Highly Efficient Green Phosphorescent Organic Light-Emitting Diodes with High Electron Mobility

We demonstrated highly efficient green organic light-emitting diodes (OLEDs) by inserting a mixed hole blocking layer (HBL) between the emitting layer (EML) and electron transporting layer (ETL). We compared 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), N-arylbenzimidazoles trimer (TPBi), and 4,7-diphenyl-1,10-phenanthroline (Bphen) as the hole blocking layer. Thereafter, we mixed BCP with TPBi and Bphen. We obtained improved efficiency from the mixed HBL devices and the TPBi mixed with BCP device showed the best efficiency.