Chemistry Letters, Vol.33, No.3, 276-277, 2004
Synthesis and properties of 9,9'-diaryl-4,5-diazafluorenes. A new type of electron-transporting and hole-blocking material in EL device
The title compounds were prepared and investigated for electron-tran sporting and hole-blocking materials in organic electroluminescent (EL) devices. EL efficiencies of the phosphorescent devices indicated high performance of hole-blocking ability in the compounds. A maximum external efficiency of 18% was achieved and a maximum power luminous efficiency was over 45 Lm W-1.