Top-emission organic light emitting diode with indium tin oxide top-electrode films deposited by a low-damage facing-target type sputtering method

Abstract

To confirm the effectiveness of the low-damage facing-target sputtering (FTS) method for the deposition of a transparent oxide electrode film on an organic layer, an indium tin oxide (ITO) top electrode was deposited via FTS, and a top emission organic light-emitting diode (OLED) was fabricated. Top and bottom electrode films were deposited using the FTS system; in addition, a top emission a bottom emission OLED were fabricated with an inverse stacking structure. Consequently, both OLEDs exhibited similar operating characteristics, and the top emission OLED had a better luminance efficiency than the bottom emission OLED did. Compared with the OLED fabricated using the evaporation method, the OLEDs fabricated using FTS exhibited similar luminance efficiencies, although they had considerably higher operating voltages. In addition, annealing treatment at 110 °C was observed to lead to a significant reduction in the operating voltages; moreover, the obtained top emission OLEDs exhibited operating characteristics similar to those of the OLED fabricated using the evaporation method. These results indicate that the FTS method is useful for the deposition of the top oxide electrode films of OLEDs.