Browsing by Author "Yeh, Pu-Cheng"

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Highly efficient p-i-n white organic light emitting devices with tandem structure
(2007-12-03)
Ho, Meng-Huan
;
Chen, Teng-Ming
;
Yeh, Pu-Cheng
;
Hwang, Shiao-Wen
;
Chen, Chin H.
Highly efficient tandem p-i-n white organic light emitting devices have been fabricated. Utilizing an optical transparent bilayer with doped organic p-n junction that consists of 4,7-diphenyl-1,10-phenanthroline: 2% cesium carbonate (Cs(2)CO(3))/N,N(')-bis(1-naphthyl)-N,N(')-diphenyl-1,1(')-biphenyl-4,4(')-diamine: 50% v/v tungsten oxide (WO(3)) as the connecting layer, the tandem p-i-n white device achieved an electroluminescence efficiency of 23.9 cd/A and a power efficiency of 7.8 lm/W at 20 mA/cm(2) with a Commission Internationale de l'Eclairage coordinates of (0.30, 0.43). The electroluminescent color of this tandem p-i-n white organic light-emitting diode device will not change significantly with respect to drive current variation and forward viewing angle. (c) 2007 American Institute of Physics.
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.
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.