Cycling stability of organic electrochemical transistors

In recent years, organic electrochemical transistors, which possess low driving voltage (<1 V), high transconductance (>10 mS), and mechanical robustness, have gained tremendous research interest in the area of bioelectronics, where low power dissipation, decent sensitivity, and biocompatibility are vital. These advantages are attributed to the novel mixed ionic-electronic (semi)conductors, where their electrical conductance can be effectively modulated through the bulk doping/dedoping process by the ions from the electrolyte dielectric. However, this process would irreversibly affect the micro/nano structures and/or chemical formula of the semiconductors, thus resulting in inferior cycling stability when compared to other transistor techniques. In this review, mechanisms on how the micro/nano structures and chemical formulas are influenced by the doping/dedoping process, are systematically summarized, followed by the presentation of state-of-the-art high-performance OECTs with decent cycling stabilities. Last, future perspectives on OECTs are provided, focusing on possible strategies to enhance cycling stability.