Analysis of current–voltage characteristics of organic light emitting diodes having a LiF/Al cathode and an Al–hydroxyquinoline/diamine junction

Abstract

The electron injection from the composite cathode consisting of a very thin LiF layer and an Al layer (LiF/Al) into Al–hydroxyquinoline (ALQ) layers showed the voltage and temperature dependence, which is characteristic to the Schottky emission mechanism. The barrier formed at the interface is lower than that formed at the interfaces between the conventional cathodes and the ALQ layer. The current–voltage characteristics of the light emitting diodes having the LiF/Al cathode and the ALQ/diamine junction were well explained on the basis of the properties of the electron injection into the ALQ layer and the hole injection into the diamine layer.