Browsing by Author "Hong, Lin-Ann"

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High color-stability for white organic light emitting devices by using phosphorescent sensitizer fluorescent
(2010)
Juang, Fuh-Shyang
;
Hong, Lin-Ann
;
Hsiao, Chih-Jen
;
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.
Performance improvement of white phosphorescent organic light-emitting diodes by using composite host structure to enhance the carrier injection
(2010)
Juang, Fuh-Shyang
;
Hong, Lin-Ann
;
Chen, Cheng-Yin
;
Wang, Shun-Hsi
;
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
;
Hong, Lin-Ann
;
Wang, Shun-Hsi
;
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