HIGH-TEMPERATURE OPERATION OF AN ELECTROLUMINESCENT DEVICE FABRICATEDUSING A NOVEL TRIPHENYLAMINE DERIVATIVE

We have fabricated thermally stable organic electroluminescent (EL) de vices using a hole transporting material, a tetramer of triphenylamine , and a typical emitting material, tris (8-quinolinolato) aluminum (Al q). The organic EL devices show uniform light emission in a continuous operation up to 140 degrees C without breakdown. A lowering of turn-o n voltage for light emission and an increase of luminous efficiency wi th increasing temperature are found; the significantly low turn-on vol tage of 2.1 V and the high luminous efficiency of 1.25 lm/W are obtain ed at 130 degrees C. Excellent durability of continuous operation is a lso achieved at the high temperature. (C) 1996 American Institute of P hysics.