Stable efficiency roll-off in phosphorescent organic light-emitting diodes
- Kim, Sung Hyun; Jang, Jyongsik; Yook, Kyoung Soo; Lee, Jun Yeob
- Issue Date
- American Institute of Physics
- Appl. Phys. Lett. 92, 023513
- Origin of efficiency roll-off in phosphorescent organic light-emitting diodes was investigated with triplet mixed host devices and stable devices with little efficiency roll-off was developed. Efficiency
roll-off was significant in the device with narrow recombination zone RZ and charge leakage out of emitting layer at high luminance was critical to efficiency roll-off. Efficiency roll-off could be reduced in triplet mixed host device with broad RZ and little charge leakage at high driving voltage.
Triplet mixed host devices with an exciton blocking layer showed a quantum efficiency over 90% of maximum quantum efficiency at a luminance of 20 000 cd/m2.
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