Browsing by Author "Li, Shiuan-Yi"

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Deep blue light-emitting diode based on high molecular weight poly(9,9-dioctylfluorene) with high efficiency and color stability
(2008-06-01)
Tseng, Shin-Rong
;
Li, Shiuan-Yi
;
Meng, Hsin-Fei
;
Yu, Yi-Hsiang
;
Yang, Chia-Ming
A highly efficient deep blue polymer light-emitting diode based on poly(9,9-dioctylfluorene) is demonstrated. The performance is found to increase significantly with the molecular weight. Two different molecular weights are compared, one is 71,000 and the other is 365,000. The electroluminescent efficiency and color stability are improved by slightly doping hole traps into the emission layer and bilayer structure. The maximum efficiency is 3.8 cd/A with the corresponding external quantum efficiency of 3.7% at deep blue with Commission Internationale de L'Eclairage (CIE) coordinate at (0.15, 0.09). Stable blue emission is maintained up to 6600 cd/m(2) without growth of green shoulder in emission spectrum. (C) 2007 Elsevier B.V. All rights reserved.
High-efficiency blue multilayer polymer light-emitting diode based on poly(9,9-dioctylfluorene)
(2007-04-15)
Tseng, Shin-Rong
;
Li, Shiuan-Yi
;
Meng, Hsin-Fei
;
Yu, Yi-Hsiang
;
Yang, Chia-Ming
A highly efficient blue polymer light-emitting diode based exclusively on commercial poly(9,9-dioctylfluorene) and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4(')-(N-(4-s-butylphenyl)) diphenylamine)] is demonstrated. High electroluminescent efficiency is achieved by enhancing electron currents and making devices in multilayered structures. CsF/Al is used as the efficient electron injection cathode, and the fabrication process is in the glove box to enhance electron mobility by reducing oxygen adsorption. The multilayer structure is prepared by the liquid buffer layer technique. The maximum efficiency is 2.5 cd/A at deep blue with the corresponding external quantum efficiency of 2%.