Browsing by Author "Meng, Hsin-Fei"

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10% Efficiency Hybrid GaAs/PEDOT:PSS Solar Cells with Monolayer Graphene
(2014-01-01)
Cheng, Kai-Yuan
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Pan, Huai-Te
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Yu, Shu-Cheng
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Weng, Wei-Sheng
;
Lai, Yi-Chun
The development of solution-processed hybrid organic-inorganic heterojunction solar cells have provoked increasing research effort due to potential to significantly reduce the fabrication cost of semiconductor solar cells while maintaining the high power conversion efficiency (PCE). With a recent record of GaAs solar cells achieving 28.8% via a wafer lift-off technique, hybrid organic/GaAs solar cells can offer an alternative route to provide more affordable solar power than current semiconductor technologies. In this work, we demonstrate the hybrid devices based on a conductive polymer poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) directly spun-cast on planar gallium arsenide materials. While still lacking for optimized antireflection, the PCE of the best performing device can achieve nearly 10% by introducing the monolayer graphene as transparent electrode. The current progress presents 2-fold enhancement in comparison to a previous record at 5% based on GaAs nanowire templates.
11%-Efficiency Hybrid Organic/Silicon-Nanowire Heterojunction Solar Cell with an Intermediate 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane Layer
(2013)
Tsai, Chia-Ying
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Chen, Po-Han
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Huang, Yang-Yue
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Pen, Huai-Te
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Yu, Peichen
Hybrid organic-inorganic heterojunction solar cells based on silicon nanowires (SiNWs) are promising candidates for next-generation photovoltaics owing to potentials for low fabrication cost and high efficiency. The SiNW array, fabricated by a simple metal-assisted wet chemical etching method, produces a large surface-area-to-volume ratio, hence allowing efficient light harvesting and charge collection via the formation of a core-sheath p-n junction. However, previously reported power conversion efficiencies (PCEs) are approximately capped at 10%, which is largely depicted by the interface defect densities that limit the open-circuit voltage (V-oc) and fill factor (FF). In this work, we introduce a solution-processed, intermediate 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) layer to mitigate the interface recombination loss for hybrid heterojunction solar cells consisted of SiNWs and conjugate polymer poly(3,4-ethylenedioxy-thiophene): poly(styrenesulfonate) (PEDOT:PSS). A record PCE of 11.0% is achieved in contrast to 9.6% from a reference counterpart without TAPC, which represents an enhancement factor of 14.2% ascribed to noticeable improvement in the V-oc and FF. The result is further supported by examining indicators for the interface quality via a suppressed dark saturation current and an enhanced minority carrier lifetime which exhibits an increase from 84 mu sec without TAPC to 87 mu sec with TAPC.
13% Efficiency Hybrid Organic/Silicon-Nanowire Heterojunction Solar Cell via Interface Engineering
(2013-12-01)
Yu, Peichen
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Tsai, Chia-Ying
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Chang, Jan-Kai
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Lai, Chih-Chung
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Chen, Po-Han
Interface carrier recombination currently hinders the performance of hybrid organic silicon heterojunction solar cells for high-efficiency low-cost photovoltaics. Here, we introduce an intermediate 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAP() layer into hybrid heterojunction solar cells based on silicon nanowires (SINWs) and conjugate polymer poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS). The highest power conversion efficiency reaches a record 13.01%, which is largely ascribed to the modified organic surface morphology and suppressed saturation current that boost the open-circuit voltage and fill factor. We show that the insertion of TAP( increases the minority carrier lifetime because of an energy offset at the heterojunction interface. Furthermore, X-ray photoemission spectroscopy reveals that TAP( can effectively block the strong oxidation reaction occurring between PEDOT:PSS and silicon, which improves the device characteristics and assurances for reliability. These learnings point toward future directions for versatile interface engineering techniques for the attainment of highly efficient hybrid photovoltaics.
