New blue phosphorescent Pt(II) complex with pyridyltriazole-based tetradentate ligand for organic light-emitting diodes

We designed and synthesized Pt-Pytz, a blue phosphorescent Pt (II) complex having 6,6-(1-methoxyethane-1,1-diyl)di (2-(3-(trifluoromethyl)-1H-1,2,4-triazol-5-yl)pyridine) as a tetradentate ligand, and investigated its photophysical, electrochemical, and electroluminescent properties. The complex showed an emission maximum at 449 nm in dichloromethane solution, with a high photoluminescence quantum efficiency of 0.81. Furthermore, the photoluminescence spectrum of Pt-Pytz in the film state contains no additional excimer emission in the long-wavelength region, indicating suppressed molecular aggregation in the solid state. An organic light-emitting diode based on Pt-Pytz as a blue dopant (10% doping) achieved the best external quantum efficiency of 7.0% with a power efficiency of 6.4%, a current efficiency of 11.2 cd/A, and the CIE coordinates of (0.146, 0.218).