Loren Kaake, SFU

https://lorenkaake.wixsite.com/lorenkaake

Organic Electro-Ionic Materials and Devices

Monday, November 6
11:30 a.m.
Engineering Computer Science Building, Room 116

and Zoom https://uvic.zoom.us/j/83657240884?pwd=3pDZp5892dS4gsAKoaplX1t2j9kgbh.1

ABSTRACT:  The number of possible organic compounds is practically infinite, making it highly probable that an organic material with excellent properties can be found for any application. However, leveraging this potential requires a deep understanding of the relationship between the property of interest and molecular structure. Molecules and polymers with extended pi conjugation exhibit conductive and semiconducting properties once thought only possible in inorganic materials. Organic solar cells, light emitting diodes, transistors, thermoelectric devices, and printed electronics rely on pi-conjugated materials as their primary active material. Many of the early investigations on this class of materials focused on their electrochemical properties; their ability to transport ions from an electrolyte to facilitate a change in their oxidation state and hence material properties. This line of investigation has re-emerged at the frontier of basic research, owing to the development of biosensors, neuromorphic computing elements, and electrochromic devices. The common feature uniting these seemingly disparate applications is that they leverage the ability of organic materials to simultaneously transport both electronic and ionic charge carriers. We have used in-situ spectroscopy to develop a first-order description of device operation and have put forward a generalizable structure-property relationship that governs the rate of ion transport in pi-conjugated materials. The key insight is the importance of local field interactions, important in material solubility, for example. With the insights gained by this knowledge, my group is developing a novel organic dielectric material based on zwitterionic liquids. Interestingly, a collective switching behavior is observed, which provides these materials with capacitances comparable to electrolyte solutions.