Engineering Mixed Conductor Transport and Device Form Factor for Neuromorphic Applications

Materials processing and synthetic design serve as ideal avenues to control the transport properties of organic mixed ionic/electronic conductors (OMIECs). Small changes in chemistry can affect the materials electronic mobility, swelling, ion uptake and stability. Devices based on these materials have thus opened up new opportunities in bioelectronics, energy, and neuromorphic computing. Furthermore, volumetric/bulk transport and charging in organic mixed conductors opens up opportunities for less common device form factors that can result in scaled down and co-localized function in circuits. In this talk I will present on the engineering of OMIECs for artificial synapses, as well as recent efforts to improve artificial neurons by engineering highly non-linear responses. Recent efforts on vertical OECTs have shown promise for co-localized on-site amplification. However, this device geometry brings additional opportunities. By assembling in-series vertical OECTs with proper thresholds, devices with anti-ambipolar (off-on-off) responses can be engineered. As compared to single-component OECTs that show anti-ambipolar response (such as with BBL), bilayer vOECTs can be tailored in their thresholds, operating voltages, and anti-ambipolar peak width. We leverage this response for logic applications, and for demonstrating artificial spiking neurons. A combination of these functions is demonstrated which mimics a retinal signal processing pathway.