Molecular Doped Polymer Light Emitting Diodes with Air - stable Aluminum as Cathode

摘要

By using air - stable aluminum as cathode, molecular doped polymer (MDP) blue light emitting diodes (LEDs) were constructed. Poly(N - vinylcarbazole) (PVK) doped with, 1,1,4, 4 - tetrapheny 1 - 1, 3 - butadiene(TPB) was used as the light - emitting layer, a layer of 2 - (4 - biphenylyl) - 5 - (4 - terbutypheny) 1 -3,4-oxadiazole(PBD) as hole - blocking, electron - transporting layer and a layer of tris(8 - quinolinolate)-Aluminum (Alq_3) film also worked as an electron - transporting layer. The device with structure of ITO/PVK: TPB/PBD/Alq_3/Al was fabricated. Blue emission began at about 4 V, more than 1 000 cd/m~2 was achieved at 14 V. This is the lowest turn- on voltage for polymeric light - emitting diodes(PLEDs) used air - stable electrodes. Such low - operating voltage, especially using air - stable aluminum as cathode, may be helpful for the devices to be used in commercially viable displays.