Over Tenfold Increase in Current Amplification Due to Anisotropic Polymer Chain Alignment in Organic Electrochemical Transistors

Abstract

Organic electrochemical transistors (OECTs) are central to the development of highly sensitive (bio)sensors, energy-efficient neuromorphic devices, and high-precision electrophysiological monitoring systems. With growing interest in these strategic electronic devices, a novel PBTTT polymer bearing single-ether side chains (PBTTT-⁸O) in OECTs is investigated. Pristine isotropic non-aligned OECT performance matches state-of-the-art transconductance, highlighting the potential of single ethers for designing high-performance organic mixed ionic-electronic conductors (OMIECs). Moreover, a 13× enhancement of current output is achieved by anisotropic polymer chain alignment of PBTTT-⁸O, opening doors to unprecedented device sensitivity. Compared to pristine ones, aligned OECTs afford a 6× increase in the normalized transconductance (g_mL/Wd), reaching an unprecedented 2 580 S cm⁻¹. Such improvement is mainly due to a gain in carrier mobility µ, as evidenced by four distinct methods. In addition, aligned OECTs exhibit faster doping front propagation, ON switching, and OFF switching compared to pristine ones. This study hence reports a versatile and easily transferable approach to concomitantly boost signal amplification and accelerate the response time of bioelectronic devices.