Red Light-Emitting-Diode Based on an Organic Salt

A novel organic salt trans-4-P-(N-ethyl-N-(hydroxylethyl)-amino) styryl-N-methylpyridinium tetraphenylborate (abbreviated as ASPT) has been employed as an active layer in an organic electroluminscent device. Bright red emission with high quantum efficiency has been obtained. The brightness of the ASPT device is one order magnitude higher than that of Alq₃ devices at about 12 V. The device shows high thermal stability because of the ionic interaction within the organic salt molecules. It is assumed that the high performance of such a device is related to the formation of dipole moments in the ASPT layer.