Enhancement of electron injection in inverted top-emitting organic light-emitting diodes using an insulating magnesium oxide buffer layer

Abstract

We report the enhancement of the electron injection by inserting a 1-nm-thick magnesium oxide (MgO) buffer layer between Al cathode and tris (8-hydroxyquinoline) aluminum in an inverted top-emitting organic light-emitting diode (OLED). The turn-on voltage of OLEDs decreased from 10 to 6 V and the luminance increased about 61% as the MgO interfacial layer was employed. The MgO interfacial layer played a role in reducing the energy barrier of electron injection, leading to the reduction of the turn-on voltage and the enhancement of luminance.