Gate Insulators in Organic Field-Effect Transistors

Veres, János; Ogier, and Simon; Lloyd, Giles; Leeuw, Dago de

doi:10.1021/cm049598q

Cited by 870 publications

(673 citation statements)

References 68 publications

Supporting

Mentioning

639

Contrasting

Unclassified

Order By: Relevance

“…Using a polar gate insulator in OFETs is known to typically yield a relatively lower field effect mobility, than otherwise attained using for instance a dielectric insulator, for disordered OSCs [36]. When comparing our extracted mobility values to similar devices, with undoped OSCs, that are gated through a polar insulator or via an electrolyte [11,26,[36][37][38][39] we find that the values extracted for P3HT and P3HT-COOH15 seem to agree to prior reported data. The relatively much higher mobility value extracted for P3CPT leads us to suspect that there might be a different operation mechanism for P3CPT-OTFTs than for the other two polymer OSCs.…”

Section: µLin = L/(wcivds)* ∂Id/∂vgssupporting

confidence: 83%

On the mode of operation in electrolyte-gated thin film transistors based on different substituted polythiophenes

Toss¹,

Suspène²,

Piro³

et al. 2014

Organic Electronics

View full text Add to dashboard Cite

Organic Thin Film Transistors (OTFT), gated through an aqueous electrolyte, have extensively been studied as sensors in various applications. These water-gated devices are known to work both as electrochemical (Organic ElectroChemical Transistor - OECT) and field-effect (Organic Field-Effect Transistor - OFET) devices. To properly model and predict the response of water-gated OTFT sensors it is important to distinguish between the mechanism, field-effect or electrochemical, by which the transistor is modulated and thus how the gate signal can be affected by the analyte. In this present study we explore three organic polymer semiconductors, poly-(3-hexyl-thiophene) (P3HT), poly-(3-carboxypentyl-thiphene) (P3CPT) and a co-polymer P3HT-co-poly-(3-ethoxypentanoic acid-thiophene) (monomer ratio 1:6, P3HT-COOH15) in water-gated OTFT structures. We report a set of transistor characteristics, including standard output parameters, impedance spectroscopy and current transients, to investigate the origin of the mode of operation in these water-gated OTFTs. Impedance characteristics, including both frequency and voltage dependence, were recorded for capacitor stacks corresponding to the gate/electrolyte/semiconductor/source structure. It is shown that P3HT as well as P3HT-COOH15 both can function as semiconductors in water gated OTFT devices operating in field-effect mode. P3CPT on the other hand shows typical signs of electrochemical mode of operation. The -COOH side group has been suggested as a possible anchoring site for biorecognition elements in EGOFET sensors, rendering P3HT-COOH15 a possible candidate for such applications.

Funding Agencies|European Union [248728]; Swedish Government (SFO-AFM); Onnersjo Foundation (Holmen); Knut and Alice Wallenberg Foundation (Power Papers); VINNOVA (PEA)

show abstract

Section: µLin = L/(wcivds)* ∂Id/∂vgssupporting

confidence: 83%

On the mode of operation in electrolyte-gated thin film transistors based on different substituted polythiophenes

Toss¹,

Suspène²,

Piro³

et al. 2014

Organic Electronics

View full text Add to dashboard Cite

Funding Agencies|European Union [248728]; Swedish Government (SFO-AFM); Onnersjo Foundation (Holmen); Knut and Alice Wallenberg Foundation (Power Papers); VINNOVA (PEA)

show abstract

“…For example, the phenomenon might be due to a variation in the gate dielectric constant of the film with the concentration of the PMMA solution. 17 Veres et al 2,18 suggested that a higher dielectric constant induces a broadening of the density of states ͑DOS͒ at the polymer/insulator interface. This results in a decrease in the DOS at the Fermi energy and subsequently causes a lower hopping probability, leading to a suppression of the carrier mobility.…”

Section: -2mentioning

confidence: 99%

“…3 The high resistivity ͑Ͼ2 ϫ 10 15 ⍀ cm͒ and low dielectric constant ͑approximately 3, similar to that of silicon dioxide͒ of poly͑methyl methacrylate͒ ͑PMMA͒ make it potential candidate as the dielectric layer in OTFTs. 2,4 Furthermore, this polymer contains hydrophobic methyl radical groups, which can play a role as moisture inhibitors, as well as encourage good ordering of the active organic overlayer as it is deposited on the surface. 5 To date, pentacene-based OTFT devices using PMMA as the gate dielectric have shown low field-effect mobilities ͑generally less than 0.1 cm 2 V −1 s −1 ͒ due to the relatively thick film of PMMA used, low on/off current ratios ͑10 3 ͒ resulting from large leakage currents, and high threshold voltages ͑Ϫ15 to Ϫ25 V͒.…”

