Multifunctional electroluminescent material based on dimesitylboron and α-naphthylamino fluorene bridge

By introducing a triarylamino and three-coordinate boron groups into a fluorene bridge, an asymmetric and bipolar compound, 2-dimesitylboron-7-(N-phenyl-α-naphthyl-amino)-9,9-diethylfluorene (BNPEF), was prepared. Light emissions of BNPEF were different in solvents of different polarities. A series of electroluminescent devices was fabricated. Device A ITO/BNPEF/LiF/Al, Device B ITO/NPB/BNPEF/LiF/Al, Devices C and D ITO/NPB/BNPEF/BCP/AlQ3/LiF/Al, Device E ITO/BNPEF/AlQ3/LiF/Al and Device F ITO/NPB/BNPEF/AlQ3/LiF/Al, were fabricated. Device A exhibited a blue emission at 456 nm. Device B showed a green emission at 512 nm with current efficiency of 0.67 cd/A. The blue EL peaks of Devices C and D were at 488 and 484 nm with current efficiencies of 2.92 and 5.03 cd/A, respectively. Devices E and F emitted green lights at 520 and 528 nm with current efficiencies of 4.03 and 2.35 cd/A, respectively. The characteristics of the devices demonstrated that BNPEF was a multifunctional molecule acting as a blue emitting, or hole- or electron-transporting materials.