Conductive polymer electrodes have exceptional promise for next generation electronic and electrochemical devices due to inherent mechanical flexibility, printability, biocompatibility, and low cost. Yet conductive polymers continue to suffer from lower conductivity than conventional semiconductors, which ultimately can limit performance. Electrical conductivity can be increased by increasing the total number of carriers through a charge transfer reaction – oxidation or reduction. The first half of this talk will focus on the use of spectroscopic methods to evaluate the effects of chemical, electronic, and physical structure changes of organic semiconductors that accompany charge transfer reactions at interfaces, with consequences on device performance.
The second half of this talk will focus on the unique hybrid electronic-ionic conduction of conductive polymers, which has enabled novel electrochemical devices including bioelectronics. Two key functionalities of potential-dependent doping at the polymer/electrolyte interface will be addressed: i.) rates of ion migration within the polymer and ii.) rates of charge transfer between a polymer and a redox active molecule. The potential-dependent microstructure and relative distribution of electronic states (percent doping) are found to be critical in both mechanisms, although happen at different time scales. For charge transfer, the presence of an inverted regime is observed for the first time, representing a path forward to redox selectivity at polymer electrodes.
