Browsing by Author "Yen, Feng-Wen"

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All-solution-processed blue small molecular organic light-emitting diodes with multilayer device structure
(2009-12-01)
You, Jia-Da
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Tseng, Shin-Rong
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Meng, Hsin-Fei
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Yen, Feng-Wen
;
Lin, I-Feng
All-solution-processed multilayer blue small molecular organic light-emitting diodes are fabricated by blade coating method. Fluorescent blue host, 1-(7 -(9.9'-bianthracen-10-yl)-9,9-dioctyl-9H-fluoren-2-yl)pyrene, and blue dopant, 4,4'-(1E,1'E)-2,2'-(naphthalene-2,6-diyl)bis(ethene-2,1-diyl)bis(N,N-bis(4-hexylphenyl)aniline),are used to achieve good solubility and pinhole-free thin film by solution process. The multilayer device structure with hole/electron transport layer is achieved by blade coating method without the dissolution problem between layers. The efficiency of the all-solution-processed device is 4.8 cd/A at 1200 cd/m(2), close to that by thermal deposition in high vacuum chamber. The device performance is optimized with the annealing temperature of TPBi layer at 50 degrees C. (C) 2009 Elsevier B.V. All rights reserved.
All-Solution-Processed Multilayered Small-Molecule OLEDs with High Device Efficiency
(2009)
Tseng, Hsin-Rong
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Meng, Hsin-Fei
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You, Jia-Da
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Horng, Sheng-Fu
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Yen, Feng-Wen
All-solution-processed multilayer blue small molecular organic light-emitting diodes are fabri-cated by blade coating method. Fluorescent blue host,1-(7-(9,9'-bianthracen-10-yl)- 9,9-dioctyl-9H-fluoren-2-yl)pyrene, and blue dopant, 4,4'-(IE,I'E)-2,2'(naphthalene-2,6-diyl)bis(ethene-2,1-diyl)bis(N,N-bis(4-hexylphenyl)aniline), are synthesized to achieve good solubility and pinhole free thin film by solution process. The multilayer device structure with holelelectron transport layer is achieved by blade coating method without the dissolution problem between layers. The efficiency of the all-solution-processed device is 4.8 cd/A at 1,200 cd/m(2), close to that by thermal deposition in high vacuum chamber.
Continuous blade coating for multi-layer large-area organic light-emitting diode and solar cell
(2011-11-01)
Chen, Chun-Yu
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Chang, Hao-Wen
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Chang, Yu-Fan
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Chang, Bo-Jie
;
Lin, Yuan-Sheng
A continuous roll-to-roll compatible blade-coating method for multi-layers of general organic semiconductors is developed. Dissolution of the underlying film during coating is prevented by simultaneously applying heating from the bottom and gentle hot wind from the top. The solvent is immediately expelled and reflow inhibited. This method succeeds for polymers and small molecules. Uniformity is within 10% for 5 cm by 5 cm area with a mean value of tens of nanometers for both organic light-emitting diode (OLED) and solar cell structure with little material waste. For phosphorescent OLED 25 cd/A is achieved for green, 15 cd/A for orange, and 8 cd/A for blue. For fluorescent OLED 4.3 cd/A is achieved for blue, 9 cd/A for orange, and 6.9 cd/A for white. For OLED with 2 cm by 3 cm active area, the luminance variation is within 10%. Power conversion efficiency of 4.1% is achieved for polymer solar cell, similar to spin coating using the same materials. Very-low-cost and high-throughput fabrication of efficient organic devices is realized by the continuous blade-only method. (C) 2011 American Institute of Physics. [doi:10.1063/1.3636398]
Highly efficient solution-processed red organic light-emitting diodes with long-side-chained triplet emitter
(2011-01-01)
Chao, Yu-Chiang
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Huang, Sheng-Yang
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Chen, Chun-Yu
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Chang, Yu-Fan
;
Meng, Hsin-Fei
Newly synthesized red It complexes tris[2-(4-n-hexyl-phenyl)quinoline]iridium(III) and tris[(4-n-hexylphenyl)isoquinoline)]iridium(III) with long alkyl side chains are utilized to demonstrate the high efficiency multi-layer solution-processed red organic light-emitting diodes. Solubilities of these triplet emitters are high which enable them to be uniformly dispersed in the polymer host. Blade coating method is utilized to prepare organic multi-layers without mutual dissolution between different layers. 17 cd/A current efficiency, 10 lm/W power efficiency, and 8.8% external quantum efficiency can be achieved for the device with CsF/Al cathode. 10,000 cd/m(2) is reached at 10 V. Similar quantum efficiency is also achieved with an electron-transport layer and LiF/Al cathode. (C) 2010 Elsevier B.V. All rights reserved.
Molecular-weight-dependent nanoscale morphology in silole-containing cyclopentadithiophene polymer and fullerene derivative blends
(2011-11-01)
Huang, Jen-Hsien
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Chen, Fang-Chung
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Chen, Cheng-Lun
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Huang, Annie Tzuyu
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Hsiao, Yu-Sheng
We have investigated the effect of polymer molecular weight (MW) on the morphology and efficiency of bulk heterojunction (BHJ) solar cells comprised of poly[(4,4'-bis(2-ethyl-hexyl)dithieno[3,2-b: 2',3'-d] silole)-2,6-diyl-alt-(5,5'-thienyl-4,4'-dihexyl-2,2'-bithiazole)2,6- diyl] (Si-PCPDTTBT) and [6,6]-phenyl C(61) butyric acid methyl ester (PCBM). Striking morphological changes are observed in BHJ films upon the change of the polymer MW. Atomic force microscopy and transmission electron microscopy studies suggest that high MW polymer generated high degree of phase separation, leading to formation of an inter-penetrating network for carrier transport. The X-ray diffraction investigation indicated that increased pi-pi stacking in Si-PCPDTTBT with increasing polymer MWs results in an increase in hole mobility of Si-PCPDTTBT and electron mobility of PCBM as well as the red shift absorption spectrum in BHJ films. The solar cells based on PCBM with high-MW Si-PCPDTTBT deliver power conversion efficiencies of 3.33%. (C) 2011 Elsevier B.V. All rights reserved.
Nanoscale Correlation between Exciton Dissociation and Carrier Transport in Silole-Containing Cyclopentadithiophene-Based Bulk Heterojunction Films
(2011-02-10)
Huang, Jen-Hsien
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Teng, Chin-Min
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Hsiao, Yu-Sheng
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Yen, Feng-Wen
;
Chen, Peilin
Understanding the effects of conjugated polymer structures on exciton lifetimes and morphologies within bulk heterojunction (BHJ) films is a necessary step toward the development of better organic solar cells. Studying the impact of a polymer's structure on the optical, morphological, and performance characteristics of a device can lead to advances in the design of new polymers. In this study, we synthesized carbon- and silicon-bridged cyclopentadithiophene- (CPDT-) based polymers and determined their photophysical properties and morphologies by measuring the exciton lifetime distributions in their BHJ films The silicon-bridged CPDT-based polymer/[6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) BHJ exhibited a higher degree of luminescence quenching, suggesting that thermodynamically favorable mixing on the molecular scale and nanoscale phase separation occurred simultaneously in the blend film. We attribute this favorable morphology to the presence of strong pi-pi stacking in the silicon-bridged CPDT-based polymers. Under AM 1.5 G illumination (100 mA cm(-2)), a device incorporating the silicon-bridged CPDT-based polymer and PCBM (1:2, w/w) gave an overall power conversion efficiency of 3.5% with a short-circuit current of 9.0 mA cm(-2), an open-circuit voltage of 0.72 V, and a fill factor of 53.6%.