Browsing by Author "Tsai, Yu-Sheng"

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A study of ultraviolet-curable organic/inorganic hybrid nanocomposites and their encapsulating applications for organic light-emitting diodes
(2009-06-15)
Chang, Ming-Hua
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Hsieh, Tsung-Eong
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Huang, Bohr-Ran
;
Hsieh, Huai-En
;
Juang, Fuh-Shyang
UV-curable organic/inorganic hybrid nanocomposites have been successfully synthesized with polymer monomers (tetramethoxysi lane (TMOS)/3-glycidoxypropyl-trimethoxysilane (GPTMS)) nano-fillers (silica/alumina), curing agents (bisphenol A (BPA)), and photoinitiators (triaryl sulfonium hexafluoroantimonate (TSH)) by in situ polymerization. Their thermal stability, coefficient of thermal expansion (CFE), adhesion strength, and gas barrier capability have also been investigated with thermogravimetry analysis (TGA), thermomechanical analysis (TMA), micro-computer universal testing machine and moisture penetration tests. Experimental results indicate that nano-fillers are completely homogeneously dispersed in the polymer matrices and the increase of nano-fillers in the nanocomposites causes the raise of decomposition temperature (Td) as well as gas resistance and the reduction of CTE as well as adhesion strength. Because lab-made organic/inorganic hybrid nanocomposites have been discovered to exhibit excellent gas barrier properties, we have also applied them for the encapsulation of organic light-emitting diodes (OLEDs) and flexible OLEDs. With lab-made nanocomposite cl, the lifetimes of OLEDs and flexible OLEDs can be successfully lengthened to 92 and 36 h, respectively, whereas those of OLEDs and flexible OLEDs without encapsulation are 11 and 7 h, respectively. (C) 2008 Elsevier B.V. All rights reserved.
Easy Process and Performance Improvement for Top-Emission Organic Light-Emitting Diodes by Using UV Glue as the Insulation Layer on Copper Substrate
(2010-07-01)
Tsai, Yu-Sheng
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Wang, Shun-Hsi
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Juang, Fuh-Shyang
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Chang, Shu-Wei
;
Chen, Chuan-hung
A high heat dissipation material (copper, Cu) was employed as the substrate for top emission organic light-emitting diodes (TEOLEDs). The UV glue was spin-coated onto the Cu substrate as the insulation layer to effectively improve Cu surface roughness and reduce process complexity. From the optoelectronic results, the optimized device with the Cu substrate shows the maximum luminance of 14110 cd/m(2) and luminance efficiency of 7.14 cd/A. The surface and junction temperatures are measured to discuss the heat-dissipating effect on device performance. From the results, TEOLED fabricated on a Cu substrate has lower junction (55.34 degrees C) and surface (25.7 degrees C) temperatures, with the lifetime extended seven times. We employed Cu foil as the substrate for flexible TEOLED with maximum luminance of 10310 cd/m(2) and luminance efficiency of 7.3 cd/A obtained.
Efficiency Improvement of Organic Solar Cells by Slow Growth and Changing Spin-Coating Parameters for Active Layers
(2011-02-01)
Tsai, Yu-Sheng
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Chu, Wei-Ping
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Juang, Fuh-Shyung
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Tang, Rong-Ming
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Chang, Ming-Hua
The derivatives of C60, [6,6]-phenyl C(61)-butyric acid methyl ester (PCBM), and 3-hexylthiophene (P3HT) were dissolved in o-dichlorobenzene (DCB) solvent, and then spin-coated as an active layer for polymer solar cells. The experimental parameters including the spin-coating speed and drying conditions for the active layer, were studied carefully to obtain the optimum power conversion efficiency (PCE). In the active layer drying procedure, the DCB solvent saturated/unsaturated vapor pressure was adjusted by controlling the amount of solvent at a half-open capacity. The DCB solution was used to enhance the self-organization of the active layer of P3HT and to reduce the number of pure PCBM clusters. In the DCB optimum solution, the PCE of a polymer solar cell can be increased from 1.36 to 1.79%. The structure corresponds to a nano-to-micron scale ordering in the unsaturation-treatment films. In the optimum unsaturation procedure, the PCE of a polymer solar cell can be increased from 1.79 to 2.53%. Using two steps with optimum rotation speeds in the active layer spin-coating, the surface uniformity can be improved, with the PCE increased from 2.53 to 3.13%. (C) 2011 The Japan Society of Applied Physics
Electroluminescent properties of color/luminance tunable organic light emitting diodes and their lifetime enhancement with encapsulation
(2008-09-25)
Chen, Chen-Ming
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Chung, Ming-Hua
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Hsieh, Tsung-Eong
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Huang, Bohr-Ran
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Hsieh, Huai-En
In this work, color/luminance tunable organic light emitting diodes (OLEDs) (ITO glass/naphthyl phenyl benzidine (NPB; 80 nm)/4,4'-bis(diphenylvinylenyl)-biphenyl (ADS082BE; 35 nm)/1,3-bis[2-(2,2'-bipyridine-6-yl)-1,3,4-oxadiazo-5-yl]benzene (Bpy-OXD; 20 nm)/tris-[8-hydroxy-quinoline]aluminum (Alq(3); 50 nm)/lithium fluoride (LiF; 3 nm)/aluminum (Al, 80 nm)) with low turn-on voltage (3 V) and high luminance (4850 cd/m(2) at 9 V) have been successfully manufactured. The experimental results reveal that their electroluminescent properties (e.g. hue, luminescent intensity, etc.) can be modulated by the manipulation for the layer thickness of NPB/ADS082BE/Bpy-OXD and the applied voltages. In addition, we have also demonstrated lab-made UV-curable silicone-acrylate encapsulating resin exhibits excellent gas barrier capability so that the half-lifetimes of OLEDs reach 98 h whereas those without encapsulation are only 9 h. (C) 2008 Elsevier B.V. All rights reserved.
