The organic magnetoresistance of aluminium tris(8-hydroxyquinoline) based organic light-emitting diodes has been modeled using the triplet polaron interaction coupled with exciton dissociation. We have demonstrated that each of the processes is proportional to the exciton concentration over a wide range of operating conditions for a number of devices with a wide range of layer thicknesses. This work demonstrates that using a magnetic field to perturb the operation of a working organic device is particularly valuable in that it provides a new technique for studying a range of processes affecting current transport such as polaron trapping, triplet-polaron interactions, and exciton dissociation in fully working devices.

• Received 17 May 2011

DOI:https://doi.org/10.1103/PhysRevB.86.075206