Study of a red shift phenomenon in organic light emitting diodes (OLEDs) with Mg: Ag cathode

摘要

We had made tris(8-hydroxyquinline) aluminum (Alq{sub}3) and 4,4'-bis(3-methylphenylphenylamino) biphenyl-based organic light emitting devices (OLEDs) with Mg:Ag cathodes by vacuum evaporation methods at 5-7×10{sup}(-6) torr. The structure of OLED was ITO/TPD/Alq3/Mg/Ag. We obtain a yellow-green light which emitting-peak is around 560nm from the device. The emitting-peak of our devices is obviously longer than 520nm which reported from references. We have found the Mg signal in the organic layer by ESCA (electronic spectra chemical analyses). Mg atoms may reach to Alq3/TPD even the TPD layer, which depends on the preparing conditions.