Effect of Indium-Oxide Deposited Using an Oxygen Ion-Beam-Assisted-Deposition to Top-Emitting Organic Light-Emitting Diodes

Abstract

Indium oxide thin films have potential applications as cathodes in top-emitting organic light-emitting diodes (TEOLEDs). This study examined the characteristics of transparent conducting indium oxide (IO) films deposited by an oxygen ion-beam-assisted-deposition (IBAD) as a function of the applied oxygen ion energy (Va). When TEOLED devices consisting of glass/Ag (100 nm)/ITO (125 nm)/2-TNATA (30 nm)/NPB (15 nm)/Alq3 (55 nm)/LiF (1 nm)/Al (2 nm)/Au (20 nm)/IO (100 nm) were fabricated at a lower Va, a lower turn-on voltage was observed even though the maximum luminance (32,000 cd/m2) was similar one another. A Va of approximately +50 V produced an IO film with a resistivity of 8.5×10-4 Ω·cm and a transmittance of 85%. The definition (I–V) characteristics of TEOLED devices with a cathode layer of Al (2 nm)/Au (20 nm)/IO (100 nm) were similar to the device fabricated with Al (2 nm)/Au (20 nm) only.