Phosphorescent Organometallic Complexes Aimed at Fabrication of Electroluminescent Devices

Organic light-emitting diode (OLED) has received growing attention as a fundamental technology for displays and lighting devices. Toward the application of circularly polarized luminescence (CPL), it is very suggestive to review the science of OLED, especially focusing on the emitting materials. Here, the authors overview the chemistry of phosphorescent emitters for OLED application. First, the history of OLED is briefly reviewed, and the general concepts for the device fabrication are introduced. Next, the advantage of phosphorescent emitters is referred, and structural characteristics of iridium(III) and platinum(II) complexes are introduced as representative examples of phosphorescent emitters for OLED. Then, recent development of phosphorescent emitters and their application to OLEDs are reviewed. In the last part, CPL from racemic or achiral phosphorescent emitters induced under external magnetic fields is discussed, along with magnetically driven circularly polarized electroluminescence from phosphorescent OLEDs.