Browsing by Author "Chao, Yu-Chiang"

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A 1-V operated polymer vertical transistor with high on/off current ratio
(2009)
Chao, Yu-Chiang
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Tsai, Wu-Wei
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Chen, Chun-Yu
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
All-Solution-Processed Red and Orange-Red Organic Light-Emitting Diodes with High-Efficiencies: The Effect of Mixed-Host Emissive Layers and Thermal Annealing Treatment
(2019-09-01)
Chang, Yu-Fan
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Yang, Lan-Sheng
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Su, Hsiao-Tso
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Liao, Si-Yi
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Niu, Mu-Chun
The instability of the organic light-emitting diodes (OLEDs) during operation can be attributed to the existence of point defects on the organic layers. In this work, the effect of mixed-host emissive layer and the thermal annealing treatment were investigated to eliminate defects and to boost the device performance. The mixed-host system includes 4,4 ',4 ''-tri (9-carbazoyl) triphenylamine (TCTA) and 2,7-bis(diphenylphosphoryl)-9, 9 '-spirobi[fluorene] (SPPO13). The mixed-host emissive layer with thermal annealing treatment showed low roughness and few pinholes, and the devices fabricated from this emissive layer exhibited high efficiencies, high stabilities, and long lifetimes. The red and orange-red OLEDs exhibited efficiencies of 13.9 cd/A and 24.35 cd/A, respectively. The longest half-lifetime (L-0=500 cd/m(2)) of the red and orange-red OLEDs were 158 h and 180 h, respectively. Efforts were made to solve problems in large-area coating and to reduce the number of defects on in organic layer. Large-active-area (active area=3 cmx4 cm) red phosphorescent OLEDs (PhOLEDs) devices were realized with very high current efficiency up to 9 cd/A.
An organic hydrogel film with micron-sized pillar array for real-time and indicator-free detection of Zn(2+)
(2011-11-01)
Chao, Yu-Chiang
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Huang, Yi-Sa
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Wang, Hsin-Ping
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Fu, Ssu-Ming
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Huang, Chien-Hao
A hydrogel sensing film for a real-time and indicator-free detection of Zn(2+) is developed by embedding a fluorescent indicator 11,16-bis( phenyl)-6,6,21,21-tetramethyl-m-benzi-6,21-porphodimethene in a hydrogel host poly(2-hydroxyethyl methacrylate). The sensing film shows high stability and selectivity to Zn(2+). The sensitivity of the sensing film is increased by fabricating a micron-sized pillar array on the surface of the sensing film to increase the surface area. For Zn(2+) concentrations of 10 (4) and 10 (3) M, the response time is 30 and 3 s, respectively. (C) 2011 Elsevier B.V. All rights reserved.
An organic hydrogel film with micron-sized pillar array for real-time and indicator-free detection of Zn2+
(2011-11-01)
Chao, Yu-Chiang
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Huang, Yi-Sa
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Wang, Hsin-Ping
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Fu, Ssu-Ming
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Huang, Chien-Hao
A hydrogel sensing film for a real-time and indicator-free detection of Zn2+ is developed by embedding a fluorescent indicator 11,16-bis( phenyl)-6,6,21,21-tetramethyl-m-benzi-6,21-porphodimethene in a hydrogel host poly(2-hydroxyethyl methacrylate). The sensing film shows high stability and selectivity to Zn2+. The sensitivity of the sensing film is increased by fabricating a micron-sized pillar array on the surface of the sensing film to increase the surface area. For Zn2+ concentrations of 10 (4) and 10 (3) M, the response time is 30 and 3 s, respectively. (C) 2011 Elsevier B.V. All rights reserved.
BIOSENSOR
(2010-11-18)
Meng, Hsin- Fei
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Hong, Sheng-Fu
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Chao, Yu-Chiang
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Horng, Yun-Ru
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Tsai, Pei-Yu
A biosensor applicable to an environment suitable for biosensing is provided, which is a solid-state element for performing detections in an aqueous environment. The biosensor at least includes a biosensing layer, a light-emitting diode and a photodiode. The biosensing layer causes changes in the light-emitting property thereof after absorbing, adsorbing and/or bonding with a biological substance released during in vivo signal transduction in an organism, and the rays of light generated by excitation of the light-emitting diode causes the biosensing layer to emit fluorescence. After the fluorescence is absorbed by the photodiode, it can be converted into an interpretable photocurrent signal. Afterwards, the meaning of the in vivo signal transduction can be understood by interpretation of the photocurrent signal.
