Stable and High Performing n-Type and Ambipolar Organic Electrochemical Transistor for Next-Generation Bioelectronics

Organic mixed ionic-electronic conductors (OMIEC), which are capable of efficiently transporting and coupling ionic and electronic charge, have gained significant attention in recent years as emerging organic materials for bioelectronic, neuromorphic computing, circuits and energy storage systems. One emerging device that uses these OMIECs is the organic electrochemical transistors (OECTs), which offer the advantages of low operation voltage (&lt; 1V), high sensitivity and excellent aqueous operating capability. To date, OMIECs for OECTs have predominantly been <i>p</i>-type materials, while their <i>n</i>-type counterparts lag far behind in performance and stability, hampering their adoption in complementary circuit designs, electrochemical energy storage, and sophisticated biosignal sensing that rely on electron transfer. In this talk, I will present our recent progress on developing new conjugated ladder-type polymers which exhibit good mixed ionic-electronic conduction properties, enabling stable and fast <i>n</i>-type organic electrochemical transistors. This is due to the polymer’s predominant edge-on packing and enhanced backbone coplanarity which promote efficient charge transport, as well as its porous structure which facilitates efficient ion penetration and transport. These unique advantages make this polymer especially suitable for bioelectronics, such as being used as a pull-down channel in a complementary inverter for long-term stable detection of electrophysiological signals. Moreover, the developed device shows a reversible anti-ambipolar behavior, enabling reconfigurable electronics to be realized using a single material. In addition, my talk will present our studies on various conjugated polymer blends with ambipolar properties, providing a facile strategy to simplify the fabrication process and reduce the manufacturing cost while simultaneously obtain high performing logic circuits.