Molecular packing and film morphology control in organic electrochemical transistors

Organic electrochemical transistors (OECTs) based on conjugated polymers have aroused great interest in flexible bioelectronics due to their high transconductance, low operating voltage, and good biocompatibility. The OECT performance is mainly determined by the mixed ionic and electronic transport properties of organic semiconductors, which are largely influenced by the molecular packing and film morphology. To date, most efforts have been devoted to the development of new polymer structures. However, understanding the relationship among the chemical structure, molecular packing, film morphology, and OECT performance remains less explored. In this review, we provide an overview of recent advances in OECTs, with special emphasis on the relationship among the chemical structure, molecular packing, film morphology, and OECT performance. Finally, the challenges and prospects of OECTs are discussed as guidelines for future exploration.