Concomitant tuning of metal work function and wetting property with mixed self-assembled monolayers
(2011-01-01)
Chen, Chun-Yu
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Wu, Kun-Yang
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Chao, Yu-Chiang
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
The effect of the surface composition of a mixed self-assembled monolayer on the work function and wetting property of silver substrate are investigated with the mixtures of a fluorinated alkanethiol and a carboxyl-terminated alkanethiol of various chain lengths. The work function of silver can be tuned from 4.3 to 5.3 eV by changing the mixing ratio while the wetting property can be modulated by adjust the relative chain length of the fluorinated thiol and the carboxyl-terminated thiol. Thus solution-processed poly(para phenylene vinylene)-based polymer light-emitting diode was made possible with high efficiency of 6.7 cd/A and brightness of 40,000 cd/m(2). (C) 2010 Elsevier B. V. All rights reserved.
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
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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]
Efficient multilayer red fluorescent polymer light-emitting diodes by host and guest blend system
(2010-05-01)
Syu, Wun-Shing
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Lin, Sheng-Chia
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Tseng, Shin-Rong
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Chen, Chun-Yu
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Liu, Chang-Yao
Efficient red light polymer light-emitting diodes are obtained by energy transfer from host and guest blend system. Two kinds of blend systems, SPB02:(10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1] benzopyrano [6,7,8-ij]quinolizin-11-one)(C545T):4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) and SuperYellow (SY):poly(3,3'''-didodecylquaterthiophene) (PQT-12), are used as the active layers. C545T is a green emitter, acting as an assistant dopant to improve the energy transfer from blue SPB02 host to red DCJTB. The efficiency can achieve to 3.3 cd/A for DCJTB and 3.5 cd/A for PQT-12 system by multilayer device structure with 2,2,2 ''-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (TPBi) as electron transport layer. The SuperYellow:PQT-12 device shows great luminance of 16,930 cd/m(2). (C) 2010 Elsevier B.V. All rights reserved.
Enhanced Conversion Efficiency of III-V Triple-junction Solar Cells with Graphene Quantum Dots
(2016-12-16)
Lin, Tzu-Neng
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Santiago, Svette Reina Merden S.
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Zheng, Jie-An
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Chao, Yu-Chiang
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Yuan, Chi-Tsu
Graphene has been used to synthesize graphene quantum dots (GQDs) via pulsed laser ablation. By depositing the synthesized GQDs on the surface of InGaP/InGaAs/Ge triple-junction solar cells, the short-circuit current, fill factor, and conversion efficiency were enhanced remarkably. As the GQD concentration is increased, the conversion efficiency in the solar cell increases accordingly. A conversion efficiency of 33.2% for InGaP/InGaAs/Ge triple-junction solar cells has been achieved at the GQD concentration of 1.2 mg/ml, corresponding to a 35% enhancement compared to the cell without GQDs. On the basis of time-resolved photoluminescence, external quantum efficiency, and work-function measurements, we suggest that the efficiency enhancement in the InGaP/InGaAs/Ge triple-junction solar cells is primarily caused by the carrier injection from GQDs to the
Enhancement-mode polymer space-charge-limited transistor with low switching swing of 96 mV/decade
(2011-05-30)
Chao, Yu-Chiang
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Tsai, Hung-Kuo
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Zan, Hsiao-Wen
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Hsu, Yung-Hsuan
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Meng, Hsin-Fei
In this letter, an enhancement-mode polymer space-charge-limited transistor was realized with a low switching swing of 96 mV/decade, a low operation voltage of 1.5 V, and a high on/off current ratio of 10(4). By investigating the influence of the device's geometric parameters on the transistor characteristics, a low switching swing was obtained by positioning the base electrode at the middle of the channel length and reducing the opening diameter. Simulations of the potential distribution at the central vertical channel verified that the base electrode has the best control over the magnitude of potential barrier, resulting in a low switching swing. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3586255]
Evaluation of Perovskite Hole Selective Contacts for Silicon Solar Cells
(2019-01-01)
Chen, Yan-Syun
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Li, Li-Yu
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Yu, Peichen
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Chao, Yu-Chiang
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Meng, HsinFei
we investigate the potential and stability of perovskite(MaPbI3) as the hole-selective contact materials for silicon solar cells because perovskite has excellent carrier transport properties for both electrons and holes. We have overcome the problem of forming a continuous perovskite thin film on silicon due to low surface energy by engineering the silicon surface roughness and native oxide. As a result, the short-circuit current density (Jsc) of the device with the perovskite layer increases by 0.6mA/cm2 from 27.73 to 28.32 mA/cm2 and the open-circuit voltage (Voc) increases by 5mV from 517.36 to 512.50 mV, reaching a power conversion efficiency of 10.53%. The solar cell with the perovskite(MaPbI3) hole selective layer exhibits better performance than the reference counterpart. Future work will be focused on tuning the composition of the PbBr2 and Pb12 to modify the work function and enlarge the hole selectivity.
