Degradation Processes and Defect States Arising from Electrochemical Cycling of Conjugated Polymers

Degradation Processes and Defect States Arising from Electrochemical Cycling of Conjugated Polymers The continued development and commercialization of conjugated polymers (CPs) will depend highly on improving their stability, which demands an in-depth understanding of degradation processes and resulting defect states. This understanding will be particularly essential to the development of CPs for use in electrochemical devices, which are garnering increased interest due to the promising applications of organic electrochemical transistors (OECTs). In electrochemical applications stability is an even greater challenge than in solid state devices due to the presence of electrolytes, which are often aqueous. Despite the importance of understanding degradation and defect states, this area has received a miniscule amount of effort relative to the field of CPs. In part, this dearth of research arises from the difficulty in measuring and probing defect states in these disordered semiconductors. This proposed research will develop and use defect state spectroscopies to probe degradation reactions in electrochemically doped CPs as a function of electrolyte chemistry, frontier energy levels of the CPs, CP monomer units, CP sidechains, and CP morphology. As a result, the project will identify how the interplay between these variables influences degradation processes and resulting defect states; thereby, providing fundamental guidance for the design of more stable CPs and more stable systems for electrochemical devices containing CPs. The development of defect state spectroscopies and their application to understanding degradation processes in CPs represents a major opportunity for the PI to build new strengths in an area that will be essential for the continued development of petroleum- derived CPs.