A Study on the Performances of White Organic Light-Emitting Diodes and the Morphologies of Their Hole-Blocking Layers

摘要

White organic light-emitting diodes (WOLEDs) with improved stability and efficiency based on an aluminum (III)bis-(2-methyl-8-quinolinato)4-phenylphenolate (BAlq)-doped 4,7-diphenyl-1,10-phenanthroline (BPhen) hole-blocking layer (HBL) have been fabricated. Compared with the WOLEDs with BPhen hole-blocking layer, approximately 2.6 times the lifetime and 1.4 times the efficiency have been achieved in the WOLEDs adopting the 10wt% BAlq-doped BPhen layer. Atomic force microscope (AFM) has been used to study the morphologies of BPhen, BAlq and BAlq-doped BPhen layers, which shows that the dopant of BAlq improves the stability of BPhen layer significantly. It is suggested that the improved performance of the WOLEDs is attributed to the stable hole-blocking layer in morphology.