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

Abstract

Here, red phosphorescent platinum(II) complexes based on tetradentate pyridine-containing lig-ands are studied. To investigate their electroluminescent properties, multilayer devices were fabricated in the following sequence; ITO (180 nm)/4,4′,4″-Tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA) (30 nm)/N, N′-di(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl)4,4′-diamine (NPB) (20 nm)/ Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) (10 nm)/4,4′-Bis(N-carbazolyl)-1,1′-biphenyl (CBP) (20 nm)/Platinum(II) complex (20 nm)/1,3,5-Tris(1-Phenyl-1H-benzimidazol-2-yl)benzene) (TPBi) (40 nm)/Liq (2 nm)/Al (100 nm). In particularly, a device using platinum(II) complex based on N-(3,5-di-tert-butylphenyl)-3-(pyridin-2-yl)-N-(3-(pyridin-2-yl)phenyl)benzenamineligand showed the efficient red emission, with a luminous efficiency, power efficiency, and external quantum efficiency of, and the Commission International de LEclairge (CIE) coordinates of 27.26 cd/A, 10.54 lm/W, 8.50% at 20 mA/cm2, and (0.65, 0.33) at 11.0 V, respectively.