Electroluminescence in novel hole-transporting emissive materials

We have fabricated highly efficient organic light-emitting diodes (OLEDs) using novel hole-transporting emissive materials with triphenylamine moiety. The novel emissive materials have a high glass transition temperature ranging from 141 - 152 degrees Celsius, which is attributed to nonplanar molecular structure. The OLEDs consist of an emitting layer of the novel emissive material and an electron-transport layer of tris(8-qunolinolato) aluminum (Alq3). Emission colors of the OLEDs were bluish-green and greenish-yellow. High external quantum efficiency of 1.2 - 2% was obtained at a luminance of 300 cd/m2, and good durability in a continuous operation at room temperature and high temperatures was achieved.