Browsing by Author "Kim, Choongik"

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Influence of polymer dielectric surface energy on thin-film transistor performance of solution-processed triethylsilylethynyl anthradithiophene (TES-ADT)
(2012-02-01)
Chen, Liang-Hsiang
;
Lin, Pang
;
Kim, Choongik
;
Chen, Ming-Chou
;
Huang, Peng-Yi
This study investigates the correlation between surface energy of polymer dielectrics and the film morphology, microstructure, and thin-film transistor performance of solution-processed 5,11-bis(triethylsilylethynyl) anthradithiophene (TES-ADT) films. The low surface energy polyimide (PI) dielectric induced large grains with strong X-ray reflections for spin-cast TES-ADT films in comparison to high surface energy poly(4-vinyl phenol) (PVP) dielectric. Furthermore, thin-film transistors based on spin-cast TES-ADT films on PI dielectric exhibited enhanced electrical performance, small hysteresis, and high stability under bias stress with carrier mobility as high as 0.43 cm(2)/Vs and a current on/off ratio of 10(7). (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Polyimide/Ta(2)O(5) nanocomposite gate insulators for enhanced organic thin-film transistor performance
(2011-08-01)
Chen, Liang-Hsiang
;
Lin, Pang
;
Ho, Jia-Chong
;
Lee, Cheng-Chung
;
Kim, Choongik
This study reports the preparation and characterization of polyimide/Ta(2)O(5) nanocomposite films as insulators for organic thin-film transistors (OTFTs). The degree of imidization, thermal, electrical, and surface properties of the nanocomposite films were characterized as a function of Ta(2)O(5) precursor contents. The nanocomposite films, with controlled/comparable insulator electrical characteristics and surface properties, have been found to enhance dielectric constant compared to pristine polyimide films, which resulted in improved pentacene TFT performance by a factor of 2-3 with carrier mobility values as high as 0.38 cm(2)/Vs. (C) 2011 Elsevier B.V. All rights reserved.
Polyimide/Ta2O5 nanocomposite gate insulators for enhanced organic thin-film transistor performance
(2011-08-01)
Chen, Liang-Hsiang
;
Lin, Pang
;
Ho, Jia-Chong
;
Lee, Cheng-Chung
;
Kim, Choongik
This study reports the preparation and characterization of polyimide/Ta2O5 nanocomposite films as insulators for organic thin-film transistors (OTFTs). The degree of imidization, thermal, electrical, and surface properties of the nanocomposite films were characterized as a function of Ta2O5 precursor contents. The nanocomposite films, with controlled/comparable insulator electrical characteristics and surface properties, have been found to enhance dielectric constant compared to pristine polyimide films, which resulted in improved pentacene TFT performance by a factor of 2-3 with carrier mobility values as high as 0.38 cm(2)/Vs. (C) 2011 Elsevier B.V. All rights reserved.
Silver nanowire-polymer composite electrode for high performance solution-processed thin-film transistors
(2012-10-01)
Chen, Liang-Hsiang
;
Lin, Pang
;
Chen, Ming-Chou
;
Huang, Peng-Yi
;
Kim, Choongik
Silver nanowires (AgNWs)/poly-(3,4-ethylenedioxythiophene/polystyrene sulphonate) (PEDOT:PSS) composite films as conductive electrode for OTFTs were prepared, and their optical and electrical properties were investigated. The conductive composite films used in this study afforded low sheet resistance of <140 Omega/sq and transmittance as high as 70% in the visible region. For the composite film with 0.1 wt.% of AgNWs, contact resistance as low as 2.7 x 10(4) Omega cm was obtained, as examined by Transfer length model (TLM) analysis, and work function of the corresponding film was 5.0 eV. Furthermore, the composite films were employed as source and drain electrodes for top-gate/bottom-contact organic thin-film transistors (OTFTs) based on solution-processed 5,11-bistriethylsilylethynyl anthradithiophene (TES-ADT) as organic semiconductor, and the resulting device showed high electrical performance with carrier mobility as high as 0.21 cm(2)/V s. (C) 2012 Elsevier B.V. All rights reserved.
Solution-Processed Small-Molecule Bulk Heterojunction Ambipolar Transistors
(2014-04-01)
Cheng, Shiau-Shin
;
Huang, Peng-Yi
;
Ramesh, Mohan
;
Chang, Hsiu-Chieh
;
Chen, Li-Ming
Solution-processed small-molecule bulk heterojunction (BHJ) ambipolar organic thin-film transistors are fabricated based on a combination of [2-phenylbenzo[d,d \']thieno[3,2-b;4,5-b \']dithiophene (P-BTDT) : 2-(4-n-octylphenyl)benzo[d,(d) under bar \']thieno[3,2-b;4,5-b\']dithiophene (OP-BTDT)] and C-60. Treating high electrical performance vacuum-deposited P-BTDT organic semiconductors with a newly developed solution-processed organic semiconductor material, OP-BTDT, in an optimized ratio yields a solution-processed p-channel organic semiconductor blend with carrier mobility as high as 0.65 cm(2) V-1 s(-1). An optimized blending of P-BTDT:OP-BTDT with the n-channel semiconductor, C-60, results in a BHJ ambipolar transistor with balanced carrier mobilities for holes and electrons of 0.03 and 0.02 cm(2) V-1 s(-1), respectively. Furthermore, a complementary-like inverter composed of two ambipolar thin-film transistors is demonstrated, which achieves a gain of 115.