Single‐Material OECT‐Based Flexible Complementary Circuits Featuring Polyaniline in Both Conducting Channels

Abstract

The organic electrochemical transistor (OECT) with a conjugated polymer as the active material is the elementary unit of organic bioelectronic devices. Improved functionalities, such as low power consumption, can be achieved by building complementary circuits featuring two or more OECTs. Complementary circuits commonly combine both p‐ and n‐type transistors to reduce power draw. While p‐type OECTs are readily available, n‐type OECTs are less common mainly due to poor stability of the n‐type active channel material in aqueous electrolyte. Here, a complementary circuit is made using a pair of OECTs having polyaniline (PANI) as the channel material in both transistors. PANI, with a finite electrochemical window accessible at voltages lower than 1 V, exhibits a peak in current versus gate voltage when used as an active channel in an OECT. The current peak has two slopes, one n‐like and one p‐like, which correspond to different electrochemical regimes of the same underlying conjugated polymer. The electrochemistry enables the design of a complementary circuit using only PANI as the channel material. The PANI‐based circuit is shown to have excellent performance with gain of ≈7 and is transferred on a flexible biocompatible chitosan substrate with demonstrated operation in aqueous electrolyte.

Combining Electrospinning and Electrode Printing for the Fabrication of Stretchable Organic Electrochemical Transistors

“…Meanwhile, the symmetry of the voltammograms confirms that the fibers can be reversibly doped and undoped with an applied potential with minimal loss of charge. This is a required behavior for use in OECT [45]. The conjugated organic components of OECTs make them suitable for use in both in vivo and in vitro bioelectronics.…”

Semiconducting Polymers for Neural Applications

“…Early conjugated polymers used primarily in the 1980s and 1990s (although some such as polyaniline have been incidentally observed more than a century prior 243 ) include structurally rather simple CPs such as polypyrrole, 244 − 249 poly( N -methylpyrrole), 245 , 250 polyaniline, 251 − 255 and poly(3-methylthiophene); 256 see Figure 20 . Importantly, in the field of neuroelectrodes, nitrogen-containing polymers, such as polypyrrole, were among the earliest demonstrations of contact between conjugated polymers and neurons.…”

Biofunctional conducting polymers: synthetic advances, challenges, and perspectives towards their use in implantable bioelectronic devices

“…Finally, the field of organic bioelectronics is shifting towards the development of advanced bioelectronic circuitry that can identify, process, and modulate electrophysiological signals. Organic bioelectronic circuits based on the organic electrochemical transistor (OECT) are being developed with promising functionalities at the biointerface [178][179][180][181][182]. The development of n-type conducting polymers, for example, will enable the development of complementary logic circuits with reduced power draw and low operating voltages [180,181].…”

“…Organic bioelectronic circuits based on the organic electrochemical transistor (OECT) are being developed with promising functionalities at the biointerface [178][179][180][181][182]. The development of n-type conducting polymers, for example, will enable the development of complementary logic circuits with reduced power draw and low operating voltages [180,181]. Integration of these novel conducting polymers into complex circuits will expand their therapeutic potential.…”