White light organic electroluminescent device using a naphthalimide derivative as the emitter layer

The electroluminescent (EL) device was fabricated using a naphthalimide derivative, N-Propyl-4-acetylamino-1,8-naphthalimide (PAAN), as the emitter layer, N,N'-diphenyl-N,N'-bis(3-methyl-phenyl)-1,1'-biphenyl)-4,4'-diamine (TPD) as the hole transport layer, ITO and Al as the anode and cathode, respectively. The EL emission of the device showed a white light. There are two peaks located at 491nm and 669nm in the EL spectrum. The emission peak at 491nm comes from PAAN, while the emission peak at 669nm results from neither the emission of PAAN molecule nor that of TPD molecule. It showed that the showing up of the new emission peak in the EL spectrum of the device is due to the exciplex formation at the PAAN and TPD bilayer interface.