Magnesium-gold binary alloy for organic light-emitting diodes with high corrosion resistance

The authors demonstrate a simple approach to obtain cathodes that have a high resistance against corrosion by water and oxygen and an air-stable work-function of -3.7 eV by doping 10 at. % of gold (Au) into a magnesium (Mg) base metal layer. Organic light-emitting diodes (OLEDs) with the Mg-Au cathodes achieved electroluminescence characteristics that are comparable to those of devices with conventional cathodes such as aluminum (Al) and Mg-silver (Ag). Although OLEDs with Al or Mg-Ag cathodes exhibited a significant reduction of their emissive area when operated in air, the emissive area of the OLEDs with Mg-Au cathodes decreased only 10% after 10 days of operation in ambient air without any specific encapsulation. These results suggest that Mg-Au cathodes can loosen the strict requirements for encapsulation, reducing the number of process steps and cost of OLED fabrication.