Energy transfer of triplet excitons between EML and ETL materials in single emissive white phosphorescent OLEDs with three primary colors

The performance of collisional quenching process between electron transport materials such as 4,7-diphenyl-l,10-phenanthroline (Bphen), 2',2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) and l,3,5-tri(3-pyrid-3-yl-phenyl)benzene (TmPyPB) and blue phosphorescent material such as 3,5-difluoro-2-(2-pyridyl)-phenyl-(2-carboxypyridyl) Iridium 111 (Flrpic) was analyzed through spectroscopic study in solution to prove energy loss of diffusive triplet excitons in single emissive white phosphorescent organic light-emitting devices. The luminous and external quantum efficiency of single emissive white phosphorescent organic light-emitting device with TmPyPB as electron transport material is higher than the other devices prepared with Bphen and TPBi as electron transport material due to preventing collisional quenching process. Therefore, TmPyPB as electron transport material allows improving efficiency of single emissive white phosphorescent organic light-emitting device as compared to the other devices.