Top-emitting organic light-emitting diode using transparent conducting indium oxide layer fabricated by a two-step ion beam-assisted deposition

To fabricate the top-emitting organic light-emitting diodes (TEOLEDs) with an improved device performance, an n-type indium oxide (IO) was deposited as the transparent conducting capping layer, by using ion beam-assisted deposition (IBAD) technique, on the device of glass/Ag (100 nm)/ITO (100 nm)/2-TNATA (60 nm)/NPB (20 nm)/Alq 3 (40 nm)/LiF (1 nm)/Al (2 nm)/Ag (20 nm), and its properties were investigated. To minimize the damage to the organic layers and the oxidation of the top Ag layer during the oxygen IBAD, two-step processing of IO thin film composed of argon IBAD followed by oxygen IBAD was used. The light output of TEOLED fabricated by using the IBAD was similar compared with that of a reference device composed of glass/Ag (100 nm)/ITO (100 nm)/2-TNATA (60 nm)/NPB (20 nm)/Alq 3 (40 nm)/LiF (1 nm)/Al (2 nm)/Ag (20 nm)/Alq 3 (52 nm), where, Alq 3 was used as the semi-passivated capping layer.