Organic light-emitting diodes (OLEDs) are promising for a variety of applications as they can be flexible, thin, and light-weight, yet still have low power consumption and full color capability. However, LEDs made solely from organic components can only utilize 25% of the available excitons created from direct charge injection so the incorporation of iridium metal centers increases device efficiency as the heavy atoms are not limited to harvesting only singlet excitons. Phosphorescent cationic iridium(III) complexes have been synthesized for use in OLEDs as the mobile counter ions facilitate charge injection into the active layer, in contrast to the more conventional charge neutral tris-cyclometalated iridium complexes. However, to date, OLEDs made from cationic iridium complexes have displayed short operational device lifetimes at luminance levels sufficient for lighting. There have been several mechanisms of degradation and device deactivation proposed to explain the short operational lifetimes. Our goal is to probe one or more of these mechanisms experimentally. To accomplish this goal, a series of seven novel cationic bis-cyclometalated iridium(III) complexes have been designed, synthesized and systematically studied. These complexes have been tested in operational OLED devices to determine device efficiency and lifetime. The design, synthesis, characterization, electrochemistry, photophysics and device testing of the seven complexes will be discussed.

Phosphorescent cationic <i>bis</i>-cyclometalated iridium complexes for applications in OLEDs

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Phosphorescent cationic bis-cyclometalated iridium complexes for applications in OLEDs