Browsing by Author "Juang, Fuh-Shyang"

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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
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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.
Adjusting optical resonance thickness to increase the conversion efficiency of polymer solar cells
(2010-05-01)
Tsai, Yu Sheng
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Lin, Jian-Shian
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Chu, Wei-Ping
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Wang, Po-Hsun
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Juang, Fuh-Shyang
The derivatives of C(60), [6,6]-phenyl C61-butyric acid methyl ester (PCBM), and 3-hexylthiophene (P3HT) were dissolved in DCB solvent, then spin coated into an active layer for polymer solar cells. The experimental parameters were studied carefully to obtain the optimum power conversion efficiency (PCE). The primary process for generation of photocurrent in an organic photovoltaic device is the generation of bound electron-hole pairs (excitons) by absorption of energy (photons) from the optical electric field. Modeling was based on the assumption that the photocurrent generation process is the result of the creation and diffusion of photogenerated species (excitons), which are dissociated by charge transfer at the active layer. Improve organic optics absorb by insert organic layer (CuPc or C60) at the active layer/Al interface. This research is divided into two components. First part, we use n-type C60 as transmission layer. When an optimum thickness of C(60) is 5 nm, the J(sc) of polymer solar cell can be increased from 7.26 mA/cm(2) to 7.7 mA/cm(2). The V(oc) decrease is because the energy level of C60 LUMO (lowest unoccupied molecular orbital) at 4.5 eV is higher than the 3.7 eV of PCBM. Second part, we use p-type CuPc as transmission layer. When an optimum thickness of CuPc is 3 nm, the short circuit photo-current density (J(sc)) and open circuit voltage (Voc) of polymer solar cell can be increased from 7.26 mA/cm2 to 8.0 mA/cm2 and 0.56-0.58 V, respectively. The reason is the same as C(60). The Voc increase is because the energy level of CuPc LUMO (lowest unoccupied molecular orbital) at 3.1 eV is lower than the 3.7 eV of PCBM. The Jsc increase is because the 3 nm of CuPc leads to a constructive interference happened in the active layer and thus optical absorption increases. In this study we used 3 nm of CuPc at the active layer/Al interface to enhance the short circuit current density, and the efficiency was increased to 2.94%. (C) 2010 Elsevier B. V. All rights reserved.
Comparison of Different Encapsulating Adhesives to Enhance the Efficiencies and Lifetimes of Polymeric Solar Cells
(2009-04-01)
Chung, Ming-Hua
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Chen, Chen-Ming
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Hsieh, Tsung-Eong
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Tang, Rong-Ming
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Tsai, Yu Sheng
Polymeric solar cells (PSCs) with a derivative of C(60) [[6,6]-phenyl C(61)-butyric acid methyl ester (PCBM)], and 3-hexylthiophene (P3HT) as active layers have been fabricated. The PSC devices were also packaged with glass and novel UV glues to improve their lifetimes and power conversion efficiencies (PCEs). After encapsulation with UV glue I, II, and III, the PCEs of PSCs reached 4, 4.82, and 6%, respectively, and their half-lifetimes increased to 16-18, 26-28, and 90 h, respectively, while the PCEs and half-lifetimes of PSCs without encapsulation were 3.76% and 2.5 h, respectively. (C) 2009 The Japan Society of Applied Physics
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
;
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.
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.
High color-stability for white organic light emitting devices by using phosphorescent sensitizer fluorescent
(2010)
Juang, Fuh-Shyang
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Hong, Lin-Ann
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Hsiao, Chih-Jen
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Wang, Shun-Hsi
;
Ho, Meng-Huan
High color-stability white OLEDs can be achieved by replacing red fluorescent dopant (DCJTB) with yellow dopant (EY-53) in phosphor-sensitized emitter and optimizing the interlayer (CBP) thickness. Device shows the E.Q.E. of 8.2%, the efficiencies of 21.5 cd/A and 8.1 lm/VV with CIE (0.40, 0.46) at 20 mA/cm(2). The shift of ClExy down to (-0.001,-0.001) at a current density of 20 and 200 mA/cm2.
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.
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
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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
Preparation of organic/inorganic hybrid nanocomposites by ultraviolet irradiation and their packaging applications for organic optoelectronic devices
(2011-08-15)
Chung, Ming-Hua
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Lin, Jian-Shian
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Hsieh, Tsung-Eong
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Chen, Nien-Po
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Juang, Fuh-Shyang
By ultraviolet (UV)-assisted synthetic procedure, we have successfully prepared several UV curable organic/inorganic hybrid nanocomposites with excellent gas barrier capabilities, moderate hardness, and good adhesive strength. The experimental results reveal that the physical properties of nanocomposites depend on their chemical structures. Therefore, introduction of silicone and polyurethane (PU) into the Acrylics backbone dramatically raises the adhesive strength as well as refractive index and lowers the gas penetration. Furthermore, we have also applied lab-made nanocomposite g for the encapsulation of organic optoelectronic devices such as OLEDs, flexible OLEDs, and organic solar cells. With the package of lab-made nanocomposite g, the organic optoelectronic devices effectively resist the entry of moisture and oxygen in the air, extending the lifetimes. (C) 2011 Elsevier B.V. All rights reserved.
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
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Liu, Mark O.
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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
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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.
Using Mixed Solvent and Changing Spin-Coating Parameters to Increase the Efficiency and Lifetime of Organic Solar Cells
(2008-10-01)
Tsai, Yu Sheng
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Chu, Wei-Ping
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Tang, Rong-Ming
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Juang, Fuh-Shyang
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Chang, Ming-Hua
The derivative of C(60), i.e., PCBM, and P3HT (3-hexylthiophene) were dissolved in chloroform: dichlorobenzene mixed solvent, then spin-coated as the active layer for organic solar cells (OSC). The experimental parameters were studied carefully to obtain the optimum power conversion efficiency (PCE), including the solvent mixing ratio, spin-coating speed, annealing conditions for the active layer, etc. The OSC devices were packaged with glass and a newly developed UV-glue to improve the lifetime and PCE. Dichlorobenzene solvent has great effect upon the PCE. Changing the spin-coating speed and increasing the number of steps increased the PCE apparently to 1.4%.