Improved efficiency of blue phosphorescence organic light-emitting diodes with irregular stepwise-doping emitting layers

Authors

  • Jun Liu,

    1. National Engineering Lab for TFT-LCD Materials and Technologies, and Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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  • Jing Wang,

    1. National Engineering Lab for TFT-LCD Materials and Technologies, and Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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  • Saijun Huang,

    1. National Engineering Lab for TFT-LCD Materials and Technologies, and Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
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  • Hsi-An Chen,

    1. Display Institute, Microelectronics and Information Systems Research Center, National Chiao Tung University, Hsinchu 30050, Taiwan
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  • Gufeng He

    Corresponding author
    1. National Engineering Lab for TFT-LCD Materials and Technologies, and Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
    • Phone: +86 21 34207045, Fax: +86 21 34204371
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Abstract

We demonstrate highly efficient blue phosphorescence organic light-emitting diodes (PHOLED) with irregular stepwise-doping emitting layers (EMLs). High efficiency is realized by inserting a high-doping EML between two relatively low-doping EMLs. Peak luminous efficiency and power efficiency of 19.2 cd A−1 and 18.0 lm W−1 are achieved, while those of a continuous stepwise-doping device are 9.8 cd A−1 and 8.6 lm W−1. The dramatic efficiency enhancement is mainly attributed to the high hole–electron recombination probability and suppressed triplet excitons quenching by fine tuning the doping concentrations in the EMLs.

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