Abstract
We report on phosphorescent organic light-emitting diodes (OLEDs) using 4,4'-bis(N-carbazolyl)-9,9'-spirobifluorene (CFL), which has spirobifluorene and two carbazole moieties, as a thermally stable host material. The thin film of CFL has good thermally stability and it wasn't crystallized at 150℃. The OLED using CFL as a host material and tris (2-phenylpyridine) iridium(III) (Ir(ppy)_3) as a guest material exhibited an external quantum efficiency over 10%. The efficiency was comparable to those of an OLED that using conventional 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) as a host.
