High-efficiency green electrophosphorescent organic light-emitting diodes with a simple device structure

摘要

In this study, we demonstrate electrophosphorescent organic light-emitting diodes (PHOLEDs)with a simple structure and high efficiency, utilizing fac-tris(2-phenylpyridine)iridium(III) (Ir(ppy)sub3/sub) asa green phosphorescent emitter. The device structure (ITO/TAPC/TAPC:Ir(ppy)sub3/sub/TPBi:Ir(ppy)sub3/sub/TPBi/LiF/Al) was fabricated by the hole transporting layer of 1,1-bis((di-4-tolylamino)phenyl)cyclohexane(TAPC; Tsub1/sub = 2.87 eV) and the electron transporting layer of 2,2,2-(1,3,5-benzenetriyl)tris-[1-phenyl-1H-benzimidazole] (TPBI; Tsub1/sub = 2.74 eV) to assemble a double emitting zone withoutcommon host materials. The emitting region with a TAPC/TPBI bilayer interface was able to providean effective energy transference of Ir(ppy)sub3/sub (Tsub1/sub = 2.4 eV). Thus, the green PHOLED exhibited highcurrent efficiency (70 cd/A at 100 cd/msup2/sup) and low roll-off in these devices.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.