Organic electrochemical transistors (OECTs) have exhibited promising performance as transducers and amplifiers of low potentials due to their exceptional transconductance, enabled by the volumetric charging of organic mixed ionic/electronic conductors (OMIECs) employed as the channel material. OECT performance in aqueous electrolytes as well as the OMIECs’ redox activity has spurred a myriad of studies employing OECTs as chemical transducers. However, the OECT's large (potentiometrically derived) transconductance is not fully leveraged in common approaches that directly conduct chemical reactions amperometrically within the OECT electrolyte with direct charge transfer between the analyte and the OMIEC, which results in sub‐unity transduction of gate to drain current. Hence, amperometric OECTs do not truly display current gains in the traditional sense, falling short of the expected transistor performance. This study demonstrates an alternative device architecture that separates chemical transduction and amplification processes on two different electrochemical cells. This approach fully utilizes the OECT's large transconductance to achieve current gains of 103and current modulations of four orders of magnitude. This transduction mechanism represents a general approach enabling high‐gain chemical OECT transducers.
- Award ID(s):
- 1804915
- NSF-PAR ID:
- 10294473
- Date Published:
- Journal Name:
- Journal of Materials Chemistry C
- ISSN:
- 2050-7526
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Organic electrochemical transistors (OECTs) have shown promise as transducers and amplifiers of minute electronic potentials due to their large transconductances. Tuning the OECT threshold voltage is important to achieve low‐powered devices with amplification properties within the desired operational voltage range. However, traditional design approaches have struggled to decouple channel and materials properties from threshold voltage, thereby compromising on several other OECT performance metrics, such as electrochemical stability, transconductance, and dynamic range. In this work, simple solution‐processing methods are utilized to chemically dope polymer gate electrodes, thereby controlling their work function, which in turn tunes the operation voltage range of the OECTs without perturbing their channel properties. Chemical doping of initially air‐sensitive polymer electrodes further improves their electrochemical stability in ambient conditions. Thus, OECTs that are simultaneously low‐powered and electrochemically resistant to oxidative side reactions under ambient conditions are demonstrated. This approach shows that threshold voltage, which is once interwoven with other OECT properties, can in fact be an independent design parameter, expanding the design space of OECTs.
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Abstract Organic electrochemical transistors (OECTs) exhibit strong potential for various applications in bioelectronics, especially as miniaturized, point‐of‐care biosensors, because of their efficient transducing ability. To date, however, the majority of reported OECTs have relied on p‐type (hole transporting) polymer mixed conductors, due to the limited number of n‐type (electron transporting) materials suitable for operation in aqueous electrolytes, and the low performance of those which exist. It is shown that a simple solvent‐engineering approach boosts the performance of OECTs comprising an n‐type, naphthalenediimide‐based copolymer in the channel. The addition of acetone, a rather bad solvent for the copolymer, in the chloroform‐based polymer solution leads to a three‐fold increase in OECT transconductance, as a result of the simultaneous increase in volumetric capacitance and electron mobility in the channel. The enhanced electrochemical activity of the polymer film allows high‐performance glucose sensors with a detection limit of 10 × 10−6
m of glucose and a dynamic range of more than eight orders of magnitude. The approach proposed introduces a new tool for concurrently improving the conduction of ionic and electronic charge carriers in polymer mixed conductors, which can be utilized for a number of bioelectronic applications relying on efficient OECT operation. -
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Abstract This work presents a soluble oligo(ether)‐functionalized propylenedioxythiophene (ProDOT)‐based copolymer as a versatile platform for a range of high‐performance electrochemical devices, including organic electrochemical transistors (OECTs), electrochromic displays, and energy‐storage devices. This polymer exhibits dual electroactivity in both aqueous and organic electrolyte systems, redox stability for thousands of redox cycles, and charge‐storage capacity exceeding 80 F g−1. As an electrochrome, this material undergoes full colored‐to‐colorless optical transitions on rapid time scales (<2 s) and impressive electrochromic contrast (Δ%
T > 70%). Incorporation of the polymer into OECTs yields accumulation‐mode devices with anI ON/OFFcurrent ratio of 105, high transconductance without post‐treatments, as well as competitive hole mobility and volumetric capacitance, making it an attractive candidate for biosensing applications. In addition to being the first ProDOT‐based OECT active material reported to date, this is also the first reported OECT material synthesized via direct(hetero)arylation polymerization, which is a highly favorable polymerization method when compared to commonly used Stille cross‐coupling. This work provides a demonstration of how a single ProDOT‐based polymer, prepared using benign polymerization chemistry and functionalized with highly polar side chains, can be used to access a range of highly desirable properties and performance metrics relevant to electrochemical, optical, and bioelectronic applications. -
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Abstract Organic electrochemical transistors (OECTs) are ideal devices for translating biological signals into electrical readouts and have applications in bioelectronics, biosensing, and neuromorphic computing. Despite their potential, developing programmable and modular methods for living systems to interface with OECTs has proven challenging. Here we describe hybrid OECTs containing the model electroactive bacterium
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d1tc02224e
