Study on the Effects of Yb: Ag Alloy Cathode on the Photoelectric Performance of the Top Emitting White Organic Light-emitting Devices

Top-emitting white organic light-emitting diode(OLED) devices with a Mg: Ag alloy as a transparent cathode were fabricated. Based on the device structure of ITO/NPB: LiQ(5%) (10 nm)/TCTA(20 nm)/FIrpic+3.5% Ir(ppy)₃+0.5%Ir(MDQ)₂(acac) (25 nm)/TPBI(10 nm)/LiF(5 nm)/Yb: Ag (X%) (X nm), the top-emitting white OLED devices were prepared by using Yb: Ag alloy of different thickness as the cathode at the evaporation ratio of 10:1, the optimum thickness of Yb: Ag cathode was 12 nm by contrasting. The effect of different proportions of Yb: Ag alloy on OLEDs was investigated by changing the doping ratio of Ag. Based on the preliminary results, the alloy with a Ag mass fraction of 10% exhibits good electron injection characteristics, which can effectively improve the light-emitting characteristics of the device. When the current density was 20 mA/cm², the driving voltage was 2.3 V, the brightness was 1406 cd/m², and the color coordinates were close to (0.3407, 0.3922).