2-V operated flexible vertical organic transistor with good air stability and bias stress reliability
(2017-11-01)
Huang, Kuan-Min
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Lin, Hung-Cheng
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Kawashima, Kazuaki
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Osaka, Itaru
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Zan, Hsiao-Wen
In this work, we demonstrated a vertical organic transistor using air-stable material to exhibit good lifetime, good bias-stress reliability, and low operation voltage on a flexible plastic substrate in air ambient. With a synthesized NTz-based semiconducting polymer, the proposed space-charge-limited transistor (SCLT) delivers high on-off current ratio of 160000 and high output current density of 10 mA/cm(2) at about 2 V. Without encapsulation, the proposed transistor keeps stable current-voltage relationship for 180 days and has only 0.1 V threshold voltage shift after 5000 s bias stress. No significant degradation can be observed after 1000-times bending and a maximum gain of 14 can be obtained when connecting the flexible transistor with a resistor to form an inverter. (C) 2017 Elsevier B.V. All rights reserved.
A 0.05 V driven ammonia gas sensor based on an organic diode with a top porous layered electrode and an air-stable sensing film
(2019-06-07)
Madhaiyan, Govindasamy
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Chen, Chao-Hsuan
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Wu, Yi-Chu
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Horng, Sheng-Fu
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Zan, Hsiao-Wen
In this work, we successfully demonstrated an extremely-low-voltage (0.05 V) gas sensor based on a vertical organic diode with work-function-matched electrodes. With the designed electrodes (MoO3/Al vs. Al), the built-in field in the vertical diode is greatly reduced and hence the diode can be turned on at a very low voltage. By producing nanometer pores in the top electrode, the diode becomes a very sensitive gas sensor to detect ammonia in parts-per-billion (ppb) concentrations. Upon reducing the voltage from 5 V to 0.05 V, this sensor device shows an over 5-times enhancement in the sensitivity. The air-stable sensing film also exhibits a lifetime of 30 days in air. Finally, by connecting with an organic photovoltaic (OPV) device, the gas sensor can be directly powered and switched on by irradiating light on the OPV.
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
A low-cost miniaturized colorimetric sensor with vertically-stacked semi-transparent finger-type organic photo detector for formaldehyde sensing
(2019-10-01)
Lin, Ching-Fu
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Zan, Hsiao-Wen
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Lu, Chia-Jung
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Meng, Hsin-Fei
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Soppera, Olivier
We proposed a sensitive colorimetric sensing system using a paper-like sensing layer on top of a vertically stacked finger-type organic photodetector (OPD) and commercial light-emitting diode (LED). The stacked OPD/LED device was small, with an area of 0.8 cm x 0.5 cm that was even smaller than a coin. Using commercial colorimetric formaldehyde (HCHO) sensing molecules to form the sensing layer, the stacked detecting system successfully detected HCHO of concentrations ranging from 40 to 1000 ppb within 20 min. Critical parameters affecting the sensitivity were investigated. The final system exhibited a stable calibration curve over 60 days. The long lifetime was attributed to using 2,6-Bis(trimethyltin)-4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo [1,2-b:4,5-b']dithiophene (PBDTTT-C-T): phenyl-C71-butyric acid methyl ester (PC71 BM) to serve as a blended system and using the current variation ratio to represent the sensing response.
A low-cost, portable and easy-operated salivary urea sensor for point-of-care application
(2019-05-01)
Wang, Kuan-Hsun
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Hsieh, Ju-Chun
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Chen, Chang-Chiang
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
Salivary urea was reported to be a useful biomarker to reflect the blood urea nitrogen in chronic kidney disease patients. However, as a new biomarker, enormous clinical trials are required to define the intended-use and to verify the specification. In this report, we demonstrated a low-cost easy-operated real-time sensing system (optical fiber-urea-sensing, OFUS, system) to detect salivary urea. We aim to make the system easily reproduced by the community to stimulate abundant clinical tests worldwide. The OFUS system is composed of a simple three-dimensional printed tank to link with two optical fibers, one connecting with a commercial light-emitting diode to deliver the input light signal, the other connecting with a commercial cadmium sulfide photo-conductive cell to detect the sensing signal. To allow on-site detection without any sample pretreatment, only 1 mu l saliva is needed to be mixed with 10 mu l urease solution and 90 mu l pH indicator solution in the reaction tank and the detection time is only 20 s. A stable and reproducible calibration curve can be easily built with a detection range as 24-300 mg/dL. The OFUS system successfully detected saliva with added synthetic urea and samples from chronic kidney disease patients. A good agreement between the OFUS system and the commercial kit was obtained. A good correlation between salivary urea and the blood urea nitrogen was also confirmed.
