G. Sakamoto et al., Significant improvement of device durability in organic light-emitting diodes by doping both hole transport and emitter layers with rubrene molecules, APPL PHYS L, 75(6), 1999, pp. 766-768
We have developed highly durable organic light-emitting diodes. The basic s
tructure of the diodes is anode/hole injection layer/hole transport layer+d
opant/emitter layer+dopant/cathode. Both the hole transport and the emitter
layers were doped with the highly fluorescent rubrene molecules. With the
doping of both layers, 85% of the initial luminance was successively mainta
ined even after 1000 h of continuous operation under constant current drivi
ng. Doping of only one of these layers, either the hole transport layer or
emitter layer, on the other hand, resulted in shorter lifetime. We mention
the possible mechanisms of the doping that enhance the device duration. (C)
1999 American Institute of Physics. [S0003-6951(99)03132-0].