High Performance, Flexible, and Thermally Stable All-Solid-State Organic Electrochemical Transistor Based on Thermoplastic Polyurethane Ion Gel

Abstract

Organic electrochemical transistors (OECTs) are a generation of transistors with high transconductance, where the whole volume of the semiconducting channel is involved in the electrochemical doping process. However, the use of liquid electrolytes limits the application of OECTs, and the doping process is also complicated due to the presence of water in the electrolyte. In this study, thermoplastic polyurethane (TPU)-based solid electrolyte was used in OECTs for the first time. Three types of ionic liquids were blended with a TPU polymer matrix as a solid electrolyte and investigated on the OECTs based on three kinds of p-type conjugated semiconductors. An in situ spectrochemistry study was further carried out to confirm the doping/dedoping process of these conjugated semiconductors by the TPU-based solid electrolyte. The robustness and high stability of the fabricated solid-state OECTs (SSOECTs) were demonstrated through continuously applied bias, long time operation under ambient conditions, and varying temperatures (−50 to 120 °C). Highly flexible SSOECTs were also obtained on a polyethylene terephthalate (PET) substrate, which showed negligible fluctuation in on/off-current (I on /I off ) after 1000 cycles of bending. Based on these highperforming SSOECTs, inverter circuits were fabricated in both unipolar and complementary configurations, where n-type and p-type OECT-based complementary inverters showed a higher gain (46) compared with that of the unipolar design.

Transient Response and Ionic Dynamics in Organic Electrochemical Transistors

“…Commonly used electrolytes include water-based, room temperature ionic liquids (RTILs), or comprise more complex mixtures. These mixtures can result in a variety of consistencies, ranging from liquid solutions to gels, including hydrogels and crosslinked solid electrolytes [ 79 , 80 ]. Among these, aqueous electrolytes typically yield a high transconductance and faster speed, despite at the cost of a lower on/off ratio.…”

Eutectogels as a Semisolid Electrolyte for Organic Electrochemical Transistors

“…For wearable applications of the OECT, solid-state or gel-like electrolytes are more convenient, limiting electrolyte leakage, volatilization, and corrosion of electronic parts . These solid-like electrolytes should have high ionic conductivity (although most suffer from low conductivities leading to slow OECT switching speeds) and be biocompatible, conformable, and stable. − …”

“… 5 These solid-like electrolytes should have high ionic conductivity (although most suffer from low conductivities leading to slow OECT switching speeds) and be biocompatible, conformable, and stable. 6 − 11 …”

3D-Printed Intrinsically Stretchable Organic Electrochemical Synaptic Transistor Array

“…Skin-like bioelectronics have gained wide application in health detection, human–computer interaction, and biological research due to their ability to seamlessly adhere in vitro or in vivo for detecting and amplifying biological signals without causing discomfort to organisms. − As a key component of bioelectronics, organic electrochemical transistors (OECTs) are devices that utilize electrochemical doping to control the conductivity of organic mixed ionic–electronic conductors to achieve switching states, which can be used as signal modulators and electronic components. , Additionally, organic electrochemical transistors with high transconductance, low operating voltage (<1 V), intrinsic stretchability, and low-cost processing technology have important research significance for developing bioelectronics. ,, Nevertheless, there are some difficulties in fabricating intrinsically stretchable (is-) OECT using a simple and versatile processing method. For example, all the components of the is-OECT, including electrodes, semiconducting layers, and dielectric layers, need to be stretchable and fabricated layer by layer. , The versatility of 3D printing enables the easy creation of highly customized and complex objects, making it a valuable tool for preparing OECTs.…”