Highly efficient bipolar deep-blue fluorescent emitters for solution-processed non-doped organic light-emitting diodes based on 9,9-dimethyl-9,10-dihydroacridine/phenanthroimadazole derivatives

Saripally Sudhaker Reddy, Vijaya Gopalan Sree, Kumarasamy Gunasekar, Woosum Cho, Yeong-Soon Gal, Myungkwan Song, Jae-Wook Kang, Sung-Ho Jin

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Highly efficient, solution-processed, deep-blue fluorescent emitters are urgently required to realize inexpensive organic light-emitting diodes (OLEDs) for full-color displays and lighting applications. Herein, two new bipolar fluorescent emitters: 2-(4-(7-(9,9-dimethylacridin-10(9H)-yl)-9,9-diethyl-9H-fluoren-2-yl)phenyl)-1-phenyl-1H-phenanthro[9,10-d]imidazole (AFpPPI) and 2-(3-(7-(9,9-dimethylacridin-10(9H)-yl)-9,9-diethyl-9H-fluoren-2-yl)phenyl)-1-phenyl-1H-phenanthro[9,10-d]imidazole (AFmPPI) are rationally designed and synthesized. These two are afforded from 9,9-dimethyl-9,10-dihydroacridine (DMACR) as an electron donor and phenylphenanthroimadazole (PPI) as an electron acceptor, using 9,9-diethylfluorene as a spacer with different substitution isomers (para or meta). The photophysical, electrochemical, thermal, and charge-transport properties, as well as the electronic distribution of AFpPPI and AFmPPI are investigated and the results are well supported by density functional theory (DFT) and semi-classical Marcus theory. Interestingly, AFpPPI and AFmPPI display deep-blue emission with high fluorescence quantum yields (ΦF). Furthermore, solution-processed, non-doped OLEDs were fabricated with AFpPPI and AFmPPI as an emitter, in which AFpPPI delivered a maximum external quantum efficiency (EQE) of 5.76% with Commission Internationale de l'Eclairage (CIE) coordinates of (0.15, 0.10) and a maximum current efficiency (CE) of 5.39 cd A−1, which is the best performance for deep-blue, solution-processed fluorescent OLEDs based on non-doped bipolar emitters.

Original languageEnglish
Pages (from-to)1236-1246
Number of pages11
JournalAdvanced Optical Materials
Issue number8
Publication statusPublished - Aug 2016
Externally publishedYes


  • blue emitters
  • fluorescence
  • organic light-emitting diodes (OLEDs)
  • solution-processed materials
  • structure-property relationships

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