Search query: Pentacene organic transistors

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abstract: We have fabricated organic thin film transistors, inverters, and ring oscillators on glass and on flexible polyethylene naphthalate, using the small molecule hydrocarbon pentacene as the semiconductor and solution processed polyvinylphenol as the gate dielectric. Depending on the choice of substrate, the transistors have a carrier mobility between 0.3 and 0.7 cm2/V s, an on/off current ratio between 105 and 106, and a subthreshold swing between 0.9 and 1.6 V/decade. To account for the positive switch on voltage of the transistors, circuits were designed to operate with integrated level shifting. Depending on the type of substrate, ring oscillators have a signal propagation delay as low as 15 ms per stage.
author_names: Hagen Klauk

Marcus Halik

Ute Zschieschang

Florian Eder

Gunter Schmid

Christine Dehm
title: Pentacene organic transistors and ring oscillators on glass and on flexible polymeric substrates
year: 2003

abstract: The phototransistor properties of pentacene organic transistors with a poly(methyl methacrylate) dielectric layer have been investigated. It was found that as the intensity of incident light increased, drain current gradually increased and threshold voltage shifted by degrees towards the positive direction, because of the higher number of more photons provided by incident light with a high intensity leading to a higher carrier density in the channel. Moreover, the prepared organic transistors showed a photocurrent response opposite to the absorption spectrum of pentacene. The photoresponse time of the pentacene transistor was determined to be shorter than 0.03 s.
author_names: Yan Hu

Guifang Dong

Liduo Wang

Yong Qiu
title: Phototransistor Properties of Pentacene Organic Transistors with Poly(methyl methacrylate) Dielectric Layer
year: 2006

abstract: Blending organic semiconductors with insulating polymers has been known to be an effective way to overcome the disadvantages of single component organic semiconductors for high performance organic field effect transistors (OFETs) We show that when a solution processable organic semiconductor (6,13 bis(triisopropylsilylethynyl)pentacene, TIPS pentacene) is blended with an insulating polymer (PS) morphological and structural characteristics of the blend films could be significantly influenced by the processing conditions like the spin coating time. Although vertical phase separated structures (TIPS pentacene top/PS bottom) were formed on the substrate regardless of the spin coating time, the spin time governed the growth mode of the TIPS pentacene molecules that phase separated and crystallized on the insulating polymer. Excess residual solvent in samples spun for a short duration induces a convective flow in the drying droplet, thereby leading to one dimensional (1D) growth mode of TIPS pentacene crystals. In contrast, after an appropriate spin coating time, an optimum amount of the residual solvent in the film led to two dimensional (2D) growth mode of TIPS pentacene crystals. The 2D spherulites of TIPS pentacene are extremely advantageous for improving the field effect mobility of FETs compared to needle like 1D structures, because of the high surface coverage of crystals with a unique continuous film structure. In addition, the porous structure observed in the 2D crystalline film allows gas molecules to easily penetrate into the channel region, thereby improving the gas sensing properties.
author_names: Jung Hun Lee

Yena Seo

Yeong Don Park

John E Anthony

Donghoon Kwak

Jung Ah Lim

Sung Lim Ko

Ho Won Jang

Kilwon Cho

Wi Hyoung Lee
title: Effect of Crystallization Modes in TIPS pentacene/Insulating Polymer Blends on the Gas Sensing Properties of Organic Field Effect Transistors
venue: Scientific Reports
year: 2019

abstract: N Heterocyclic carbenes (NHCs) which react with the surface of Au electrodes, have been successfully applied in pentacene transistors. With the application of NHCs, the charge carrier mobility of pentacene transistors increased by five times, while the contact resistance at the pentacene Au interface was reduced by 85 Even after annealing the NHC Au electrodes at 200 degC for 2 h before pentacene deposition, the charge carrier mobility of the pentacene transistors did not decrease. The distinguished performance makes NHCs as excellent alternatives to thiols as metal modifiers for the application in organic field effect transistors (OFETs)
author_names: Aifeng Lv

M Freitag

Kathryn M Chepiga

Andreas H Schafer

Frank Glorius

Lifeng Chi
title: N Heterocyclic Carbene Treated Gold Surfaces in Pentacene Organic Field Effect Transistors: Improved Stability and Contact at the Interface.
venue: Angewandte Chemie
year: 2018

abstract: Abstract Flexible organic field effect transistors with high electrical stability upon bending are demonstrated on indium tin oxide coated polyethylene terephthalate substrates with TIPS Pentacene semiconductor crystals formed by drop casting on a hybrid gate dielectric consisting hafnium dioxide grown by atomic layer deposition and spin coated poly(4 vinylphenol) Fabricated devices exhibited excellent p channel characteristics with field effect mobility up to 0.12 cm2/Vs with high current on/off ratio >104 and low threshold voltage of 0.2 V. Device performance was slightly affected by mechanical strain applied by bending for 5 min with radius varying from 12.5 mm to as low as 5.0 mm; and a high stability in performance was demonstrated upon applying constant tensile strain for more than 48 h at bending radius of 5.0 mm. It was found that strain induced changes in the device performance primarily occur due to increase in dielectric surface roughness; and the semiconductor dielectric interface uniformity is influenced more with magnitude of strain rather than its duration.
author_names: Vivek Raghuwanshi

