Charge injection barrier modification in organic LEDs

Abstract

Balanced injection of positive and negative charge carriers is a key issue for the operation of highly efficient organic light emitting devices at low operating voltage. In this article, we will give an overview of our investigations on the optimization of charge carrier injection from the anode and the cathode into organic semiconductors. These investigations include proper pretreatment of the indium–tin oxide substrate, and stacking of several organic hole transporting layers to increase the hole injection current from the transparent anode into the emissive layer. On the cathode side, binary metal alloys, and the effect of an insulating layer between the respective metal cathode and the first electron transporting layer are investigated.