Phenyl- and Pyrazolyl-Functionalized Pyrimidine : Versatile Chromophore of Bis-Tridentate Ir(III) Phosphors for Organic Light-Emitting Diodes

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

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Author(s)

  • Yi-Kuang Chen
  • Hsin-Hung Kuo
  • Dian Luo
  • Yi-Ning Lai
  • Wei-Cheng Li
  • Chih-Hao Chang
  • Daniel Escudero
  • Ling-Yang Hsu

Detail(s)

Original languageEnglish
Pages (from-to)6453−6464
Journal / PublicationChemistry of Materials
Volume31
Issue number17
Online published26 Nov 2018
Publication statusPublished - 10 Sep 2019

Abstract

There is growing interest in the bis-tridentate Ir(III) emitters as they are expected to display both improved emission efficiency and improved photostability. Herein, we turned to the new emitters m2h-1–3 and m6h-1–3, bearing a pincer carbene ancillary and a chromophoric chelate derived from judiciously selected phenyl-pyrimidine-pyrazole entities (pzm2hF)H2 and (pzm6hF)H2, which differ in terms of the location of phenyl and pyrazole substituents on the central pyrimidine. Density functional theory calculations revealed a notable change in the spin density distribution from the pyrimidine-pyrazolate entity in m2h to the pyrimidine-phenyl fragment in m6h. As a consequence, the m6h emitters exhibited both shortened emission lifetimes and improved stabilities during extensive photolysis in solution, while corresponding organic light-emitting diodes (OLEDs) doped with green-emitting m6h-1 and sky-blue-emitting m6h-2 and m6h-3 exhibited external quantum efficiencies of 17.6, 15.9, and 17.6%, respectively, superior to those of all of their m2h counterparts at a practical luminance of 103 cd/m2. This finding suggests a new methodology for fine-tuning the electronic transition that is important to high-performance and durable phosphorescent OLEDs.

Citation Format(s)

Phenyl- and Pyrazolyl-Functionalized Pyrimidine : Versatile Chromophore of Bis-Tridentate Ir(III) Phosphors for Organic Light-Emitting Diodes. / Chen, Yi-Kuang; Kuo, Hsin-Hung; Luo, Dian; Lai, Yi-Ning; Li, Wei-Cheng; Chang, Chih-Hao; Escudero, Daniel; Jen, Alex K.-Y.; Hsu, Ling-Yang; Chi, Yun.

In: Chemistry of Materials, Vol. 31, No. 17, 10.09.2019, p. 6453−6464.

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