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High-Performance Flexible Bottom-Gate Organic Field-Effect Transistors with Gravure Printed Thin Organic Dielectric.

Vaklev NL, Müller R, Muir BV, James DT, Pretot R, van der Schaaf P, Genoe J, Kim JS, Steinke JH, Campbell AJ - Adv Mater Interfaces (2014)

View Article: PubMed Central - PubMed

Affiliation: Experimental Solid State Group and the Centre for Plastic Electronics, Department of Physics, Blackett Laboratory, South Kensington Campus, Imperial College London London, SW7 2AZ, UK E-mail: alasdair.campbell@imperial.ac.uk.

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One of the key advantages of organic field-effect transistors (OFETs) is their ability to form flexible, conformable and lightweight electronic devices, e.g. radio frequency identification (RFID) tags, microprocessors and flexible displays... While high performance source, drain and gate electrodes and interconnects require metal evaporation under vacuum, ideally the dielectric and organic semiconductor (OSC) should be processed from solution under ambient conditions to reduce fabrication costs... These can be processed by techniques such as spin-casting, gravure printing and ink-jet printing at room temperature in ambient conditions... To avoid significant gate leakage current these polymer dielectrics have typically been deposited with film thicknesses ≥ 500 nm, resulting in high OFET operating voltages ≥20 V... To fabricate the BG BC OFETs, non-birefringent plastic substrates coated with a transparent conducting oxide (TCO) were used as required for flexible display applications... Breakdown voltages of the spin-cast and printed films were typically >2.4 MV cm (Figure S4)... Therefore, we conclude that gravure printing can produce dielectric films with comparable surface properties and homogeneity as spin-casting... Semiconductor crystallinity and charge-carrier mobility in BG BC OFETs is known to be affected by the dielectric surface energy, increasing with increasing water contact angle... The water contact angle of the dielectric surface with and without PαMS was found to be 90 ± 2° and 69 ± 2°, respectively... The SSV can be associated with the ratio between mobile and trapped charge-carriers at the semiconductor–dielectric interface as carriers first enter the channel when the OFET is switched from off- to on-state... The presence of PαMS therefore reduces the density of interfacial traps responsible for the SSV in TIPS-pentacene... Therefore, the triacrylate based dielectric can be processed using large-area compatible coating techniques such as gravure to give equally high performance devices as when it is spin-cast... In conclusion, we have demonstrated that it is possible to fabricate state-of-the-art flexible small molecule BG BC OFETs on plastic foil using a large-area scalable platform... Evaporated pentacene OFETs achieved an average mobility of 0.6 cm V s, which is state-of-the-art for this device geometry for flexible transistors on plastic... We also demonstrated that zone-casting can be used to fabricate small molecule OFETs on plastic with a polymer dielectric, TIPS-pentacene achieving an average mobility of 0.3 cm V s, which is state-of-the-art for this device geometry for flexible devices.

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(a) Optical image of a plastic substrate, 50 × 50 mm, with arrays of OFETs and capacitors (bottom right). (b) Optical micrograph of a single OFET on the plastic substrate. The dielectric is a square patch (3 × 3 mm) surrounded by source, drain and gate electrodes. (c) Schematic representation of bottom-gate bottom-contact OFET device stack; (d) chemical structures of the corresponding materials.
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fig01: (a) Optical image of a plastic substrate, 50 × 50 mm, with arrays of OFETs and capacitors (bottom right). (b) Optical micrograph of a single OFET on the plastic substrate. The dielectric is a square patch (3 × 3 mm) surrounded by source, drain and gate electrodes. (c) Schematic representation of bottom-gate bottom-contact OFET device stack; (d) chemical structures of the corresponding materials.

Mentions: One of the key advantages of organic field-effect transistors (OFETs) is their ability to form flexible, conformable and lightweight electronic devices, e.g. radio frequency identification (RFID) tags,[1] microprocessors[2] and flexible displays.[3] These require fabrication over large-areas on flexible plastic substrates, the poor dimensional stability of such substrates creating the additional demand of low-temperature processing (<200 °C).[4] While high performance source, drain and gate electrodes and interconnects require metal evaporation under vacuum, ideally the dielectric and organic semiconductor (OSC) should be processed from solution under ambient conditions to reduce fabrication costs. Regarding device architecture, OFETs with a bottom-gate (BG) bottom-contact (BC) geometry (Figure1c) have an advantage in that the organic semiconducting layer is deposited last.[5] This affords easy fabrication and patterning of micron-scale OFET channels, electrodes and interconnects by conventional photolithographic methods, whilst avoiding exposure of the active OSC material to UV radiation and aggressive or solubilising chemicals. Furthermore, this architecture is compatible with vacuum sublimation or vapour phase techniques for OSC deposition, allowing access to a wide range of high-performance materials. Such OFETs can form the building blocks of high performance, low-cost electronic circuitry.


