Electronic structure of carbazole-based phosphine oxides as ambipolar host materials for deep blue electrophosphorescence: A density functional theory study

Dongwook Kim*, Lingyun Zhu, Jean-Luc Bredas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

We report the results of Density Functional Theory calculations on a series of carbazole-based phosphine oxides that experimental data have shown to be promising ambipolar host molecules for deep blue electrophosphorescence. The hosts under investigation contain either 1, 2, or 3 carbazole subunits attached to the phenyl rings of a triphenylphosphoryl group, with the carbazoles acting as hole transporters/acceptors and the triphenylphosphoryl groups as electron transporters/acceptors. The results underline that, in addition to the strong inductive effect of the phosphoryl groups, the LUMO of these hosts is further stabilized by the molecular orbital interactions among the phenyl rings of the triphenylphosphoryl group, which is modulated by the electron-withdrawing inductive effects of the carbazole subunits. The lowest triplet state of the hosts correspond to localized transitions within the carbazole units, which leads to a high triplet energy on the order of 3 eV. We describe the important buffer role of the phenyl rings in preventing the phosphoryl moiety from negatively affecting the hole-accepting characteristics and high triplet energies of the carbazole units.

Original languageEnglish (US)
Pages (from-to)2604-2610
Number of pages7
JournalChemistry of Materials
Volume24
Issue number13
DOIs
StatePublished - Jul 10 2012

Keywords

  • DFT calculation
  • ambipolar hosts
  • deep blue OLED
  • electroluminescence
  • phosphine oxides

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Fingerprint

Dive into the research topics of 'Electronic structure of carbazole-based phosphine oxides as ambipolar host materials for deep blue electrophosphorescence: A density functional theory study'. Together they form a unique fingerprint.

Cite this