Bi‐stable and Dynamic Current Modulation in Electrochemical Organic Transistors

Nilsson, David; Chen, Miaoxiang; Kugler, Thomas; Remonen, Tommi; Armgarth, M.; Berggren, Magnus

doi:10.1002/1521-4095(20020104)14:1<51::aid-adma51>3.0.co;2-#

Cited by 228 publications

(169 citation statements)

References 12 publications

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“…The nonlinear relationship apparent in Fig. 5 is likely caused by the increase in resistance of the PEDOT cathode [PEDOTs conductivity decreases as it is dedoped, see (Johansson et al 2002;Nilsson et al 2002)] and the "consumption" of the polymer available for oxidation/reduction during longer periods of operation (in the same direction) at elevated potential. Otherwise, the relationship between J and E depends very little on whether the pump is operated by controlling potential (and measuring the current) or driving a specific current (and measuring the potential).…”

Section: Resultsmentioning

confidence: 91%

A large-area, all-plastic, flexible electroosmotic pump

Bengtsson

Robinson

2017

Microfluid Nanofluid

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A large-area, fabric-like pump would potentially have applications, for example, in controlling water transport through a garment, such as a rain jacket, regardless of the external temperature and humidity. This paper presents an all-plastic, flexible electroosmotic pump, constructed from commercially available materials: A polycarbonate membrane combined with the electrochemically active polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate that actively transports water using an electric potential that can be supplied by a small battery. By using electrochemically active polymer electrodes instead of metal electrodes, the electrochemical reaction that drives flow avoids the oxygen and hydrogen gas production or pH changes associated with water electrolysis. We observe a water mass flux up to 23 mg min −1 per cm 2 polycarbonate membrane (porosity 10-15%), at an applied potential of 5 V, and a limiting operating pressure of 0.3 kPa V −1 , similar to previously reported membrane-based electroosmotic pumps.

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Section: Resultsmentioning

confidence: 91%

A large-area, all-plastic, flexible electroosmotic pump

Bengtsson

Robinson

2017

Microfluid Nanofluid

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“…44,45 This dedoping process causes a decrease in the conductivity of the PEDOT:PSS film. EC transistors [44][45][46] and bistable memories 45 are examples operating in switching between the oxidized or reduced state of a conjugated polymer. Wang et al 47 visualized ion current in dedoping a fully oxidized polypyrrole film.…”

Section: Discussionmentioning

confidence: 99%

“…This is the crucial difference from an electrochemical dedoping reaction by modulating charge carrier concentration through a large amount of ion charge flow. 45,46 Though the device working principles are different, our devices show little difference in the I D -V D characteristics 44 and dynamic switching 45 from an EC transistor.…”

Section: R Is Found Asmentioning

confidence: 99%

Electric-field-controlled conductance of “metallic” polymers in a transistor structure

2006

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It was recently reported that use of a doped "metallic" polymer as the active channel in a field effect transistor structure results in unexpected "normally on" transistorlike behavior. We report here the role of ion migration in transistors based on metallic polymer ͓poly͑3,4-ethylenedioxythiophene͒ doped with poly͑styrene sulfonic acid͒ ͑PEDOT:PSS͔͒. The analysis of the ion flow into the active channel due to the gate voltage suggests that for the transistors studied compensating ϳ2 counterions per 100 dopant molecules suppresses PEDOT conductance up to three orders of magnitude. We determine from the temperature dependence of the conductivity of the active channel that the change in conductance of the active channel is throughout the channel in contrast to confinement of gate field induced charge carriers to the channel/dielectric interface in conventional transistors. The decrease of channel conductance reflects an increase of activation energy of carriers. Therefore, we propose that removal of intermediate hopping sites in the disoriented PEDOT:PSS by a small fraction of ion charge compensation causes carriers to anisotropically hop over longer distance leading to a conductor-nonconductor transition.

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“…Relatively slow switching times (< 1 kHz) are typical for unoptimised electrolyte-gated OTFTs limited by ionic diffusion. 6,36,37 A straightforward way to improve the operating frequency of the devices would be to use a different PIL/IL system with a higher ionic conductivity, or that allows for a higher IL content without loss of the mechanical properties of the resulting ion gel. Pushing the IL content in the current system to 75 wt% resulted in a slight improvement in switching speed (around 10 ms), at the cost of the gel's mechanical properties, making the deposition of the PEDOT:PSS gate electrode difficult and resulting in a high number of short-circtuited devices and larger disparities between the characteristics of working devices.…”

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confidence: 99%

High performance photolithographically-patterned polymer thin-film transistors gated with an ionic liquid/poly(ionic liquid) blend ion gel

Thiburce

Porcarelli

Mecerreyes

et al. 2017

Applied Physics Letters

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We demonstrate the fabrication of polymer thin-film transistors gated with an ion gel electrolyte made of the blend of an ionic liquid and a polymerised ionic liquid. The ion gel exhibits a high stability and ionic conductivity, combined with facile processing by simple drop-casting from solution. In order to avoid parasitic effects such as high hysteresis, high off-currents and slow switching, a fluorinated photoresist is employed in order to enable high-resolution orthogonal patterning of the polymer semiconductor over an area that precisely defines the transistor channel. The resulting devices exhibit excellent characteristics, with an on/off ratio of 10 6 , low hysteresis and a very large transconductance of 3 mS. We show that this high transconductance value is mostly the result of ions penetrating the polymer film and doping the entire volume of the semiconductor, yielding an effective capacitance per unit area of about 200 µF cm −2 , one order of magnitude higher than the double layer capacitance of the ion gel. This results in channel currents larger than 1 mA at an applied gate bias of only -1 V. We also investigate the dynamic performance of the devices and obtain a switching time of 20 ms, which is mostly limited by the overlap capacitance between the ion gel and the source and drain contacts.Electrolyte-gated organic thin-film transistors (OTFTs) have received a lot of attention over the past years, thanks to their ability to operate at very low voltages (< |1| V), 1-3 which makes them particularly attractive for use in portable devices powered by low supply voltage sources such as thin-film batteries, and interfacing with conventional Si CMOS electronics. If an electrolyte is placed in contact with two electrodes, to which a small voltage is applied, ionic species within the electrolyte migrate towards the electrode of opposite polarity, forming ultra-thin electrical double layers at both electrolyte/electrode interfaces. When one of these electrodes is the channel of a transistor, large charge densities arise within the semiconductor, as a result of the ionic accumulation within a small volume close to the interface or within the bulk of the semiconductor, depending on the mode of operation of the device. In the case where ionic charges are contained at the interface with the semiconductor, for example by using a polyelectrolyte in which the ionic charges are covalently linked to the polymer chains 4 or a crystalline semiconductor impermeable to ion penetration, 5 the device operates much like a field-effect transistor. On the other hand, when ions penetrate inside the bulk of a polymer semiconductor, the capacitance must be considered as a volumetric parameter and the doping process is electrochemical in nature, 6-8 resulting in very large currents flowing through the whole channel volume. As a) Electronic mail: alasdair.campbell@imperial.ac.uk a consequence, large transconductances surpassing that of silicon-based TFTs can be obtained, 9 even in OTFTs employing polymer semiconductors with modest ...

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Bi‐stable and Dynamic Current Modulation in Electrochemical Organic Transistors

Cited by 228 publications

References 12 publications

A large-area, all-plastic, flexible electroosmotic pump

A large-area, all-plastic, flexible electroosmotic pump

Electric-field-controlled conductance of “metallic” polymers in a transistor structure

High performance photolithographically-patterned polymer thin-film transistors gated with an ionic liquid/poly(ionic liquid) blend ion gel

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