Fast and Durable Nanofiber Mat Channel Organic Electrochemical Transistors

Abstract

Bioelectronic devices that offer real-time measurements, biological signal processing, and continuous monitoring while maintaining stable performance are in high demand. The materials used in organic electrochemical transistors (OECTs) demonstrate high transconductance (GM) and excellent biocompatibility, making them suitable for bioelectronics in a biological environment. However, ion migration in OECTs induces a delayed response time and low cut-off frequency, and the adverse biological environment causes OECT durability problems. Herein, we present OECTs with a faster response time and improved durability, made possible by using a nanofiber mat channel of a conventional OECT structure. Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/polyacrylamide (PAAm) nanofiber mat channel OECTs are fabricated and subjected to various durability tests for the first time based on continuous measurements and mechanical stability assessments. The results indicate that the nanofiber mat channel OECTs have a faster response time and longer life spans compared to those of film channel OECTs. The improvements can be attributed to the increased surface area and fibrous structure of the nanofiber mat channel. Furthermore, the hydrogel helps to maintain the structure of the nanofiber, facilitates material exchange, and eliminates the need for a crosslinker.

Hydrogel-Gated FETs in Neuromorphic Computing to Mimic Biological Signal: A Review

“…A series of investigations on EDLT-based flexible synaptic devices was carried out by Wan’s research group [ 81 ]. They developed flexible planar gate synaptic transistors using a polymer electrolyte as the gate dielectric material, successfully accomplishing multiple synaptic functions in their research [ 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 ]. They introduced a laterally coupled oxide-based EDLT, enabling spike logic operation and modulation by incorporating multiple presynaptic inputs.…”

“…In 2023, Oh et al demonstrated an electrochemical neuromorphic organic device fabricated on flexible substrates. The device architecture involved a postsynaptic electrode (PEI/PEDOT:PSS film) interfacing with a presynaptic electrode (PEDOT:PSS) through an electrolyte [ 89 ]. Notably, this device displayed a vast array of nonvolatile and reproducible states, exceeding 500, while operating at remarkably low operating voltages [ 91 ].…”

Improved Organic Electrochemical Transistors via Directed Crystallizable Small Molecule Templating

“…Recent work demonstrated that acid crystallization of PEDOT:PSS dramatically improves OECT performance . Aligning polymers for OECT applications has also been demonstrated as an effective technique recently. − Some of these processing techniques have the perhaps unintended but beneficial effect of increasing the surface area/porosity of the organic semiconductor, which has been shown to improve steady state capacitance as well as doping kinetics. − …”

Signal Modulation of Organic Photoelectrochemical Transistor by a Z-Scheme Photocathodic Gate: An Innovative Dual Amplification Strategy for Sensitive Aptasensing Application

“…Organic electrochemical transistor (OECT), on the basis of the modulated channel conductivity by the ionic injection from the electrolyte, is especially desirable due to its advantages, including excellent environmental stability, being conducive to miniaturization, and especially, an extremely high signal amplification ability. − Generally, the extra input gate bias potential ( V G ) is essential during the OECT process, which is disadvantageous for reducing power consumption . Inspired by the conversion of the noninvasive and clean stimulus of light to the electricity energy in the PEC process, several organic photoelectrochemical transistor (OPECT) sensors have been proposed by the combination of OECT and PEC strategies. − In the OPECT process, the light-induced voltage could not only principally save the power supply to make the device simplified but also permit the zero-gate-biased operation for its promising applications. − For instance, Wang’s group fabricated an OPECT sensor with zero gating voltage based on poly­(3,4-ethylenedioxythiophene) doped with poly­(styrenesulfonate) (PEDOT/PSS) channel and Fe-metal organic framework@PEDOT (Fe-MOF@PEDOT) photogate, which exhibited a 100-fold enhanced channel signal; as a result, the OPECT sensor had a better sensitivity than the general PEC method for target detection .…”