Novel Tetradentate Platinum(II) Complexes and Their Use in Blue Phosphorescent Organic Light-Emitting Diodes

Although the remarkable growth of the organic light-emitting diode (OLED) industry has occurred via continuous, extensive efforts toward the utilization of various organometallic luminophores as phosphorescent emitters, the development of blue phosphorescent emitters with improved efficiencies and high electrochemical stabilities is essential. To this end, herein the preparation of two novel tetradentate Pt(II) complexes, Pt1 and Pt2, and their application as blue phosphorescent emitters in OLED devices is described. Both complexes exhibit intense bluish emission in the solution and solid states. In addition, these complexes display very high phosphorescent quantum efficiencies (>89%) with host materials and thermal stabilities (>390 °C). Multilayer phosphorescent OLEDs containing Pt1 or Pt2 as emitters with mCBP/CNmCBP-CN mixed-host systems are fabricated. The devices exhibit outstanding performances, including high current, power, external efficiencies, and potential device lifetime in addition to sky-blue (Pt1) or blue (Pt2) electroluminescence. These results clearly suggest that these tetradentate Pt(II) dopants are promising candidates as highly efficient, stable blue phosphorescent emitters in OLEDs.