Understanding organic electrochemical transistors
Organic electrochemical transistors (OECTs) are an emerging class of biocompatible organic semiconductor device with transconductance nearly as high as graphene at one of the lowest gate voltages demonstrated in any technology, making them ideal platforms for bioelectronics. However much is yet to be understood or optimized in these devices. Until recently, published dynamical models were contradictory and did not predict observed behavior such as carrier density dependence of the mobility. In this talk I will highlight the difference between OECTs and existing devices such as MOSFETs to drive predictive models for OECT behavior. Simultaneous measurements of electrical response and the natural electrochromism of the organic semiconductor will be used to elucidate the nonlinear dependence of conductivity on charge carrier concentration. Material disorder will be explored and shown to explain the non-monotonic relationship between signal amplification and applied voltage. Finally, a model for transient response will be proposed and shown to enable switching, in certain regimes, 30 times faster (or under 20 microseconds) than the native RC time constant of the device.