Inverted organic light-emitting diodes using different transparent conductive oxide films as a cathode

Abstract

We report on poly(dioctylfluorene-alt-benzothiadiazole) (F8BT) based inverted organic light-emitting diodes (iOLEDs) using commercially available transparent conductive oxide (TCO) films as a cathode, indium tin oxide (ITO), Ga doped ZnO (GZO), and Al doped ZnO (AZO). The ITO, GZO, and AZO glasses work as an electron-injecting layer (EIL) and cathode. The device configuration that we prepared is ITO, GZO, or AZO/F8BT/MoO3/Au. The device characteristics of these iOLEDs are almost comparable to those of conventional iOLEDs with ZnO films prepared by spray pyrolysis as an EIL, indicating that the electron injection properties of ITO, GZO, or AZO as a cathode are similar to those of ZnO layer in conventional iOLEDs. These results demonstrate the low-cost fabrication of iOLEDs utilizing commercially available TCO glasses as a cathode without deposition of ZnO layers on ITO glass.