It is found that the electric field inside the device is not uniform, and the potential distribution changes with external bias.

Applied Physics Letters

Internal potential distribution of organic light-emitting diodes (OLEDs) is an essential problem. By using dc bridge to eliminate errors due to high resistance of the devices at low bias, the potential distribution has been accurately measured for both double-layer and single-layer OLEDs. It is found that the electric field inside the device is not uniform, and the potential distribution changes with external bias. This phenomenon could be the effect of space charge originating from the unequal injections of holes and electrons, which is confirmed by the results of the device with modified work function of the anode.

It is found that the electric field inside the device is not uniform, and the potential distribution changes with external bias.

Internal potential distribution in organic light emitting diodes measured by dc bridge