Device performance of the top-emitting organic light-emitting diodes using the Ba/Au/indium tin oxide cathode system with long skin depth

This paper reports the favorable performance of a top-emitting organic light-emitting diode (TEOLED) using a Ba/Au/indium tin oxide (ITO) cathode. A cathode with a Ba layer and a long skin depth of 44.1 nm not only prevented damage to the underlying organic layers from ion bombardment during ITO sputtering, but also improved the light out-coupling of devices by increasing the transmittance. With increasing Ba thickness, the turn-on voltage and leakage current of the devices were lower than of those without Ba. The Ba layer in the cathode enhanced the optical characteristics of the devices by the balanced carrier injection.