High-Performance Flexible Bottom-Gate Organic Field-Effect Transistors with Gravure Printed Thin Organic Dielectric.

Vaklev NL, Müller R, Muir BV, James DT, Pretot R, van der Schaaf P, Genoe J, Kim JS, Steinke JH, Campbell AJ - Adv Mater Interfaces (2014)

(a) Optical image of a plastic substrate, 50 × 50 mm, with arrays of OFETs and capacitors (bottom right). (b) Optical micrograph of a single OFET on the plastic substrate. The dielectric is a square patch (3 × 3 mm) surrounded by source, drain and gate electrodes. (c) Schematic representation of bottom-gate bottom-contact OFET device stack; (d) chemical structures of the corresponding materials.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4493673&req=5

fig01: (a) Optical image of a plastic substrate, 50 × 50 mm, with arrays of OFETs and capacitors (bottom right). (b) Optical micrograph of a single OFET on the plastic substrate. The dielectric is a square patch (3 × 3 mm) surrounded by source, drain and gate electrodes. (c) Schematic representation of bottom-gate bottom-contact OFET device stack; (d) chemical structures of the corresponding materials.
Mentions: One of the key advantages of organic field-effect transistors (OFETs) is their ability to form flexible, conformable and lightweight electronic devices, e.g. radio frequency identification (RFID) tags,[1] microprocessors[2] and flexible displays.[3] These require fabrication over large-areas on flexible plastic substrates, the poor dimensional stability of such substrates creating the additional demand of low-temperature processing (<200 °C).[4] While high performance source, drain and gate electrodes and interconnects require metal evaporation under vacuum, ideally the dielectric and organic semiconductor (OSC) should be processed from solution under ambient conditions to reduce fabrication costs. Regarding device architecture, OFETs with a bottom-gate (BG) bottom-contact (BC) geometry (Figure1c) have an advantage in that the organic semiconducting layer is deposited last.[5] This affords easy fabrication and patterning of micron-scale OFET channels, electrodes and interconnects by conventional photolithographic methods, whilst avoiding exposure of the active OSC material to UV radiation and aggressive or solubilising chemicals. Furthermore, this architecture is compatible with vacuum sublimation or vapour phase techniques for OSC deposition, allowing access to a wide range of high-performance materials. Such OFETs can form the building blocks of high performance, low-cost electronic circuitry.

View Article: PubMed Central - PubMed

Affiliation: Experimental Solid State Group and the Centre for Plastic Electronics, Department of Physics, Blackett Laboratory, South Kensington Campus, Imperial College London London, SW7 2AZ, UK E-mail: alasdair.campbell@imperial.ac.uk.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

One of the key advantages of organic field-effect transistors (OFETs) is their ability to form flexible, conformable and lightweight electronic devices, e.g. radio frequency identification (RFID) tags, microprocessors and flexible displays... While high performance source, drain and gate electrodes and interconnects require metal evaporation under vacuum, ideally the dielectric and organic semiconductor (OSC) should be processed from solution under ambient conditions to reduce fabrication costs... These can be processed by techniques such as spin-casting, gravure printing and ink-jet printing at room temperature in ambient conditions... To avoid significant gate leakage current these polymer dielectrics have typically been deposited with film thicknesses ≥ 500 nm, resulting in high OFET operating voltages ≥20 V... To fabricate the BG BC OFETs, non-birefringent plastic substrates coated with a transparent conducting oxide (TCO) were used as required for flexible display applications... Breakdown voltages of the spin-cast and printed films were typically >2.4 MV cm (Figure S4)... Therefore, we conclude that gravure printing can produce dielectric films with comparable surface properties and homogeneity as spin-casting... Semiconductor crystallinity and charge-carrier mobility in BG BC OFETs is known to be affected by the dielectric surface energy, increasing with increasing water contact angle... The water contact angle of the dielectric surface with and without PαMS was found to be 90 ± 2° and 69 ± 2°, respectively... The SSV can be associated with the ratio between mobile and trapped charge-carriers at the semiconductor–dielectric interface as carriers first enter the channel when the OFET is switched from off- to on-state... The presence of PαMS therefore reduces the density of interfacial traps responsible for the SSV in TIPS-pentacene... Therefore, the triacrylate based dielectric can be processed using large-area compatible coating techniques such as gravure to give equally high performance devices as when it is spin-cast... In conclusion, we have demonstrated that it is possible to fabricate state-of-the-art flexible small molecule BG BC OFETs on plastic foil using a large-area scalable platform... Evaporated pentacene OFETs achieved an average mobility of 0.6 cm V s, which is state-of-the-art for this device geometry for flexible transistors on plastic... We also demonstrated that zone-casting can be used to fabricate small molecule OFETs on plastic with a polymer dielectric, TIPS-pentacene achieving an average mobility of 0.3 cm V s, which is state-of-the-art for this device geometry for flexible devices.

No MeSH data available.