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Meta Junction Promoting Efficient Thermally Activated Delayed Fluorescence in Donor-Acceptor Conjugated Polymers.

Jiancheng RaoLiuqing YangXuefei LiLei ZhaoShumeng WangJunqiao DingLixiang Wang
Published in: Angewandte Chemie (International ed. in English) (2020)
The meta junction is proposed to realize efficient thermally activated delayed fluorescence (TADF) in donor-acceptor (D-A) conjugated polymers. Based on triphenylamine as D and dicyanobenzene as A, as a proof of concept, a series of D-A conjugated polymers has been developed by changing their connection sites. When the junction between D and A is tuned from para to meta, the singlet-triplet energy splitting (ΔEST ) is found to be significantly decreased from 0.44 to 0.10 eV because of the increasing hole-electron separation. Unlike the para-linked analogue with no TADF, consequently, the meta-linked polymer shows a strong delayed fluorescence. Its corresponding solution-processed organic light-emitting diodes (OLEDs) achieve a promising external quantum efficiency (EQE) of 15.4 % (51.9 cd A-1 , 50.9 lm W-1 ) and CIE coordinates of (0.34, 0.57). The results highlight the bright future of D-A conjugated polymers used for TADF OLEDs.
Keyphrases
  • energy transfer
  • photodynamic therapy
  • quantum dots
  • solar cells
  • light emitting
  • current status
  • mass spectrometry
  • molecular dynamics
  • liquid chromatography
  • electron microscopy