The sandwiched-p-doped-layer hole injection structure to enhance the performance of inverted organic light-emitting diodes

Abstract The performance of inverted organic light-emitting diodes (IOLEDs) has been improved based on $ MoO_{3} $-doped N,N′-bis-(1-naphthyl)-diphenyl-1,1′-biphenyl-4,4′-diamine (2:1 NPB:$ MoO_{3} $ in mass ratio) and 4,4′-N,N′-dicarbazole-biphenyl (2:1 CBP:$ MoO_{3} $ in mass ratio). The sandwiche...
Ausführliche Beschreibung

Abstract The performance of inverted organic light-emitting diodes (IOLEDs) has been improved based on $ MoO_{3} $-doped N,N′-bis-(1-naphthyl)-diphenyl-1,1′-biphenyl-4,4′-diamine (2:1 NPB:$ MoO_{3} $ in mass ratio) and 4,4′-N,N′-dicarbazole-biphenyl (2:1 CBP:$ MoO_{3} $ in mass ratio). The sandwiched-p-doped-layer hole injection structure of CBP:$ MoO_{3} $ 10 nm/NPB:$ MoO_{3} $ 5 nm/CBP:$ MoO_{3} $ 5 nm/Al showed increased device performance via enhancing hole current into the CBP, compared to the single-p-doped-layer hole injection structure of CBP:$ MoO_{3} $ 20 nm/Al, mostly due to the higher conductivity of NPB:$ MoO_{3} $ than that of CBP:$ MoO_{3} $; it also improved device current and thereby performance than the double-p-doped-layer hole injection structure of CBP:$ MoO_{3} $ 10 nm/NPB:$ MoO_{3} $ 10 nm/Al, mostly attributed to that the hole injection from Al to CBP:$ MoO_{3} $ was more efficient than that from Al to NPB:$ MoO_{3} $. The current research provides some insights in reducing the power loss toward the commercialization of IOLEDs. Ausführliche Beschreibung