Browsing by Author "Ma, Jia-Wei"

Now showing 1 - 3 of 3

Highly-efficient tandem White Organic light emitting devices
(2007)
Yeh, Pu-Cheng
;
Hwang, Shiao-Wen
;
Ma, Jia-Wei
;
Ho, Meng-Huan
;
Hsu, Shih Feng
We demonstrate efficient tandem p-i-n White Organic Light Emitting Diodes (WOLEDs) with the transparent NPB:WO3 interconnecting layer. The CIEx,y coordinate, luminance yield and E.Q.E of the tandem OLEDs (at 20 mA/cm(2)) are (0.30, 0.43), 23.9 cd/A and 8.5%, respectively. The CIEx,y coordinates of the tandem OLEDs neither change (Delta x,y < 0.02) with driving current nor with forward viewing angle (+/- 60 degree). This performance of tandem WOLEDs represents considerable improvement over what have been known in the literature.
Using tunneling junction to enhance hole-injection in organic light-emitting diodes
(2005)
Chang, Chan-Ching
;
Hwang, Shiao-Wen
;
Hsieh, Ming-Ta
;
Ma, Jia-Wei
;
Chen, Chin H.
We demonstrate enhanced hole-injection and lower driving voltage in vacuum-deposited organic light-emitting diodes (OLEDs) with a novel tunneling junction composed of the Mg:Alq(3)/WO3 layer. The device, ITO/Mg:Alq(3)/WO3/NPB/Alq(3)/LiFAl achieved one of the lowest driving voltages of 5.8 V at 20mA/cm(2) for conventional small molecule OLEDs. We propose the laminated Mg:Alq(3)/WO3/NPB functions as a Fowler Nordheim tunneling junction, which can improve hole-injection. It was found to also prolong device lifetime under dc driving, that is comparable to the best reported for the Alq(3) emitter.
White p-i-n organic light-emitting devices with high power efficiency and stable color
(2007-09-10)
Ho, Meng-Huan
;
Hsu, Shih-Feng
;
Ma, Jia-Wei
;
Hwang, Shiao-Wen
;
Yeh, Pu-Cheng
Highly efficient p-i-n two-component white organic light-emitting devices have been fabricated with a thin dual emission layer system comprised of one codeposited emitting layer with blue and yellow dyes and one blue emitting layer, which gives rise to a balance white emission. The p-i-n white device achieved an electroluminescence efficiency of 10 cd/A and a power efficiency of 9.3 lm/W at 1000 cd/m(2) and a low voltage of 3.4 V with a Commission Internationale de l'Eclairage coordinates of (0.32, 0.43). The electroluminescent color of this p-i-n white organic light-emitting diode device has been shown to be immune to drive current density variations.