Browsing by Author "Hwang, Gue-Wuu"

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High-performance poly(3-hexylthiophene) top-gate transistors incorporating TiO(2) nanocomposite dielectrics
(2010-01-01)
Yang, Feng-Yu
;
Hsu, Meei-Yu
;
Hwang, Gue-Wuu
;
Chang, Kuo-Jui
;
電子工程學系及電子研究所
This paper describes the fabrication of top-gate P3HT organic field effect transistors (OFETs) incorporating polymer/TiO(2) nanocomposite bilayer dielectrics. The TiO(2) nanocomposite comprised PVP, the cross-linking agent PMF, and TiO(2) nanoparticles (NPs), which possessed rod-like anatase structures and were solution-processable using polar solvents; thus, the composite dielectric solutions were easy to be prepared for the use in top-gate OFET devices without damaging and dissolution of the underlying P3HT film. SEM and AFM images revealed the high uniformity of the nanocomposite films. To determine the effects of the composite dielectrics with/without TiO(2) on the performance of the OFET devices, we inserted a buffer layer of PMMA between the semiconductor layer and the gate dielectric to maintain a constant semiconductor-dielectric interface. The device incorporating the PMMA/TiO(2) nanocomposite bilayer gate dielectric operated effectively at supply voltages within 20 V, with a good mobility (mu) of 1.5 x 10(-2) cm(2) V(-1) s(-1), which was three times greater than that of the devices featuring the PMMA/PVP/PMF dielectric; the on/off ratio of nanocomposite device (8.6 x 10(6)) was significantly better than that of the PVP/PMF device (1.5 x 105). The PMMA/TiO(2) nanocomposite was also performed acceptably at supply voltages of less than 10 V. The performance of the OFET incorporating a single dielectric layer of the TiO(2) nanocomposite (mu = 0.001 cm(2) V(-1) s(-1); on/off ratio = 5.7 x 10(2)) was inferior to those of the bilayer gate dielectric devices. (C) 2009 Elsevier B.V. All rights reserved.
High-performance poly(3-hexylthiophene) top-gate transistors incorporating TiO2 nanocomposite dielectrics
(2010-01-01)
Yang, Feng-Yu
;
Hsu, Meei-Yu
;
Hwang, Gue-Wuu
;
Chang, Kuo-Jui
;
電子工程學系及電子研究所
This paper describes the fabrication of top-gate P3HT organic field effect transistors (OFETs) incorporating polymer/TiO2 nanocomposite bilayer dielectrics. The TiO2 nanocomposite comprised PVP, the cross-linking agent PMF, and TiO2 nanoparticles (NPs), which possessed rod-like anatase structures and were solution-processable using polar solvents; thus, the composite dielectric solutions were easy to be prepared for the use in top-gate OFET devices without damaging and dissolution of the underlying P3HT film. SEM and AFM images revealed the high uniformity of the nanocomposite films. To determine the effects of the composite dielectrics with/without TiO2 on the performance of the OFET devices, we inserted a buffer layer of PMMA between the semiconductor layer and the gate dielectric to maintain a constant semiconductor-dielectric interface. The device incorporating the PMMA/TiO2 nanocomposite bilayer gate dielectric operated effectively at supply voltages within 20 V, with a good mobility (mu) of 1.5 x 10(-2) cm(2) V-1 s(-1), which was three times greater than that of the devices featuring the PMMA/PVP/PMF dielectric; the on/off ratio of nanocomposite device (8.6 x 10(6)) was significantly better than that of the PVP/PMF device (1.5 x 105). The PMMA/TiO2 nanocomposite was also performed acceptably at supply voltages of less than 10 V. The performance of the OFET incorporating a single dielectric layer of the TiO2 nanocomposite (mu = 0.001 cm(2) V-1 s(-1); on/off ratio = 5.7 x 10(2)) was inferior to those of the bilayer gate dielectric devices. (C) 2009 Elsevier B.V. All rights reserved.
New Thiophene-Phenylene-Thiophene Acceptor Random Conjugated Copolymers for Optoelectronic Applications
(2010-06-01)
Tsai, Jung-Hsun
;
Chueh, Chu-Chen
;
Chen, Wen-Chang
;
Yu, Chao-Ying
;
Hwang, Gue-Wuu
New low band gap thiophene-phenylene-thiophene (TPT)-based donor-acceptor-donor random copolymers were synthesized for optoelectronic device applications by a palladium-catalyzed Stille coupling reaction under microwave heating. The acceptors included 2,3-bis(4-(2-ethylhexyloxy)phenyl)-5,8-bis[5'-bromo-dithien-2-yl-quinoxalines] (DTQ) and 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-ethyl-hexyl)-pyrrolo[3,4-c]-pyrrole-1,4-dione (DPP). The prepared random copolymers were named as PTPTDTQ(0.55), PTPTDTQ(0.34)DPP(0.14), and PTPTDTQ(0.26)DPP(0.34) depending on the copolymer ratio. The optical band gaps (Er) of PTPTDTQ(0.55), PTPTDTQ(0.34)DPP(0.14), and PTPTDTQ(0.26)DPP(0.34) were 1.74, 1.56, and 1.48 eV, respectively. The hole mobility obtained from the field-effect transistor devices prepared from PTPTDTQ(0.55), PTPTDTQ(0.34)DPP(0.14), and PTPTDTQ(0.26)DPP(0.34) were 2.2 x 10(-3), 2.4 x 10(-3), and 4.7 x 10(-3) cm(2) V s(-1), respectively, with the on-off ratios of 4.0 x 10(4), 4.0 x 10(4), and 5.3 x 10(4). It suggested that the significant intramolecular charge transfer between the TPT and acceptor led to the band gap reduction and hole mobility enhancement. Polymer solar cells of these TPT-based copolymers blended with 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-C-71 (PC(71) BM) under illumination of AM 1.5G (100 mW cm(-2)) solar simulator exhibited a power conversion efficiency (PCE) as high as 3.71%. Besides, the near-infrared photodetector device prepared from PTPTDTQ(0.26)DPP(0.34) showed a high external quantum efficiency exceeding 32% at 700 nm (under -3 V bias) and fast-speed response. This study suggests that the prepared TPT-based donor-acceptor random copolymers exhibited promising and versatile applications on optoelectronic devices. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2351-2360, 2010