Influence of reduced graphene oxide on material, antibacterial, and piezoelectric behaviors of ZnO nanorods on foldable indium tin oxide substrates
(2019-07-01)
Tsai, Yu-Sheng
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Chen, Yan Yu
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Xu, Chun Yu
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Chang, Yu Cheng
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Tsai, Yang Yang
In this study, zinc oxide nanostructures integrated with reduced graphene oxide (RGO) were fabricated on foldable indium tin oxide substrates. To study the influence of RGO on the material, antibacterial, and piezoelectric properties on the nanostructures, multiple material, antibacterial, and electrical measurements were performed. Results indicate that inserting a RGO layer on the foldable substrate could form nanocylinder ZnO structures, which induced hydrophobicity and better antibacterial properties. Moreover, addition of appropriate RGO into ZnO seed layer may cause the growth of finer ZnO nanorods (NRs) and enhance piezoelectric effects. With stable electrical pulse generative piezoelectric effects and antibacterial properties, ZnO nanostructures with addition of RGO on foldable substrates have potential for future flexible biomedical and electronics applications.
Lifetime improvement of organic light emitting diodes using LiF thin film and UV glue encapsulation
(2008-07-01)
Huang, Jian-Ji
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Su, Yan-Kuin
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Chang, Ming-Hua
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Hsieh, Tsung-Eong
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Huang, Bohr-Ran
This work demonstrates the use of lithium fluoride (LiF) as a passivation layer and newly developed UV glue for encapsulation on the LiF passivation layer to enhance the stability of organic light-emitting devices (OLEDs). Devices with double protective layers showed a 25-fold increase in operational lifetime compared to those without any packaging layers. LiF has a low melting point and insulating characteristics and it can be adapted as both a protective layer and preencapsulation film. The newly developed UV glue has a fast curing time of only 6 s and can be directly spin-coated onto the surface of the LiF passivationlayer. The LiF thin film plus spin-coated UV glue is a simple packaging method that reduces the fabrication costs of OLEDs.
Material characterizations of ZnO/ZnS core-shell structures on glass substrate
(2019-12-01)
Tai, Shih-Tse
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Tsai, Yu-Sheng
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Wu, YewChung Sermon
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Wang, Jiun-, Jr.
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Hsiang, Chen
ZnO/ZnS core-shell nanostructures were hydrothermally fabricated on glass substrates. Multiple material characterizations were used to examine the nanostructures. Results indicate that a ZnS shell with a thickness around 10 nm could be viewed on the ZnO/ZnS core-shell structures. Furthermore, different crystalline phases and element compositions in different locations around nearby nanostructures could be found in selected area diffraction patterns and energy dispersive X-ray spectroscopy. ZnS/ZnO nanostructures on glass substrates show promise for future optoelectronic and electronic device applications.
Morphological and crystalline analysis of ZnO/ZnS nanostructures on porous silicon substrate
(2020-08-01)
Tsai, Yu-Sheng
;
Hung, Chen Hao
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Chan, Wei Lun
;
Tsai, Shang Je
;
Lee, Yu Shan
ZnO/ZnS core-shell nanostructures were successfully synthesized on porous silicon substrates using hydrothermal methods. Multiple morphological and crystalline characterizations were performed on the structures. Results indicate that a uniformly grown ZnS shell with a thickness of around 10 nm could be observed on the cross-section of ZnO/ZnS core-shell structures. Furthermore, different crystalline phases and morphologies could be observed in selected area diffraction patterns between neighboring nanostructures. Material compositional analysis conducted by energy-dispersive X-ray spectroscopy indicate that varied nanostructure element compositions grew perpendicular to the substrate. ZnS/ZnO nanostructures on porous silicon substrates show promise for future optoelectronic and electronic device applications.
