Molecular Design of Semiconducting Polymers for High-Performance Organic Electrochemical Transistors

Nielsen, Christian B.; Giovannitti, Alexander; Sbircea, Dan-Tiberiu; Bandiello, Enrico; Niazi, Muhammad Rizwan; Hanifi, David; Sessolo, Michele; Amassian, Aram; Malliaras, George G.; Rivnay, Jonathan; McCulloch, Iain

doi:10.1021/jacs.6b05280

Cited by 324 publications

(481 citation statements)

References 26 publications

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“…Since the operation mechanism of OECTs is based on doping or de‐doping of a conducting polymer, in recent years researchers have been focusing on optimizing the semiconducting materials suitable for OECTs . However, not only does the choice of organic semiconductor influence OECT performance, but the electrolyte has a profound effect as well, the drain current is modulated by the injection of ions from the electrolyte into the organic semiconductor under certain gate bias conditions .…”

Section: Introductionmentioning

confidence: 99%

Organic Electrochemical Transistors Based on Room Temperature Ionic Liquids: Performance and Stability

Kaphle

Liu

Keum

et al. 2018

Physica Status Solidi (a)

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Organic electrochemical transistors (OECTs) are becoming a key device in the field of organic bioelectronics. For many applications of OECTs, in particular for enzymatic sensing, a complex mixture of room temperature ionic liquids (RTILs) combined with other electrolytes is used as a gate electrolyte, making the interpretation of experimental trends challenging. Here, the switching mechanism of OECTs using such RTILs is studied. It shows that ions smaller in size than the ions contained in the RTIL (e.g., Na+) have to be added to the ionic liquid to ensure switching of the OECTs. Furthermore, it is shown that OECTs based on RTILs exhibit noticeable gate‐bias stress effects and a hysteresis in the electrical transfer characteristics. A model based on incomplete charging/discharging of the effective gate capacitance during operation of the OECT and a dispersion in the ion mobilities is proposed to explain these instabilities, and thus it shows that the hysteresis can be minimized by optimizing the geometry of the device. Overall, a better understanding of the underlying mechanisms of switching and stability of OECTs based on RTILs is the first step toward various applications such as lactate acid sensors and neurotransmitter recording.

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Section: Introductionmentioning

confidence: 99%

Organic Electrochemical Transistors Based on Room Temperature Ionic Liquids: Performance and Stability

Kaphle

Liu

Keum

et al. 2018

Physica Status Solidi (a)

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“…[18][19][20] These polymers are naturally nonconductive and can be used to make OECTs. Furthermore, because the polymer blend is highly conductive in its pristine state, transistors are normally ON and consume electrical power.…”

mentioning

confidence: 99%

A Universal Platform for Fabricating Organic Electrochemical Devices

Duong

Tuchman

Chakthranont

et al. 2018

Adv Elect Materials

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cost-effectively processed at room temperature, and to volumetrically uptake large amounts of electrolytes, OEDs have recently garnered much interest for applications in bioelectronics. [1][2][3] These include biosensing, energy storage, neural recording, and stimulation, [4,5] drug delivery, [6] and electroceuticals [7] to name a few. Out of the many available architectures, a device of choice that has been heavily investigated in recent years is the organic electrochemical transistor (OECT). In a typical OECT device, the conductivity of a polymer channel, which is probed by a set of source and drain electrodes, is actively controlled by varying the voltage applied between the channel and a third gate electrode both of which reside in the same electrolyte solution. The choice for gate materials, channel materials, electrolyte solutions, and device dimensions can all be designed to obtain desired device characteristics. Thin photolithographically defined devices, for instance, are favored for high speed (>1 kHz) operation whereas large devices with thick polymer channels are more often chosen for their high transconductance. [8][9][10] In general, OECTs operate at relatively low voltages (<1 V) that are suitable for aqueous environments and biological tissues, and have been successfully used to monitor the integrity of barrier tissues, [11,12] in vitro glucose concentrations [13,14] and in vivo neural activities. [15] In OECTs, ions penetrate the whole polymer film, as facilitated by the swelling processes induced by the solvent. While such process is not strictly necessary, as ionic liquids have been shown to also induce transistor-like behavior in conjugated polymers, [16,17] compared to ionic liquid-gated devices, OECTs provide the opportunity to decouple ionic transport, through swelling caused by the electrolyte solvent, from the ability of the ions to generate mobile charges in the polymer.Despite recent advances in device fabrication and materials development, however, only a select few polymers have been found to stably operate as active OECT channels in aqueous environments. Current state-of-the-art OECTs are fabricated using the highly conductive mixture of poly(3,4ethylenedioythiophene) doped with poly(styrene sulphonate) (PEDOT:PSS). [8] While this materials blend exhibits high transconductance and good stability, the details of the chemical composition are often unknown due to the proprietary nature A general method and accompanying guidelines for fabricating both nonaqueous and aqueous based organic electrochemical devices (OECTs) using water-insoluble hydrophobic semiconducting polymers are presented. By taking advantage of the interactions of semiconducting polymers in certain organic solvents and the formation of a stable liquid-liquid interface between such solvents and water, OECTs with high transconductance, ON/OFF ratios of up to 10 6 , and enhancements in stability are successfully fabricated. Additionally, key fundamental properties are extracted of both the device and the active channel ma...

