Efficiency enhancement utilizing hybrid charge generation layer in tandem organic light-emitting diodes

摘要

We report the incorporation of lithium fluoride doped 4,7-diphenyl-1,10-phenanthroline, Al, and molybdenum trioxide which is utilized to form the charge generation layer in tandem organic light-emitting diodes. Both the fluorescent and phosphorescent tandem devices based on this hybrid charge generation layer show the enhanced luminous efficiency and reduced operating voltage compared with the devices using conventional charge generation layer. The mechanism of the efficiency enhancement is ascribed to the improvement of charge balance due to the efficient charge separation in the hybrid charge generation layer. The hybrid layer can act as the effective charge injection buffer layer as well.