A dinuclear aluminum 8-hydroxyquinoline complex with high electron mobility for organic light-emitting diodes

Abstract

A dinuclear aluminum 8-hydroxyquinoline complex (DAlq3) with improved electron mobility was designed for organic light-emitting diodes. The electron mobility in DAlq3 was determined via transient electroluminescence (EL) from bilayer devices with structure of indium tin oxide (ITO)/N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB)/DAlq3/Mg:Ag. It was found that the electron mobility in DAlq3 is between 3.7–8.4×10−6 cm2/Vs at electric fields ranging between 1.2×106 and 4.0×106 V/cm, which is a factor of two higher than that in Alq3. The DAlq3 also shows a higher EL efficiency of 2.2 cd/A (1.2 Lm/W), as compared to Alq3 with an EL efficiency of 2.0 cd/A (1.0 Lm/W), which is attributed to more balanced electron and hole recombination due to the improved electron mobility of DAlq3.