Fabrication of flexible organic light-emitting diodes with Alq3 as emitting layer

Fabrication of flexible organic light-emitting diodes (FOLEDs) with ITO/PVK: TPD/Alq₃/Al configuration prepared on PET substrates is reported. Alq₃ is used as the light-emitting material. The curves of the current density vs. voltage, optical current vs. voltage and quantum efficiency vs. current density of the devices are investigated. Compared the devices with the ones that have the same configuration and are fabricated under the same conditions but on glass substrates, the characteristics of the two kinds of devices are very similar except that the threshold voltage of the flexible FOLEDs is a little higher. Under the driving voltage of 20V, the corresponding brightness and the external quantum efficiency are 1000 cd/m² and 0.27%, respectively. In addition, the anti-bend ability of the devices is tested and the reasons of failure of the devices are analyzed. Supported by the National Natural Science Foundation (60276027), Tianjin Natural Science key Foundation (023800511), Tianjin Science Foundation (033601211), Tianjin Science Development Foundation for University (9903114), and the key subject of the material physics and the chemistry of Tianjin.