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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.

Dynamic glucose monitoring is important to reduce the risk of metabolic diseases such as diabetes. Wearable biosensors based on organic electrochemical transistors (OECTs) have been developed due to their excellent signal amplification capabilities and biocompatibility. However, traditional wearable biosensors are fabricated on flat substrates with limited gas permeability, resulting in the inefficient evaporation of sweat, reduced wear comfort, and increased risk of inflammation. Here, we proposed breathable OECT-based glucose sensors by designing a porous structure to realize optimal breathable and stretchable properties. The gas permeability of the device and the relationship between electrical properties under different tensile strains were carefully investigated. The OECTs exhibit exceptional electrical properties (gm ~1.51 mS and Ion ~0.37 mA) and can retain up to about 44% of their initial performance even at 30% stretching. Furthermore, obvious responses to glucose have been demonstrated in a wide range of concentrations (10−7–10−4 M) even under 30% strain, where the normalized response to 10−4 M is 26% and 21% for the pristine sensor and under 30% strain, respectively. This work offers a new strategy for developing advanced breathable and wearable bioelectronics.