Phosphorescence Variation on the Electron Density of Donor Acceptor-type Iridium(III) Complex Ligands

Abstract

Organic light-emitting diodes (OLEDs) using phosphorescent iridium(III) complexes attract enormous attention because they allow highly efficient electrophosphorescence, and the OLED displays and lighting applications market has been growing continually. We synthesized phosphorescent iridium(III) complexes. The donor acceptor-type ligands for the iridium(III) complexes were synthesized by the Suzuki coupling reaction. The ligands, through changes in oxidative addition materials (electron acceptor) and organic borane (electron donor) to obtain the red color, were used to study appropriate iridium(III) complexes. Oxidative addition materials were used, such as 2-bromo-4-(trifluoromethyl)pyridine and 2-bromopyridin-4-amine. Dithieno[3,2-b:2′,3′-d]thiophen-2-ylboronic acid, phenanthren-9-ylboronic acid, and (3-aminophenyl)boronic acid were used as organic borane. Iridium(III) complexes were synthesized through the two steps of the Nonoyama reaction, as well as measured by nuclear magnetic resonance (NMR), UV-visible spectroscopy, and photoluminescence (PL). The phosphorescence emission maxima were dependent on the electron density of the donor and acceptor moieties of the ligands.

Keywords:

• OLED
• Iridium(III) complex
• Phosphorescent

Acknowledgments

This work was supported by the Technology Innovation Program (201210940003, Materials Development for 50-inches UD OLED TV Using Super Hybrid Process) and funded by the Ministry of Knowledge Economy (MKE, Korea).