Fabrication of Organic Light-Emitting Diodes With Metal Oxides by Wet Process

Abstract

We investigate inverted organic light-emitting diodes (iOLEDs) using poly (9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) as an emissive layer and metal oxide thin films, titanium oxide (TiO₂) or zinc oxide (ZnO) as an electron-injecting layer by wet processes. The device characteristics of the iOLEDs with TiO₂ films prepared by spray pyrolysis are almost comparable to those of the iOLEDs reported in literature. iOLEDs with ZnO films were prepared by an electrochemical method. The characteristics of the iOLEDs are similar to those of the iOLEDs by spray pyrolysis reported in literature, demonstrating that the electrochemical method for the deposition of ZnO is applicable to iOLEDs. The electroluminescent characteristics of iOLEDs with ZnO are better than those with TiO₂ because of higher electron injection barrier at TiO₂/F8BT interface.