High-temperature operation of an electroluminescent device fabricated using a novel triphenylamine derivative

We have fabricated thermally stable organic electroluminescent (EL) devices using a hole transporting material, a tetramer of triphenylamine, and a typical emitting material, tris (8-quinolinolato) aluminum (Alq). The organic EL devices show uniform light emission in a continuous operation up to 140 degrees C without breakdown. A lowering of turn-on voltage for light emission and an increase of luminous efficiency with increasing temperature are found; the significantly low turn-on voltage of 2.1 V and the high luminous efficiency of 1.25 lm/W are obtained at 130 degrees C. Excellent durability of continuous operation is also achieved at the high temperature. (C) 1996 American Institute of Physics.