By employing redox-active and redox-inactive polymers in a mixed-dimensional heterostructure architecture, Northwestern University MRSEC IRG-1 has achieved vertical organic electrochemical transistors (vOECTs) for the first time. These vOECTs allow p-type and n-type devices to be stacked into high-density complementary logic circuits, including inverters and ring oscillators, with exceptional gain, stability, and operating frequency. This mixed-dimensional architecture opens many possibilities for fundamental studies of organic semiconductor redox chemistry and physics in nanoscopically confined spaces without macroscopic electrolyte contact. Moreover, this work demonstrates the potential of vOECTs as a viable alternative to conventional inorganic transistors for digital logic circuits, especially in low-cost, flexible, and energy-efficient electronic applications such as wearable and implantable sensors.
