Rational Tuning of Bis-Tridentate Ir(III) Phosphors to Deep-Blue with High Efficiency and Sub-microsecond Lifetime

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

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Author(s)

  • Wun-Shan Tai
  • Premkumar Gnanasekaran
  • Yi-Yang Chen
  • Wen-Yi Hung
  • Xiuwen Zhou
  • Tai-Che Chou
  • Gene-Hsiang Lee
  • Pi-Tai Chou
  • Caifa You

Detail(s)

Original languageEnglish
Pages (from-to)15437-15447
Journal / PublicationACS Applied Materials & Interfaces
Volume13
Issue number13
Online published24 Mar 2021
Publication statusPublished - 7 Apr 2021

Abstract

A new class of bis-tridentate Ir(III) complexes (Dap-1-4) was synthesized using carbene pincer pro-chelates PC1·H3(PF6)2 or PC2·H3(PF6)2 with either imidazolylidene or imidazo[4,5-b]pyridin-2-ylidene appendages, together with a second cyclometalating 2,6-diaryoxypyridine chelate, L1H2 and L2H2, differed by a NMe2 donor at the central pyridinyl fragment. The respective emission tuning between the ultraviolet and blue region was rationalized using time-dependent density functional theory (TD-DFT) approaches. Next, a highly efficient blue emitter (Dap-5) was synthesized by concomitant addition of two methyl groups and a single CF3 substituent at the central phenyl and peripheral imidazo[4,5-b]pyridin-2-ylidene entities of the carbene pincer chelate, respectively. The organic light-emitting diode (OLED) device with 15 wt % Dap-5 in DPEPO shows electroluminescence at 468 nm and with CIE (0.14, 0.15) and a max external quantum efficiency (max EQE) of 16.8% with low efficiency roll-off (EQE of 14.4% at 1000 cd m-2); the latter is attributed to the relatively shortened triplet excited-state radiative lifetime. These results highlight the adequateness of bis-tridentate Ir(III) phosphors in fabrication of practical blue-emitting OLEDs.

Research Area(s)

  • blue, carbene, cyclometalate, iridium, organic light-emitting diodes

Citation Format(s)

Rational Tuning of Bis-Tridentate Ir(III) Phosphors to Deep-Blue with High Efficiency and Sub-microsecond Lifetime. / Tai, Wun-Shan; Gnanasekaran, Premkumar; Chen, Yi-Yang; Hung, Wen-Yi; Zhou, Xiuwen; Chou, Tai-Che; Lee, Gene-Hsiang; Chou, Pi-Tai; You, Caifa; Chi, Yun.

In: ACS Applied Materials & Interfaces, Vol. 13, No. 13, 07.04.2021, p. 15437-15447.

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