High-mobility polymer space-charge-limited transistor with grid-induced crystallinity
(2011-01-01)
Chao, Yu-Chiang
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Niu, Mu-Chun
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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Ku, Ming-Che
The vertical mobility of a polymer film prepared on a textured substrate is enhanced from 10 (5) cm(2)/Vs to 10 (3) cm(2)/Vs by a slow drying process which is unattainable in planar substrate. Highly ordered structure is observed for polymer film treated with high-boiling-point solvent and slow solvent annealing. The enhanced vertical mobility enables the polymer space-charge-limited transistor (SCLT) capable of outputting current density as high as 100 mA/cm(2) while maintaining good current gain and on-off ratio. Such vertical transistor is able to drive high-power devices or mechanical actuator in large-area and flexible array. (C) 2010 Elsevier B. V. All rights reserved.
High-performance poly(2,3-diphenyl-1,4-phenylene vinylene)-based polymer light-emitting diodes by blade coating method
(2011-08-03)
Liao, Yung-Ming
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Shih, Hung-Min
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Hsu, Kuang-Hui
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Hsu, Chain-Shu
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Chao, Yu-Chiang
A new series of super high brightness and luminance efficient poly(2,3-diphenyl-1,4-phenylene vinylene) (DP-PPV)-based electroluminescent (EL) polymers containing methoxy or long branched alkoxy chains were synthesized via Gilch polymerization. The branched alkoxy groups were introduced to enhance solubility for blade and spin-coating processes. Monomers of DMeO-PPV and m-Ph-PPV were used to increase steric hindrance and prevent close packing of the main chain. By controlling the feeding ratio of different monomers during polymerization, DP-PPV derivatives with high molecular weight were obtained. All synthesized polymers possess high glass transition temperatures and thermal stabilities. The maximum photoluminescent emissions of the thin films are located between 544 and 547 nm. Cyclic voltammetry analysis reveals that the band gaps of these light-emitting materials are in the range of 2.75 -2.84 eV. Blade coating was used to fabricate multilayer polymer light-emitting diodes. A multilayer electroluminescent device with the configuration of ITO/PEDOT:PSS/TFB/P1/TPBi/LiF/Al exhibited a very high luminescence efficiency (10.96 cd A(-1)). The maximum brightness of the multilayer EL device ITO/PEDOT:PSS/TFB/P3/CsF/Al reached up to 78,050 cd m(-2) with a low turn-on voltage (4.0 V). For further investigation, polymer P3 was blended with DPPFBNA to achieve white light-emitting device; the multilayer devices generated a maximum brightness of 1085 cd m(-2) and a luminance efficiency of 0.75 cd A(-1), with CIE coordinates (0.28, 0.33) at 11 V. (C) 2011 Elsevier Ltd. All rights reserved.
High-performance solution-processed polymer space-charge-limited transistor
(2008-06-01)
Chao, Yu-Chiang
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Meng, Hsin-Fei
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Horng, Sheng-Fu
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Hsu, Chain-Shu
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應用化學系
We demonstrate a polymer non-field-effect transistor in a vertical architecture with an Al grid embedded in a polymer sandwiched between another two electrodes. The Al grid containing high density of self-assembled submicron openings is fabricated by a non-lithography method. This device modulates the space-charge-limited current of a unipolar polymer diode with the Al grid. The operating voltage of the device is as low as 4 V, the on/off ratio is higher than one hundred, and the current gain is 10(4). The current density is higher than 1 mA/cm(2). (C) 2007 Elsevier B.V. All rights reserved.
