Finding the equilibrium of organic electrochemical transistors

Kaphle, Vikash; Paudel, Pushpa Raj; Dahal, Drona; Krishnan, Raj Kishen Radha; Lüssem, Björn

doi:10.1038/s41467-020-16252-2

Cited by 68 publications

(96 citation statements)

References 27 publications

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“…The 2D device model used here deviates from this assumption and calculates the ion concentration under the assumption that cations reach their equilibrium, [ 30 ] which leads to a significantly different ion distribution along the transistor channel. To test if the geometric scaling law described by Equation (3), can be reproduced by the device model used here, the transconductance as a function of

\frac{d}{L}

is plotted in Figure a.…”

Section: Resultsmentioning

confidence: 99%

“…However, as recently shown, the assumption of a gate capacitance does not describe the equilibrium state of the OECT. [ 30 ] A 2D model was developed that treats ion and hole currents consistently, ensuring the the device is reaching its equilibrium. Based on this model, it was shown that the ion concentration inside the transistor channel is not proportional to the channel potential, that is, it cannot be described by a capacitive term.…”

Section: Resultsmentioning

confidence: 99%

“…To better understand the origin of the peak in transconductance and to be able to derive scaling laws for OECTs, the 2D drift-diffusion simulation as described in ref. [30] is used. In this model, the steady state of the device is found by solving Poisson's equation and continuity equations for ions and holes self-consistently using the Gummel algorithm.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, however, we were able to show that this assumption does not describe the steady‐state solution of the device, that is, it neglects a strong ion redistribution along the transistor channel, leading to an accumulation of cations at the drain electrode. [ 30 ] A 2D drift‐diffusion model was developed that describes ion and hole conduction in both dimensions, which led to a better reproduction of the transistor behavior.…”

Section: Introductionmentioning

confidence: 99%

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Tuning the Transconductance of Organic Electrochemical Transistors

Paudel

Kaphle

Dahal

et al. 2020

Adv Funct Materials

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Organic electrochemical transistors (OECTs) operate at very low voltages, transduce ions into electronic signals, and reach extremely large transconductance values, making them ideally suited for bio-sensing applications. However, despite their promising performance, the dependence of their maximum transconductance on device geometry and applied voltages are not correctly captured by current capacitive device models. Here, current scaling laws are revised in the light of a recently developed 2D device model that adequately accounts for drift and diffusion of ions inside the polymer channel. It is shown that the maximum transconductance of the devices is found at the transition between the depletion and accumulation region of the transistors, which as well provides an explanation for the observed shift of the transconductance peak with geometric dimensions and the drain potential. Overall, the results provide a better understanding of the working mechanisms of OECTs, and facilitate design rules to optimize OECT performance further.

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\frac{d}{L}

is plotted in Figure a.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tuning the Transconductance of Organic Electrochemical Transistors

Paudel

Kaphle

Dahal

et al. 2020

Adv Funct Materials

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“…[ 83,84,88,89 ] The presence of both ionic and electronic currents in conjugated polymer–polyelectrolyte systems further complicates interpretation, with many ongoing attempts to accurately model this behavior. [ 89–92 ] Tybrandt et al. recently proposed a two‐phase model based on drift‐diffusion equations.…”

Section: Fundamental Mechanismsmentioning

confidence: 99%

Organic Bioelectronics: Using Highly Conjugated Polymers to Interface with Biomolecules, Cells, and Tissues in the Human Body

Higgins

Fiego

Patrick

et al. 2020

Adv Materials Technologies

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Conjugated polymers exhibit interesting material and optoelectronic properties that make them well‐suited to the development of biointerfaces. Their biologically relevant mechanical characteristics, ability to be chemically modified, and mixed electronic and ionic charge transport are captured within the diverse field of organic bioelectronics. Conjugated polymers are used in a wide range of device architectures, and cell and tissue scaffolds. These devices enable biosensing of many biomolecules, such as metabolites, nucleic acids, and more. Devices can be used to both stimulate and sense the behavior of cells and tissues. Similarly, tissue interfaces permit interaction with complex organs, aiding both fundamental biological understanding and providing new opportunities for stimulating regenerative behaviors and bioelectronic based therapeutics. Applications of these materials are broad, and much continues to be uncovered about their fundamental properties. This report covers the current understanding of the fundamentals of conjugated polymer biointerfaces and their interactions with biomolecules, cells, and tissues in the human body. An overview of current materials and devices is presented, along with highlighted major in vivo and in vitro applications. Finally, open research questions and opportunities are discussed.

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High‐Performance n‐Type Organic Electrochemical Transistors Enabled by Aqueous Solution Processing of Amphiphilicity‐Driven Polymer Assembly

Jeong

Lee

et al. 2022

Adv Funct Materials

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Despite the growing attention on organic electrochemical transistors (OECTs), most research has focused on the design of p-type active materials, and the number of high-performance n-type materials is limited. Herein, a series of naphthalene diimide-based polymers incorporated with asymmetrically branched oligo(ethylene glycol) (OEG) side chains are developed to enable green-solvent-processed, high-performance n-type OECTs. The branched OEG side chains afford sufficient solubility in eco-friendly ethanol/water solvent mixtures. Importantly, taking advantage of the amphiphilic nature of OEGbased polymers, ethanol/water solvents selectively solvate hydrophilic OEG side chains, while producing assembled π−π stacks of hydrophobic backbones. This enables highly ordered polymer packing with a preferential edge-on orientation, and thus excellent lateral charge transport. In particular, the fine-tuned OEG side chains of P(NDIMTEG-T) provide compact backbone packing, effective polaron generation, and superior electrochemical stability with optimized swelling capability. The resultant n-type OECT shows the best electrical/ electrochemical performance in the family, represented by a high transconductance (g m ) of 0.38 S cm −1 and a large figure-of-merit (µC*) of 0.56 F V −1 cm −1 s −1 .This study demonstrates the use of aqueous processing in OECTs, for the first time, and suggests important guidelines for the design of n-type organic mixed ionic-electronic conductors with excellent OECT characteristics.

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Finding the equilibrium of organic electrochemical transistors

Cited by 68 publications

References 27 publications

Tuning the Transconductance of Organic Electrochemical Transistors

Tuning the Transconductance of Organic Electrochemical Transistors

Organic Bioelectronics: Using Highly Conjugated Polymers to Interface with Biomolecules, Cells, and Tissues in the Human Body

High‐Performance n‐Type Organic Electrochemical Transistors Enabled by Aqueous Solution Processing of Amphiphilicity‐Driven Polymer Assembly

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