The Blue Phosphorescent Iridium Complexes Containing New Triazole Ligands for OLEDs

For the application to organic light-emitting diodes (OLEDs), the blue light emitting iridium complexes containing a new triazole (trzl) ancillary ligand were prepared and their photophysical properties was studied with respect to substituent effect at the 5-position of the triazole in the complexes. As substituents, electron donating groups, CMe3 and CH2OMe were introduced to the triazole ligand of the complex to investigate the electronic effect on their chromacity and efficiency. The absorption patterns of the iridium complexes, Ir(F-2-ppy)(2)(trzl-CMe3) and Ir(F-2-ppy)(2)(trzl-CH2OMe) prepared in this study were very similar. Their PL spectra exhibited the blue emission at 464 and 462 nm with the shoulder at 490 nm, respectively. Previously reported Ir(F-2-ppy)(2)(trzl-Me) showed almost identical emission maxima at 461 nm with a shoulder at 492 nm. Such similar emission patterns of these complexes indicate that the ancillary ligands, derivatives of triazole, did not make significant influence on chromaticity of their iridium complexes.