High-performance vertical polymer nanorod transistors based on air-stable conjugated polymer
(2011-12-05)
Chao, Yu-Chiang
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Chung, Chin-Ho
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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Ku, Ming-Che
A vertical polymer nanorod transistor was realized based on an air-stable poly[5,5'-bis(3-dodecyl-2-thienyl)-2,2'-bithiophene] with a high highest occupied molecular orbital energy level. The influence of the work function of the emitter on the performances of the space-charge-limited transistor was investigated. When MoO3/Al was used as the top emitter and indium tin oxide was used as the bottom collector, the operating voltage of 0.6 V, the on/off current ratio of 4 x 10(4), and the switching swing of 105 mV/decade were achieved. A low-power-consumption inverter was also demonstrated. (C) 2011 American Institute of Physics. [doi:10.1063/1.3668086]
Highly efficient and stable organic solar cell modules processed by blade coating with 5.6% module efficiency and active area of 216 cm(2)
(2019-03-01)
Huang, Kuan-Min
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Wong, Ying Qian
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Lin, Man-Chun
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Chen, Chao-Hsuan
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Liao, Chung-Hung
In this study, an efficient and stable large-area blade-coated organic solar cell (OSC) module with an active area of 216 cm(2) (16 elementary cells connected in series) is demonstrated by combining appropriate thermal annealing treatment with the use of 4,4 '-(((methyl(4-sulphonatobutyl)ammonio)bis(propane-3,1-diyl))bis(dimethyl-ammoniumdiyl))bis-(butane-1-sulfonate) (MSAPBS) as the cathode interfacial layer. For the opaque device using poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b ']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PBDTTT-EFT (PTB7-Th)):[6,6]-phenyl C-71-butyric acid methyl ester (PC71BM) blend film as the active layer, the power conversion efficiency (PCE) of 5.6% is achieved under AM 1.5G solar light illumination. Very encouragingly, our strategy can be applicable for semitransparent OSCs, and a remarkable PCE up to 4.5% is observed. To the best of our knowledge, the PCE of 5.6% for opaque device and 4.5% for semitransparent device represent the highest PCE ever reported for OSCs with the active area exceeding 100 cm(2). The devices also show an impressive stability under outdoor environment, where the efficiency decay is less than 30% for 60 days. Our findings can pave the way toward the development of organic solar cell modules with high performance and long-term stability.
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
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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.
Increasing organic vertical carrier mobility for the application of high speed bilayered organic photodetector
(2009-11-23)
Tsai, Wu-Wei
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Chao, Yu-Chiang
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Chen, En-Chen
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
The direct influence of the vertical carrier mobility on the frequency response of bilayered organic photodiodes (PDs) is investigated for the first time. With fullerene as the acceptor material, changing vertical hole mobility from 2.3x10(-5) to 2.8x10(-4) cm(2)/V s increases PD bandwidth from 10 to 80 MHz under a 4 V operation. The influence of deposition rate on vertical hole mobility of pentacene film is also discussed. Our results facilitate the application of bilayered organic PDs on the detection of very-high-frequency optical signals.
Infrared proximity sensor using organic light-emitting diode with quantum dots converter
(2012-11-01)
Chen, En-Chen
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Yeh, Han-Cheng
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Chao, Yu-Chiang
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Meng, Hsin-Fei
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Zan, Hsiao-Wen
An efficient visible-to-infrared conversion film is made by blending CdTe quantum dots (CdTe QDs) of 12 nm diameter in a polyvinylpyrrolidone 360 (PVP 360) polymer matrix cast by water solution. The solid-state photoluminescence quantum efficiency exceeds 10% with emission peak at 810 nm. Strong 810 emission is obtained by combining the quantum dot film and a green polyfluorene light-emitting diode. Color filter is used to remove residual light below 780 nm to make it entirely invisible. Infrared photo-detector is made by blending poly[5-(5-(2,5-bis(decyloxy)-4-methylphenyl)thiophen-2-yl)-2,3-bis(4-(2-ethylhexyloxy)phenyl)-7-(5-methylthiophen-2-yl)thieno[3,4-b]pyrazine] (PBDOTTP) with band-gap 1.2 eV and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM). The pixel contains one PD surrounded by four PLED on its four sides. The active areas of the five devices are all I cm by 1 cm and they are on the same plane. Infrared proximity sensor with photo-current over 300 nA at 10 cm object distance is achieved by detecting the reflected infrared signal. (C) 2012 Elsevier B.V. All rights reserved.
Integrated semiconductor optoelectronic devices for real-time and indicator-free detection of aqueous nitric oxide
(2011-05-01)
Chao, Yu-Chiang
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Yeh, Shih-De
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Zan, Hsiao-Wen
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Chang, Gao-Fong
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Meng, Hsin-Fei
A real-time and indicator-free sensor specific to nitric oxide (NO) is realized for the first time by integrating a sensing hydrogel film, a top-emitting polymer light-emitting diode (PLED), and a silicon photodetector. The top-emitting PLED is utilized to excite the sensing film specific to NO, and the photoluminescence of the sensing film is transformed into electric signal by the photodetector. The influence of the excitation light on the out-put photocurrent of the photodetector is diminished by two delicately selected organic filters based on their absorption spectra. Lead phthalocyanine is deposited on a top-emitting PLED as a filter for generating an excitation light without overlapping the emission maximum of the sensing hydrogel film. Poly(3-hexylthiophene) is placed in front of the photodetector as another filter to remove the excitation light. This sensor demonstrated a fast photocurrent response to NO with response time within 5 min. (C) 2011 Elsevier B.V. All rights reserved.