Study on electrical characteristics of organic electrophosphorescent devices based on new Ir complex

The organic light-emitting devices (OLEDs) based on fluorescence have low efficiencies due to the requirement of spin-symmetry conservation. By using the phosphorescent material, the internal quantum efficiency can reach 100%, compared to 25% in the case of the fluorescent material. Thus, the phosphorescent OLEDs have recently been extensively studied and showed higher internal quantum efficiencies than the conventional OLEDs. In this study, an orange-red electrophosphorescent devices have been fabricated with a new Ir complex, synthesized by coordinating a new electrowithdrawing lignad to (ppy)2 Iracac, as the emitting dopant. It has been investigated the electrical and optical characteristics of the devices fabricated with a structure of ITO/NPB/Ir complex doped in CBP/BCP/Alq3/Li:Al/Al. The device with the Ir complex demonstrated an efficiency of 3.53 cd/A with an initial brightness of 100 cd/m2. The CIE coordinates for devices held at a current density of 1 mA/cm2 were (0.585, 0.410).