中国物理B ›› 2020, Vol. 29 ›› Issue (11): 117101-.doi: 10.1088/1674-1056/ab9c13

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Ya-Dong Wang(王亚东)1,†(), Jian-Jun Liu(刘建军)1, Xi-Ru Wang(王溪如)2, Yan-Xia Liu(刘艳霞)1, Yan Meng(孟艳)3,()   

  • 收稿日期:2020-05-11 修回日期:2020-06-08 接受日期:2020-06-12 出版日期:2020-11-05 发布日期:2020-11-03

Dynamic recombination of triplet excitons in polymer heterojunctions

Ya-Dong Wang(王亚东)1, †, Jian-Jun Liu(刘建军)1, Xi-Ru Wang(王溪如)2, Yan-Xia Liu(刘艳霞)1, and Yan Meng(孟艳)3, ‡   

  1. 1 College of Information Science and Engineering, Hebei North University, Zhangjiakou 075000, China
    2 Department of Electronics, Polytech Nice Sophia, Nice 06200, France
    3 Department of Physics, Xingtai University, Xingtai 054001, China
  • Received:2020-05-11 Revised:2020-06-08 Accepted:2020-06-12 Online:2020-11-05 Published:2020-11-03
  • Contact: Corresponding author. E-mail: zjkwangyadong@sina.com Corresponding author. E-mail: my882154@126.com
  • Supported by:
    the National Natural Science Foundation of China (Grant No. 11347171), the Doctoral Foundation (Grant No. 12995563), and the Research Fund (Grant No. YB2018026) from Hebei North University.

Abstract:

The dynamic recombination of two triplet excitons with opposite spins in the heterojunction structure has been investigated using a nonadiabatic evolution method. We demonstrate that luminous composite states including the excited polaron and the biexciton can be formed efficiently via the triplet exciton–triplet exciton reaction in the heterojunction and therefore this reaction can enhance the electroluminescence efficiency considerably, which is consistent qualitatively with experimental observations. Meanwhile, we find that, although the heterojunctions are beneficial to the generation of luminescent particles, large band offset caused by the heterojunction structure is not helpful to improve the electroluminescence efficiency. In addition, the mechanism of the triplet exciton–triplet exciton reaction in heterojunction is different from that of two similar coupling chains. Our results may deepen the understanding of the electroluminescence mechanism in polymer light-emitting devices.

Key words: polymers, electron-lattice interaction, excitons