Influence of the deposition temperature on the structure and performance of tris(8-hydroxyquinoline) aluminum based flexible organic light-emitting devices

Based on indium tin oxide (ITO)/NA,diphenyl-N-N'-di(m-tdyl) benzidine (TPD)/Alq(3)/Al structure, flexible OLEDs on polyethylene tereplithalate (PET) substrates were fabricated by physical vapor deposition (PVD) method. Tris(8-hydroxyquinoline)aluminum (Alq(3)) films were deposited at 90, 120 and 150 degrees C to examine the influence of the deposition temperature on the structure and performance of OLEDs. Electroluminescence (EL) spectra and current-voltage-luminance (I-V-L) characteristics of the OLEDs were examined. It was found that the device fabricated at a high temperature had a higher external efficiency and longer lifetime. Atomic force microscope (AFM) was adopted to characterize the surface morphology of ITOfrPD/Alq(3). The higher uniform morphology of the Alq3 formed at high temperature might contribute to the performance improvement of the OLEDs. (c) 2006 Elsevier B.V. All rights reserved.