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“…The best transconductance value reported so far is 20 mS/cm for drop casted semiconducting materials. 42 Transient responses are measured by recording the drain current for gate voltage switches at fixed drain voltage. This measurements allow to appreciate the switching ability of the devices and the amount of time required to oxidize and reduce the active material, and therefore switch ON and OFF the devices, respectively.…”

Section: Oects Characterizationmentioning

confidence: 99%

“…Only recently, synthetic efforts have been spent on the development of new semiconducting materials with improved characteristics for the production of better accumulation mode OECTs. 38,42 …”

Section: Operation Modes Of Oectsmentioning

confidence: 99%

“…52 Hydrophobic semiconducting materials could also be used to produce accumulation mode OECTs. 42 In Paper 2 it has been shown that hydrophobic PEDOT-S:ammonium salts can be used to prepare films exhibiting high stability in water solution. The hydrophobic CPEs could, therefore, be incorporated as additive-free active materials for OECTs comprising a water-based electrolyte ( Figure 3.12).…”

Section: Stability In Water-based Electrolytesmentioning

confidence: 99%

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Self-doped Conjugated Polyelectrolytes for Bioelectronics Applications

Zeglio¹

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Self-doped conjugated polyelectrolytes (CPEs) are a class of conducting polymers constituted of a π-conjugated backbone and charged side groups. The ionic groups provide the counterions needed to balance the charged species formed in the CPEs backbones upon oxidation. As a result, addition of external counterions is not required, and the CPEs can be defined as selfdoped. The combination of their unique optical and electrical properties render them the perfect candidates for optoelectronic applications. Additionally, their “soft” nature provide for the mechanical compatibility necessary to interface with biological systems, rendering them promising materials for bioelectronics applications. CPEs solubility, aggregation state, and optoelectronic properties can be easily tuned by different means, such as blending or interaction with oppositely charged species (such as surfactants), in order to produce materials with the desired properties. In this thesis both the strategies have been explored to produce new functional materials that can be deposited to form a thin film and, therefore, used as an active layer in organic electrochemical transistors (OECTs). Microstructure formation of the films as well as influence on devices operation and performance have been investigated. We also show that these methods can be exploited to produce materials whose uniquecombination of self-doping ability and hydrophobicity allows incorporation into the phospholipid double layer of biomembranes, while retaining their properties. As a result, self-doped CPEs can be used both as sensing elements to probe the physical state of biomembranes, and as functional ones providing them with new functionalities, such as electrical conductivity. Integration of conductive electronic biomembranes into OECTs devices has brought us one step forward on the interface of manmade technologies with biological systems

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Molecular Design of Semiconducting Polymers for High-Performance Organic Electrochemical Transistors

Cited by 324 publications

References 26 publications

Organic Electrochemical Transistors Based on Room Temperature Ionic Liquids: Performance and Stability

Organic Electrochemical Transistors Based on Room Temperature Ionic Liquids: Performance and Stability

A Universal Platform for Fabricating Organic Electrochemical Devices

Self-doped Conjugated Polyelectrolytes for Bioelectronics Applications

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