Blue Phosphorescent Organic Light-Emitting Diodes with Low Operating Voltages at 1000 cd m ^–2 Using Methoxy-Modified Tetradentate Platinum(II) Complexes

Tetradentate platinum(II) complexes have attracted considerable attention for their potential application as blue phosphorescent emitters in organic light-emitting diodes (OLEDs). Herein, two methoxy-functionalized complexes, Pt1-Cz-OMe and Pt2-Cz-OMe, were synthesized and characterized comprehensively. The introduction of a methoxy group shortens the Pt-ligand bond, thus enhancing the molecular compactness of the complexes and raising both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels. Consequently, the intraligand charge transfer (ILCT) component was significantly increased, and the photoluminescence quantum yields (PLQYs) of the obtained complexes Pt1-Cz-OMe and Pt2-Cz-OMe were enhanced to 95.3 and 91.0%, respectively. Finally, blue phosphorescence OLEDs with double light-emitting layers employing Pt1-Cz-OMe or Pt2-Cz-OMe as emitters exhibited remarkably high performances, especially at a low operating voltage (3.9 V at 1000 cd m–2). These studies provide a new strategy for the design of excellent tetradentate platinum(II) complexes and high-performance blue phosphorescent OLEDs.