Gate bias modulation towards organic electrochemical transistors with ultra-high cycling stability

Abstract

Organic electrochemical transistors (OECTs) show great potential in next-generation bioelectronics due to their high transconductance, low driving voltage, and biocompatibility. These advantages rely on efficient electrochemical doping/dedoping of the transistor channel consisting of organic mixed ionic–electronic conductors (OMIECs). Nevertheless, during device operation, hydration and electrolyte swelling lead to inferior cycling/operation stability of OECTs when compared with other conventional transistors. To enable further development and commercialization of OECTs, long-term stable operation is mandatory. Here, it is discovered that a slight variation in gate bias (V_G) during operation would result in contrasting degradation in OECT performance with a conventional planar structure based on p-type p(g2T-T), which is the result of the alternating consumption of active OMIEC content due to the swelling effect during cycling. The introduction of the vertical architecture along with a crosslinking agent in the channel would largely decelerate/avoid such a process, which could yield an OECT with more than 250 000 full cycles (cycling duration of 10 000 s). Moreover, this strategy can be extended to another n-type OMIEC (Homo-gDPP). This work reveals a unique class of bioelectronics where their lifetime can be managed and controlled by device structure engineering, showing extensive potential in biomedical and bio-implantable functional devices.