Tuning electrical properties of phenanthroimidazole derivatives to construct multifunctional deep-blue electroluminescent materials

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

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Author(s)

  • Shao-Fei Ni
  • Miao Chen
  • Jie-Ji Zhu
  • Yi Yuan
  • Qing-Xiao Tong
  • Fu-Lung Wong

Detail(s)

Original languageEnglish
Pages (from-to)3584-3592
Journal / PublicationJournal of Materials Chemistry C
Volume6
Issue number14
Early online date12 Jan 2018
Publication statusPublished - 14 Apr 2018

Abstract

In this work, we introduce an n-type group, TPPO (triphenyl phosphine), to the N1-position of violet-blue fluorophore phenanthroimidazole (PI) and successfully develop one deep-blue (TPAPOPPI) and two violet-blue emitters (3-CzPOPPI and CzBPOPPI) for OLEDs (organic light-emitting diodes). With a highly twisted linkage, the TPPO group shows negligible influences on their photophysical properties of the new materials and the materials inherit highly efficient deep-blue and violet-blue emission of the PI unit and its C2-connected arylamine skeletons. Meanwhile, the TPPO group can open a new channel to transport the electron. The electron injection and transport abilities of the developed emitters are enhanced. Non-doped devices using the 3-CzPOPPI and the CzBPOPPI emitters exhibit an EQEmax (external quantum efficiency) of 5.08% and 4.42% with CIE (Commission Internationale de l'Èclarage) coordinates of (0.156, 0.061) and (0.157, 0.071), respectively. Similar efficiencies and even deeper blue emissions (CIEy = 0.050 for 3-CzPOPPI and 0.044 for CzBPOPPI) were observed in OLEDs with these emitters doped with 4,4′-bis(N-carbazolyl)-1,1′-biphenyl. TPAPOPPI is demonstrated to be a multifunctional deep-blue emitter and presents impressive performances when serving as non-doped (EQEmax = 6.69%, CIE: (0.152, 0.095)), and doped (EQEmax = 6.61%, CIE: (0.154, 0.068)) as well as a high-performance host for yellow phosphorescent OLED. By doping a yellow phosphorescent dye (PO-01) into a TPAPOPPI host, a white OLED with a high EQE of 20.3% and a low driving voltage of 3.2 V (at 1000 cd m-2) is achieved.

Citation Format(s)

Tuning electrical properties of phenanthroimidazole derivatives to construct multifunctional deep-blue electroluminescent materials. / Zhu, Ze-Lin; Ni, Shao-Fei; Chen, Wen-Cheng; Chen, Miao; Zhu, Jie-Ji; Yuan, Yi; Tong, Qing-Xiao; Wong, Fu-Lung; Lee, Chun-Sing.

In: Journal of Materials Chemistry C, Vol. 6, No. 14, 14.04.2018, p. 3584-3592.

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