Pyridyltriazole as a Main Ligand in the Iridium Complexes for Blue Phosphorescence

Abstract

New blue-phosphorescent iridium complexes containing pyridyltriazole derivatives (trzl-CH₂OMe) as main ligands and benzyldiphenylphosphines (bdp) as ancillary ligands were synthesized and their photophysical properties were investigated. As a main ligand, 2-(5-(methoxymethyl)-2H-1,2,4-triazol-3-yl) pyridine (trzl-CH₂OMe), which has the strong electron-withdrawing ability was chosen to give the deep blue emission of its iridium complexes. As ancillary ligands, bdp and bdp-F₂, were employed where they represents benzyldiphenylphosphine and (3,5-difluorobenzyl)-diphenylphosphine, respectively. The resulting iridium complexes, Ir(trzl-CH₂OMe)₂(bdp) and Ir(trzl-CH₂OMe)₂(bdp-F₂), exhibited the blue emission at 484 and 481 nm in CH₂Cl₂ solution, respectively. These emission was blue shifted, compared to that of the previously reported Ir complex containing a fluorinated phenylpyridine and bdp, Ir(4-Me-4′-F-ppy)₂(bdp) at 491 nm. We also investigated the solid state luminescence properties of the complexes prepared herein in a polymer film of PMMA (poly (methylmetacrylate)) for their application to the polymeric process.

Keywords:

• Blue phosphorescence
• iridium complex
• OLED
• pyridyltriazole

Acknowledgement

This work was supported by National Research Foundation of Korea Grant funded by the Korean Government (2009-0065382).