UChicago PME Materials Seminar Series- Jonathan Rivnay

Fundamental processes in organic mixed conductors and their applications in sensing and circuits

Organic mixed ionic/electronic conductors (OMIECs) have gained considerable interest in bioelectronics, power electronics, circuits and neuromorphic computing. These organic, often polymer-based, semiconductors rely on a combination of ionic transport, electronic transport, and high volumetric charge storage capacity. These properties enable new capabilities; for example, in the realm of bioelectronics, OMIEC-based electrochemical devices can efficiently amplify local bio-signals and can be engineered for spiking behavior to mimic basic neural pathways promising efficient biohybrid systems. However, despite recent progress and a rapidly expanding library of new materials, a full understanding of fundamental processes of OMIECs remains elusive. Critically, useful studies require us to probe these systems in device-relevant conditions, fully considering the effects of ions and solvent on microstructure and transport. To this end, we report on recent efforts towards structure/composition-property relations in high performance organic mixed conductors using operando techniques. For example, using resonant scattering and molecular dynamics simulations, we find ion condensation at semiconducting backbones at high charge densities. Such characterization opens new avenues to understand and design more stable, high-performance materials and devices.