Deepak Bharti

Shree Prakash Tiwari
title: Flexible organic field effect transistors with TIPS Pentacene crystals exhibiting high electrical stability upon bending
year: 2016

abstract: Abstract 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) from simple drop casting typically forms crystals with random orientation and poor areal coverage, which leads to device to device performance variation of organic thin film transistors (OTFTs) Previously, a temperature gradient technique was developed to address these problems. However, this approach simultaneously introduced thermal cracks due to the thermally induced stress during crystallization. These thermal cracks accounted for a reduction of charge transport, thereby impacting the device performance of TIPS pentacene based OTFTs. In this work, an insulating polymer, poly(a methyl styrene) (PaMS) was blended with TIPS pentacene to relieve the thermal stress and effectively prevent the generation of thermal cracks. The results demonstrate that the incorporation of PaMS polymer combined with the temperature gradient technique improves both the hole mobility and performance consistency of TIPS pentacene based OTFTs.
author_names: Kyeiwaa Asare-Yeboah

Sheng Bi

Zhengran He

Dawen Li
title: Temperature gradient controlled crystal growth from TIPS pentacene poly(a methyl styrene) blends for improving performance of organic thin film transistors
year: 2016

abstract: Abstract Flexible organic field effect transistors (OFETs) with TIPS pentacene: polystyrene (PS) blend are demonstrated to exhibit enhanced mobility and significantly improved electrical stability compared to neat TIPS pentacene on poly(4 vinylphenol) (PVP) dielectric (bi layer OFETs) along with high mechanical stability. Due to merit of high quality dielectric semiconductor interface, pristine TIPS pentacene: PS blend OFETs exhibited maximum mobility of 0.93 cm2 V 1 s 1 with average of 0.44( 0.25) cm2 V 1 s 1 compared to 0.14( 0.10) cm2 V 1 s 1 for bi layer OFETs with high current on off ratios on the order 105 for both. Both types of devices exhibited high electrical stability upon bending with increasing magnitude of strain or its duration up to 5 days. However, significant differences in electrical stability of devices were observed upon applying constant bias stress for 40 min to 1 h. Pristine blend devices exhibited outstanding electrical stability with very low drain current decay of
author_names: Vivek Raghuwanshi

Deepak Bharti

Ishan Varun

Ajay Kumar Mahato

Shree Prakash Tiwari
title: Performance enhancement in mechanically stable flexible organic field effect transistors with TIPS pentacene:polymer blend
year: 2016

abstract: Pentacene based organic thin film transistors (OTFTs) were fabricated on several types of flexible substrate: commercial photo paper, ultra smooth specialty paper and ultra thin (100 mM) flexible glass. The transistors were fabricated entirely through dry step processing. The transconductance and field effect mobility of OTFTs on photo paper reached values of ~0.52 mS m( 1) and 0.1 cm(2) V 1) s( 1) respectively. Preliminary results on the lifetime of OTFTs on photo paper yielded stable transconductance and mobility values over a period of more than 250 h. The comparable characteristics of OTFTs fabricated on widely available, low cost paper and high quality expensive liquid crystal display glass indicate the potential importance of cellulose based electronic devices.
author_names: Adam T Zocco

Han You

Joshua A Hagen

Andrew J Steckl
title: Pentacene organic thin film transistors on flexible paper and glass substrates.
venue: Nanotechnology
year: 2014

abstract: In this work, we report for the first time the use of a nonconjugated semicrystalline polymer as a film forming agent to control the crystallization and tune the charge transport of solution processed, small molecule organic semiconductors. When 6,13 bis (triisopropylsilylethynyl) pentacene (TIPS pentacene) was demonstrated as a representative material to blend with polyethylene oxide (PEO) polymer, it crystallized into uniformly aligned needles with reduced random orientation, enhanced long range order and elevated areal coverage. Specifically, an ultra low misorientation angle of 7.9deg 3.5deg was obtained with 10% PEO additive, beneficial for charge transport in the TIPS pentacene/PEO hybrid film. Bottom gate, top contact organic thin film transistors (OTFTs) based on TIPS pentacene/PEO mixture were found to show a field effect mobility up to 2.5 x 10 2 cm 2 /Vs. This work may be universally applied to other organic semiconductors to regulate their crystal formation, enhance film forming and improve device performance of OTFTs. It contributes to the utilization of flexible substrates for future generation high performance organic electronics.
author_names: Zhengran He

Ziyang Zhang

Sheng Bi

Kyeiwaa Asare-Yeboah

Jihua Chen
title: Ultra low misorientation angle in small molecule semiconductor/polyethylene oxide blends for organic thin film transistors
venue: Journal of Polymer Research
year: 2020

abstract: Flexible ammonia (NH3) gas sensors based on solution processable organic thin film transistors (OTFTs) are fabricated using a TIPS pentacene active layer/PMMA dielectric layer on glass and plastic substrates. These OTFT sensors exhibit outstanding NH3 gas response and recovery characteristics under multiple exposure/evacuation cycles at controlled NH3 concentrations.
author_names: Xinge Yu

Nanjia Zhou

Shijiao Han

Hui Li Lin

Donald B Buchholz

Junsheng Yu

R P H Chang

Tobin J Marks

Antonio F Facchetti
title: Flexible spray coated TIPS pentacene organic thin film transistors as ammonia gas sensors
year: 2013