Ultra-high µC* beyond 10 000 F cm-1 V-1 s-1 in organic electrochemical transistors

Abstract Organic electrochemical transistors (OECTs) are the heart of promising high-sensitivity biosensors, electrophysiological monitors, and neuromorphic devices. In a context of growing interest for such strategic electronics, we investigate a novel PBTTT polymer bearing single ether side chains (PBTTT-8O) in OECTs. Pristine, non-aligned, devices match state-of-the-art transconductance, confirming the value of single ethers for designing next-generation organic mixed ionic-electronic conductors (OMIECs). Moreover, a ten-fold enhancement of 𝜇C*, reaching 12 000 F cm-1 V-1 s-1, is achieved by unidirectional alignment of PBTTT-8O, opening doors to unprecedented device sensitivity. Such improvement is mainly attributed to enhanced hopping along ordered polymer chains, resulting in ultra high mobility over 25 cm2 V-1 s-1. Interestingly, aligned channels dope twice and dedope fifteen times faster than pristine ones, offering a path to achieve rapid ON/OFF device switching. This study reports an easily transferable solution to concomitantly boost the signal amplification and switching speed of bioelectronic devices.