Synthesis and electroluminescent property of highly efficient phosphorescent red dopants based on modulated main ligands

ABSTRACT

Novel red phosphorescent iridium(III) complexes, (DPAP-MQ)₂Ir(tmd), (DMAP-MQ)₂Ir(tmd), (PN-MQ)₂Ir(tmd) were synthesized for red emitter of the phosphorescent organic light-emitting diodes (phOLEDs). The ligands have sites of both the electron donor and acceptor in a molecule. The main ligands consisted of electron-donors ((dimethylamino)phenyl, (diphenylamino)phenyl, (dimethylamino)naphthalene) and electron-acceptor methyl quinoline were synthesized by suzuki coupling reaction. The iridium(III) complexes based on main ligands and 2,2,6,6-tetramethyl-3,5-heptanedione(tmd) ancillary ligand were synthesized by Nonoyama reaction. Their luminescence property was investigated by UV-visible spectroscopy and photoluminescence (PL) spectroscopy. The manufactured PHOLEDs were characterized by investigation of current density-voltage-luminance, luminance efficiency, external quantum efficiency, electroluminescence spectrum. These phosphorescent iridium complexes will be promising candidates for highly efficient red emitters.

KEYWORDS:

• Iridium(III) complexes
• phosphorescent organic light-emitting diodes
• red dopant

Funding

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2015R1A6A1A03031833)