A bilayer organic light-emitting diode using flexible ITO anode

Flexible organic light-emitting diodes (OLEDs) with ITO (Indium-Tin-Oxide)/TPD (N, N'-diphenyl-N, N'-(3-methylphenyl)-1, 1'-biphenyl-4, 4'-diamine)/Alq(3)(tris (8-hydroxyquinoline) aluminum)/ Al configuration prepared on polyester substrates (polyester devices) were fabricated. The light-emitting and current-voltage (I-V) characteristics of the devices were investigated. Compared to those with glass substrates (glass devices) fabricated under the same conditions, the threshold voltage of the polyester devices was almost the same. The current and luminescent characteristics showed an obvious improvement when the thickness of the organic layers is increased. Distributive bursting emerged when the applied voltage increased over a certain value. The reasons causing the failure of the devices were analyzed. It was found that weaker adhesion and larger surface fluctuation of the flexible ITO films were leading factors affecting the stability of the polyester devices, which was different fr om that of glass devices.