Alignment-free process for asymmetric contact electrodes and their application in light-emitting organic field-effect transistors

We developed an alignment-free process for asymmetric contacts of Au and Al and applied it to light-emitting organic field-effect transistors. Because electrons were injected efficiently from Al contacts, the emission intensity and onset voltages for light were significantly better than those in a device with conventional AuCr contacts. Moreover, a device with 1 μm channel length asymmetric contacts of Au and Al showed about 50 times higher current than that of the device with conventional AuCr contacts. This significant improvement can be ascribed to both dual space-charge formation of holes and electrons and low carrier injection barriers.