Section: Introductionmentioning

confidence: 99%

Pentacene thin film transistors with a poly(methyl methacrylate) gate dielectric: Optimization of device performance

Yun¹,

Pearson²,

Petty³

2009

Journal of Applied Physics

View full text Add to dashboard Cite

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The electrical characteristics of pentacene-based organic thin film transistors ͑OTFTs͒ using poly͑methyl methacrylate͒ ͑PMMA͒ as the gate dielectric are reported. Uniform pinhole-free and crack-free films of PMMA could be obtained by spin coating, with a lower limit of thickness of about 150 nm. The effects of the insulator thickness and channel dimensions on the performance of the devices have been investigated. Leakage currents, which are present in many polymeric gate dielectrics, were reduced by patterning the pentacene active layer. The resulting devices exhibited minimal hysteresis in their output and transfer characteristics. Optimized OTFT structures possessed a field-effect mobility of 0.33 cm 2 V −1 s −1 , a threshold voltage of Ϫ4 V, a subthreshold slope of 1.5 V/decade, and an on/off current ratio of 1.2ϫ 10 6 .

show abstract

“…19,20 It has also reported that PCBM molecules are intercalating between the side chains of some conjugated polymers and that this behavior influences significantly the device performance including the charge carrier transport. [21][22][23] More recently, it was also proved that PCBM molecules and/or their aggregates are miscible with P3HT and mobile in amorphous region of P3HT even at low temperature, 50 C. 24 Although charges are generally expected to be better transported in a well-ordered structure of a conjugated polymer, it has been reported that some disordered conjugated polymers [25][26][27][28][29][30] also exhibit high charge mobility in spite of their amorphous nature. Thus, it is very important to understand the charge transport mechanism in amorphous low bandgap conjugated polymer for development of high efficiency OPVs.…”

Section: Introductionmentioning

confidence: 99%

Charge transport in amorphous low bandgap conjugated polymer/fullerene films

Kim¹,

Cho²,

Noh³

et al. 2012

Journal of Applied Physics

View full text Add to dashboard Cite

The structural and charge transport properties of a low bandgap copolymer poly(3-hexylthiophene-alt-6,7-dimethyl-4,9-bis-(4-hexylthien-2yl)-[1,2,5]thiadiazolo[3,4-g]quinoxaline) (P(3HT-MeTDQ)) and its blend with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) are investigated. Thermal analysis, X-ray scattering diffraction (XRD), atomic force microscopy and transmission electron microscopy (TEM) of P(3HT-MeTDQ) reveal that the polymer is amorphous in solid state. As the hole mobility of P(3HT-MeTDQ) was measured by the time-of-flight photoconductivity method, the mobility was 3.35 × 10−4 cm2/V s, which is very comparable to that of semicrystalline poly(3-hexyl thiophene). When the mobility of amorphous P(3HT-MeTDQ) was analyzed according to the Gaussian disorder model, the polymer has the energetic and positional disorders with the values of σ = 62 meV and Σ = 1.7, respectively, indicating that the polymer has a relatively narrow Gaussian distribution of transport states. Interestingly, when P(3HT-MeTDQ) is blended with PCBM, the amorphous P(3HT-MeTDQ) becomes partially ordered, as evidenced by observation of two discernible XRD peaks at 2θ = 5° (d = 17.7 Å) and 25.5° (d = 3.5 Å) corresponding to the interchain distance and π-stacking distance, respectively. The bicontinuous network morphology was identified at the blend with 60 wt. % PCBM by TEM, at which the charge carrier transport changes from hole-only to ambipolar.

show abstract

Gate Insulators in Organic Field-Effect Transistors

Cited by 870 publications

References 68 publications

On the mode of operation in electrolyte-gated thin film transistors based on different substituted polythiophenes

On the mode of operation in electrolyte-gated thin film transistors based on different substituted polythiophenes

Pentacene thin film transistors with a poly(methyl methacrylate) gate dielectric: Optimization of device performance

Charge transport in amorphous low bandgap conjugated polymer/fullerene films

Contact Info

Product

Resources

About