NSF postdoctoral fellow at Harvard. His research focuses on materials for printed electronics, including organic semiconductors and their applications in devices such as transistors and electrochromic displays. Research themes include the synthesis of novel organic semiconductors, structure-property relationships, organic device physics and the application of scanning probe techniques. Recent efforts also include new manufacturing approaches for flexible electronics and the use of gel electrolytes as high capacitance gate insulators in OTFTs to lower drive voltages. From 2002-2014, Frisbie led a multi-investigator effort in organic optoelectronics at the University of Minnesota, sponsored by the Materials Research Science and Engineering Center (MRSEC) program of the NSF. He is currently the lead investigator on a Multi-University Research Initiative (MURI) grant funded by the Office of Naval Research for development of a roll-to-roll printed electronics manufacturing platform.
Host: Allon Hochbaum