Effect of doping profile on the lifetime of green phosphorescent organic light-emitting diodes

The lifetime of green phosphorescent light-emitting diodes was improved by using a graded doping structure in light-emitting layer. A green device with high doping concentration at the hole transport layer and light-emitting layer interface showed longer lifetime than a conventional device with uniform doping concentration for the whole light-emitting layer by more than 60%. (c) 2006 American Institute of Physics.