Blue-light-emitting organic electroluminescence via exciplex emission based on a fluorene derivative

The synthesis of a high photoluminescence efficiency (88%, compared with tris(8-hydroxyquinoline)(Alq(3))) organic material 9,9-Dibutyl-N,N,N,N-tetraphenyl-9H-fluorene-2,7-diamine (DTFD) via Ullmann condensation was reported. Exiciplex emission of the ITO/DTFD/2.2-[1,2-phenylenebis(oxy)]bis(N,N-diphenylacetamide)/Alq(3)/LiF/Al device was observed and the peak wavelength of the emission was measured to be 480 nm, which belongs to the blue region. A turn-on voltage as low as 4 V and maximal brightness as large as 400 cd m(-2) were measured. The electroluminescence spectrum was observed to be blue-shifted with increase in applied voltage.