Platinum (II) Complexes Based on Tetradentate Pyridine-Containing Ligands for Phosphorescent Organic Light-Emitting Diodes

Abstract

<jats:p>In this study, we designed and synthesized two phosphorescent emitting materials based on tetradentate pyridine-containing ligands. Their photophysical properties were examined for OLEDs and multilayer devices using these materials were fabricated in the following sequence; ITO (180 nm)/4,4′,4″-Tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA) (30 nm)/<jats:italic>N</jats:italic>,<jats:italic>N</jats:italic>′-di(1-naphthyl)-<jats:italic>N</jats:italic>,<jats:italic>N</jats:italic>′-diphenyl-1,1′-biphenyl)4,4′-diamine (NPB) (20 nm)/Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) (10 nm)/4,4′-Bis(<jats:italic>N</jats:italic>-carbazolyl)-1,1′-biphenyl(CBP): 5, 8, 15% Platinum (II) complexes (20 nm)/1,3,5-Tris(1-Phenyl-1<jats:italic>H</jats:italic>-benzimidazol-2-yl)benzene) (TPBi) (40 nm)/Liq (2 nm)/Al (100 nm). In particularly, a device using Platinum (II) complex based on A/-(3,5-di-tert-butylphenyl)-6-phenyl-<jats:italic>N</jats:italic>-(6-phenylpyridin-2-yl)pyridin-2-amine ligand showed the efficient emission, with luminous efficiency, power efficiency, and external quantum efficiency, and the Commission International de LEclairge (CIE) coordinates of 29.29 cd/A, 9.37 lm/W, 8.66% at 20 mA/cm2, and (0.32, 0.62) at 8.0 V, respectively.</jats:p>