A solvent-free lift-off method for realizing vertical organic transistors with low leakage current and high ON/OFF ratio
(2016-04)
Fang, Xiang
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Lin, Chia-Ho
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Sun, Yung-Tai
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Chin, Huei-Tzu
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Zan, Hsiao-Wen
A solvent-free lift-off method has been introduced to fabricate the aluminum nano-hole array with diameter down to 80 nm as the base electrode for a vertical organic transistor. The imprinted vertical organic transistor exhibited base leakage current density as low as 5 x 10(-5) mA/cm(2) and high ON/OFF current ratio as high as 10(5). (C) 2016 Elsevier B.V. All rights reserved.
A Versatile Method to Enhance the Operational Current of Air-Stable Organic Gas Sensor for Monitoring of Breath Ammonia in Hemodialysis Patients
(2019-04-01)
Yu, Shang-Yu
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Tung, Tin-Wei
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Yang, Hong-Yu
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Chen, Guan-Yu
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Shih, Che-Chi
Point-of-care (POC) application for monitoring of breath ammonia (BA) in hemodialysis (HD) patients has emerged as a promising noninvasive health monitoring approach. In this context, many organic gas sensors have been reported for BA detection. However, one of the major challenges for its integration with affordable household POC application is to achieve stable performance for accuracy and high operational current at low voltage for low-cost read-out circuitry. Herein, we exploited the stability of the Donor Acceptor polymer on the cylindrical nanopore structure to realize the sensors with a high sensitivity and stability. Then, we proposed a double active layer (DL) strategy that exploits an ultrathin layer of Poly(3-hexylthiophene-2,5-diyl) (P3HT) to serve as a work function buffer to enhance the operational current. The DL sensor exhibits a sustainable operational current of microampere level and a stable sensing response even with the presence of P3HT layer. This effect is carefully examined with different aspects, including vertical composition profile of DL configuration, lifetime testing on different sensing layer, morphological analysis, and the versatility of the DL strategy. Finally, we utilize the DL sensor to conduct a tracing of BA concentration in two HD patients before and after HD, and correlate it with the blood urea nitrogen (BUN) levels. A good correlation coefficient of 0.96 is achieved. Moreover, the feasibility of DL sensor integrated into a low-cost circuitry was also verified. The results demonstrate the potential of this DL strategy to be used to integrate organic sensor for affordable household POC devices.
Accurate real-time sensing tip for aqueous NO with optical fibers embedded in active hydrogel waveguide
(2018-02-01)
Chung, Chieh-Wen
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Tsai, May-Jywan
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Lin, Peng-Wei
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Huang, Ding-Wen
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Wang, Kuan-Hsun
A NO sensing tip is made by inserting two parallel optical fibers inside a poly 2-hydroxyethyl methacrylate (PolyHEMA) hydrogel waveguide mixed with the probe molecule 1, 2-Diaminoanthraquinone (DAQ). There is a length difference of 1 mm between the two fibers, and the light has to propagate through the difference from the short fiber to the long fiber. The total cross section area of the active hydrogel waveguide embedded with the fibers is only 3mm x 1.2 mm. For practical use the tip is housed in a needle for mechanical protection and the sensing tip is able to detect aqueous NO concentration around 1 mu M with time resolution about 5 minutes. Such a sensing tip can be used to monitor the medical conditions inside the brain after a stroke or a brain injury. (C) 2018 Author(s).
Achieving a Good Life Time in a Vertical-Organic-Diode Gas Sensor
(2014-09-01)
Dai, Ming-Zhi
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Chen, Yen-Ho
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Chuang, Ming-Yen
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
In this study, we investigate the keys to obtain a sensitive ammonia sensor with high air stability by using a low-cost polythiophene diode with a vertical channel and a porous top electrode. Poly(3-hexylthiophene) (P3HT) and air-stable poly(5,5'-bis(3-dodecyl-2-thienyl)-2,2'-bithiophene) (PQT-12) are both evaluated as the active sensing layer. Two-dimensional current simulation reveals that the proposed device exhibits numerous connected vertical nanometer junctions (VNJ). Due to the de-doping reaction between ammonia molecules and the bulk current flowing through the vertical channel, both PQT-12 and P3HT VNJ-diodes exhibit detection limits of 50-ppb ammonia. The P3HT VNJ-diode, however, becomes unstable after being stored in air for two days. On the contrary, the PQT-12 VNJ-diode keeps an almost unchanged response to 50-ppb ammonia after being stored in air for 25 days. The improved storage lifetime of an organic-semiconductor-based gas sensor in air is successfully demonstrated.
