A pyridine based : Meta -linking deep-blue emitter with high conjugation extent and electroluminescence efficiencies

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

27 Scopus Citations
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  • Liang-Dong Zhang
  • Xiao-Le Liu
  • Qing-Xiao Tong
  • Fu-Lung Wong
  • Feng Lu


Original languageEnglish
Pages (from-to)6249-6255
Journal / PublicationJournal of Materials Chemistry C
Issue number26
Publication statusPublished - 2016


We designed and synthesized a bipolar deep-blue emitter 2,6-bis(4-(1-(4-(tert-butyl)phenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)pyridine (26BTPIPy) based on a meta-linking D-π-A-π-D structure. Compared to its para-linking analogue (25BTPIPy), the meta-linking in 26BTPIPy effectively shortens molecular conjugated length and restricts intramolecular charge transfer. Interestingly, unlike most other meta-linking emitters, a high fluorescence yield can be maintained in 26BTPIPy. This may be attributed to a relatively planar structure at the benzene-pyridine-benzene joint in 26BTPIPy leading to considerable overlapping of its frontier molecular orbitals. These suitable combinations of properties endow 26BTPIPy with efficient deep-blue emission and good bipolar carrier transporting characteristics. An organic light-emitting device using 26BTPIPy as an emitter shows a low turn-on voltage (2.8 V), deep-blue emission with a color index of (0.15, 0.09) and high current and external quantum efficiencies (4.16 cd A-1 and 5.15%). Besides, a bilayer device using 26BTPIPy as both an emitting and electron-transporting material also gives high performance with a current efficiency of 4.22 cd A-1 and a color purity of (0.15, 0.11).

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