Electrophosphorescent organic light-emitting diodes with modified hole blocking layer

摘要

The electrical and optical properties of electrophosphorescent organic light-emitting diodes (OLEDs) with modified hole blocking layer (HBL) were investigated. Well-known 2,9-dimethyl-4,7- diphenyl-1,10-phenanthroline (BCP) HBL is mixed with electrophosphorescent host material (4,4’-N,N’- dicarbazole-biphenyl: CBP) or electrophosphorescent dopant material (fac-tris(2-phenylpyridine) iridium: Ir(ppy)3) or both. The highest external quantum efficiency was obtained in the device with BCP-CBPIr( ppy)3 mixed HBL and we attribute this result to the additional charge recombination in mixed-HBL.