High Transconductance on Thiophene‐Based Vertical Organic Electrochemical Transistors

Abstract Organic electrochemical transistors (OECTs) are highly efficient ion‐to‐electron transducers, capable of achieving extremely large signal amplification, quantified by high transconductance ( g m ) levels. Optimizing this parameters is crucial for developing highly sensitive electronic and bioelectronic devices. Here, record‐high transconductances values exceeding 100 mS are obtained in vertical step‐edge OECTs (vOECTs) utilizing two well‐known p‐type organic semiconductors: poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) and poly(3‐2‐[2‐(2‐methoxyethoxy)ethoxyethyl]thiophene‐2,5‐diyl) (P3MEEET). Both materials exhibit high on‐currents, small hysteresis and an on/off ratio on the order of 10 5 . To benchmark the performance of vertical OECT architectures, it is proposed to normalize the maximum transconductance to the minimal footprint of the devices, which is equivalent to the cross‐sectional area of the transistor channel defined by the product of channel width W and channel thickness d . By comparing g m /( Wd ), these devices achieve one of the highest values reported to date. This work demonstrate record transconductances in well‐known materials using step‐edge vOECTs with a small cross‐sectional area, establishing a robust platform for high‐performance OECT‐based applications.