Blue-green emission from organic light emitting diodes based on aluminum complex

Abstract

Bluish-green emission from double layer organic light emitting diode (OLED), based on an aluminium complex, bis-(2-methyl 8-hydroxyquinoline) aluminium hydroxide (Almq₂OH), as an emissive material and <i style="">N</i>,<i style="">N</i>'-bis(3-methylphenyl)-<i style="">N</i>,<i style="">N</i>'-bis(phenyl)benzidine (TPD), as hole transport material with an electro-luminescence maximum at 506 nm, has been reported. The good thermal stability, good performance for the OLED applications, and a noticeable blue shift in the electroluminescence, in comparison to Alq₃, make this Al complex a good contender for OLED applications for light emission in the blue-green region. It was also found that the devices based on this material have a slightly higher turn-on voltage than similar Alq₃ devices. This can be attributed to the higher energy-gap of the material. The photoluminescence and electroluminescence spectra are reported and a shift of 9 nm in peaks is observed. The current-voltage characteristics of the device have also been studied.