Multilayer Porous Polymer Films for High-Performance Stretchable Organic Electrochemical Transistors

Abstract

Porous films offer a general and simple strategy for balancing the electron/hole transport, and ion doping/dedoping process in organic electrochemical transistor (OECT) channel. Here a universal 3D integrated approach that simultaneously achieves both enhanced transconductance (gm) and mechanical stretchability via constructing a multilayer breath-figured porous polymer channel by poly(3-hexylthiophene) (P3HT)/ polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) and poly(2,5-bis(3-triethyleneglycoloxythiophen-2-yl)-co-thiophene) (Pg2T-T)/SEBS mixture is demonstrated. The formed multilayer elastic porous structure provides efficient and tunable ionic-electronic coupling and transport pathways, while also introducing immunity toward mechanical tensile deformation. Remarkably, an obvious increase in gm [from 10.05 mS (2.13 mS) to 29.23 mS (7.38 mS) for Pg2T-T (P3HT)] is acquired by assembling the OECT porous channel from a single layer to a 3D trilayer. Moreover, mechanical stretchability as high as 40% for Pg2T-T and 60% for P3HT, is obtained with >21% gm retained. Furthermore, high gms (9.34 mS and 0.92 mS for Pg2T-T and P3HT, respectively) are maintained after 600 stretching cycles (20% and 30% tensile strains for Pg2T-T and P3HT, respectively). Overall, the 3D porous structure provides an effective strategy to enhance stretchability and electrical performance for OECTs, as well as opens possibilities for other electronics where both stretchability and a large surface-to-volume ratio are needed.