Seminar & Colloquium
[세미나: 10월 6일(금), 오전 10시] Prof. Sungjun Park, Ajou University
Title
Ion-Carrier Interactions in Organic Electrochemical Transistors
Speaker
Distinguished Prof. C. Daniel Frisbie, Chemical Engineering and Materials Science, University of Minnesota
Education
- 1993 Massachusetts Institute of Technology, Ph. D., physical chemistry
- 1989 Carleton College, B.A., Chemistry
Experience
- 2014 ~ Department Head
- 2012 ~ Distinguished McKnight University Professor
- 2006 ~ 2012 Professor
- 2000 ~ 2006 Associate Professor
- 1994 ~ 2000 Assistant Professor, University of Minnesota
- 1993 ~ 1994 NSF Postdoctoral Fellow in Chemistry, Harvard University
| Date | Tuesday, October 17, 2023
| Time | 16:00 ~
| Venue | 33동 223호(동부세미나실)
[Abstract]
Organic electrochemical transistors (OECTs) are currently of great interest for a variety of applications in neuromorphic computing, human-machine interfacing, and chemical sensing. These transistors are also excellent platforms for investigating the fundamental transport physics of organic semiconductors at very large carrier densities, which is the focus of this talk. Application of a gate voltage in OECTs results in electrochemical doping of the organic semiconductor channel which allows carrier densities as high as 1021 cm-3 (volumetric) or over 1014cm-2 (areal) to be achieved. At these high carrier densities metallic behavior might be expected, but often what one observes is that conductivity first increases, then peaks, and subsequently decreases as a function of carrier density. The low conductivity at high carrier density is important to understand, as it may be key to developing organic semiconductors with improved performance in OECTs. This talk will show that Coulombic attraction between charge carriers and counter ions in OECTs plays a very important role. In fact, it appears that at high carrier densities, ions can pin the charge carriers, dramatically lowering their mobility. Minimizing the ion-carrier interaction is therefore key to improving charge transport. We will demonstrate that essentially all types of organic semiconductors exhibit the ion pinning effect at high charge densities and this understanding provides a pathway to improve the transport performance of highly doped organic semiconductors.
| Host | 이태우 교수(02-880-8021)