Effect of horizontal molecular orientation on triplet-exciton diffusion in amorphous organic films

摘要

Triplet harvesting is a candidate technology for highly efficient and long-life white OLEDs, where green or redphosphorescent emitters are activated by the triplet-excitons diffused from blue fluorescent emitters. We examined twooxadiazole-based electron transport materials with different horizontal molecular orientation as a triplet-exciton diffusionlayer (TDL) in triplet-harvesting OLEDs. The device characteristics and the transient electroluminescent analyses of thered phosphorescent emitter showed that the triplet-exciton diffusion was more effective in the highly oriented TDL. Theresults are ascribed to the strong orbital overlap between the oriented molecules, which provides rapid electron exchange(Dexter energy transfer) in the TDL.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.