Study of sequential dexter energy transfer in high efficient phosphorescent white organic light-emitting diodes with single emissive layer.
In this study, we report our effort to realize high performance single emissive layer three color white phosphorescent organic light emitting diodes (PHOLEDs) through sequential Dexter energy transfer of blue, green and red dopants. The PHOLEDs had a structure of; ITO(1500 Å)/NPB(700 Å)/mCP:Firpic-x%:Ir(ppy)3-0.5%:Ir(piq)3-y%(300 Å)/TPBi(300 Å)/Liq(20 Å)/Al(1200 Å). The dopant concentrations of FIrpic, Ir(ppy)3 and Ir(piq)3 were adjusted and optimized to facilitate the preferred energy transfer processes attaining both the best luminous efficiency and CIE color coordinates. The presence of a deep trapping center for charge carriers in the emissive layer was confirmed by the observed red shift in electroluminescent spectra. White PHOLEDs, with phosphorescent dopant concentrations of FIrpic-8.0%:Ir(ppy)3-0.5%:Ir(piq)3-0.5% in the mCP host of the single emissive layer, had a maximum luminescence of 37,810 cd/m(2) at 11 V and a luminous efficiency of 48.10 cd/A at 5 V with CIE color coordinates of (0.35, 0.41).
Department of Green Energy &Semiconductor Engineering, Hoseo University, Asan, Korea.
Jin Wook
JW
Kim
Department of Green Energy &Semiconductor Engineering, Hoseo University, Asan, Korea.
Seung Il
SI
You
Department of Green Energy &Semiconductor Engineering, Hoseo University, Asan, Korea.
Nam Ho
NH
Kim
Department of Green Energy &Semiconductor Engineering, Hoseo University, Asan, Korea.
Ju-An
JA
Yoon
Department of Physics and Institute of Advanced Materials, Hong Kong Baptist University, Hong Kong, China.
Kok Wai
KW
Cheah
Department of Physics and Institute of Advanced Materials, Hong Kong Baptist University, Hong Kong, China.
Fu Rong
FR
Zhu
1] Department of Green Energy &Semiconductor Engineering, Hoseo University, Asan, Korea [2] Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4L7, Canada.
Woo Young
WY
Kim