Doping Concentration of Fluorescent Dyes on the Properties of Yellow Organic Electroluminescent Devices

The devices were fabricated with the structure of ITO/m-MTDATA (20 nm)/NPB(10 nm)/DPAVBi: Rubrene (z%, 20 nm)/Alq3(30 nm)/LiF(0.5 nm)/AI (100 nm) by the vacuum evaporation method. The doped concentration of z was fixed at 2, 5, 8 and 10, and the thickness of emitting layer DPAVBi: Rubrene was 20 nm. The luminance and the current efficiency of the devices were studied by adjusting the different doping concentrations. The results show that the yellow organic light-emitting diodes had a maximum current efficiency of 3.56 cd/A and maximum luminance of 23150 cd/m(2) at 11.5 V when the doping concentration was 5%. And the color coordinates was near (0.48, 0.50), closing to the standard yellow light.