Performance improvement of white phosphorescent organic light-emitting diodes by using composite host structure to enhance the carrier injection
(2010)
Juang, Fuh-Shyang
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Hong, Lin-Ann
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Chen, Cheng-Yin
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Wang, Shun-Hsi
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Tsai, Yu-Sheng
Device characteristics of phosphorescent OLEDs with composite host structure were investigated by co-doping hole and electron transport-type hosts in emitting layer. The improved of charge injection and the confined of triplet excitons within recombination zone were achieved. White-OLED shows the efficiencies of 34.5 cd/A and 24 lm/W at 1000 cd/m(2).
Power Efficiency Improvement of White Phosphorescent Organic Light-Emitting Diode with Thin Double-Emitting Layers and Hole-Trapping Mechanism
(2011-04-01)
Juang, Fuh-Shyang
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Hong, Lin-Ann
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Wang, Shun-Hsi
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Tsai, Yu-Sheng
;
Gao, Ming-Hong
This study is carried out to discuss how to reduce the driving voltage of blue phosphorescent organic light-emitting diodes (PHOLEDs) by using a thin double-emission layer. A hole transport-type host (TCTA) is inserted between the hole transport layer (TAPC) and the emitting layer (EML), constituting a buffer layer between them with the aim of improving charge carrier balance. Furthermore, in this study, we also utilize the interface between double light-emitting layers of devices by codoping them with a red phosphorescent dopant [Os(bpftz)(2)(PPh(2)Me)(2)]. An Os complex with a high-lying highest occupied molecular orbital (HOMO) energy level (trapping holes) is codoped at the interface between emitting layers and an exciton-formation zone is expanded to obtain a white PHOLED with high efficiency. From the results, the optimal structure of the white device exhibits a yield of 35 cd A(-1), a power efficiency of 22 lm W(-1), and CIE coordinates of (0.33; 0.38) at a luminance of 1000 cdm(-2). Furthermore, the power efficiency can be improved to 30 lm W(-1) by attaching the outcoupling enhancement film. (C) 2011 The Japan Society of Applied Physics
Synthesis, thermal characterization, and gas barrier properties of UV curable organic/inorganic hybrid nanocomposites with metal alloys and their application for encapsulation of organic solar cells
(2008-11-01)
Chen, Chen-Ming
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Chung, Ming-Hua
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Hsieh, Tsung-Eong
;
Liu, Mark O.
;
Lin, Jen-Lien
We have successfully prepared ultraviolet (UV) curable organic/inorganic hybrid nanocomposites with good thermal stability, moderate adhesion strength, and excellent barrier capability. In order to improve the gas blocking properties, the metal alloy (Invar) has been blended with lab-made organic/inorganic hybrid nanocomposites, dramatically not only raising the gas resistance but also reducing the shrinkage after UV curing. Moreover, we have also applied lab-made nanocomposite IV for the encapsulation of organic solar cells. The experimental results reveal that introduction of nanocomposite IV can effectively block the penetration of moisture as well as oxygen in the air into the devices and consequently promote the lifetime of organic solar cells. (C) 2008 Elsevier Ltd. All rights reserved.
Ultraviolet-assisted synthesis of encapsulating adhesives and their application for lifetime improvement of organic light emitting diodes
(2009-07-01)
Chen, Chen-Ming
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Chung, Ming-Hua
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Hsieh, Tsung-Eong
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Huang, Bohr-Ran
;
Hsieh, Huai-En
The lifetimes of organic light emitting diodes (OLEDs) have been Successfully enhanced with the modulation of LiF thickness mid the utilization of encapsulating adhesives, which have been successfully and synthesized with UV irradiation. Experimental results demonstrate that LiF and lab-made encapsulating adhesives can block the invasion of moisture as well as oxygen in the atmosphere into the OLEDs so that the lifetimes of devices with their encapsulation are 18-folds longer than those without encapsulation. (c) 2008 Elsevier B.V. All rights reserved.
ZnO/ZnS core-shell nanostructures for hydrogen gas sensing performances
(2019-10-01)
Tsai, Yu-Sheng
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Chou, Tsung-Wei
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Xu, Chun Yu
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Huang, Wen Chang
;
Lin, Chia Feng
ZnO/ZnS core-shell structures were hydrothermally grown on SiO2 substrates functioning as hydrogen gas sensing chips. Results indicate that a core-shell structure with an appropriate sulfurization period of 10 min had better H-2 sensing performance than those of all other growth conditions. Furthermore, multiple material characterizations revealed that ZnS with a growth time of 10 min could form high-quality and good-adherent ZnS powders with moderate thickness attached to the ZnO nanorods. Because of their small size, portability, simple fabrication and high sensitivity, ZnO/ZnS core-shell based H-2 gas sensors show promise for future H-2 detecting applications.