Achieving good bias stress reliability in organic transistor with vertical channel
(2014-07-01)
Lin, Hung-Cheng
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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物理研究所
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電機學院
Unlike organic field-effect transistor with accumulated channel at dielectric/semiconductor interface, vertical organic transistor exhibits bulk channel current and hence performs good bias stress reliability. Adding self-assemble-monolayer to treat vertical channel can further modulate the charge-trapping surrounding the base electrode and hence influence the bias stress reliability. During 4300-s positive/negative bias stresses, stable output current and on/off ratio are demonstrated by using octadecyltrichlorosilane (OTS)-passivated vertical channel. The good reliability together with the low operation voltage and the high output current make vertical organic transistors capable of driving organic light emitting diode. (C) 2014 Elsevier B.V. All rights reserved.
Achieving High Directionality and Extraction of Light Emission from Polymer Light Emitting Diodes via ITO/Organic Photonic Crystals
(2009)
Liao, Lun-De
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Chao, Paul C. -P.
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Chen, In-Chen
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Meng, Hsin-Fei
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Chai, Che-Hong
The objective of this study is to achieve high directionality and extraction of light emission from polymer light-emitting diodes via optimizing photonic crystals (PCs). Genetic Algorithm is employed to search the optimal PC period, depth and filling factor. The large-area PCs are fabricated by Focus Ion Beams for PLED, which is commercially viable, even applicable to active matrix PLED displays.
Achieving High Field-Effect Mobility in Amorphous Indium-Gallium-Zinc Oxide by Capping a Strong Reduction Layer
(2012-07-10)
Zan, Hsiao-Wen
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Yeh, Chun-Cheng
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Meng, Hsin-Fei
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Tsai, Chuang-Chuang
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Chen, Liang-Hao
Achieving saturation in vertical organic transistors for organic light-emitting diode driving by nanorod channel geometric control
(2013-04-22)
Li, Chang-Hung
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Stehlin, Fabrice
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Wang, Kai-Ruei
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Lin, Yu-Hsin
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Wieder, Fernand
When conventional field-effect transistors with short channel length suffer from non-saturated output characteristics, this work proposed a vertical channel transistor to operate like a solid-state vacuum tube and exhibit good saturated curves. We utilized deep ultra-violet interference lithography to produce ordered grid-like metal to control the potential profile in vertical channel. We compared experimental and simulated characteristics to investigate the keys to achieve saturation. Finally, with an optimized design, a vertical organic transistor is used to drive a solution-processed white-light organic light-emitting diode to perform a luminescence control (0-260 cd/m(2)) with a 3.3-V base potential swing. (C) 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4802999]
All-small-molecule efficient white organic light-emitting diodes by multi-layer blade coating
(2012-05-01)
Yeh, Han-Cheng
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Meng, Hsin-Fei
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Lin, Hao-Wu
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Chao, Teng-Chih
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Tseng, Mei-Rurng
Blue and white small-molecule organic light-emitting diodes are fabricated by multi-layer blade coating on hot plate at 80 degrees C with hot wind. Uniform multi-layer structures are made without dissolution due to rapid drying. Only small molecules originally developed for vacuum deposition are used. For hole transport layer of, 4',4 ''-tris(carbazol-9-yl)triphenylamine (TCTA), electron transport layer of 2,2',2 ''-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TBPI), emissive layer host of, 6-bis(3-(9H-carbazol-9-yl)phenyl)pyridine(26DCzPPy), triplet emitters of bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III) (FIrpic), and cathode of LiF/Al, the peak current efficiency for blue emission is 25.1 cd/A (10.8% and 9.3 lm/W). Orange emitter iridium(III) bis (4-(4-t-butylphenyl) thieno[3,2-c] pyridinato-N,C2')acetylacetonate (PO-01-TB) is added to obtain white emission with CIE coordinate of (0.39, 0.46) [1]. The current efficiency is 34.2 cd/A (11.6% and 12 lm/W) at maximum, 32.4 cd/A at 1000 cd/m(2), and 31 cd/A at 10,000 cd/m(2). (C) 2012 Elsevier B.V. All rights reserved.
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
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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.
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.