Improved characteristics of organic light-emitting devicesby surface modification of nickel-doped indium tin oxide anode

This letter presents the optoelectrical performance of an organic light-emitting diode (OLED) through the elevation of indium tin oxide (ITO) anode work function by Ni co-sputter surface doping and additional O2 plasma treatment. The turn-on voltage of OLED devices can be reduced by 2.3V for Ni atomic concentration greater than 1.8% and by 2.7V for the additional O2 plasma treatment. Devices with Ni(2.6%)-doped and O2 plasma treated ITO anodes perform the highest luminance efficiency (0.91lm∕W), three times larger than undoped ITO (0.31lm∕W) at 250cd∕m2.