Organic Light-Emitting Devices with In-Doped (4 at. %) ZnO Thin Films as the Anodic Electrode

Abstract

We have investigated transparent conducting properties of using In-doped (4 at. %) zinc oxide (IZO) thin films deposited on glass substrate by pulsed DC magnetron sputtering at low processing substrate temperatures. As increase of the substrate temperature, IZO thin films with better c-axis orientations were grown in perpendicular to the substrate and work functions of IZO films slightly decrease. The optical properties showed high transmittance of higher than 85% in the UV–visible region and exhibited the absorption edge of about 350 nm. The electrical properties exhibited the low resistivity of 1.1 ×10-3 Ω cm and the high mobility of ∼7.8 cm2 V-1 s-1. The organic light emitting diodes (OLEDs) with an IZO anode achieved a maximum luminance efficiency of 2.7 cd/A and external quantum efficiency of 0.47%, which are compared to the values of a control device fabricated on commercial ITO anode. These results indicate that IZO films hold promise for anodic electrodes in the OLEDs application.