Browsing by Author "Wang, Shun-Hsi"

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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.
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
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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
;
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