Transparent Anodic Properties of In-doped ZnO thin Films for Organic Light Emitting Devices

Transparent In-doped zinc oxide (IZO) thin films are deposited with variation of pulsed DC power at Ar atmosphere on coming 7059 glass substrate by pulsed DC magnetron sputtering. A c-axis oriented IZO thin films were grown in perpendicular to the substrate. The optical transmittance spectra showed high transmittance of over 80% in the UV-visible region and exhibited the absorption edge of about 350 nm. Also, the IZO films exhibited the resistivity of similar to 10(-3) Omega.cm and the mobility of similar to 6 cm/V.s. Organic Light-emitting diodes (OLEDs) with IZO/N,N'-diphenyl-N,N'-bis(3-methylphenl)-1, 1'-biphenyl-4,4'-diamine (TPD)/tris (8-hydroxyquinoline) aluminum (Alq(3))/LiF/Al configuration were fabricated. LiF layer inserted is used as an interfacial layer to increase the electron injection. Under a current density of 100 mA/cm(2), the OLEDs show an excellent efficiency (9.4 V turn-on voltage) and a good brightness (12000 cd/m(2)) of the emission light from the devices. These results indicate that IZO films hold promise for anode electrodes in the OLEDs application.