Electroluminescent characteristics of organic light emitting devices by close-spaced sublimation

Abstract

We have demonstrated organic light emitting diodes by using a close spaced sublimation method. Small molecular electron transporting layers of BAIq and TAZ were investigated for improving device performance by using close-spaced sublimation method. It was found that device with an electron transporting layer of TAZ exhibits a better performance compare to BAIq. The white organic light emitting diodes with an ITO/PVK:Ir(piq)(3):FIrpic/TAZ/Li/Al structure is chosen as a device with different doping concentration of Flrpic emission materials. The PVK, Ir(piq)(3) and Flrpic organic materials as the host and guest emission materials were spin coated at various concentration of Flrpic ranging from 1wt% to 10 wt%. The maximum luminance and current efficiency were 1037 cd/m(2) and 3.26 cd/A, for white organic light emitting diodes with 10 wt% of Flrpic. The white light, with a Commission Internationale d'Eclairage chromaticity coordinates of (0.38, 0.36), is obtained with an applied voltage of 16V, showing a good white emission color for the 10 wt% of Flrpic device.