Neuromorphic memory effect in aerosol-jet-printed thick-PEDOT:PSS organic electrochemical transistors

Organic electrochemical transistors (OECTs) based on poly(3,4ethylenedioxythiophene) doped with poly (styrene sulfonate) (PEDOT:PSS) semiconductor have emerged as promising candidates for neuromorphic devices due to their mixed ionic–electronic transport of this polymer and their ability to emulate biological synaptic behavior. In this work, we report on the fabrication and characterization of flexible thick-film PEDOT:PSS OECTs produced by aerosol jet printing to explore the relationship between drain bias and memory performance in thick PEDOT:PSS channels. We found that these devices exhibited both short-term and long-term memory dynamics, depending on the applied gate-pulse number and pulse duration. We found that thick PEDOT:PSS channels displayed enhanced hysteresis in transfer curves, consistent with a larger ionic reservoir that allows prolonged charge trapping and a slower dedoping. A systematic study of the drain voltage ( V D ) revealed that higher | V D | values enhance the memory level by increasing both the current modulation and transconductance, as a larger fraction of the PEDOT:PSS channel participates in the electrochemical redox process, although the conventional voltage memory window exhibits a non-monotonic dependence on drain bias. Instead of relying exclusively on the conventional voltage memory window, an analysis of the effective memory window, which was defined as the enclosed area of the forward and backward transfer characteristics, was proposed to evaluate the effective ionic memory behavior of the OECTs, finding a linear trend with respect to V D . These findings highlight the effect of drain bias in thick PEDOT:PSS channels offering design guidelines for future bioinspired, and memory-based printed and flexible organic electronics.